The Pedro Barrie de la Maza Foundation supported this work.

1) Intragastric Administration of Rotenone
<ol>
<li>Weigh the animal.</li>
<li>Calculate the total volume of rotenone/vehicle solution needed. In this case 0.01 ml per gram of the animal weight.</li>
<li>Charge a 1 mL syringe with the previously calculated volume of rotenone solution (0.625 mg/mL rotenone, 4% carboxymethylcellulose and 1.25% chloroform) or vehicle solution (4% carboxymethylcellulose and 1.25% chloroform). In this case it corresponds to a 5 mg/kg rotenone dose.</li>
<li>Pick up the mouse and, holding the mouse's tail with one hand, stretch the skin of the neck by pulling it with the first two fingers of the other hand.</li>
<li>Once the head is fixed between the two fingers, lean it against the palm of the hand and turn it upside-down. Fix the tail using the fourth and fifth fingers.</li>
<li>Keeping the head towards the back, press the palate to open the mouse's mouth. Gently introduce the gavage in the mouth. It is important to use a gavage needle and not a regular needle. Slowly, move the gavage in the direction of the stomach far enough. This will avoid material getting in the lungs.</li>
<li>Administer the rotenone solution or vehicle by gently pressing the embolus. When completed, slowly extract the gavage.</li>
<li>Place the animal back in another cage until all animals from one cage are done.</li>
</ol>
2) Immunostaining Procedures
<ol>
<li>Following treatment, mice are anesthetized using Ketamin 100 mg/kg und Xylazin 10 mg/kg i.p. and intracardially perfused with 4% Paraformaldehyde in PBS.</li>
<li>The guts are then extracted by dissection, and placed in 15% sucrose overnight. The next day, the tissue is transferred to 30% sucrose and incubated again overnight at 4&deg;C.</li>
<li>The tissue is then placed in Tissue-tek and stored in a -80&deg;C freezer until use.</li>
<li>Using a cryostat, 20 micron intestine cross-sections are transferred to Superfrost slides.</li>
<li>Blocking and immunostaining procedures using anti-&beta;III-tubulin and anti-alpha-synuclein antibodies are then performed as previously described 9.</li>
</ol>
3)	Alpha-synuclein Inclusion Image Analysis
It is recommended that an external person unaware of images' origin performs the analysis. Therefore, the data should be codified. Image analysis was performed using FIJI software.
<ol>
<li>Open the confocal image file. Then, split the channels so that it is possible to work on each channel independently.</li>
<li>Close those channels that are not going to be use and select Analyse&gt;Set Scale and set the Pixel size to 1. Set the known distance to 0.13 (this will depend on the objective and the resolution used) and click on global. The size of the image will now be shown in microns.</li>
<li>Select alpha-synuclein channel and select ganglion, make sure that the selection encloses the ganglion in all slices.</li>
<li>Press Image>Duplicate to duplicate the image. With the ganglion selected, only an image the size of the ganglion will be duplicated.</li>
<li>Press Edit&gt;Clear Outside. The part of the image outside the selected region will become black.</li>
<li>Duplicate the image again to determine in later steps how well the procedure went. Images that have a high signal to noise to background ratio should not be used for image analysis.</li>
<li>Select Image&gt;Adjust&gt;Threshold and then select MaxEntropy. Then move over the slices in the cropped image and the original one to ensure that the procedure went well. The entropic threshold selects an intensity signal level based on the image histogram and only those pixels with intensities higher than this threshold will be displayed in a white over black image.</li>
<li>Select Process, then click on Smooth. This step transforms the pixeled edges of the images in smooth edges.</li>
<li>Select Process, then click on Binary, and choose Make Binary. The image will be displayed as a black over white image.</li>
<li>Duplicate image to perform next step on the duplicated image.</li>
<li>Click on Analyze&gt;Analyze particles. Then select Show:Outlines and click on Summarize. The rest of settings should be leaved in default. This function recognizes the total number of pixels with a signal and those that are grouped together. The total surface of pixels with signal plus the number of groups of pixels and the mean size are reported.</li>
<li>Compare and select the largest slice that adjusts well. The slice will be marked.</li>
<li>Copy the data table with the total alpha-synuclein surface, the number of inclusions and the mean particle size. Paste the data into an excel spreadsheet or annotated elsewhere.</li>
<li>Return to FIJI and find the previously selected slice in the &beta;-tubulin channel, and select it.</li>
<li>Select ganglion area and click on Analyze then select Measure. Another table will appear showing the total surface of the ganglion.</li>
<li>Extract the data from the table to the excel sheet near the alpha-synuclein measurement or copy it down elsewhere.</li>
<li>Using excel, divide the different parameters obtained in the alpha-synuclein measurement by the ganglion surface to obtain total alpha-synuclein surface and inclusion number normalized by ganglion size.</li>
</ol>
4) Representative Results
When gavage administration protocol is performed correctly the inconveniences for the animal are minimal. Treatment using this concentration of rotenone enables a local effect of rotenone on the ENS without rotenone levels in blood and no inhibition of muscle or brain mitochondrial Complex I even after 1.5 months of treatment (see Figure 1). If image analysis is performed correctly a rigorous analysis of alpha-synuclein pattern should be possible. It gives reliable data on the total amount of alpha-synuclein (total surface), alpha-synuclein pattern in the cell (number of inclusions) and the presence of alpha-synuclein inclusions (inclusion size) (Figure 2).
 <img src="/files/ftp_upload/2123/2123fig1.jpg" alt="Figure 1" /> 
Figure 1. Motor dysfunction in rotenone treated mice without detection of rotenone in blood or CNS. A, standard (50 ng/mL) and chromatogram from brain samples of 20, 10 and 5 mg/kg treated mice. B and C, quantification of rotenone levels in blood (B) and CNS (C). B, blood levels 1, 2 and 3 hours after treatment. Mice were divided in three groups (n=3) and treated with 2.5, 5, 10 and 20 mg/kg rotenone (n=3), 300 &mu;L of blood was extracted 1, 2 and 3 hours after rotenone administration and pooled together for HPLC analysis. C, mice were treated for one week once a day with 5 (n=3), 10 (n=3) and 20 (n=1) mg/kg rotenone, brain and brainstem were extracted 1 and 2 hours after last administration and prepared for HPLC analysis. D, mitochondrial Complex I activity in muscle and brain samples of 1.5 month treated mice.
 <img src="/files/ftp_upload/2123/2123fig2.jpg" alt="Figure 2" /> 
Figure 2. Locally administered rotenone induces alpha-synuclein phosphorylation, accumulation and aggregation with gliosis in ENS ganglia. (scale bars 20 &mu;m). A, B, C, anti &beta;III-tubulin, alpha-synuclein and DAPI staining in duodenum (B) and ileum (A,C) sections. Arrow in B, 1.5 months treatment induced an increased alpha-synuclein punctate pattern inside enteric nervous system ganglia when compared to 3 months controls (A). Arrow in C, 3 months treatment induced formation of larger alpha-synuclein inclusions (&#248;&gt;6 &mu;m). D, immunofluorescence staining using anti-alpha-synuclein, Thioflavine S and DAPI. Arrow in D, only 3 month treated mice showed aggregation of these larger alpha-synuclein accumulations. E, E', E'', image analysis quantification steps. E, example of image used in quantification showing an ENS ganglion immunostained against alpha synuclein showing different inclusions. E', example of image obtained after image analysis protocol. E'', overlap between some of the original inclusions (green) and the representation obtained after performing the protocol (yellow lines). F-G, quantification of the experiment shown in A-C was made using automatic segmentation and entropy-based thresholding methods. Single-asterisk, P&lt;0.05, and double-asterisk, P&lt;0.01. F, each column represents total alpha-synuclein surface/ganglion surface. G, each column represents total number of alpha-synuclein inclusions/ganglion surface. All graphs show mean &plusmn; s.e.m.

<ol>
	<li>Braak, H., de Vos, R. A., Bohl, J., Del Tredici, K., K, . <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gastric+alpha-synuclein+immunoreactive+inclusions+in+Meissner's+and+Auerbach's+plexuses+in+cases+staged+for+Parkinson's+disease-related+brain+pathology.">Gastric alpha-synuclein immunoreactive inclusions in Meissner's and Auerbach's plexuses in cases staged for Parkinson's disease-related brain pathology.</a> Neurosci Lett. 396, 67-72 (2006).</li><li>Wakabayashi, K., Takahashi, H., Ohama, E., Ikuta, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Parkinson's+disease:+an+immunohistochemical+study+of+Lewy+body-containing+neurons+in+the+enteric+nervous+system.">Parkinson's disease: an immunohistochemical study of Lewy body-containing neurons in the enteric nervous system.</a> Acta Neuropathol. 79, 581-583 (1990).</li><li>Wakabayashi, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Restricted+occurrence+of+Lewy+bodies+in+the+dorsal+vagal+nucleus+in+a+patient+with+late-onset+parkinsonism.">Restricted occurrence of Lewy bodies in the dorsal vagal nucleus in a patient with late-onset parkinsonism.</a> J Neurol Sci. 165, 188-191 (1999).</li><li>Braak, H., Sastre, M., Bohl, J. R., de Vos, R. A., Del Tredici, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Parkinson's+disease:+lesions+in+dorsal+horn+layer+I,+involvement+of+parasympathetic+and+sympathetic+pre-+and+postganglionic+neurons.">Parkinson's disease: lesions in dorsal horn layer I, involvement of parasympathetic and sympathetic pre- and postganglionic neurons.</a> Acta Neuropathol. 113, 421-429 (2007).</li><li>Braak, H., Ghebremedhin, E., Rub, U., Bratzke, H., Del Tredici, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stages+in+the+development+of+Parkinson's+disease-related+pathology.">Stages in the development of Parkinson's disease-related pathology.</a> Cell Tissue Res. 318, 121-134 (2004).</li><li>Gorell, J. M., Johnson, C. C., Rybicki, B. A., Peterson, E. L., Richardson, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+risk+of+Parkinson's+disease+with+exposure+to+pesticides,+farming,+well+water,+and+rural+living.">The risk of Parkinson's disease with exposure to pesticides, farming, well water, and rural living.</a> Neurology. 50, 1346-1350 (1998).</li><li>Semchuk, K. M., Love, E. J., Lee, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Parkinson's+disease+and+exposure+to+agricultural+work+and+pesticide+chemicals.">Parkinson's disease and exposure to agricultural work and pesticide chemicals.</a> Neurology. 42, 1328-1335 (1992).</li><li>Butterfield, P. G., Valanis, B. G., Spencer, P. S., Lindeman, C. A., Nutt, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environmental+antecedents+of+young-onset+Parkinson's+disease.">Environmental antecedents of young-onset Parkinson's disease.</a> Neurology. 43, 1150-1158 (1993).</li><li>Pan-Montojo, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Progression+of+Parkinson's+disease+pathology+is+reproduced+by+intragastric+administration+of+rotenone+in+mice.">Progression of Parkinson's disease pathology is reproduced by intragastric administration of rotenone in mice.</a> PLoS One. 5, e8762-e8762 (2010).</li><li>Sherer, T. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanism+of+toxicity+in+rotenone+models+of+Parkinson's+disease.">Mechanism of toxicity in rotenone models of Parkinson's disease.</a> J Neurosci. 23, 10756-10764 (2003).</li><li>Bove, J., Prou, D., Perier, C., Przedborski, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toxin-induced+models+of+Parkinson's+disease.">Toxin-induced models of Parkinson's disease.</a> NeuroRx. 2, 484-494 (2005).</li><li>Inden, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurodegeneration+of+mouse+nigrostriatal+dopaminergic+system+induced+by+repeated+oral+administration+of+rotenone+is+prevented+by+4-phenylbutyrate,+a+chemical+chaperone.">Neurodegeneration of mouse nigrostriatal dopaminergic system induced by repeated oral administration of rotenone is prevented by 4-phenylbutyrate, a chemical chaperone.</a> J Neurochem. 101, 1491-1504 (2007).</li></ol>

Francisco Pan-Montojo has a patent application pending for this animal model (Application number PCT/EP 2009/005688).

Intragastric administration has been previously performed 12. However, according to Inden's manuscript, rotenone was administered dissolved in 0.5% carboxymethylcellulose sodium salt (CMSS) alone. Rotenone is a high liphophylic substance. Therefore, rotenone cannot be dissolved in 0.5% CMSS alone and will precipitate if done so. The use of chloroform creates an evenly distributed rotenone suspension avoiding precipitation. Moreover, due to the higher concentrations of the pesticide in the CMSS, the final volu...

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">	
		
		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Rotenone</td>
<td>&nbsp;</td>
<td>SIGMA-Aldrich</td>
<td>R8875</td>
<td>Germany</td>
</tr>
<tr>
<td>Chloroform</td>
<td>&nbsp;</td>
<td>Carl Roth</td>
<td>3313.1</td>
<td>Germany</td>
</tr>
<tr>
<td>Carboxymethylcellulose</td>
<td>&nbsp;</td>
<td>SIGMA-Aldrich</td>
<td>C5678</td>
<td>Germany</td>
</tr>
<tr>
<td>Gavage 1,2 mm x 60 mm</td>
<td>&nbsp;</td>
<td>Unimed</td>
<td>&nbsp;</td>
<td>Switzerland</td>
</tr>
<tr>
<td>LSM 510</td>
<td>&nbsp;</td>
<td>Zeiss Microscopes</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>FIJI</td>
<td>&nbsp;</td>
<td>http://pacific.mpi-cbg.de</td>
<td>&nbsp;</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

oral administration of rotenone using a gavage and image analysis of alpha-synuclein inclusions in the enteric nervous system

In Parkinson's disease (PD) patients, the associated pathology follows a characteristic pattern involving inter alia the enteric nervous system (ENS) 1,2, the olfactory bulb (OB), the dorsal motor nucleus of the vagus (DMV)3, the intermediolateral nucleus of the spinal cord 4 and the substantia nigra, providing the basis for the neuropathological staging of the disease4,5. The ENS and the OB are the most exposed nervous structures and the first ones to be affected. Interestingly, PD has been related to pesticide exposure6-8. Here we show in detail two methods used in our previous study 9. In order to analyze the effects of rotenone acting locally on the ENS, we administered rotenone using a gavage to one-year old C57/BL6 mice. Rotenone is a widely used pesticide that strongly inhibits mitochondrial Complex I 10. It is highly lipophylic and poorly absorbed in the gastrointestinal tract 11. Our results showed that the administration of 5 mg/kg of rotenone did not inhibit mitochondrial Complex I activity in the muscle or the brain. Thus, suggesting that using our administration method rotenone did not cross the hepatoportal system and was acting solely on the ENS. Here we show a method to administer pesticides using a gavage and the image analysis protocol used to analyze the effects of the pesticide in alpha-synuclein accumulation in the ENS. The first part shows a method that allows intragastric administration of pesticides (rotenone) at a desired precise concentration. The second method shows a semi-automatic image analysis protocol to analyze alpha-synuclein accumulation in the ENS using an image analysis software.

Watch this Scientific Journal Video about Oral Administration of Rotenone using a Gavage and Image Analysis of Alpha-synuclein Inclusions in the Enteric Nervous System at JoVE.com

Oral Administration of Rotenone using a Gavage and Image Analysis of Alpha-synuclein Inclusions in the Enteric Nervous System

Parkinson's disease has been related to the exposure to pesticides. Here we show a method to deliver pesticides using a gastric tube at the desired concentration and a method to analyze their effect in alpha-synuclein accumulation in the enteric nervous system.

In Parkinson's disease (PD) patients, the associated pathology follows a characteristic pattern involving inter alia the enteric nervous system (ENS) 1,2, ...

oral-administration-rotenone-using-gavage-image-analysis-alpha

Research

JoVE Journal

Neuroscience

16.8K Views.  Technische Universität Dresden. Parkinson's disease has been related to the exposure to pesticides. Here we show a method to deliver pesticides using a gastric tube at the desired concentration and a method to analyze their effect in alpha-synuclein accumulation in the enteric nervous system.

Video: Oral Administration of Rotenone using a Gavage and Image Analysis of Alpha-synuclein Inclusions in the Enteric Nervous System

Visualization and Genetic Manipulation of Dendrites and Spines in the Mouse Cerebral Cortex and Hippocampus using In utero Electroporation

In utero electroporation (IUE) has become a powerful technique to study the development of different regions of the embryonic nervous system 1-5. To date this tool has been widely used to study the regulation of cellular proliferation, differentiation and neuronal migration especially in the developing cerebral cortex 6-8. Here we detail our protocol to electroporate in utero the cerebral cortex and the hippocampus and provide evidence that this approach can be used to study dendrites and spines in these two cerebral regions.
Visualization and manipulation of neurons in primary cultures have contributed to a better understanding of the processes involved in dendrite, spine and synapse development. However neurons growing in vitro are not exposed to all the physiological cues that can affect dendrite and/or spine formation and maintenance during normal development. Our knowledge of dendrite and spine structures in vivo in wild-type or mutant mice comes mostly from observations using the Golgi-Cox method 9. However, Golgi staining is considered to be unpredictable. Indeed, groups of nerve cells and fiber tracts are labeled randomly, with particular areas often appearing completely stained while adjacent areas are devoid of staining. Recent studies have shown that IUE of fluorescent constructs represents an attractive alternative method to study dendrites, spines as well as synapses in mutant / wild-type mice 10-11 (Figure 1A). Moreover in comparison to the generation of mouse knockouts, IUE represents a rapid approach to perform gain and loss of function studies in specific population of cells during a specific time window. In addition, IUE has been successfully used with inducible gene expression or inducible RNAi approaches to refine the temporal control over the expression of a gene or shRNA 12. These advantages of IUE have thus opened new dimensions to study the effect of gene expression/suppression on dendrites and spines not only in specific cerebral structures (Figure 1B) but also at a specific time point of development (Figure 1C).
Finally, IUE provides a useful tool to identify functional interactions between genes involved in dendrite, spine and/or synapse development. Indeed, in contrast to other gene transfer methods such as virus, it is straightforward to combine multiple RNAi or transgenes in the same population of cells. 
In summary, IUE is a powerful method that has already contributed to the characterization of molecular mechanisms underlying brain function and disease and it should also be useful in the study of dendrites and spines.

Visualization and Genetic Manipulation of Dendrites and Spines in the Mouse Cerebral Cortex and Hippocampus using In utero Electroporation

This article describes in detail a protocol to electroporate in utero the cerebral cortex and the hippocampus at E14.5 in mice. We also show that this is a valuable method to study dendrites and spines in these two cerebral regions.

In utero electroporation (IUE) has become a powerful technique to study the development of different regions of the embryonic nervous system 1-5. To date ...

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 ...

In vivo Optogenetic Stimulation of the Rodent Central Nervous System

The ability to probe defined neural circuits in awake, freely-moving animals with cell-type specificity, spatial precision, and high temporal resolution has been a long sought tool for neuroscientists in the systems-level search for the neural circuitry governing complex behavioral states. Optogenetics is a cutting-edge tool that is revolutionizing the field of neuroscience and represents one of the first systematic approaches to enable causal testing regarding the relation between neural signaling events and behavior. By combining optical and genetic approaches, neural signaling can be bi-directionally controlled through expression of light-sensitive ion channels (opsins) in mammalian cells. The current protocol describes delivery of specific wavelengths of light to opsin-expressing cells in deep brain structures of awake, freely-moving rodents for neural circuit modulation. Theoretical principles of light transmission as an experimental consideration are discussed in the context of performing in vivo optogenetic stimulation. The protocol details the design and construction of both simple and complex laser configurations and describes tethering strategies to permit simultaneous stimulation of multiple animals for high-throughput behavioral testing.

In vivo Optogenetic Stimulation of the Rodent Central Nervous System

Optogenetics has become a powerful tool for use in behavioral neuroscience experiments. This protocol offers a step-by-step guide to the design and set-up of laser systems, and provides a full protocol for carrying out multiple and simultaneous in vivo optogenetic stimulations compatible with most rodent behavioral testing paradigms.

The ability to probe defined neural circuits in awake, freely-moving animals with cell-type specificity, spatial precision, and high temporal resolution ...

In Situ Ca2+ Imaging of the Enteric Nervous System

Reflex behaviors of the intestine are controlled by the enteric nervous system (ENS). The ENS is an integrative network of neurons and glia in two ganglionated plexuses housed in the gut wall. Enteric neurons and enteric glia are the only cell types within the enteric ganglia. The activity of enteric neurons and glia is responsible for coordinating intestinal functions. This protocol describes methods for observing the activity of neurons and glia within the intact ENS by imaging intracellular calcium (Ca2+) transients with fluorescent indicator dyes. Our technical discussion focuses on methods for Ca2+ imaging in whole-mount preparations of the myenteric plexus from the rodent bowel. Bulk loading of ENS whole-mounts with a high-affinity Ca2+ indicator such as Fluo-4 permits measurements of Ca2+ responses in individual neurons or glial cells. These responses can be evoked repeatedly and reliably, which permits quantitative studies using pharmacological tools. Ca2+ responses in cells of the ENS are recorded using a fluorescence microscope equipped with a cooled charge-coupled device (CCD) camera. Fluorescence measurements obtained using Ca2+ imaging in whole-mount preparations offer a straightforward means of characterizing the mechanisms and potential functional consequences of Ca2+ responses in enteric neurons and glial cells.

In Situ Ca2+ Imaging of the Enteric Nervous System

The enteric nervous system (ENS) is a network of neurons and glia located in the gut wall that controls intestinal reflexes. This protocol describes methods for recording the activity of enteric neurons and glia in live preparations of ENS using Ca2+ imaging.

Reflex behaviors of the intestine are controlled by the enteric nervous system (ENS). The ENS is an integrative network of neurons and glia in two ...

Sequential Extraction of Soluble and Insoluble Alpha-Synuclein from Parkinsonian Brains

Alpha-synuclein (&#945;-syn) protein is abundantly expressed mainly within neurons, and exists in a number of different forms - monomers, tetramers, oligomers and fibrils. During disease, &#945;-syn undergoes conformational changes to form oligomers and high molecular weight aggregates that tend to make the protein more insoluble. Abnormally aggregated &#945;-syn is a neuropathological feature of Parkinson&#39;s disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). Biochemical characterization and analysis of insoluble &#945;-syn using buffers with increasing detergent strength and high-speed ultracentrifugation provides a powerful tool to determine the development of &#945;-syn pathology associated with disease progression. This protocol describes the isolation of increasingly insoluble/aggregated &#945;-syn from post-mortem human brain tissue. This methodology can be adapted with modifications to studies of normal and abnormal &#945;-syn biology in transgenic animal models harbouring different &#945;-syn mutations as well as in other neurodegenerative diseases that feature aberrant fibrillar deposits of proteins related to their respective pathologies.

Here, we present a protocol for the isolation of increasingly insoluble/aggregated alpha-synuclein (&#945;-syn) from post-mortem human brain tissue. Through the utilization of buffers with increasing detergent strength and high-speed ultracentrifugation techniques, the variable properties of &#945;-syn aggregation in diseased and non-diseased tissue can be examined.

Alpha-synuclein (&#945;-syn) protein is abundantly expressed mainly within neurons, and exists in a number of different forms - monomers, tetramers, ...

Bioluminescence Imaging of Neuroinflammation in Transgenic Mice After Peripheral Inoculation of Alpha-Synuclein Fibrils

To study the prion-like behavior of misfolded alpha-synuclein, mouse models are needed that allow fast and simple transmission of alpha-synuclein prionoids, which cause neuropathology within the central nervous system (CNS). Here we describe that intraglossal or intraperitoneal injection of alpha-synuclein fibrils into bigenic Tg(M83+/-:Gfap-luc+/-) mice, which overexpress human alpha-synuclein with the A53T mutation from the prion protein promoter and firefly luciferase from the promoter for glial fibrillary acidic protein (Gfap), is sufficient to induce neuropathologic disease. In comparison to homozygous Tg(M83+/+) mice that develop severe neurologic symptoms beginning at an age of 8 months, heterozygous Tg(M83+/-:Gfap-luc+/-) animals remain free of spontaneous disease until they reach an age of 22 months. Interestingly, injection of alpha-synuclein fibrils via the intraperitoneal route induced neurologic disease with paralysis in four of five Tg(M83+/-:Gfap-luc+/-) mice with a median incubation time of 229 &#177;17 days. Diseased animals showed severe deposits of phosphorylated alpha-synuclein in their brains and spinal cords. Accumulations of alpha-synuclein were sarkosyl-insoluble and colocalized with ubiquitin and p62, and were accompanied by an inflammatory response resulting in astrocytic gliosis and microgliosis. Surprisingly, inoculation of alpha-synuclein fibrils into the tongue was less effective in causing disease with only one of five injected animals showing alpha-synuclein pathology after 285 days. Our findings show that inoculation via the intraglossal route and more so via the intraperitoneal route is suitable to induce neurologic illness with relevant hallmarks of synucleinopathies in Tg(M83+/-:Gfap-luc+/-) mice. This provides a new model for studying prion-like pathogenesis induced by alpha-synuclein prionoids in greater detail.

Peripheral injection of alpha-synuclein fibrils into the peritoneum or tongue of Tg(M83+/-:Gfap-luc+/-) mice, which express human alpha-synuclein with the familial A53T mutation and firefly luciferase, can induce neuropathology, including neuroinflammation, in their central nervous system.

To study the prion-like behavior of misfolded alpha-synuclein, mouse models are needed that allow fast and simple transmission of alpha-synuclein ...

Methods and Tips for Intravenous Administration of Adeno-associated Virus to Rats and Evaluation of Central Nervous System Transduction

Adeno-associated virus (AAV) vectors are a key reagent in the neurosciences for clustered regularly interspaced short palindromic repeats (CRISPR), optogenetics, cre-lox targeting, etc. The purpose of this manuscript is to aid the investigator attempting expansive central nervous system (CNS) gene transfer in the rat via tail vein injection of AAV. Wide-scale expression is relevant for conditions with widespread pathology, and a rat model is significant due to its greater size and physiologic similarities to humans compared to mice. In this example application, a wide-scale neuronal transduction is used to mimic a neurodegenerative disease that affects the entire spinal cord, amyotrophic lateral sclerosis (ALS). The efficient wide-scale CNS transduction can also be used to deliver therapeutic protein factors in pre-clinical studies. After a post-injection expression interval of several weeks, the effects of the transduction are evaluated. For a green fluorescent protein (GFP) control vector, the amount of GFP in the cerebellum is estimated quickly and reliably by a basic imaging program. For motor disease phenotypes that are induced by the ALS related protein transactive response DNA-binding protein of 43 kDa (TDP-43), the deficits are scored by escape reflex and rotarod. Beyond disease modeling and gene therapy, there are diverse potential applications for the wide-scale gene targeting described here. The expanded use of this method will aid in expediting hypothesis testing in the neurosciences and neurogenetics.

Methods for a wide-scale central nervous system gene delivery in the rat are covered. In this example, the purpose is to mimic a disease that affects the entire spinal cord. The widespread transduction can be used to deliver a therapeutic protein to the CNS from a one-time, peripheral administration.

Adeno-associated virus (AAV) vectors are a key reagent in the neurosciences for clustered regularly interspaced short palindromic repeats (CRISPR), ...

Exogenous Administration of Microsomes-associated Alpha-synuclein Aggregates to Primary Neurons As a Powerful Cell Model of Fibrils Formation

For years, the inability of replicating formation of insoluble alpha-synuclein (&#945;S) inclusions in cell cultures has been a great limitation in the study of &#945;S aggregation in Parkinson&#39;s Disease (PD). Recently, the development of new animal models through the exogenous inoculation of brain extracts from diseased &#945;S transgenic mice or PD patients has given new hopes to the possibility of creating more adequate cell models of &#945;S aggregation. Unfortunately, when it comes to cells in cultures, administration of raw brain extracts has not proven as successful as in mice and the source of choice of exogenous aggregates is still in vitro preformed &#945;S fibrils.
We have developed a method to induce the formation of intracellular &#945;S inclusions in primary neurons through the exogenous administration of native microsomes-associated &#945;S aggregates, a highly toxic &#945;S species isolated from diseased areas of transgenic mice. This fraction of &#945;S aggregates that is associated with the microsomes vesicles, is efficiently internalized and induces the formation of intracellular inclusions positive for aggregated and phosphorylated &#945;S. Compared to in vitro-preformed fibrils which are made from recombinant &#945;S, our method is faster and guarantees that the pathogenic seeding is made with authentic &#945;S aggregates extracted from diseased animal models of PD, mimicking more closely the type of inclusions obtained in vivo. As a result, availability of tissues rich in &#945;S inclusions is mandatory.
We believe that this method will provide a versatile cell-based model to study the microscopic aspects of &#945;S aggregation and the related cellular pathophysiology in vivo and will be a starting point for the creation of more accurate and sophisticated cell paradigm of PD.

The goal of this protocol is to provide a cell-based system that replicates the formation of alpha-synuclein aggregates in vivo. Intracellular alpha-synuclein inclusions are seeded in primary neurons by the internalization and propagation of exogenous administered native microsomes-associated alpha-synuclein aggregates isolated from diseased alpha-synuclein transgenic mice.

For years, the inability of replicating formation of insoluble alpha-synuclein (&#945;S) inclusions in cell cultures has been a great limitation in the ...

Transplantation of Chemogenetically Engineered Cortical Interneuron Progenitors into Early Postnatal Mouse Brains

Neuronal development is regulated by a complex combination of environmental and genetic factors. Assessing the relative contribution of each component is a complicated task, which is particularly difficult in regards to the development of &#947;-aminobutyric acid (GABA)ergic cortical interneurons (CIs). CIs are the main inhibitory neurons in the cerebral cortex, and they play key roles in neuronal networks, by regulating both the activity of individual pyramidal neurons, as well as the oscillatory behavior of neuronal ensembles. They are generated in transient embryonic structures (medial and caudal ganglionic eminences -&#160;MGE and CGE) that are very difficult to efficiently target using in utero electroporation approaches. Interneuron progenitors migrate long distances during normal embryonic development, before they integrate in the cortical circuit. This remarkable ability to disperse and integrate into a developing network can be hijacked by transplanting embryonic interneuron precursors into early post-natal host cortices. Here, we present a protocol that allows genetic modification of embryonic interneuron progenitors using focal ex vivo electroporation. These engineered interneuron precursors are then transplanted into early post-natal host cortices, where they will mature into easily identifiable CIs. This protocol allows the use of multiple genetically encoded tools, or the ability to regulate the expression of specific genes in interneuron progenitors, in order to investigate the impact of either genetic or environmental variables on the maturation and integration of CIs.

Here we present a protocol, designed to use chemogenetic tools to manipulate the activity of cortical interneuron progenitors transplanted into the cortex of early postnatal mice.

Neuronal development is regulated by a complex combination of environmental and genetic factors. Assessing the relative contribution of each component is ...

Generation of Alpha-Synuclein Preformed Fibrils from Monomers and Use In Vivo

Use of the in vivo alpha-synuclein preformed fibril (&#945;-syn PFF) model of synucleinopathy is gaining popularity among researchers aiming to model Parkinson&#39;s disease synucleinopathy and nigrostriatal degeneration. The standardization of &#945;-syn PFF generation and in vivo application is critical in order to ensure consistent, robust &#945;-syn pathology. Here, we present a detailed protocol for the generation of fibrils from monomeric &#945;-syn, post-fibrilization quality control steps, and suggested parameters for successful neurosurgical injection of &#945;-syn PFFs into rats or mice. Starting with monomeric &#945;-syn, fibrilization occurs over a 7-day incubation period while shaking at optimal buffer conditions, concentration, and temperature. Post-fibrilization quality control is assessed by the presence of pelletable fibrils via sedimentation assay, the formation of amyloid conformation in the fibrils with a thioflavin T assay, and electron microscopic visualization of the fibrils. Whereas successful validation using these assays is necessary for success, they are not sufficient to guarantee PFFs will seed &#945;-syn inclusions in neurons, as such aggregation activity of each PFF batch should be tested in cell culture or in pilot animal cohorts. Prior to use, PFFs must be sonicated under precisely standardized conditions, followed by examination using electron microscopy or dynamic light scattering to confirm fibril lengths are within optimal size range, with an average length of 50 nm. PFFs can then be added to cell culture media or used in animals. Pathology detectable by immunostaining for phosphorylated &#945;-syn (psyn; serine 129) is apparent days or weeks later in cell culture and rodent models, respectively.&#160;

The goal of this article is to outline the steps required for the generation of fibrils from monomeric alpha-synuclein, subsequent quality control, and use of the preformed fibrils in vivo.

Use of the in vivo alpha-synuclein preformed fibril (&#945;-syn PFF) model of synucleinopathy is gaining popularity among researchers aiming to model ...