This work was supported by DGAPA-UNAM IN224616-RN224616 grant. The authors want to thank Mrs. Josefina Bolado, Head of the Scientific Paper Translation Department, from Divisi&#243;n de Investigaci&#243;n at Facultad de Medicina, UNAM, for editing the English-language version of this manuscript.

NOTE: The experiments comply with the Laws of Animal Protection of Mexico.
1. Experimental Setup
<ol>
	<li>General connections
	<ol>
		<li>Connect the amplifier to a suitable computer through an analog-to-digital converter and use an oscilloscope to monitor the experiment (Figure 1).</li>
		<li>Connect the photostimulator to the A/D converted.</li>
	</ol>
	</li>
	<li>Recording chamber
	<ol>
		<li>Place the recording chamber on top of an anti-vibration table and ...

<ol>
	<li>Barriga-Montoya, C., G&#243;mez-Lagunas, F., Fuentes-Pardo, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+pigment+dispersing+hormone+on+the+electrical+activity+of+crayfish+visual+photoreceptors+during+the+24-h+cycle.">Effect of pigment dispersing hormone on the electrical activity of crayfish visual photoreceptors during the 24-h cycle.</a> Comp. Biochem. Physiol. A Comp. Physiol. 157 (4), 338-345 (2010).</li><li>Barriga-Montoya, C., de la O-Mart&#237;nez, A., Fuentes-Pardo, B., G&#243;mez-Lagunas, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Desensitization+and+recovery+of+crayfish+photoreceptors.+Dependency+on+circadian+time,+and+pigment-dispersing+hormone.">Desensitization and recovery of crayfish photoreceptors. Dependency on circadian time, and pigment-dispersing hormone.</a> Comp. Biochem. Physiol. A Comp. Physiol. 203, 297-303 (2017).</li><li>Wickenden, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overview+of+electrophysiological+techniques.">Overview of electrophysiological techniques.</a> Curr. protoc. pharmacol. 11, 1-17 (2014).</li><li>Brette, R., Destexhe, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intracellular+recording.">Intracellular recording.</a> Handbook of Neural Activity Measurement. , 44-91 (2012).</li><li>Cummins, D., Goldsmith, T. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+identification+of+the+violet+receptor+in+the+crayfish+eye.">Cellular identification of the violet receptor in the crayfish eye.</a> J. Comp. Physiol. 142 (2), 199-202 (1981).</li><li>Eguchi, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rhabdom+structure+and+receptor+potentials+in+single+crayfish+retinular+cells.">Rhabdom structure and receptor potentials in single crayfish retinular cells.</a> J. Cell and Comp. Physiol. 66, 411-430 (1965).</li><li>Nosaki, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophysiological+study+of+color+encoding+in+the+compound+eye+of+crayfish,+Procambarus+clarkii.">Electrophysiological study of color encoding in the compound eye of crayfish, Procambarus clarkii.</a> Z. vergl. Physiologie. 64 (3), 318-323 (1969).</li><li>Miller, C. S., Glantz, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visual+adaptation+modulates+a+potassium+conductance+in+retinular+cells+of+the+crayfish.">Visual adaptation modulates a potassium conductance in retinular cells of the crayfish.</a> Vis Neurosci. 17 (3), 353-368 (2000).</li><li>Hamill, O. P., Marty, A., Neher, E., Sakmann, B., Sigworth, F. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+patch-clamp+techniques+for+high-resolution+current+recording+from+cells+and+cell-free+membrane+patches.">Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches.</a> Pflugers Arch. 391 (2), 85-100 (1981).</li><li>Lishko, P., Clapham, D. E., Navarro, B., Kirichok, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sperm+patch-clamp.">Sperm patch-clamp.</a> Methods Enzymol. 525, 59-79 (2013).</li><li>Finkel, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Axoclamp-2A+microelectrode+clamp+theory+and+operation.">Axoclamp-2A microelectrode clamp theory and operation.</a> Axon Instruments, Inc. , (1990).</li><li>Sakmann, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Single-channel recording. , (2013).</li><li>Van Harreveld, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+physiological+solution+for+freshwater+crustacea.">A physiological solution for freshwater crustacea.</a> Proc. Soc. Exp. Biol. Med. 34 (4), 428-432 (1936).</li><li>Oesterle, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> pipette cookbook. , 97 (2008).</li><li>Fuentes-Pardo, B., Ramos-Carvajal, 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+phase+response+curve+of+electroretinographic+circadian+rhythm+of+crayfish.">The phase response curve of electroretinographic circadian rhythm of crayfish.</a> Comp. Biochem. Physiol. A Comp. Physiol. 74 (3), 711-714 (1983).</li><li>Pace-Schott, E. F., Hobson, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+neurobiology+of+sleep:+genetics,+cellular+physiology+and+subcortical+networks.">The neurobiology of sleep: genetics, cellular physiology and subcortical networks.</a> Nat. Rev. Neurosci. 3 (8), 591-605 (2002).</li><li>Pittendrigh, C. S., Aschoff, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+mechanism+of+the+entrainment+of+a+circadian+rhythm+by+light+cycles.">On the mechanism of the entrainment of a circadian rhythm by light cycles.</a> Circadian Clocks. , 277-297 (1965).</li><li>Pittendrigh, C. S., Aschoff, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circadian+systems:+entrainment.">Circadian systems: entrainment.</a> Handbook Behavioral Neurobiology Biological Rhythms. , 94-124 (1981).</li><li>Vitaterna, M. H., Takahashi, J. S., Turek, F. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overview+of+circadian+rhythms.">Overview of circadian rhythms.</a> Alcohol Res. Health. 25 (2), 85-93 (2001).</li><li>Hille, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Ion channels of excitable membranes. 507, (2001).</li><li>Dircksen, H., Strauss, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circadian+clocks+in+crustaceans:+identified+neuronal+and+cellular+systems.">Circadian clocks in crustaceans: identified neuronal and cellular systems.</a> Front Biosci. 15, 1040-1074 (2010).</li><li>Terakita, A., Hariyama, T., Tsukahara, Y., Katsukura, Y., Tashiro, H. <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+GTP-binding+protein+Gq+with+photoactivated+rhodopsin+in+the+photoreceptor+membranes+of+crayfish.">Interaction of GTP-binding protein Gq with photoactivated rhodopsin in the photoreceptor membranes of crayfish.</a> FEBS Lett. 330, 197-200 (1993).</li><li>Terakita, A., Takahama, H., Hariyama, T., Suzuki, T., Tsukahara, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Light+regulated+localization+of+the+beta-subunit+of+Gq-type+G-protein+in+the+crayfish+photoreceptors.">Light regulated localization of the beta-subunit of Gq-type G-protein in the crayfish photoreceptors.</a> J Comp Physiol A. 183 (4), 411-417 (1998).</li><li>Terakita, A., Takahama, H., Tamotsu, S., Suzuki, T., Hariyama, T., Tsukahara, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Light-modulated+subcellular+localization+of+the+alpha-subunit+of+GTP-binding+protein+Gq+in+crayfish+photoreceptors.">Light-modulated subcellular localization of the alpha-subunit of GTP-binding protein Gq in crayfish photoreceptors.</a> Vis Neurosci. 13 (3), 539-547 (1996).</li></ol>

We have nothing to disclose.

The crayfish has proven to be an excellent model due to its ability to survive under non-natural conditions. There is easy access to in vivo and in vitro electrophysiological analyses. In addition, crustaceans are a favorable group for neurobiological research in the field of comparative chronobiology21.
In this paper, the study of desensitization and recovery of the light-activated transduction-current of crayfish photoreceptor cells is shown using th...

In order to be perceived as a visual stimulus, light reaching the eyes must be transduced into an electrical signal. Hence, in all visual organisms, light triggers a transduction ion-current, which in turn produces a change in the membrane potential of photoreceptor cells, the so-called receptor potential. Due to this, the light sensitivity of the eye primarily depends on the state of the light activated conductance, which can be either available to be activated or desensitized.
In crayfish photoreceptors, light triggers a slow, transient, ionic current1. Upon illumination, the transduction current arises after a lag or latency before reaching its maximum; thereafter it decays, as the transduction channels fall into a desensitized state in which they are unresponsive to further light stimulus2. That is, light, in addition to activating the transduction current responsible of vision, also induces a transient decrement of the sensitivity of photoreceptor cells. Desensitization may represent a general protective mechanism against overexposure to an adequate stimulus. The eye&#39;s sensitivity to light is recovered as the transduction conductance recovers from desensitization.
Intracellular recording is a useful technique for measuring electrical activity of excitable cells3,4,5,6,7,8. Although intracellular recording has become less frequent with the advent of the patch-clamp technique9, it is still a convenient approach when cells are either difficult to isolate, or present a geometry that makes the formation of the patch-clamping giga-seals difficult (i.e., seals or tight-contacts between the patch electrode and membranes with electrical resistance of the order of 109ohms). Examples of the latter are sperm cells10 and the photoreceptor cells herein studied. In our experience, Procambarus clarkii photoreceptors are difficult to isolate and keep in primary culture; additionally, they are thin rods that make giga-seal formation difficult to achieve. In intracellular recordings, a sharp electrode is advanced into a cell that is kept in place by the surrounding tissue. The electrode is chopped by the high-speed switching circuitry of the amplifier, so current is sampled between voltage pulses. This mode is known as discontinuous single-electrode voltage clamp (dSEVC mode)11. The high resistance (small opening) of the electrode hinders the diffusional exchange between the cell and the pipette solutions, yielding a minimal disturbance of the intracellular milieu3. A potential drawback of this technique is that electrode insertion may produce a non-selective leak current; therefore, care must be taken to avoid recording from cells where the size of the leak current may interfere with the intended measurements4,12.
Herein, we use isolated crayfish eyestalks to assess desensitization and recovery of the light-activated ion conductance by performing intracellular electrical recordings of photoreceptor cells under voltage clamp conditions.

<table border="0" cellpadding="0" cellspacing="0" style="width:644px;" width="644">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Axoclamp2A&#160;</td>
			<td style="width:129px;">Axon Instruments Inc</td>
			<td style="width:119px;"></td>
			<td style="width:180px;">Amplifier</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Digidata 1200 Interface</td>
			<td style="width:129px;">Axon Instruments Inc</td>
			<td style="width:119px;"></td>
			<td>Digitizer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Oscilloscope TDS430A</td>
			<td style="width:129px;">Tektronix</td>
			<td style="width:119px;"></td>
			<td>Analogic Oscilloscope</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Photostimulator PS33 Plus</td>
			<td style="width:129px;">Grass</td>
			<td style="width:119px;"></td>
			<td>Lamp</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Puller PC-100</td>
			<td style="width:129px;">Narishige</td>
			<td style="width:119px;"></td>
			<td>Micropipette Puller</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Puller P-97</td>
			<td style="width:129px;">Sutter Instruments</td>
			<td style="width:119px;"></td>
			<td>Micropipette Puller</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Glass Capillary Tube Kimax-51</td>
			<td style="width:129px;">Kimble Products</td>
			<td style="width:119px;">34502</td>
			<td>0.8, 1.10, 100 mm</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">HS-2 Headstage</td>
			<td style="width:129px;">Axon Instruments Inc</td>
			<td style="width:119px;"></td>
			<td>Headstage</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Micromanipulator MX-4</td>
			<td>Narishige</td>
			<td style="width:119px;"></td>
			<td>Mechanical Micromanipulator</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Stereoscopic Microscope</td>
			<td>Zeiss</td>
			<td></td>
			<td>Microscope</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">pClamp</td>
			<td>Axon Instruments Inc</td>
			<td></td>
			<td style="width:180px;">Data acquisition software for digidata 1200 interface</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Clampfit</td>
			<td>Axon Instruments Inc</td>
			<td></td>
			<td style="width:180px;">Analysis software linked to pClamp</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Origin</td>
			<td>OriginLab Corp.</td>
			<td></td>
			<td style="width:180px;">Data analysis and graphing software</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sodium Chloride</td>
			<td style="width:129px;">Sigma</td>
			<td style="width:119px;">S7653</td>
			<td>&#62;99.5%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Potassium Chloride</td>
			<td style="width:129px;">Sigma</td>
			<td style="width:119px;">P-9333</td>
			<td>Minimum 99%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Magnesium Sulfate</td>
			<td style="width:129px;">Sigma</td>
			<td style="width:119px;">M7506</td>
			<td>Minimum 99.5%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Calcium Chloride</td>
			<td style="width:129px;">Sigma</td>
			<td style="width:119px;">C5080</td>
			<td>Minimum 99.0%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Hepes</td>
			<td style="width:129px;">Sigma</td>
			<td style="width:119px;">H7523</td>
			<td>&#62;99.5%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium Hydroxide</td>
			<td style="width:129px;">Sigma</td>
			<td style="width:119px;">S8045</td>
			<td>98.00%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sodium hypochlorite solution</td>
			<td style="width:129px;">Sigma</td>
			<td style="width:119px;">425044</td>
			<td style="width:180px;">Available chlorine, 10-15%&#160;</td>
		</tr>
	</tbody>
</table>

desensitization and recovery of crayfish photoreceptors upon delivery of a light stimulus

A method to study desensitization and recovery of crayfish photoreceptors is presented. We performed intracellular electrical recordings of photoreceptor cells in isolated eyestalks using the discontinuous single electrode-switched voltage-clamp configuration. First, with a razor blade we made an opening in the dorsal cornea to get access to the retina. Thereafter, we inserted a glass electrode through the opening, and penetrated a cell as reported by the recording of a negative potential. Membrane potential was clamped at the photoreceptor's resting potential and a light-pulse was applied to activate currents. Finally, the two light-flash protocol was employed to measure current desensitization and recovery. The first light-flash triggers, after a lag period, the transduction ionic current, which after reaching a peak amplitude decays towards a desensitized state; the second flash, applied at varying time intervals, assesses the state of the light-activated conductance. To characterize the light-elicited current, three parameters were measured: 1) latency (the time elapsed between light flash delivery and the moment in which current achieves 10% of its maximum value); 2) peak current; and 3) desensitization time constant (exponential time constant of the current decay phase). All parameters are affected by the first pulse.
To quantify recovery from desensitization, the ratio p2/p1 was employed versus time between pulses. p1 is the peak current evoked by the first light-pulse, and p2 is the peak current evoked by the second pulse. These data were fitted to a sum of exponential functions. Finally, these measurements were carried out as function of circadian time.

First, a representative receptor potential of crayfish photoreceptor cells is obtained (Figure 4). Afterwards, a test light-flash was applied to trigger the light transduction current (Figure 5). The cationic transduction current1 activates after a lag, reaching a maximal and thereafter slowly drops into an absorbing desensitized state from which it slowly recovers.
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Watch this Scientific Journal Video about Desensitization and Recovery of Crayfish Photoreceptors Upon Delivery of a Light Stimulus at JoVE.com

Desensitization and Recovery of Crayfish Photoreceptors Upon Delivery of a Light Stimulus

A protocol for the study of desensitization and sensitivity recovery of crayfish photoreceptors as a function of circadian time is presented.

A method to study desensitization and recovery of crayfish photoreceptors is presented. We performed intracellular electrical recordings of photoreceptor ...

The overall goal of this procedure is to study desensitization and sensitivity recovery of crayfish photoreceptors as a function of circadian time, using intercellular electrical recordings of photoreceptor cells in isolated eye stocks, employing the discontinuous single electrode switched voltage clamp configuration. This method can help answer key questions in the neurobiology field, such as the circadian time dependency of so many electro-physiological properties of photoreceptors in inactivation and recovery. The main advantage of this technique, is that it allows the measurement of photoreceptors'electrical activity.In spite of the difficulty to isolate cells and without disturbing the intracellular milieu. Demonstrating this procedure will be Doctors Carolina Barriga-Montoya and Araceli de la O-Maritnez, coworkers of our laboratory. To prepare the intracellular electrode, pull the glass capillary tube with a micropipette puller to obtain a thin tip with a small opening.Next, fill the pulled capillary glass with 2.7-molar potassium chloride solution by capillarity and then, fill half of the pipette with a fine injection needle. If necessary, tap the electrode pipette to eliminate air bubbles. After that, place the electrode on its holder.Connect the holder to amplifier head stage with the amplifier. Following that, position the electrode holder head stage with a stable 3-D micromanipulator. Lower the electrode until bath solution covers its tip.Select the bridge mode of the amplifier and measure the electrode resistance. Make sure that the resistance is about 50 megaohms. Null the offset current and compensate capacitive transients using the holding position button in the section voltage clamp of the amplifier and the capacitance neutralization button in the Microelectrode 1 section of the amplifier.To construct the super fusion system, pour the bath solution into a suitable receptacle and connect it to an irrigation tubing set, thus connecting the recording chamber. Use a gravity-driven superfusion system. Regulate the flow rate to 0.5 milliliters per second.Connect the chamber to a suction device. Regulate the solution suction system with a vacuum pump in such a way that the total volume of recording chamber does not vary. To isolate the eye stock of an adult crayfish, detach it from the base with a pair of fine scissors.Make an opening of one square millimeter in the dorsal cornea using a razor blade to access the retina. Next, place the eye stock in the center of the recording chamber with the opening to the retina facing up. Keep the eye stock in darkness for 20 minutes.Place the microelectrode parallel to the eye stocks longitudinal axis in such a way that the microelectrode is centered to access the retina. Use a stereoscopic microscope to place the devices in the correct configuration. Next, monitor the voltage difference between the reference and recording electrodes by selecting the bridge mode of the amplifier.Lower the electrode into the bath and place it right over the retina. Remove the microscope and position the photostimulator lamp parallel to the eye stocks longitudinal axis. Then, slowly lower the microelectrode until a sudden voltage drop is detected.Subsequently, deliver a test light flash to record the photoreceptor's receptor potential. To obtain appropriate recordings of light-elicited currents, it is critical to make a good impairment of a healthy photoreceptor cell. In this procedure, clamp the voltage at the measured resting membrane potential of the cell by selecting holding amplitude in the data acquisition software.Then, select the DSEVC mode of the amplifier. In the mode section of the amplifier, select the SEVC button and switch the lever to the Discont. SEVC position.Set the switching rate to 500 to 1, 000 hertz, as determined by the speed of electrode. After that, deliver a light flash and observe the evoked ion flux. Then, deliver a pair of light pulses and apply the second flash after a desired time interval.Digitize the currents at 10 kilohertz sampling with the data acquisition software and save the data for offline analysis. Shown here is a two-pulse protocol. Light stimuli were applied at zero milliseconds and 700 milliseconds.This figure shows the recovery from desensitization. Here is latency recovery, here is peak current recovery, and here is the desensitization time constant tau recovery. Experiments were performed at zero hours circadian time.This figure shows the recovery from desensitization as a function of circadian time. This is iP recovery, this is L recovery, and this is tau recovery, and this graph shows the weighted time constants. Biphasic processes are marked with an arrow.Once mastered, this technique can be done in two hours, if it's done properly. While attempting this procedure, it is important to remember to aim for a low noise and low leakage current, photoreceptor impairment. Following this procedure, other methods, like pharmacological assays, can be done in order to answer additional questions, like the involvement of particular channels, receptors, or signaling pathways.After its development, this technique paved the way for researchers in the field of neurobiology to explore the circadian time dependence of electrophysiological properties of photoreceptor cells. After watching this video, you should have a good understanding of how to study desensitization and recovery of light-activated transduction current by using the intracellular recording technique.

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6.5K visualizações.  Universidad Nacional Autónoma de México. O objetivo geral deste procedimento é estudar a dessensibilização e a recuperação da sensibilidade dos fotorreceptores de lagostim em função do tempo circadiano, utilizando gravações elétricas intercelulares de células fotorreceptoras em estoques oculares isolados, empregando a configuração de grampo de tensão de eletrodo único descontínua. Este método pode ajudar a responder a perguntas-chave no campo da neurobiologia, como a dependência do tempo circadiano de tantas propri...