Supported by the NIH grant R01 MH 099557

1. Fabrication of Recording Electrodes
<ol>
	<li>Pulling the glass electrodes
	<ol>
		<li>Use the following protocol for the microelectrode puller (see Table of Materials):
		<ol>
			<li>Line 1: Heat 510 Pull - Velocity 30 Time 250; Line 2: Heat 490 Pull - Velocity 30 Time 250. 
			NOTE: Time units correspond to 0.5 ms per unit; the other units are relative. The value of the heat should be adjusted for every filament after the ramp test is performed.</li>
		</ol>
		</li>
		<li>Use...

<ol>
	<li>Jan, L. Y., Jan, Y. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Properties+of+the+larval+neuromuscular+junction+in+Drosophila+melanogaster.">Properties of the larval neuromuscular junction in Drosophila melanogaster.</a> J Physiol. 262 (1), 189-214 (1976).</li><li>Katz, B., Miledi, 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+effect+of+temperature+on+the+synaptic+delay+at+the+neuromuscular+junction.">The effect of temperature on the synaptic delay at the neuromuscular junction.</a> J Physiol. 181 (3), 656-670 (1965).</li><li>Macleod, G. T., Gan, J., Bennett, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vesicle-associated+proteins+and+quantal+release+at+single+active+zones+of+amphibian+(Bufo+marinus)+motor-nerve+terminals.">Vesicle-associated proteins and quantal release at single active zones of amphibian (Bufo marinus) motor-nerve terminals.</a> J Neurophysiol. 82 (3), 1133-1146 (1999).</li><li>Macleod, G. T., Farnell, L., Gibson, W. G., Bennett, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantal+secretion+and+nerve-terminal+cable+properties+at+neuromuscular+junctions+in+an+amphibian+(Bufo+marinus).">Quantal secretion and nerve-terminal cable properties at neuromuscular junctions in an amphibian (Bufo marinus).</a> J Neurophysiol. 81 (3), 1135-1146 (1999).</li><li>Zefirov, A., Benish, T., Fatkullin, N., Cheranov, S., Khazipov, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Localization+of+active+zones.">Localization of active zones.</a> Nature. 376 (6539), 393-394 (1995).</li><li>Macleod, G. T., Lavidis, N. A., Bennett, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calcium+dependence+of+quantal+secretion+from+visualized+sympathetic+nerve+varicosities+on+the+mouse+vas+deferens.">Calcium dependence of quantal secretion from visualized sympathetic nerve varicosities on the mouse vas deferens.</a> J Physiol. 480 (Pt 1), 61-70 (1994).</li><li>Samigullin, D., Bill, C. A., Coleman, W. L., Bykhovskaia, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+transmitter+release+by+synapsin+II+in+mouse+motor+terminals.">Regulation of transmitter release by synapsin II in mouse motor terminals.</a> J Physiol. 561 (Pt 1), 149-158 (2004).</li><li>Coleman, W. L., Bykhovskaia, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rab3a-mediated+vesicle+recruitment+regulates+short-term+plasticity+at+the+mouse+diaphragm+synapse.">Rab3a-mediated vesicle recruitment regulates short-term plasticity at the mouse diaphragm synapse.</a> Mol Cell Neurosci. 41 (2), 286-296 (2009).</li><li>Atwood, H. L., Parnas, H., Parnas, I., Wojtowicz, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantal+currents+evoked+by+graded+intracellular+depolarization+of+crayfish+motor+axon+terminals.">Quantal currents evoked by graded intracellular depolarization of crayfish motor axon terminals.</a> J Physiol. 383, 587-599 (1987).</li><li>Parnas, H., Dudel, J., Parnas, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurotransmitter+release+and+its+facilitation+in+crayfish.+I.+Saturation+kinetics+of+release,+and+of+entry+and+removal+of+calcium.">Neurotransmitter release and its facilitation in crayfish. I. Saturation kinetics of release, and of entry and removal of calcium.</a> Pflugers Arch. 393 (1), 1-14 (1982).</li><li>Wojtowicz, J. M., Marin, L., Atwood, H. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activity-induced+changes+in+synaptic+release+sites+at+the+crayfish+neuromuscular+junction.">Activity-induced changes in synaptic release sites at the crayfish neuromuscular junction.</a> J Neurosci. 14 (6), 3688-3703 (1994).</li><li>Zucker, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crayfish+neuromuscular+facilitation+activated+by+constant+presynaptic+action+potentials+and+depolarizing+pulses.">Crayfish neuromuscular facilitation activated by constant presynaptic action potentials and depolarizing pulses.</a> J Physiol. 241 (1), 69-89 (1974).</li><li>Zucker, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+the+statistics+of+transmitter+release+during+facilitation.">Changes in the statistics of transmitter release during facilitation.</a> J Physiol. 229 (3), 787-810 (1973).</li><li>Worden, M. K., Bykhovskaia, M., Hackett, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Facilitation+at+the+lobster+neuromuscular+junction:+a+stimulus-dependent+mobilization+model.">Facilitation at the lobster neuromuscular junction: a stimulus-dependent mobilization model.</a> J Neurophysiol. 78 (1), 417-428 (1997).</li><li>Bykhovskaia, M., Hackett, J. T., Worden, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Asynchrony+of+quantal+events+in+evoked+multiquantal+responses+indicates+presynaptic+quantal+interaction.">Asynchrony of quantal events in evoked multiquantal responses indicates presynaptic quantal interaction.</a> J Neurophysiol. 81 (5), 2234-2242 (1999).</li><li>Bykhovskaia, M., Polagaeva, E., Hackett, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechnisms+underlying+different+facilitation+forms+at+the+lobster+neuromuscular+synapse.">Mechnisms underlying different facilitation forms at the lobster neuromuscular synapse.</a> Brain Res. 1019 (1-2), 10-21 (2004).</li><li>Cooper, R. L., Stewart, B. A., Wojtowicz, J. M., Wang, S., Atwood, H. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantal+measurement+and+analysis+methods+compared+for+crayfish+and+Drosophila+neuromuscular+junctions,+and+rat+hippocampus.">Quantal measurement and analysis methods compared for crayfish and Drosophila neuromuscular junctions, and rat hippocampus.</a> J Neurosci Methods. 61 (1-2), 67-78 (1995).</li><li>Stewart, B. A., Atwood, H. L., Renger, J. J., Wang, J., Wu, C. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+stability+of+Drosophila+larval+neuromuscular+preparations+in+haemolymph-like+physiological+solutions.">Improved stability of Drosophila larval neuromuscular preparations in haemolymph-like physiological solutions.</a> J Comp Physiol A. 175 (2), 179-191 (1994).</li><li>Pawlu, C., DiAntonio, A., Heckmann, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postfusional+control+of+quantal+current+shape.">Postfusional control of quantal current shape.</a> Neuron. 42 (4), 607-618 (2004).</li><li>Akbergenova, Y., Bykhovskaia, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synapsin+maintains+the+reserve+vesicle+pool+and+spatial+segregation+of+the+recycling+pool+in+Drosophila+presynaptic+boutons.">Synapsin maintains the reserve vesicle pool and spatial segregation of the recycling pool in Drosophila presynaptic boutons.</a> Brain Res. 1178, 52-64 (2007).</li><li>Akbergenova, Y., Bykhovskaia, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhancement+of+the+endosomal+endocytic+pathway+increases+quantal+size.">Enhancement of the endosomal endocytic pathway increases quantal size.</a> Mol Cell Neurosci. 40 (2), 199-206 (2009).</li><li>Vasin, A., Volfson, D., Littleton, J. T., Bykhovskaia, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interaction+of+the+Complexin+Accessory+Helix+with+Synaptobrevin+Regulates+Spontaneous+Fusion.">Interaction of the Complexin Accessory Helix with Synaptobrevin Regulates Spontaneous Fusion.</a> Biophys J. 111 (9), 1954-1964 (2016).</li><li>Wong, K., Karunanithi, S., Atwood, H. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantal+unit+populations+at+the+Drosophila+larval+neuromuscular+junction.">Quantal unit populations at the Drosophila larval neuromuscular junction.</a> J Neurophysiol. 82 (3), 1497-1511 (1999).</li><li>Dudel, 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+effect+of+reduced+calcium+on+quantal+unit+current+and+release+at+the+crayfish+neuromuscular+junction.">The effect of reduced calcium on quantal unit current and release at the crayfish neuromuscular junction.</a> Pflugers Arch. 391 (1), 35-40 (1981).</li><li>Dudel, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contribution+of+Ca2++inflow+to+quantal,+phasic+transmitter+release+from+nerve+terminals+of+frog+muscle.">Contribution of Ca2+ inflow to quantal, phasic transmitter release from nerve terminals of frog muscle.</a> Pflugers Arch. 422 (2), 129-142 (1992).</li><li>Marrero, H. G., Lemos, 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=.">.</a> Loose-Patch-Clamp method. , (2007).</li><li>Wu, W. H., Cooper, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiological+recordings+of+high+and+low+output+NMJs+on+the+crayfish+leg+extensor+muscle.">Physiological recordings of high and low output NMJs on the crayfish leg extensor muscle.</a> J Vis Exp. (45), (2010).</li><li>Verstreken, P., Ohyama, T., Bellen, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FM+1-43+labeling+of+synaptic+vesicle+pools+at+the+Drosophila+neuromuscular+junction.">FM 1-43 labeling of synaptic vesicle pools at the Drosophila neuromuscular junction.</a> Methods Mol Biol. 440, 349-369 (2008).</li><li>Brent, J. R., Werner, K. M., McCabe, B. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+larval+NMJ+dissection.">Drosophila larval NMJ dissection.</a> J Vis Exp. (24), (2009).</li><li>Imlach, W., McCabe, B. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophysiological+methods+for+recording+synaptic+potentials+from+the+NMJ+of+Drosophila+larvae.">Electrophysiological methods for recording synaptic potentials from the NMJ of Drosophila larvae.</a> J Vis Exp. (24), (2009).</li><li>Bykhovskaia, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Making+quantal+analysis+more+convenient,+fast,+and+accurate:+user-friendly+software+QUANTAN.">Making quantal analysis more convenient, fast, and accurate: user-friendly software QUANTAN.</a> J Neurosci Methods. 168 (2), 500-513 (2008).</li><li>Huntwork, S., Littleton, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+complexin+fusion+clamp+regulates+spontaneous+neurotransmitter+release+and+synaptic+growth.">A complexin fusion clamp regulates spontaneous neurotransmitter release and synaptic growth.</a> Nat Neurosci. 10 (10), 1235-1237 (2007).</li><li>Zhong, Y., Wu, C. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Altered+synaptic+plasticity+in+Drosophila+memory+mutants+with+a+defective+cyclic+AMP+cascade.">Altered synaptic plasticity in Drosophila memory mutants with a defective cyclic AMP cascade.</a> Science. 251 (4990), 198-201 (1991).</li><li>Delgado, R., Maureira, C., Oliva, C., Kidokoro, Y., Labarca, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Size+of+vesicle+pools,+rates+of+mobilization,+and+recycling+at+neuromuscular+synapses+of+a+Drosophila+mutant,+shibire.">Size of vesicle pools, rates of mobilization, and recycling at neuromuscular synapses of a Drosophila mutant, shibire.</a> Neuron. 28 (3), 941-953 (2000).</li><li>Melom, J. E., Akbergenova, Y., Gavornik, J. P., Littleton, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spontaneous+and+evoked+release+are+independently+regulated+at+individual+active+zones.">Spontaneous and evoked release are independently regulated at individual active zones.</a> J Neurosci. 33 (44), 17253-17263 (2013).</li></ol>

Drosophila represents an advantageous model organism to study synaptic transmission. Several recording configurations have been used at the larval NMJ, including intracellular recordings of synaptic potentials, recordings of synaptic currents with two electrode voltage clamp33,34, and focal macropatch recordings of synaptic currents described here. The latter technique allows the precise quantification of synaptic transmission at visualized boutons.
...

Drosophila is an excellent model system to study the molecular mechanisms controlling synaptic transmission. The neuromuscular system in Drosophila is glutamatergic, and therefore the Drosophila neuromuscular junction (NMJ) can be used to study the conserved features of glutamatergic release. Since Jan and Jan&#39;s study1, the third instar larvae has been broadly used to study evoked and spontaneous synaptic transmission by monitoring excitatory junction potentials (EJPs) or currents (EJCs). EJPs are commonly recorded intracellularly with a sharp glass micro-electrode, and they reflect the activity of the entire NMJ, including all the boutons making synapses at the given muscle fiber.
In contrast, the activity of a limited number of the sites of release can be recorded focally by positioning a micropipette tip near neuronal terminals or synaptic varicosities. This technique was originally employed by Katz and Miledi2, and focal extracellular recordings have been successfully employed at several NMJ preparations, including frog3,4,5, mouse6,7,8, crustacean9,10,11,12,13,14,15,16, and Drosophila17,18,19,20,21,22,23. This approach was further developed by Dudel, who optimized macropatch recoding electrodes24,25. In Dudel&#39;s implementation, this technique closely matched the loose-patch-clamp method26.
The Drosophila larval NMJ has clearly defined synaptic boutons, and transgenic lines with genetically encoded neuronal fluorescent tags (see Table of Materials) are readily available. These advantages enabled us to record EJCs and mEJCs from a selected synaptic bouton20,21,22. Here, we describe this technique in detail.

<table width="1251">
	<tbody>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Sutter P-97</td>
			<td style="width:288px;">Sutter instrument</td>
			<td style="width:180px;">P-97</td>
			<td style="width:495px;">Microelectrode puller</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Narishige MF-830</td>
			<td style="width:288px;">Narishige</td>
			<td style="width:180px;">MF-830</td>
			<td>Microforge</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">WPI MF200</td>
			<td style="width:288px;">WPI</td>
			<td>MF200</td>
			<td>Microforge</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Glass capilaries</td>
			<td style="width:288px;">WPI</td>
			<td>B150-86-10</td>
			<td style="width:495px;">Glass capilaries</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Microtorch 1WG61</td>
			<td style="width:288px;">Grainer</td>
			<td style="width:180px;">1WG61</td>
			<td>Microtorch</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Sylgard 184 Silicone Elastomer Kit</td>
			<td style="width:288px;">Dow Corning</td>
			<td style="width:180px;">SYLGARD 184</td>
			<td>Silicone for dissection plates preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Dissection pins</td>
			<td style="width:288px;">Amazon</td>
			<td>B00J5PMPJA</td>
			<td>Pins for larvae positioning</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Tweezers</td>
			<td style="width:288px;">WPIINC</td>
			<td>500342</td>
			<td>Tweezers for placing pins, removing the guts and tracheas.&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Scissors</td>
			<td style="width:288px;">WPIINC</td>
			<td>501778</td>
			<td>Scissors for cutting the cuticula of the larvae and nerves.</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Olympus BX61WI</td>
			<td style="width:288px;">Olympus</td>
			<td style="width:180px;">BX61WI</td>
			<td>Upright microscope</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Olympus Lumplan FL N 60x</td>
			<td style="width:288px;">Olympus</td>
			<td style="width:180px;">UPLFLN 60X</td>
			<td>Microscope objective 60X</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Olympus UPlan FL N 10x</td>
			<td style="width:288px;">Olympus</td>
			<td style="width:180px;">Uplanfl N 10X</td>
			<td>Microscope objective 10X</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Narishige Micromanipulator</td>
			<td style="width:288px;">Narishige</td>
			<td style="width:180px;">MHW-3</td>
			<td>Three-axis Water Hydraulic Micromanipulator</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">npi Electronic GmbH ELC-03XS</td>
			<td style="width:288px;">npi Electronic GmbH</td>
			<td style="width:180px;">ELC-03XS</td>
			<td>Electrophysiological amplifier</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">A.M.P.I Master 8</td>
			<td style="width:288px;">A.M.P.I.</td>
			<td style="width:180px;">Master 8</td>
			<td>Electrical stimulator</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">A.M.P.I Iso-Flex</td>
			<td style="width:288px;">A.M.P.I.</td>
			<td style="width:180px;">Iso-Flex</td>
			<td>Stimulus isolator</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">TMC antivibration table</td>
			<td style="width:288px;">TMC</td>
			<td style="width:180px;">63-9090</td>
			<td>Antivibration table</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">TMC Faraday cage</td>
			<td style="width:288px;">TMC</td>
			<td style="width:180px;">81-333-90</td>
			<td>Faraday cage</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Digidata 1322A</td>
			<td style="width:288px;">Axon Instruments</td>
			<td style="width:180px;">Digidata 1322A</td>
			<td>Digidata</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Computer</td>
			<td style="width:288px;">Dell</td>
			<td style="width:180px;">Dell Dimension 5150</td>
			<td>Computer with Win XP OS&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Electrode holder</td>
			<td style="width:288px;">WPI</td>
			<td>MEH3SW&#160;</td>
			<td style="width:495px;">Electrode holder</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Optical filter</td>
			<td style="width:288px;">Omega optical</td>
			<td style="width:180px;">XF 115-2</td>
			<td style="width:495px;">Filter cube for Green Fluorescent Protein (GFP) detection&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">pCLAMP 8</td>
			<td style="width:288px;">Axon Instruments</td>
			<td style="width:180px;">8.0.0.81</td>
			<td>Software for signal recording</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Quantan</td>
			<td style="width:288px;">In-house software</td>
			<td style="width:180px;">-</td>
			<td>Software for signal processing</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">Canton-S (Wildtype)</td>
			<td style="width:288px;">Bloomington Stock Center</td>
			<td>64349</td>
			<td>Control fly line</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">cpx SH1</td>
			<td style="width:288px;">Generous Gift of J.T. Littleton</td>
			<td style="width:180px;">-</td>
			<td>Complexin knock-out fly line with increased spontaneous exocytosis</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:288px;height:21px;">CD8-GFP</td>
			<td style="width:288px;">Bloomington Stock Center</td>
			<td style="width:180px;">5137</td>
			<td>Fly line with neuronal fluorescent (GFP) Tag</td>
		</tr>
	</tbody>
</table>

focal macropatch recordings of synaptic currents from the drosophila larval neuromuscular junction

Drosophila neuromuscular junction (NMJ) is an excellent model system to study glutamatergic synaptic transmission. We describe the technique of focal macropatch recordings of synaptic currents from visualized boutons at the Drosophila larval NMJ. This technique requires customized fabrication of recording micropipettes, as well as a compound microscope equipped with a high magnification, long-distance water immersion objective, differential interference contrast (DIC) optics, and a fluorescent attachment. The recording electrode is positioned on the top of a selected synaptic bouton visualized with DIC optics, epi-fluorescence, or both. The advantage of this technique is that it allows monitoring the synaptic activity of a limited number of sites of release. The recording electrode has&#160;a diameter of several microns, and the release sites positioned outside of the electrode rim do&#160;not significantly affect the recorded currents. The recorded synaptic currents have fast kinetics and can be readily resolved. These advantages are especially important for the studies of mutant fly lines with enhanced spontaneous or asynchronous synaptic activity.

Focal macropatch recordings enable monitoring synaptic activity from selected synaptic boutons (Figure 5). When the electrode is positioned on the top of a synaptic bouton (Figure 5A, site 1), the recorded mEJCs (Figure 5C, site 1) have a amplitudes significantly exceeding the noise level and sharp rising phases (at a sub-millisecond range). When the recording electrode is moved away from the synapti...

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Focal Macropatch Recordings of Synaptic Currents from the Drosophila Larval Neuromuscular Junction

Synaptic currents can be recorded focally from visualized synaptic boutons at the Drosophila third instar larvae neuromuscular junction. This technique enables monitoring the activity of a single synaptic bouton.

Focal Macropatch Recordings of Synaptic Currents from the Drosophila Larval Neuromuscular Junction

Drosophila neuromuscular junction (NMJ) is an excellent model system to study glutamatergic synaptic transmission. We describe the technique of focal ...

The overall goal of this technique is to monitor synaptic activity of visualized synaptic boutons at the drosophila larval neuromuscular junction. An excellent model system readily amendable to genetic manipulations. This technique can address key questions in your science.Such as how mutations of synaptic proteins regulate synaptic transmission. The main advantage of this technique is that the activity of a limited number of release sites can be monitored and recorded currents of fast kinetics and can be easily resolved. To begin the experiment:prepare the microelectrode puller.Use a microscope at 35X magnification to ensure the inner diameter of the pulled electrode is in the range of seven to ten micrometers. Store the capillaries in tightly closed containers to prevent dust accumulation. Next, fire polished capillaries using a micro forge.Ensure the final inner diameter of the polished electrode is five micrometers. Then, move on to bending. Fix the electrode in the manipulator and position the tip over the filament not touching it.Set the heat value to 60-70%of the maximum and press the pedal of the micro forge for one to two seconds to heat the filament. Use an L-shaped needle to gently pull down the tip of the electrode and make the bend at approximately 90 degrees. Hold the electrode over the flame of the torch by hand and make the second bend at seven to ten millimeters from the first bend and at an angle of approximately 120 degrees.Prepare a hemolymph-like, or HL3 solution. Keep the solution in the refigerator and make it fresh every week. Prepare stimulation pipettes the same way as recording glass pipettes without bending them.Next, insert a stimulation pipette in a microelectrode holder connected to a syringe. Manufactured dissection plates from small Petri dishes coated with silicone rubber epoxy. Then, using forceps pick a wandering third instar larvae from a vial.Pin the larvae placing the first pin in the posterior and another pin anterior close to mouth hooks. Add HL3 solution. On the dorsal side of the larvae make a cut using spring scissors from the top pin to the bottom pin.Pin the larvae filet placing two additional pins on the left and right sides of the larvae. Remove the guts and trachea using forceps. Cut the nerves just outside the ventral nerve cord using spring scissors.Place the petri dish with the preparation on the microscope stage. Insert the reference electrode in the bath. Fill the recording electrode with HL3 solution.Under the 10X objective immerse the electrode into the bath and place it over muscles six and seven of the abdominal segements of two, three or four using the micro manipulator. Next, switch the objective to 60X and focus on the area of interest using either epi-florescence or DIC optics. Place the tip of the electrode on top of the synaptic bouton then press the electrode very gently onto the muscle as excessive pressure may damage the NMJ or induce an increase in spontaneous synaptic activity.Next, switch on the amplifier, AD board and the computer. Then, choose the voltage clamp mode on the amplifier. Start the acquisition software and choose the gap-free mode and observe the appearance of MEJCs on the computer screen.Ensure the amplitude of the MEJCs is in the range of 0.2 to 0.7 nanoamperes. Using a micro manipulator under a visual control place the stimulation electrode near the axon innervating abdominal segments two through four. Apply negative pressure by pulling the piston of the syringe connected to the electrode holder so that the axon is pulled inside of the electrode.Next, turn on the stimulator. Turn the knob on the isolation unit to set a zero current and then gently increase it until the EJCs appear or until the threshold is reached. Perform the stimulation in a superthreshold regime.With the stimulation current increase approximately twice compared to the threshold for the observation of EJCs. Measure the seal resistance of the recording macro-patch electrode by turning the electrode resistance switch of the amplifier to seal test position. Observe the value of seal resistance in giga ohms which will be displayed in the current window.Focal macro patch recordings enable monitoring synaptic activity from selected synaptic boutons. When the electrode is positioned on top of a synaptic bouton the recorded MEJCs have amplitudes significantly exceeding the noise level and sharp rising phases at a sub millisecond range. When the recording electrode is moved away from the synaptic bouton by several microns the amplitudes of recorder MEJCs decline almost to the noise level.The recorded EJCs can barely be distinguished from the noise and they have prolonged rising phases. Focal recordings enable accurate detection of MEJCs in the complex and gnome mutant. While the intercellular recordings from this mutant exhibit release events that overlap and can not be reliably detected.Adjustment of the angles of electro chip is critical for positioning of the electrode. Following this procedure other methods like checking imaging of individual release events can be performed in order to answer additional questions like the integration of the activity of individual active zones.

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6.0K visualizações.  Wayne State University. The overall goal of this technique is to monitor synaptic activity of visualized synaptic boutons at the drosophila larval neuromuscular junction. An excellent model system readily amendable to genetic manipulations. This technique can address key questions in your science.Such as how mutations of synaptic proteins regulate synaptic transmission. The main advantage of this technique is that the activity of a limited number of release sites can be monitored and recorded currents of fast...