The present works were supported by National Institutes of Health (NIH) grants HD043680, MH106392, DA013137, and NS100624. Partial fund was provided by a NIH T32 training grant in Biomedical-Behavioral science.

The experimental protocol was approved by the Animal Care and Use Committee (IACUC) at the University of South Carolina (federal assurance number: A3049-01).
1. Preparation of Fresh Frozen Brain Sections
<ol>
	<li>Use the F344/N rat strain: three rats of each sex, 13 months of age, body weight approximately 320&#160;g.</li>
	<li>Adjust the sevoflurane concentration to 5% (overdose of sevoflurane). Continue sevoflurane exposure after breathing stops for an additional minute.</li>
	<li>Decapitate the rat and remove the brain.</li>
	<li>Submerge the rat brain in liquid nitrogen for 15 s within 5&#160;min of tissue harvest.</li>
	<li>Equilibrate the brain to -20 &#176;C in a cryostat for 1&#160;h.</li>
	<li>Cut 30 &#181;m sections and transfer onto slides (see Table of Materials).</li>
	<li>Choose sections from the nucleus accumbens region, approximately 2.76 mm to 2.28 mm anterior to Bregma14.</li>
	<li>Continuously slice the rat brain from the olfactory bulb through the nucleus accumbens region according to the stereotaxic brain structure of the rat.</li>
	<li>Mount samples onto the slides. Keep the sections at -20 &#176;C for 10 min to dry.</li>
	<li>Immediately immerse slides in the pre-chilled 4% paraformaldehyde for 1 h at 4 &#176;C.</li>
	<li>Place the slides in an increasing ethanol gradient at room temperature (RT): 50% EtOH for 5&#160;min; 70% EtOH for 5&#160;min; and 100% EtOH for 5&#160;min.</li>
	<li>Repeat with fresh 100% EtOH.</li>
	<li>Place slides on absorbent paper, and air dry.</li>
	<li>Draw a barrier around each section with a barrier pen (see Table of Materials). Let the barrier dry completely for 1 min.</li>
</ol>
2. Pretreatment of Brain Sections
<ol>
	<li>Turn on the oven and set the temperature to 40 &#176;C.</li>
	<li>Add 3 drops (90 &#181;L) of Pretreatment 4 reagent (see Table of Materials) on each brain section (one section per slide).</li>
	<li>Incubate the sections for 30 min at RT.</li>
	<li>Submerge the slides in 1x PBS for 1 min at RT. Repeat with fresh 1x PBS. 
	NOTE: Slides should not stay in 1x PBS for longer than 15 min.</li>
</ol>
3. RNA In Situ Hybridization Fluorescent Multiplex Assay
<ol>
	<li>Warm the target probe for 10 min at 40 &#176;C in a water bath, and then cool to RT.</li>
	<li>Place the RNA reagent (e.g., Amp 1-4 FL) at RT.</li>
	<li>Remove excess liquid from slides with absorbent paper and place back on the slide rack (see Table of Materials).</li>
	<li>Add 3 drops (90 &#181;L) of the Drd1&#945; probe (C1) on the sample slice. Incubate for 2 h at 40 &#176;C.</li>
	<li>Submerge slides in 1x wash buffer for 2 minutes at RT. Repeat with fresh 1x wash buffer.</li>
	<li>Remove excess liquid from the slides with absorbent paper and place back on the slide rack (see Table of Materials).</li>
	<li>Add 3 drops (90 &#181;L) of Amp 1-FL on the sample slice. Incubate for 30 min at 40 &#176;C.</li>
	<li>Submerge slides in 1 wash buffer for 2 min at RT. Repeat with fresh 1wash buffer.</li>
	<li>Remove excess liquid from the slides with absorbent paper and place back on the slide rack (see Table of Materials).</li>
	<li>Add 3 drops (90 &#181;L) of Amp 2-FL on the sample slice. Incubate for 15 min at 40 &#176;C.</li>
	<li>Submerge slides in 1x wash buffer for 2 minutes at RT. Repeat with fresh 1x wash buffer.</li>
	<li>Remove excess liquid from the slides with absorbent paper and place back on the slide rack (see Table of Materials).</li>
	<li>Add 3 drops (90 &#181;L) of Amp 3-FL on the sample slice. Incubate for 30 min at 40 &#176;C.</li>
	<li>Submerge slides in 1x wash buffer for 2 min at RT. Repeat with fresh 1x wash buffer.</li>
	<li>Remove excess liquid from the slides with absorbent paper and place back on the slide rack (see Table of Materials).</li>
	<li>Add 3 drops (90 &#181;L) of Amp 4-FL-Alt A on the sample slice. Incubate for 15 min at 40 &#176;C.</li>
	<li>Submerge slides in 1x wash buffer for 2 minutes at RT. Repeat with fresh 1x wash buffer.</li>
	<li>Remove excess liquid from slides and immediately place 2 drops of mounting reagent (see Table of Materials) onto each section.</li>
	<li>Place a 22 mm 22 mm coverslip (see Table of Materials) over each brain section.</li>
	<li>Store slides in the dark at 2-8 &#176;C until dry.</li>
	<li>Turn on the confocal microscope and switch to a 60X objective.</li>
	<li>Obtain Z-stack images with a confocal microscope. See the supplemental video for a detail procedure of confocal imaging.</li>
	<li>Acquire images of Drd1&#945; labeled cells in the nucleus accumbens region (Excitation: 488 nm; Emission: 515/30 nm). 
	NOTE: Do not let brain sections dry out between incubation steps.</li>
</ol>
4. Data Analysis
<ol>
	<li>Semi-quantitatively analyze the staining pattern: &#34;discrete dots&#34;.
	<ol>
		<li>To identify the individual cell from the image, perform DAPI staining as a nuclear marker. However, it is still difficult to analyze certain parts of brain tissue since it has multiple types of cells with irregular shape of nuclei and/or cells. Here, two experienced researchers separately assign each cell from images to define cell region.</li>
		<li>Visually score each cell within the representative confocal images based on the number of dots per cell using the specific criteria (Figure 1B).</li>
		<li>Determine the total cell number in each category and divide by the total cell number x100 to create relative frequency graphs that display the percent frequency of cells within each category for all tissue sections (Figure 2A) and for males and females separately (Figure 2E).</li>
		<li>Divide the sum of cells within all prior categories by the total cell number x100 to determine the cumulative frequency of cells for all tissue sections (Figure 2B) and for males and females separately (Figure 2F).</li>
	</ol>
	</li>
	<li>Statistically analyze the &#34;discrete dots&#34; staining pattern (Optional).
	<ol>
		<li>Examine the number of dots per cell to provide a categorical variable that is ordinal in nature (i.e., the number of cells which fall into each rank category from lowest cell expression (1) to highest cell expression (9)) for further statistical analyses.</li>
		<li>After examination of descriptive statistics, use three main approaches: a Mantel-Haenszel statistic, a Mann-Whitney U test, and a Kruskal-Wallis test. Although the precise statistical approach will be dependent upon the experimental design and research question of interest, a statistical decision tree (Figure 4) may aid in making decisions regarding one&#39;s analytical approach.</li>
	</ol>
	</li>
	<li>Quantify the signal intensity in the region of interest (ROI) for staining pattern: &#34;clusters&#34;.
	<ol>
		<li>Calculate the signal intensity of each image using the following equation: 
		Signal intensity = Total intensity of ROI image - (Average background intensity &#215; Total image area)</li>
		<li>Count the total number of cells within ROI image to calculate the approximate signal expression per cell. Group differences in signal intensity/image as well as the number of cells/image may be of interest to consider mechanisms that may contribute to group differences seen in signal expression/cell (Figure 3B-3D).</li>
	</ol>
	</li>
	<li>Statistically analyze the &#34;clusters&#34; staining pattern (Optional).
	<ol>
		<li>Examine the signal expression/cell to provide a continuous variable for further statistical analysis. Use two approaches, including an independent sample t-test and analysis of variance (ANOVA), based on the number of between-subjects factors included in the design. A statistical decision tree (Figure 4) may aid in making decisions regarding the most appropriate statistical approach.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Goldman-Rakic, P. S., Castner, S. A., Svensson, T. H., Siever, L. J., Williams, G. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+the+dopamine+D1+receptor+in+schizophrenia:+insights+for+cognitive+dysfunction.">Targeting the dopamine D1 receptor in schizophrenia: insights for cognitive dysfunction.</a> Psychopharmacology (Berl). 174 (1), 3-16 (2004).</li><li>Beaulieu, J. M., Gainetdinov, R. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+physiology,+signaling,+and+pharmacology+of+dopamine+receptors.">The physiology, signaling, and pharmacology of dopamine receptors.</a> Pharmacol Rev. 63, 182-217 (2011).</li><li>Zahrt, J., Taylor, J. R., Mathew, R. G., Arnsten, A. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Supranormal+stimulation+of+D1+dopamine+receptors+in+the+rodent+prefrontal+cortex+impairs+spatial+working+memory+performance.">Supranormal stimulation of D1 dopamine receptors in the rodent prefrontal cortex impairs spatial working memory performance.</a> J Neurosci. 17, 8528-8535 (1997).</li><li>Floresco, S. B., Magyar, O., Ghods-Sharifi, S., Vexelman, C., Tse, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiple+dopamine+receptor+subtypes+in+the+medial+prefrontal+cortex+of+the+rat+regulate+set-shifting.">Multiple dopamine receptor subtypes in the medial prefrontal cortex of the rat regulate set-shifting.</a> Neuropsychopharmacology. 31, 297-309 (2006).</li><li>Arnsten, A. F., Girgis, R. R., Gray, D. L., Mailman, R. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+dopamine+therapeutics+for+cognitive+deficits+in+schizophrenia.">Novel dopamine therapeutics for cognitive deficits in schizophrenia.</a> Biol Psychiatry. 81, 67-77 (2017).</li><li>Ellenbroek, B. A., Budde, S., Cools, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prepulse+inhibition+and+latent+inhibition:+the+role+of+dopamine+in+the+medial+prefrontal+cortex.">Prepulse inhibition and latent inhibition: the role of dopamine in the medial prefrontal cortex.</a> Neuroscience. 75 (2), 535-542 (1996).</li><li>Parker, K. L., Alberico, S. L., Miller, A. D., Narayanan, N. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prefrontal+D1+dopamine+signaling+is+necessary+for+temporal+expectation+during+reaction+time+performance.">Prefrontal D1 dopamine signaling is necessary for temporal expectation during reaction time performance.</a> Neuroscience. 255, 246-254 (2013).</li><li>Manduca, A., Servadio, M., Damsteegt, R., Campolongo, P., Vanderschuren, L. J., Trezza, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dopaminergic+Neurotransmission+in+the+Nucleus+Accumbens+Modulates+Social+Play+Behavior+in+Rats.">Dopaminergic Neurotransmission in the Nucleus Accumbens Modulates Social Play Behavior in Rats.</a> Neuropsychopharmacology. 41 (9), 2215-2223 (2016).</li><li>Okubo, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decreased+prefrontal+dopamine+D1+receptors+in+schizophrenia+revealed+by+PET.">Decreased prefrontal dopamine D1 receptors in schizophrenia revealed by PET.</a> Nature. 385 (6617), 634-636 (1997).</li><li>Abi-Dargham, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prefrontal+dopamine+D1+receptors+and+working+memory+in+schizophrenia.">Prefrontal dopamine D1 receptors and working memory in schizophrenia.</a> J Neurosci. 22 (9), 3708-3719 (2002).</li><li>Shinohara, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dopamine+D1+receptor+subtype+mediates+acute+stress-induced+dendritic+growth+in+excitatory+neurons+of+the+medial+prefrontal+cortex+and+contributes+to+suppression+of+stress+susceptibility+in+mice.">Dopamine D1 receptor subtype mediates acute stress-induced dendritic growth in excitatory neurons of the medial prefrontal cortex and contributes to suppression of stress susceptibility in mice.</a> Mol Psychiatry. 19, (2017).</li><li>Okubo, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decreased+prefrontal+dopamine+D1+receptors+in+schizophrenia+revealed+by+PET.">Decreased prefrontal dopamine D1 receptors in schizophrenia revealed by PET.</a> Nature. 385, 634-636 (1997).</li><li>Wang, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RNAscope:+a+novel+in+situ+RNA+analysis+platform+for+formalin-fixed,+paraffin-embedded+tissues.">RNAscope: a novel in situ RNA analysis platform for formalin-fixed, paraffin-embedded tissues.</a> J Mol Diagn. 14 (1), 22-29 (2012).</li><li>Paxinos, G., Watson, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The rat brain in stereotaxic coordinates. , (2014).</li></ol>

There are no conflicts of interest to declare.

In this protocol, we describe a novel technique of in situ hybridization for fresh-frozen brain slices to evaluate Drd1&#945; receptor expression in the nucleus accumbens (NAc) and tyrosine hydroxylase (TH) expression in the substantia nigra (SNR) region. We also provide methods of data analysis for different staining patterns: &#34;discrete dot&#34; or &#34;clusters&#34;.
The critical steps for a successful multiplex fluorescence RNA in situ hybridization assay are included....

Dysfunction of the striatal dopamine system is involved in the progression of clinical symptoms observed in multiple neurocognitive diseases. Dopamine D1 receptors are present in the prefrontal cortex (PFC) and striatal regions of the brain and heavily influence cognitive processes1, including working memory, temporal processing, and locomotive behavior2,3,4,5,6,7. Previous studies elucidated that changes of dopamine D1 receptors were associated with the progression of attention deficit-hyperactivity disorder (ADHD)8, the neurocognitive symptoms in schizophrenia9,10 and stress susceptibility11. Specifically, in schizophrenia, positron emission tomography (PET) studies indicated that the binding ability of dopamine D1 receptors in the prefrontal cortices was highly related to cognitive deficits and the presence of negative symptoms11. The dendritic growth of excitatory neurons in the prefrontal cortex regulated by the dopamine D1 receptor alleviates stress susceptibility. Furthermore, the knockdown of D1 receptor in medial prefrontal cortical (mPFC) neurons could enhance the social defeat stress-induced social avoidance12.
Here, we introduce a novel technique of RNA in situ hybridization to visualize single RNA molecules in a cell with fresh-frozen tissue samples. The present technique has multiple advantages over methods that exist within the current literature. First, the current procedure preserves the spatial and morphological context of the tissue and was performed on fresh-frozen tissue samples so that other procedures requiring fresh, non-embedded tissues may be combined with the current methods. Similar procedures in formalin-fixed and paraffin-embedded tissues have illustrated that single transcription resolution can be achieved using an RNA in situ hybridization technique13. Detection of RNA at the single transcription level provides superior sensitivity to low copy number expression as well as the opportunity to compare gene expression at the level of individual cells that cannot be achieved by other nucleic acid detection methods, such as polymerase chain reaction (PCR) techniques. Additionally, the current method maintains images with a high signal-to-noise ratio through highly specific RNA probes that are hybridized to single target RNA transcripts, and sequentially bound with a cascade of signal amplification molecules in the detection system. Finally, the present technology provides the opportunity to evaluate multiple biological systems with its target-specific proprietary probes, rather than limiting our investigation to only one class of system-related markers such as protein detection by immunohistochemistry methods.
In our study, we used this novel RNA in situ hybridization to evaluate Drd1&#945; receptor expression in the nucleus accumbens (NAc) and tyrosine hydroxylase (TH) expression in the substantia nigra (SNR) of both male and female F344/N rats. The innovative RNA in situ hybridization enabled us to investigate mechanisms influencing both DA uptake and DA release simultaneously, improving our understanding of the striatal DA system&#39;s complexities. Here, we describe the procedure for fresh-frozen brain slices and provide methods of data analysis for different staining patterns: &#34;discrete dot&#34; or &#34;clusters&#34;.

<table border="0" cellpadding="0" cellspacing="0" width="857">
	<tbody>
		<tr height="23">
			<td height="23" style="height:23px;width:329px;">HybEZ Oven system</td>
			<td style="width:205px;">Advanced Cell Diagnostics&#160;</td>
			<td style="width:135px;">310010</td>
			<td style="width:188px;"></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">RNAscope Probe - Rn-Drd1a</td>
			<td>Advanced Cell Diagnostics&#160;</td>
			<td>317031</td>
			<td>Color channel 1, Green</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">RNAscope Probe - Rn-Th-C2</td>
			<td>Advanced Cell Diagnostics&#160;</td>
			<td>314651-C2</td>
			<td>Color channel 2, Orange</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">RNAscope Fluorescent Multiplex Reagent Kit</td>
			<td>Advanced Cell Diagnostics&#160;</td>
			<td>320850</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">ImmEdge Hydrophobic Barrier Pen</td>
			<td>Vector Laboratory</td>
			<td>H-4000</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">SuperFrost Plus Slides</td>
			<td>Fisher Scientific</td>
			<td>12-550-154%&#160;</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">4% paraformaldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>158127-500G</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">Sevoflurane</td>
			<td>Merritt Veterinary Supply</td>
			<td>347075</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">Tissue-Tek vertical 24 slide rack</td>
			<td>Fisher Scientific</td>
			<td>NC9837976</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">Tissue-Tek staining dish</td>
			<td>Fisher Scientific</td>
			<td>NC0731403</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">Precision General Purpose Baths</td>
			<td>ThermoFisher Scientific</td>
			<td>TSGP28</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:329px;">Pretreatment 4</td>
			<td>Advanced Cell Diagnostics&#160;</td>
			<td>320850</td>
			<td>parts of kits</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:329px;">ProLong Gold anti-fade reagent</td>
			<td style="width:205px;">Life Technologies</td>
			<td style="width:135px;">P36930</td>
			<td style="width:188px;"></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:329px;">Amp 1-FL</td>
			<td>Advanced Cell Diagnostics&#160;</td>
			<td>320850</td>
			<td>parts of kits</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:329px;">Amp 2-FL</td>
			<td>Advanced Cell Diagnostics&#160;</td>
			<td>320850</td>
			<td>parts of kits</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:329px;">Amp 3-FL</td>
			<td>Advanced Cell Diagnostics&#160;</td>
			<td>320850</td>
			<td>parts of kits</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:329px;">Amp 4-FL-Alt A</td>
			<td>Advanced Cell Diagnostics&#160;</td>
			<td>320850</td>
			<td>parts of kits</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:329px;">EZ-C1 software package</td>
			<td style="width:205px;">Nikon Instruments</td>
			<td style="width:135px;"></td>
			<td>version 3.81b</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:329px;">SAS/STAT Software</td>
			<td style="width:205px;">SAS Institute, Inc.,</td>
			<td style="width:135px;"></td>
			<td>version 9.4</td>
		</tr>
	</tbody>
</table>

identification of dopamine d1-alpha receptor within rodent nucleus accumbens by an innovative rna in situ detection technology

In the central nervous system, the D1-alpha subtype receptor (Drd1&#945;) is the most abundant dopamine (DA) receptor, which plays a vital role in regulating neuronal growth and development. However, the mechanisms underlying Drd1&#945; receptor abnormalities mediating behavioral responses and modulating working memory function are still unclear. Using a novel RNA in situ hybridization assay, the current study identified dopamine Drd1&#945; receptor and tyrosine hydroxylase (TH) RNA expression from DA-related circuitry in the nucleus accumbens (NAc) area and substantia nigra region (SNR), respectively. Drd1&#945; expression in the NAc shows a &#34;discrete dot&#34; staining pattern. Clear sex differences in Drd1&#945; expression were observed. In contrast, TH shows a &#34;clustered&#34; staining pattern. Regarding TH expression, female rats displayed a higher signal expression per cell relative to male animals. The methods presented here provide a novel in situ hybridization technique for investigating changes in dopamine system dysfunction during the progression of central nervous system diseases.

The current study observed a &#34;discrete dots&#34; staining pattern for RNA expression in the dopamine D1-alpha receptors (Drd1&#945;) of the NAc in F344/N rats (Figure 1A). Individual fluorescence signals were easily identified and can be seen as single &#34;dots,&#34; each of which represents a single RNA transcript within the cell. For images from the NAc that display the &#34;discrete dots&#34; staining pattern, we assessed the dynamic range of expressi...

Watch this Scientific Journal Video about Identification of Dopamine D1-Alpha Receptor Within Rodent Nucleus Accumbens by an Innovative RNA In Situ Detection Technology at JoVE.com

Identification of Dopamine D1-Alpha Receptor Within Rodent Nucleus Accumbens by an Innovative RNA In Situ Detection Technology

Identification of dopamine D1-alpha receptor in the nucleus accumbens is critical for clarifying D1 receptor dysfunction during a central nervous system disease. We performed a novel RNA in situ hybridization assay to visualize single RNA molecules in a specific brain area.

Identification of Dopamine D1-Alpha Receptor Within Rodent Nucleus Accumbens by an Innovative RNA In Situ Detection Technology

In the central nervous system, the D1-alpha subtype receptor (Drd1&#945;) is the most abundant dopamine (DA) receptor, which plays a vital role in ...

identification-dopamine-d1-alpha-receptor-within-rodent-nucleus

Research

JoVE Journal

Neuroscience

8.5K Views.  University of South Carolina. Identification of dopamine D1-alpha receptor in the nucleus accumbens is critical for clarifying D1 receptor dysfunction during a central nervous system disease. We performed a novel RNA in situ hybridization assay to visualize single RNA molecules in a specific brain area.

Video: Identification of Dopamine D1-Alpha Receptor Within Rodent Nucleus Accumbens by an Innovative RNA In Situ Detection Technology

Simultaneous fMRI and Electrophysiology in the Rodent Brain

To examine the neural basis of the blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) signal, we have developed a rodent model in which functional MRI data and in vivo intracortical recording can be performed simultaneously. The combination of MRI and electrical recording is technically challenging because the electrodes used for recording distort the MRI images and the MRI acquisition induces noise in the electrical recording. To minimize the mutual interference of the two modalities, glass microelectrodes were used rather than metal and a noise removal algorithm was implemented for the electrophysiology data. In our studies, two microelectrodes were separately implanted in bilateral primary somatosensory cortices (SI) of the rat and fixed in place. One coronal slice covering the electrode tips was selected for functional MRI. Electrode shafts and fixation positions were not included in the image slice to avoid imaging artifacts. The removed scalp was replaced with toothpaste to reduce susceptibility mismatch and prevent Gibbs ringing artifacts in the images. The artifact structure induced in the electrical recordings by the rapidly-switching magnetic fields during image acquisition was characterized by averaging all cycles of scans for each run. The noise structure during imaging was then subtracted from original recordings. The denoised time courses were then used for further analysis in combination with the fMRI data. As an example, the simultaneous acquisition was used to determine the relationship between spontaneous fMRI BOLD signals and band-limited intracortical electrical activity. Simultaneous fMRI and electrophysiological recording in the rodent will provide a platform for many exciting applications in neuroscience in addition to elucidating the relationship between the fMRI BOLD signal and neuronal activity.

We have developed a method for simultaneous functional magnetic resonance imaging and electrophysiological recording in the rodent brain, providing a platform for the investigation of the relationship between neural activity and the blood oxygenation level dependent (BOLD) MRI signal.

To examine the neural basis of the blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) signal, we have developed a rodent model in ...

VisioTracker, an Innovative Automated Approach to Oculomotor Analysis

Investigations into the visual system development and function necessitate quantifiable behavioral models of visual performance that are easy to elicit, robust, and simple to manipulate. A suitable model has been found in the optokinetic response (OKR), a reflexive behavior present in all vertebrates due to its high selection value. The OKR involves slow stimulus-following movements of eyes alternated with rapid resetting saccades. The measurement of this behavior is easily carried out in zebrafish larvae, due to its early and stable onset (fully developed after 96 hours post fertilization (hpf)), and benefitting from the thorough knowledge about zebrafish genetics, for decades one of the favored model organisms in this field. Meanwhile the analysis of similar mechanisms in adult fish has gained importance, particularly for pharmacological and toxicological applications.
Here we describe VisioTracker, a fully automated, high-throughput system for quantitative analysis of visual performance. The system is based on research carried out in the group of Prof. Stephan Neuhauss and was re-designed by TSE Systems. It consists of an immobilizing device for small fish monitored by a high-quality video camera equipped with a high-resolution zoom lens. The fish container is surrounded by a drum screen, upon which computer-generated stimulus patterns can be projected. Eye movements are recorded and automatically analyzed by the VisioTracker software package in real time.
Data analysis enables immediate recognition of parameters such as slow and fast phase duration, movement cycle frequency, slow-phase gain, visual acuity, and contrast sensitivity.
Typical results allow for example the rapid identification of visual system mutants that show no apparent alteration in wild type morphology, or the determination of quantitative effects of pharmacological or toxic and mutagenic agents on visual system performance.

The VisioTracker is an automated system for the quantitative analysis of visual performance of larval and small adult fish based on the recording of eye movements. It features full control over visual stimulus properties and real-time analysis, enabling high-throughput research in fields such as visual system development and function, pharmacology, neural circuit studies and sensorimotor integration.

Investigations into the visual system development and function necessitate quantifiable behavioral models of visual performance that are easy to elicit, ...

Direct Intraventricular Delivery of Drugs to the Rodent Central Nervous System

Due to an inability to cross the blood brain barrier, certain drugs need to be directly delivered into the central nervous system (CNS). Our lab focuses specifically on antisense oligonucleotides (ASOs), though the techniques shown in the video here can also be used to deliver a plethora of other drugs to the CNS. Antisense oligonucleotides (ASOs) have the capability to knockdown sequence-specific targets 1 as well as shift isoform ratios of specific genes 2. To achieve widespread gene knockdown or splicing in the CNS of mice, the ASOs can be delivered into the brain using two separate routes of administration, both of which we demonstrate in the video.
The first uses Alzet osmotic pumps, connected to a catheter that is surgically implanted into the lateral ventricle. This allows the ASOs to be continuously infused into the CNS for a designated period of time. The second involves a single bolus injection of a high concentration of ASO into the right lateral ventricle. Both methods use the mouse cerebral ventricular system to deliver the ASO to the entire brain and spinal cord, though depending on the needs of the study, one method may be preferred over the other.

We describe a method to target drugs to the central nervous system by either implanting a catheter or performing a bolus injection into the right lateral ventricle in mice. We focus specifically on the delivery of antisense oligonucleotides. This technique is readily adaptable to other drugs and to rats.

Due to an inability to cross the blood brain barrier, certain drugs need to be directly delivered into the central nervous system (CNS). Our lab focuses ...

Detection of the Genome and Transcripts of a Persistent DNA Virus in Neuronal Tissues by Fluorescent In situ Hybridization Combined with Immunostaining

Single cell codetection of a gene, its RNA product and cellular regulatory proteins is critical to study gene expression regulation. This is a challenge in the field of virology; in particular for nuclear-replicating persistent DNA viruses that involve animal models for their study. Herpes simplex virus type 1 (HSV-1) establishes a life-long latent infection in peripheral neurons. Latent virus serves as reservoir, from which it reactivates and induces a new herpetic episode. The cell biology of HSV-1 latency remains poorly understood, in part due to the lack of methods to detect HSV-1 genomes in situ in animal models. We describe a DNA-fluorescent in situ hybridization (FISH) approach efficiently detecting low-copy viral genomes within sections of neuronal tissues from infected animal models. The method relies on heat-based antigen unmasking, and directly labeled home-made DNA probes, or commercially available probes. We developed a triple staining approach, combining DNA-FISH with RNA-FISH&#160;and immunofluorescence, using peroxidase based signal amplification to accommodate each staining requirement. A major improvement is the ability to obtain, within 10 &#181;m tissue sections, low-background signals that can be imaged at high resolution by confocal microscopy and wide-field conventional epifluorescence. Additionally, the triple staining worked with a wide range of antibodies directed against cellular and viral proteins. The complete protocol takes 2.5 days to accommodate antibody and probe penetration within the tissue.

Detection of the Genome and Transcripts of a Persistent DNA Virus in Neuronal Tissues by Fluorescent In situ Hybridization Combined with Immunostaining

We established a fluorescent in situ hybridization protocol for the detection of a persistent DNA virus genome within tissue sections of animal models. This protocol enables studying infection process by codetection of the viral genome, its RNA products, and viral or cellular proteins within single cells.

Single cell codetection of a gene, its RNA product and cellular regulatory proteins is critical to study gene expression regulation. This is a challenge ...

Detection of Axonally Localized mRNAs in Brain Sections Using High-Resolution In Situ Hybridization

mRNAs are frequently localized to vertebrate axons and their local translation is required for axon pathfinding or branching during development and for maintenance, repair or neurodegeneration in postdevelopmental periods. High throughput analyses have recently revealed that axons have a more dynamic and complex transcriptome than previously expected. These analysis, however have been mostly done in cultured neurons where axons can be isolated from the somato-dendritic compartments. It is virtually impossible to achieve such isolation in whole tissues in vivo. Thus, in order to verify the recruitment of mRNAs and their functional relevance in a whole animal, transcriptome analyses should ideally be combined with techniques that allow the visualization of mRNAs in situ. Recently, novel ISH technologies that detect RNAs at a single-molecule level have been developed. This is especially important when analyzing the subcellular localization of mRNA, since localized RNAs are typically found at low levels. Here we describe two protocols for the detection of axonally-localized mRNAs using a novel ultrasensitive RNA ISH technology. We have combined RNAscope ISH with axonal counterstain using fluorescence immunohistochemistry or histological dyes to verify the recruitment of Atf4 mRNA to axons in vivo in the mature mouse and human brains.

Detection of Axonally Localized mRNAs in Brain Sections Using High-Resolution In Situ Hybridization

RNA in situ hybridization (ISH) enables the visualization of RNAs in cells and tissues. Here we show how combination of RNAscope ISH with immunohistochemistry or histological dyes can be successfully used to detect mRNAs localized to axons in sections of mouse and human brains.

mRNAs are frequently localized to vertebrate axons and their local translation is required for axon pathfinding or branching during development and for ...

Interfacing 3D Engineered Neuronal Cultures to Micro-Electrode Arrays: An Innovative In Vitro Experimental Model

Currently, large-scale networks derived from dissociated neurons growing and developing in vitro on extracellular micro-transducer devices are the gold-standard experimental model to study basic neurophysiological mechanisms involved in the formation and maintenance of neuronal cell assemblies. However, in vitro studies have been limited to the recording of the electrophysiological activity generated by bi-dimensional (2D) neural networks. Nonetheless, given the intricate relationship between structure and dynamics, a significant improvement is necessary to investigate the formation and the developing dynamics of three-dimensional (3D) networks. In this work, a novel experimental platform in which 3D hippocampal or cortical networks are coupled to planar Micro-Electrode Arrays (MEAs) is presented. 3D networks are realized by seeding neurons in a scaffold constituted of glass microbeads (30-40 &#181;m in diameter) on which neurons are able to grow and form complex interconnected 3D assemblies. In this way, it is possible to design engineered 3D networks made up of 5-8 layers with an expected final cell density. The increasing complexity in the morphological organization of the 3D assembly induces an enhancement of the electrophysiological patterns displayed by this type of networks. Compared with the standard 2D networks, where highly stereotyped bursting activity emerges, the 3D structure alters the bursting activity in terms of duration and frequency, as well as it allows observation of more random spiking activity. In this sense, the developed 3D model more closely resembles in vivo neural networks.

Interfacing 3D Engineered Neuronal Cultures to Micro-Electrode Arrays: An Innovative In Vitro Experimental Model

In this work, a novel experimental model in which 3D neuronal cultures are coupled to planar Micro-Electrode Arrays (MEAs) is presented. 3D networks are built by seeding neurons in a scaffold made up of glass microbeads on which neurons grow and form interconnected 3D structures.

Currently, large-scale networks derived from dissociated neurons growing and developing in vitro on extracellular micro-transducer devices are the ...

Reliable Identification of Living Dopaminergic Neurons in Midbrain Cultures Using RNA Sequencing and TH-promoter-driven eGFP Expression

In Parkinson&#39;s Disease (PD) there is widespread neuronal loss throughout the brain with pronounced degeneration of dopaminergic neurons in the SNc, leading to bradykinesia, rigidity, and tremor. The identification of living dopaminergic neurons in primary Ventral Mesencephalic (VM) cultures using a fluorescent marker provides an alternative way to study the selective vulnerability of these neurons without relying on the immunostaining of fixed cells. Here, we isolate, dissociate, and culture mouse VM neurons for 3 weeks. We then identify dopaminergic neurons in the cultures using eGFP fluorescence (driven by a Tyrosine Hydroxylase (TH) promoter). Individual neurons are harvested into microcentrifuge tubes using glass micropipettes. Next, we lyse the harvested cells, and conduct cDNA synthesis and transposon-mediated &#34;tagmentation&#34; to produce single cell RNA-Seq libraries1,2,3,4,5. After passing a quality-control check, single-cell libraries are sequenced and subsequent analysis is carried out to measure gene expression. We report transcriptome results for individual dopaminergic and GABAergic neurons isolated from midbrain cultures. We report that 100% of the live TH-eGFP cells that were harvested and sequenced were dopaminergic neurons. These techniques will have widespread applications in neuroscience and molecular biology.

In Parkinson&#39;s Disease (PD), Substantia Nigra (SNc) dopaminergic neurons degenerate, leading to motor dysfunction. Here we report a protocol for culturing ventral midbrain neurons from a mouse expressing eGFP driven by a Tyrosine Hydroxylase (TH) promoter sequence, harvesting individual fluorescent neurons from the cultures, and measuring their transcriptome using RNA-seq.

In Parkinson&#39;s Disease (PD) there is widespread neuronal loss throughout the brain with pronounced degeneration of dopaminergic neurons in the SNc, ...

Localization of Odorant Receptor Genes in Locust Antennae by RNA In Situ Hybridization

Insects have evolved sophisticated olfactory reception systems to sense exogenous chemical signals. These chemical signals are transduced by Olfactory Receptor Neurons (ORNs) housed in hair-like structures, called chemosensilla, of the antennae. On the ORNs&#39; membranes, Odorant Receptors (ORs) are believed to be involved in odor coding. Thus, being able to identify genes localized to the ORNs is necessary to recognize OR genes, and provides a fundamental basis for further functional in situ studies. The RNA expression levels of specific ORs in insect antennae are very low, and preserving insect tissue for histology is challenging. Thus, it is difficult to localize an OR to a specific type of sensilla using RNA in situ hybridization. In this paper, a detailed and highly effective RNA in situ hybridization protocol particularly for lowly expressed OR genes of insects, is introduced. In addition, a specific OR gene was identified by conducting double-color fluorescent in situ hybridization experiments using a co-expressing receptor gene, Orco, as a marker.

Localization of Odorant Receptor Genes in Locust Antennae by RNA In Situ Hybridization

This paper describes a detailed and highly effective RNA in situ hybridization protocol particularly for low-level expressed Odorant Receptor (OR) genes, as well as other genes, in insect antennae using digoxigenin (DIG)-labeled or biotin-labeled probes.

Insects have evolved sophisticated olfactory reception systems to sense exogenous chemical signals. These chemical signals are transduced by Olfactory ...

Assessment of Dopaminergic Homeostasis in Mice by Use of High-performance Liquid Chromatography Analysis and Synaptosomal Dopamine Uptake

Dopamine (DA) is a modulatory neurotransmitter controlling motor activity, reward processes and cognitive function. Impairment of dopaminergic (DAergic) neurotransmission is strongly associated with several central nervous system-associated diseases such as Parkinson&#39;s disease, attention-deficit-hyperactivity disorder and drug addiction1,2,3,4. Delineating disease mechanisms involving DA imbalance is critically dependent on animal models to mimic aspects of the diseases, and thus protocols that assess specific parts of the DA homeostasis are important to provide novel insights and possible therapeutic targets for these diseases.
Here, we present two useful experimental protocols that when combined provide a functional read-out of the DAergic system in mice. Biochemical and functional parameters on DA homeostasis are obtained through assessment of DA levels and dopamine transporter (DAT) functionality5. When investigating the DA system, the ability to reliably measure endogenous levels of DA from adult brain is essential. Therefore, we present how to perform high-performance liquid chromatography (HPLC) on brain tissue from mice to determine levels of DA. We perform the experiment on tissue from dorsal striatum (dStr) and nucleus accumbens (NAc), but the method is also suitable for other DA-innervated brain areas.
DAT is essential for reuptake of DA into the presynaptic terminal, thereby controlling the temporal and spatial activity of released DA. Knowing the levels and functionality of DAT in the striatum is of major importance when assessing DA homeostasis. Here, we provide a protocol that allows to simultaneously deduce information on surface levels and function using a synaptosomal6 DA uptake assay.
Current methods combined with standard immunoblotting protocols provide the researcher with relevant tools to characterize the DAergic system.

Synaptosomal dopamine uptake and high-performance liquid chromatography analysis represent experimental tools to investigate dopamine homeostasis in mice by assessing the function of the dopamine transporter and levels of dopamine in striatal tissue, respectively. Here we present protocols to measure dopamine tissue content and assess the functionality of the dopamine transporter.

Dopamine (DA) is a modulatory neurotransmitter controlling motor activity, reward processes and cognitive function. Impairment of dopaminergic (DAergic) ...

Isolation of Adult Spinal Cord Nuclei for Massively Parallel Single-nucleus RNA Sequencing

Probing an individual cell&#39;s gene expression enables the identification of cell type and cell state. Single-cell RNA sequencing has emerged as a powerful tool for studying transcriptional profiles of cells, particularly in heterogeneous tissues such as the central nervous system. However, dissociation methods required for single cell sequencing can lead to experimental changes in the gene expression and cell death. Furthermore, these methods are generally restricted to fresh tissue, thus limiting studies on archival and bio-bank material. Single nucleus RNA sequencing (snRNA-Seq) is an appealing alternative for transcriptional studies, given that it accurately identifies cell types, permits the study of tissue that is frozen or difficult to dissociate, and reduces dissociation-induced transcription. Here, we present a high-throughput protocol for rapid isolation of nuclei for downstream snRNA-Seq. This method enables isolation of nuclei from fresh or frozen spinal cord samples and can be combined with two massively parallel droplet encapsulation platforms.

Here, we present a protocol to rapidly isolate high-quality nuclei from the fresh or frozen tissue for downstream massively parallel RNA sequencing. We include detergent-mechanical and hypotonic-mechanical tissue disruption and cell lysis options, both of which can be used for isolation of nuclei.

Probing an individual cell&#39;s gene expression enables the identification of cell type and cell state. Single-cell RNA sequencing has emerged as a ...