Name: using enzyme-based biosensors to measure tonic and phasic glutamate in alzheimer's mouse models
Uploaded: 2017-05-03T13:00:00
Description: Watch this Scientific Journal Video about Using Enzyme-based Biosensors to Measure Tonic and Phasic Glutamate in Alzheimer's Mouse Models at JoVE.com

This work was supported by the National Institute of General Medical Sciences (MNR; U54GM104942), NIA (MNR; R15AG045812), Alzheimer's Association (MNR; NIRG-12-242187), WVU Faculty Research Senate Grant (MNR), and WVU PSCOR Grant (MNR).

1. Coating the Microelectrode Array with Enzymes or Matrix Layer
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	<li>Preparing the protein matrix solution
	<ol>
		<li>Weigh out 10 mg of bovine serum albumin (BSA) and transfer to the 1.5 mL microcentrifuge tube.</li>
		<li>Add 985 &#181;L of DI water to the microcentrifuge tube containing BSA. Mix the solution by manual agitation (re-pipetting using 1,000 &#181;L pipette ~ 3 times, until the BSA is dissolved). 
		NOTE: Do not use vortex to mix the solution as doing so may introduce air int...

<ol>
	<li>Bito, L., Davson, H., Levin, E., Murray, M., Snider, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+concentrations+of+free+amino+acids+and+other+electrolytes+in+cerebrospinal+fluid,+in+vivo+dialysate+of+brain,+and+blood+plasma+of+the+dog.">The concentrations of free amino acids and other electrolytes in cerebrospinal fluid, in vivo dialysate of brain, and blood plasma of the dog.</a> J Neurochem. 13 (11), 1057-1067 (1966).</li><li>Cavus, I., 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=Extracellular+metabolites+in+the+cortex+and+hippocampus+of+epileptic+patients.">Extracellular metabolites in the cortex and hippocampus of epileptic patients.</a> Ann Neurol. 57 (2), 226-235 (2005).</li><li>Montgomery, A. J., Lingford-Hughes, A. R., Egerton, A., Nutt, D. J., Grasby, P. 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C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytokine+effects+on+glutamate+uptake+by+human+astrocytes.">Cytokine effects on glutamate uptake by human astrocytes.</a> Neuroimmunomodulation. 7 (3), 153-159 (2000).</li><li>He, X., 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=The+association+between+CCL2+polymorphisms+and+drug-resistant+epilepsy+in+Chinese+children.">The association between CCL2 polymorphisms and drug-resistant epilepsy in Chinese children.</a> Epileptic Disord. 15 (3), 272-277 (2013).</li><li>Xie, 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=Resolution+of+High-Frequency+Mesoscale+Intracortical+Maps+Using+the+Genetically+Encoded+Glutamate+Sensor+iGluSnFR.">Resolution of High-Frequency Mesoscale Intracortical Maps Using the Genetically Encoded Glutamate Sensor iGluSnFR.</a> J Neurosci. 36 (4), 1261-1272 (2016).</li><li>Marvin, J. S., 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=An+optimized+fluorescent+probe+for+visualizing+glutamate+neurotransmission.">An optimized fluorescent probe for visualizing glutamate neurotransmission.</a> Nat Methods. 10 (2), 162-170 (2013).</li><li>Hefendehl, J. K., 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=Mapping+synaptic+glutamate+transporter+dysfunction+in+vivo+to+regions+surrounding+Abeta+plaques+by+iGluSnFR+two-photon+imaging.">Mapping synaptic glutamate transporter dysfunction in vivo to regions surrounding Abeta plaques by iGluSnFR two-photon imaging.</a> Nat Commun. 7, 13441 (2016).</li><li>Hinzman, J. M., Thomas, T. C., Quintero, J. E., Gerhardt, G. A., Lifshitz, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Disruptions+in+the+regulation+of+extracellular+glutamate+by+neurons+and+glia+in+the+rat+striatum+two+days+after+diffuse+brain+injury.">Disruptions in the regulation of extracellular glutamate by neurons and glia in the rat striatum two days after diffuse brain injury.</a> J Neurotrauma. 29 (6), 1197-1208 (2012).</li><li>Thomas, T. C., Hinzman, J. M., Gerhardt, G. A., Lifshitz, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypersensitive+glutamate+signaling+correlates+with+the+development+of+late-onset+behavioral+morbidity+in+diffuse+brain-injured+circuitry.">Hypersensitive glutamate signaling correlates with the development of late-onset behavioral morbidity in diffuse brain-injured circuitry.</a> J Neurotrauma. 29 (2), 187-200 (2011).</li><li>Hinzman, J. M., 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=Diffuse+brain+injury+elevates+tonic+glutamate+levels+and+potassium-evoked+glutamate+release+in+discrete+brain+regions+at+two+days+post-injury:+an+enzyme-based+microelectrode+array+study.">Diffuse brain injury elevates tonic glutamate levels and potassium-evoked glutamate release in discrete brain regions at two days post-injury: an enzyme-based microelectrode array study.</a> J Neurotrauma. 27 (5), 889-899 (2010).</li><li>Stephens, M. L., Quintero, J. E., Pomerleau, F., Huettl, P., Gerhardt, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Age-related+changes+in+glutamate+release+in+the+CA3+and+dentate+gyrus+of+the+rat+hippocampus.">Age-related changes in glutamate release in the CA3 and dentate gyrus of the rat hippocampus.</a> Neurobiol Aging. 32 (5), 811-820 (2009).</li><li>Nickell, J., Salvatore, M. F., Pomerleau, F., Apparsundaram, S., Gerhardt, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reduced+plasma+membrane+surface+expression+of+GLAST+mediates+decreased+glutamate+regulation+in+the+aged+striatum.">Reduced plasma membrane surface expression of GLAST mediates decreased glutamate regulation in the aged striatum.</a> Neurobiol Aging. 28 (11), 1737-1748 (2006).</li><li>Hascup, E. 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=An+allosteric+modulator+of+metabotropic+glutamate+receptors+(mGluR(2)+)+(+)-TFMPIP,+inhibits+restraint+stress-induced+phasic+glutamate+release+in+rat+prefrontal+cortex.">An allosteric modulator of metabotropic glutamate receptors (mGluR(2) ) (+)-TFMPIP, inhibits restraint stress-induced phasic glutamate release in rat prefrontal cortex.</a> J Neurochem. 122 (2), 619-627 (2012).</li><li>Rutherford, E. C., Pomerleau, F., Huettl, P., Stromberg, I., Gerhardt, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronic+second-by-second+measures+of+L-glutamate+in+the+central+nervous+system+of+freely+moving+rats.">Chronic second-by-second measures of L-glutamate in the central nervous system of freely moving rats.</a> J Neurochem. 102 (3), 712-722 (2007).</li><li>Matveeva, E. 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=Reduction+of+vesicle-associated+membrane+protein+2+expression+leads+to+a+kindling-resistant+phenotype+in+a+murine+model+of+epilepsy.">Reduction of vesicle-associated membrane protein 2 expression leads to a kindling-resistant phenotype in a murine model of epilepsy.</a> Neuroscience. 202, 77-86 (2011).</li><li>Matveeva, E. 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=Kindling-induced+asymmetric+accumulation+of+hippocampal+7S+SNARE+complexes+correlates+with+enhanced+glutamate+release.">Kindling-induced asymmetric accumulation of hippocampal 7S SNARE complexes correlates with enhanced glutamate release.</a> Epilepsia. 53 (1), 157-167 (2012).</li><li>Hunsberger, H. C., Rudy, C. C., Batten, S. R., Gerhardt, G. A., Reed, M. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=P301L+tau+expression+affects+glutamate+release+and+clearance+in+the+hippocampal+trisynaptic+pathway.">P301L tau expression affects glutamate release and clearance in the hippocampal trisynaptic pathway.</a> J Neurochem. 132 (2), 169-182 (2015).</li><li>Hunsberger, H. C., 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=Riluzole+rescues+glutamate+alterations,+cognitive+deficits,+and+tau+pathology+associated+with+P301L+tau+expression.">Riluzole rescues glutamate alterations, cognitive deficits, and tau pathology associated with P301L tau expression.</a> J Neurochem. 135 (2), 381-394 (2015).</li><li>Hunsberger, H. C., 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=Peripherally+restricted+viral+challenge+elevates+extracellular+glutamate+and+enhances+synaptic+transmission+in+the+hippocampus.">Peripherally restricted viral challenge elevates extracellular glutamate and enhances synaptic transmission in the hippocampus.</a> J Neurochem. , (2016).</li><li>Obrenovitch, T. P., Urenjak, J., Zilkha, E., Jay, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Excitotoxicity+in+neurological+disorders--the+glutamate+paradox.">Excitotoxicity in neurological disorders--the glutamate paradox.</a> Int J Dev Neurosci. 18 (2-3), 281-287 (2000).</li><li>Hillered, L., Vespa, P. M., Hovda, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Translational+neurochemical+research+in+acute+human+brain+injury:+the+current+status+and+potential+future+for+cerebral+microdialysis.">Translational neurochemical research in acute human brain injury: the current status and potential future for cerebral microdialysis.</a> J Neurotrauma. 22 (1), 3-41 (2005).</li><li>Burmeister, J. J., Gerhardt, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-referencing+ceramic-based+multisite+microelectrodes+for+the+detection+and+elimination+of+interferences+from+the+measurement+of+L-glutamate+and+other+analytes.">Self-referencing ceramic-based multisite microelectrodes for the detection and elimination of interferences from the measurement of L-glutamate and other analytes.</a> Anal Chem. 73 (5), 1037-1042 (2001).</li><li>Burmeister, J. J., 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=Improved+ceramic-based+multisite+microelectrode+for+rapid+measurements+of+L-glutamate+in+the+CNS.">Improved ceramic-based multisite microelectrode for rapid measurements of L-glutamate in the CNS.</a> J Neurosci Methods. 119 (2), 163-171 (2002).</li><li>Diamond, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deriving+the+glutamate+clearance+time+course+from+transporter+currents+in+CA1+hippocampal+astrocytes:+transmitter+uptake+gets+faster+during+development.">Deriving the glutamate clearance time course from transporter currents in CA1 hippocampal astrocytes: transmitter uptake gets faster during development.</a> J Neurosci. 25 (11), 2906-2916 (2005).</li><li>Greene, J. G., Borges, K., Dingledine, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+transcriptional+neuroanatomy+of+the+rat+hippocampus:+evidence+for+wide-ranging,+pathway-specific+heterogeneity+among+three+principal+cell+layers.">Quantitative transcriptional neuroanatomy of the rat hippocampus: evidence for wide-ranging, pathway-specific heterogeneity among three principal cell layers.</a> Hippocampus. 19 (3), 253-264 (2009).</li><li>Borland, L. M., Shi, G., Yang, H., Michael, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Voltammetric+study+of+extracellular+dopamine+near+microdialysis+probes+acutely+implanted+in+the+striatum+of+the+anesthetized+rat.">Voltammetric study of extracellular dopamine near microdialysis probes acutely implanted in the striatum of the anesthetized rat.</a> J Neurosci Methods. 146 (2), 149-158 (2005).</li><li>Jaquins-Gerstl, A., Michael, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+the+brain+penetration+injury+associated+with+microdialysis+and+voltammetry.">Comparison of the brain penetration injury associated with microdialysis and voltammetry.</a> J Neurosci Methods. 183 (2), 127-135 (2009).</li><li>Azbill, R. D., Mu, X., Springer, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Riluzole+increases+high-affinity+glutamate+uptake+in+rat+spinal+cord+synaptosomes.">Riluzole increases high-affinity glutamate uptake in rat spinal cord synaptosomes.</a> Brain Res. 871 (2), 175-180 (2000).</li><li>Gourley, S. L., Espitia, J. W., Sanacora, G., Taylor, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antidepressant-like+properties+of+oral+riluzole+and+utility+of+incentive+disengagement+models+of+depression+in+mice.">Antidepressant-like properties of oral riluzole and utility of incentive disengagement models of depression in mice.</a> Psychopharmacology (Berl). 219 (3), 805-814 (2011).</li><li>Frizzo, M. E., Dall'Onder, L. P., Dalcin, K. B., Souza, D. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Riluzole+enhances+glutamate+uptake+in+rat+astrocyte+cultures).">Riluzole enhances glutamate uptake in rat astrocyte cultures).</a> Cell Mol Neurobiol. 24 (1), 123-128 (2004).</li><li>Fumagalli, E., Funicello, M., Rauen, T., Gobbi, M., Mennini, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Riluzole+enhances+the+activity+of+glutamate+transporters+GLAST,+GLT1+and+EAAC1.">Riluzole enhances the activity of glutamate transporters GLAST, GLT1 and EAAC1.</a> Eur J Pharmacol. 578 (2-3), 171-176 (2008).</li><li>Day, B. K., Pomerleau, F., Burmeister, J. J., Huettl, P., Gerhardt, G. 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The MEA technique allows for measurement of fast kinetics of neurotransmitter release and uptake in vitro and in vivo. Hence, the technology produces a wide variety of data output including tonic neurotransmitter levels, evoked neurotransmitter release, and neurotransmitter clearance. However, because use of MEAs is a relatively complex procedure, there are numerous factors that may need to be optimized for successful use. For example, during calibration, one may note that there are no signal waveforms ...

Measuring neurotransmitter alterations in the brain is an essential tool for neuroscientists studying diseases of the central nervous system (CNS) that are often characterized by neurotransmitter dysregulation. Though microdialysis in combination with high pressure liquid chromatography (HPLC/EC) has been the most widely used method to measure changes in extracellular neurotransmitter levels1,2,3,4, the spatial and temporal resolution of microdialysis probes may not be ideal for neurotransmitters, such as glutamate, that are tightly regulated in the extracellular space5,6. Because of the recent advances in genetics and imaging, there are additional methods that can be used to map glutamate in vivo. Using genetically encoded glutamate fluorescent reporters (iGluSnFR) and two-photon imaging, researchers are able to visualize glutamate release by neurons and astrocytes both in vitro and in vivo7,8,9. Notably, this allows for recording from a larger field of view and does not disrupt the intrinsic connections of the brain. While these new optical techniques allow for visualization of glutamate kinetics and measurement of sensory evoked responses and neuronal activity, they lack the ability to quantify the amount of glutamate in the extracellular space in discrete brain regions.
An alternative method is the enzyme-linked microelectrode array (MEA) that can selectively measure extracellular neurotransmitter levels, such as glutamate, through the use of a self-referenced recording scheme. The MEA technique has been used to study alterations in extracellular glutamate following traumatic brain injury10,11,12, aging13,14, stress15,16, epilepsy17,18, Alzheimer&#39;s disease19,20, and injection of a viral mimic21 and represents an improvement over the spatial and temporal limitations inherent in microdialysis. Whereas microdialysis restricts the ability to measure near the synapse22,23, MEAs have a high spatial resolution that allows for selective measures of extracellular glutamate spillover near synapses24,25. Second, the low temporal resolution of microdialysis (1 - 20 min) limits the ability to investigate the fast dynamics of glutamate release and clearance occurring in the millisecond to second range26. Because differences in the release or clearance of glutamate may not be evident in measures of tonic, resting glutamate levels, it may be essential that glutamate release and clearance be directly measured. MEAs allow for such measures due to their high temporal resolution (2 Hz) and low limits of detection (&#60; 1 &#181;M). Third, MEAs allow for examination of subregional variations in neurotransmitters within a particular brain region, such as the rat or mouse hippocampus. For example, using MEAs we can separately target the dentate gyrus (DG), cornu ammonis 3 (CA3) and cornu ammonis 1 (CA1) of the hippocampus, which are connected via a trisynaptic circuit27, to examine subregional differences in extracellular glutamate. Because of the size of microdialysis probes (1 - 4 mm length) and the damage caused by implantation28,29, subregional differences are difficult to address. Furthermore, the optical systems only allow stimulation through external stimuli, such as a whisker stimulation or light flicker, which does not permit subregional stimulation7. A final benefit of MEAs over other methods is the ability to study these subregions in vivo without disrupting their extrinsic and intrinsic connections.
Here, we describe how a recording system (e.g., FAST16mkIII) in combination with MEAs, consisting of a ceramic-based multisite microelectrode, can be differentially coated on the recording sites to allow for interfering agents to be detected and removed from the analyte signal. We also demonstrate these arrays can be used for amperometry-based studies of in vivo glutamate regulation within the DG, CA3, and CA1 hippocampal subregions of anesthetized rTg(TauP301L)4510 mice, a commonly used mouse model of Alzheimer&#39;s disease. In addition, we provide confirmation of the sensitivity of the MEA system to the fast dynamics of glutamate release and clearance by treating the mice with riluzole, a drug shown in vitro to decrease glutamate release and increase glutamate uptake30,31,32,33, and demonstrating these respective changes in vivo in the TauP301L mouse model.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>FAST-16mkIII-8 channel</td>
			<td>Quanteon</td>
			<td>16mkIII</td>
			<td></td>
		</tr>
		<tr>
			<td>Microelectrode arrays</td>
			<td>CenMet</td>
			<td>W4 or 8-TRK</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin (BSA)</td>
			<td>Sigma-Aldrich</td>
			<td>A-3059</td>
			<td>10 g (expires after 1 month)</td>
		</tr>
		<tr>
			<td>Glutaraldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>G-6257</td>
			<td>100 mL (expires after 6 months)</td>
		</tr>
		<tr>
			<td>Glutamate Oxidase</td>
			<td>US Biological or Sigma Aldrich</td>
			<td>G4001-01 or 100646</td>
			<td>50 UI (expires after 6 months)</td>
		</tr>
		<tr>
			<td>Hamilton Syringes</td>
			<td>Hamilton</td>
			<td>#701</td>
			<td>2 syringes</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>BDH</td>
			<td>UN1230</td>
			<td>4 L</td>
		</tr>
		<tr>
			<td>m-Phenylenediamine dihydrochloride (mPD)</td>
			<td>ACROS Organics</td>
			<td>1330560250</td>
			<td>25 g</td>
		</tr>
		<tr>
			<td>Reference Electrodes (RE-5B)</td>
			<td>BAS</td>
			<td>MF-2079</td>
			<td>3 electrodes</td>
		</tr>
		<tr>
			<td>Magnetic stir plate</td>
			<td>Cole-parmer</td>
			<td>EW-04804-01</td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Glutamate</td>
			<td>Sigma-Aldrich</td>
			<td>G-1626</td>
			<td>100 g</td>
		</tr>
		<tr>
			<td>Ascorbic Acid</td>
			<td>TCI</td>
			<td>50-81-7</td>
			<td>500 g</td>
		</tr>
		<tr>
			<td>Dopamine Hydrochloride</td>
			<td>Alfa Aesar</td>
			<td>62-31-7</td>
			<td>5 g</td>
		</tr>
		<tr>
			<td>Perchloric acid</td>
			<td>VWR</td>
			<td>UN2920</td>
			<td>500 mL</td>
		</tr>
		<tr>
			<td>Postassium chloride</td>
			<td>VWR</td>
			<td>7447-40-7</td>
			<td>1 kg</td>
		</tr>
		<tr>
			<td>Sodium chloride</td>
			<td>VWR</td>
			<td>7647-40-7</td>
			<td>1 kg</td>
		</tr>
		<tr>
			<td>Calcium Chloride</td>
			<td>MP</td>
			<td>153502</td>
			<td>100 g</td>
		</tr>
		<tr>
			<td>Sodium Hydroxide</td>
			<td>BDH</td>
			<td>1310732</td>
			<td>500 g</td>
		</tr>
		<tr>
			<td>Glass pressure ejection pipettes</td>
			<td>CenMet</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sticky wax</td>
			<td>Kerrlab</td>
			<td>625</td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Microsyringe</td>
			<td>World Precision Instruments</td>
			<td>MF28G-5</td>
			<td></td>
		</tr>
		<tr>
			<td>Modeling clay</td>
			<td>WalMart</td>
			<td></td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Picospritzer III</td>
			<td>Parker</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Silver wire</td>
			<td>AM systems</td>
			<td>782000</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrochloric acid</td>
			<td>BDH</td>
			<td>7647010</td>
			<td>2.5 L</td>
		</tr>
		<tr>
			<td>Platinum wire</td>
			<td>AM Systems</td>
			<td>778000</td>
			<td></td>
		</tr>
		<tr>
			<td>Solder gun</td>
			<td>Lowes or Home Depot</td>
			<td></td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Multimeter</td>
			<td>WalMart</td>
			<td></td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>PhysioSuite</td>
			<td>Kent Scientific</td>
			<td></td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>SomnoSuite</td>
			<td>Kent Scientific</td>
			<td></td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Stereotaxic device</td>
			<td>Stoelting</td>
			<td></td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Digital Lab Standard</td>
			<td>Stoelting</td>
			<td></td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Meiji EMZ microscope</td>
			<td>Meiji</td>
			<td>EMZ-5</td>
			<td></td>
		</tr>
		<tr>
			<td>Drill</td>
			<td>Dremel</td>
			<td>Micro</td>
			<td></td>
		</tr>
		<tr>
			<td>Metricide</td>
			<td>Metrex</td>
			<td>102800</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel</td>
			<td>VWR</td>
			<td></td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Surgery scissors</td>
			<td>VWR</td>
			<td></td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Sterile cotton swabs</td>
			<td>Puritan</td>
			<td>25806</td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Eye ointment</td>
			<td>Puralube Vet Ointment</td>
			<td></td>
			<td>Obtain from the vet</td>
		</tr>
		<tr>
			<td>Iodine swabs</td>
			<td>VWR</td>
			<td>S48050</td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Alcohol swabs</td>
			<td>Local drug store</td>
			<td></td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Sterile surgery drape</td>
			<td>Dynarex</td>
			<td>4410</td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Sterile saline</td>
			<td>Teknova</td>
			<td>S5815</td>
			<td>Can make own soltuion using filters</td>
		</tr>
		<tr>
			<td>Hydrogen Peroxide (3%)</td>
			<td>Local drug store</td>
			<td></td>
			<td>Can purchase from different supplier</td>
		</tr>
		<tr>
			<td>Heating Pad</td>
			<td>WalMart</td>
			<td></td>
			<td>Can purchase from different supplier</td>
		</tr>
	</tbody>
</table>

using enzyme-based biosensors to measure tonic and phasic glutamate in alzheimer's mouse models

Neurotransmitter disruption is often a key component of diseases of the central nervous system (CNS), playing a role in the pathology underlying Alzheimer's disease, Parkinson's disease, depression, and anxiety. Traditionally, microdialysis has been the most common (lauded) technique to examine neurotransmitter changes that occur in these disorders. But because microdialysis has the ability to measure slow 1-20 minute changes across large areas of tissue, it has the disadvantage of invasiveness, potentially destroying intrinsic connections within the brain and a slow sampling capability. A relatively newer technique, the microelectrode array (MEA), has numerous advantages for measuring specific neurotransmitter changes within discrete brain regions as they occur, making for a spatially and temporally precise approach. In addition, using MEAs is minimally invasive, allowing for measurement of neurotransmitter alterations in vivo. In our laboratory, we have been specifically interested in changes in the neurotransmitter, glutamate, related to Alzheimer's disease pathology. As such, the method described here has been used to assess potential hippocampal disruptions in glutamate in a transgenic mouse model of Alzheimer's disease. Briefly, the method used involves coating a multi-site microelectrode with an enzyme very selective for the neurotransmitter of interest and using self-referencing sites to subtract out background noise and interferents. After plating and calibration, the MEA can be constructed with a micropipette and lowered into the brain region of interest using a stereotaxic device. Here, the method described involves anesthetizing rTg(TauP301L)4510 mice and using a stereotaxic device to precisely target sub-regions (DG, CA1, and CA3) of the hippocampus.

While this technology can be used to measure alterations in glutamatergic signaling in many types of animal models, such as traumatic brain injury, aging, stress, and epilepsy, here we demonstrate how the MEA technology can be used to examine glutamatergic alterations in transgenic mouse model of human tauopathy19,20. The rTg(TauP301L)4510 mouse expresses the P301L mutation in tau associated with frontotemporal dementia and parkin...

Watch this Scientific Journal Video about Using Enzyme-based Biosensors to Measure Tonic and Phasic Glutamate in Alzheimer's Mouse Models at JoVE.com

Using Enzyme-based Biosensors to Measure Tonic and Phasic Glutamate in Alzheimer's Mouse Models

Here, we describe the setup, software navigation, and data analysis for a spatially and temporally precise method of measuring tonic and phasic extracellular glutamate changes in vivo using enzyme-linked microelectrode arrays (MEA).

Neurotransmitter disruption is often a key component of diseases of the central nervous system (CNS), playing a role in the pathology underlying ...

Research

JoVE Journal

Neuroscience

Mouse Models of Periventricular Leukomalacia

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Detection of Neuritic Plaques in Alzheimer's Disease Mouse Model

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GABA-activated Single-channel and Tonic Currents in Rat Brain Slices

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Fast Micro-iontophoresis of Glutamate and GABA: A Useful Tool to Investigate Synaptic Integration

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of ...

Stereotaxic Infusion of Oligomeric Amyloid-beta into the Mouse Hippocampus

Alzheimer&#8217;s disease is a neurodegenerative disease affecting the aging population. A key neuropathological feature of the disease is the ...

Combined Optogenetic and Freeze-fracture Replica Immunolabeling to Examine Input-specific Arrangement of Glutamate Receptors in the Mouse Amygdala

Freeze-fracture electron microscopy has been a major technique in ultrastructural research for over 40 years. However, the lack of effective means to ...

A Simple Way to Measure Alterations in Reward-seeking Behavior Using Drosophila melanogaster

A Simple Way to Measure Alterations in Reward-seeking Behavior Using Drosophila melanogaster

We describe a protocol for measuring ethanol self-administration in fruit flies (Drosophila melanogaster) as a proxy for changes in reward states. We ...

A High-throughput Calcium-flux Assay to Study NMDA-receptors with Sensitivity to Glycine/D-serine and Glutamate

N-methyl-D-aspartate (NMDA) receptors (NMDAR) are classified as ionotropic glutamate receptors and have critical roles in learning and memory. NMDAR ...

Using Near-infrared Fluorescence and High-resolution Scanning to Measure Protein Expression in the Rodent Brain

Neuroscience is the study of how cells in the brain mediate various functions. Measuring protein expression in neurons and glia is critical for the study ...