This work was supported by the Natural Sciences &#38; Engineering Council Discovery Program (US: RGPIN-2016-06694).

All rats are treated according to the guidelines of the Canadian Council on Animal Care. Approval for all the experimental procedures was granted by the Concordia University Animal Research Ethics Committee.
1. Animals
<ol>
	<li>Acquire Long Evans rats weighing 275-300 g (males) or 225-250 g (females). Double house rats in standard plastic cages with corncob bedding and shredded paper until surgery.</li>
	<li>Keep the rats on a reversed light-dark cycle (lights off at 9:30 A...

<ol>
	<li>Jaffe, J. H., Gilman, A. G., Rall, T. W., Nies, A. S., Taylor, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drug+addiction+and+drug+abuse.">Drug addiction and drug abuse.</a> Goodman &amp; Gilman's the Pharmacological Basis of Therapeutics. , 522-573 (1990).</li><li>O'Brien, C. P., McLellan, A. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myths+about+the+treatment+of+addiction.">Myths about the treatment of addiction.</a> Lancet. 347, 237-240 (1996).</li><li>Miczek, K. A., de Wit, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Challenges+for+translational+psychopharmacology+research--some+basic+principles.">Challenges for translational psychopharmacology research--some basic principles.</a> Psychopharmacology (Berl). 199 (3), 291-301 (2008).</li><li>Sinha, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+does+stress+increase+risk+of+drug+abuse+and+relapse.">How does stress increase risk of drug abuse and relapse.</a> Psychopharmacology. 158, 343-359 (2001).</li><li>Cheskin, L. J., Hess, J. M., Henningfield, J., Gorelick, 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=Calorie+restriction+increases+cigarette+use+in+adult+smokers.">Calorie restriction increases cigarette use in adult smokers.</a> Psychopharmacology. 179, 430-436 (2005).</li><li>Krahn, D., Kurth, C., Demitrack, M., Drewnowski, 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+relationship+of+dieting+severity+and+bulimic+behaviors+to+alcohol+and+other+drug+use+in+young+women.">The relationship of dieting severity and bulimic behaviors to alcohol and other drug use in young women.</a> Journal of Substance Abuse. 4, 341-353 (1992).</li><li>Shalev, U., Highfield, D., Yap, J., Shaham, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress+and+relapse+to+drug+seeking+in+rats:+studies+on+the+generality+of+the+effect.">Stress and relapse to drug seeking in rats: studies on the generality of the effect.</a> Psychopharmacology. 150, 337-346 (2000).</li><li>Peck, J. A., Ranaldi, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drug+abstinence:+exploring+animal+models+and+behavioral+treatment+strategies.">Drug abstinence: exploring animal models and behavioral treatment strategies.</a> Psychopharmacology (Berl). 231 (10), 2045-2058 (2014).</li><li>Cooper, A., Barnea-Ygael, N., Levy, D., Shaham, Y., Zangen, 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+conflict+rat+model+of+cue-induced+relapse+to+cocaine+seeking).">A conflict rat model of cue-induced relapse to cocaine seeking).</a> Psychopharmacology (Berl). 194 (1), 117-125 (2007).</li><li>Barnea-Ygael, N., Yadid, G., Yaka, R., Ben-Shahar, O., Zangen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cue-induced+reinstatement+of+cocaine+seeking+in+the+rat+&amp;#34;conflict+model&amp;#34;:+effect+of+prolonged+home-cage+confinement.">Cue-induced reinstatement of cocaine seeking in the rat &amp;#34;conflict model&amp;#34;: effect of prolonged home-cage confinement.</a> Psychopharmacology (Berl). 219 (3), 875-883 (2012).</li><li>Fredriksson, I., Applebey, S. V., Minier-Toribio, A., Shekara, A., Bossert, J. M., Shaham, Y. <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+the+dopamine+stabilizer+(-)-OSU6162+on+potentiated+incubation+of+opioid+craving+after+electric+barrier-induced+voluntary+abstinence.">Effect of the dopamine stabilizer (-)-OSU6162 on potentiated incubation of opioid craving after electric barrier-induced voluntary abstinence.</a> Neuropsychopharmacology. 45 (5), 770-779 (2020).</li><li>Pelloux, Y., Everitt, B. J., Dickinson, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Compulsive+drug+seeking+by+rats+under+punishment:+effects+of+drug+taking+history.">Compulsive drug seeking by rats under punishment: effects of drug taking history.</a> Psychopharmacology (Berl). 194 (1), 127-137 (2007).</li><li>Marchant, N. J., Campbell, E. J., Kaganovsky, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Punishment+of+alcohol-reinforced+responding+in+alcohol+preferring+P+rats+reveals+a+bimodal+population:+Implications+for+models+of+compulsive+drug+seeking.">Punishment of alcohol-reinforced responding in alcohol preferring P rats reveals a bimodal population: Implications for models of compulsive drug seeking.</a> Progress in Neuro-Psychopharmacology &amp; Biological Psychiatry. 87, 68-77 (2018).</li><li>Krasnova, I. N., 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=Incubation+of+methamphetamine+and+palatable+food+craving+after+punishment-induced+abstinence.">Incubation of methamphetamine and palatable food craving after punishment-induced abstinence.</a> Neuropsychopharmacology. 39 (8), 2008-2016 (2014).</li><li>Panlilio, L. V., Thorndike, E. B., Schindler, C. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reinstatement+of+punishment-suppressed+opioid+self-administration+in+rats:+an+alternative+model+of+relapse+to+drug+abuse.">Reinstatement of punishment-suppressed opioid self-administration in rats: an alternative model of relapse to drug abuse.</a> Psychopharmacology (Berl). 168 (1-2), 229-235 (2003).</li><li>Economidou, D., Pelloux, Y., Robbins, T. W., Dalley, J. W., Everitt, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+impulsivity+predicts+relapse+to+cocaine-seeking+after+punishment-induced+abstinence.">High impulsivity predicts relapse to cocaine-seeking after punishment-induced abstinence.</a> Biological Psychiatry. 65 (10), 851-856 (2009).</li><li>Sedki, F., D'Cunha, T., Shalev, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+procedure+to+study+the+effect+of+prolonged+food+restriction+on+heroin+seeking+in+abstinent+rats.">A procedure to study the effect of prolonged food restriction on heroin seeking in abstinent rats.</a> Journal of Visualized Experiments: JoVE. (81), e50751 (2013).</li><li>Venniro, M., Caprioli, D., Shaham, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+drug+relapse+and+craving:+From+drug+priming-induced+reinstatement+to+incubation+of+craving+after+voluntary+abstinence.">Animal models of drug relapse and craving: From drug priming-induced reinstatement to incubation of craving after voluntary abstinence.</a> Progress in Brain Research. 224, 25-52 (2016).</li><li>Deroche-Gamonet, V., Piazza, P. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Psychobiology+of+cocaine+addiction:+Contribution+of+a+multi-symptomatic+animal+model+of+loss+of+control.">Psychobiology of cocaine addiction: Contribution of a multi-symptomatic animal model of loss of control.</a> Neuropharmacology. 76, 437-449 (2014).</li><li>Pelloux, Y., Everitt, B. J., Dickinson, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Compulsive+drug+seeking+by+rats+under+punishment:+effects+of+drug+taking+history.">Compulsive drug seeking by rats under punishment: effects of drug taking history.</a> Psychopharmacology (Berl). 194 (1), 127-137 (2007).</li><li>Epstein, D. H., Kowalczyk, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Compulsive+seekers:+Our+take.+Two+clinicians'+perspective+on+a+new+animal+model+of+addiction.">Compulsive seekers: Our take. Two clinicians' perspective on a new animal model of addiction.</a> Neuropsychopharmacology. 43 (4), 677-679 (2018).</li><li>Hser, Y. I., Hoffman, V., Grella, C. E., Anglin, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+33-year+follow-up+of+narcotics+addicts.">A 33-year follow-up of narcotics addicts.</a> Archives of General Psychiatry. 58 (5), 503-508 (2001).</li><li>Chen, B. T., 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=Rescuing+cocaine-induced+prefrontal+cortex+hypoactivity+prevents+compulsive+cocaine+seeking.">Rescuing cocaine-induced prefrontal cortex hypoactivity prevents compulsive cocaine seeking.</a> Nature. 496 (7445), 359-362 (2013).</li></ol>

There are two important demonstrations in this paper. First, the validation of the punishment-imposed abstinence using the seek and take chain with heroin. Second, it was demonstrated that stress-induced relapse could be observed in a punishment-imposed abstinence procedure. These are important demonstrations because (i) The punishment-induced abstinence procedure more closely mimics the human condition as it results in voluntary abstinence, i.e., not due to extinction of drug-seeking or forced removal from the drug-taki...

Relapse is the most challenging problem in the treatment of drug use1,2. However, only a handful of pharmacological treatments are approved to help avoid relapse in humans3. The opioid epidemic that North America is currently facing is a striking example of it, and it demands considering different approaches on animal models of relapse to opioids.
Acute stress has been shown to be a key trigger to relapse in humans4. One environmental stressor that is often associated with drug addiction is food deprivation. Drug users often choose to allocate resources towards obtaining drugs instead of food. Caloric deficit has been shown to be correlated with higher relapse to cigarettes5 and alcohol6 use. Due to ethical and practical issues, animal models have been developed over the last decades to facilitate research in the field. In animal models, acute food deprivation has been demonstrated to robustly reinstate extinguished heroin seeking7. Currently, most animal models of relapse are based on abstinence procedures that are either not representative of human abstinence (e.g., extinction-based models) or encompass only the small percentage of drug users that are forced to abstain due to incarceration or inpatient treatment (e.g., forced abstinence models). The main reason drug users choose to abstain is the negative consequences associated with drug-seeking and taking8. Punishment-imposed abstinence is an animal model that mimics the negative consequences associated with drug-seeking on self-imposed abstinence in humans. This model introduces an aversive stimulus, e.g., a mild footshock, with drug-seeking or taking, which leads the animal to stop taking the drug voluntarily. Another procedure that incorporates negative consequences for drug-seeking is the electrical barrier conflict model for drug abstinence and relapse9. The rat must cross an electrical barrier to perform the operant behavior linked with drug self-administration. The model was used successfully to demonstrate voluntary abstinence and relapse to psychostimulant and opioid drugs10,11. However, under the electrical barrier procedure, drug-seeking efforts are always associated with an aversive event, unlike the human condition. Moreover, drug-taking itself might overlap with the electrical footshock as the animal returns to the safe area following the infusion by crossing the barrier again.
Punishment-imposed abstinence has been used with other drugs of abuse such as cocaine12, alcohol13, methamphetamine14, remifentanil15, but it was never applied to heroin-trained animals. The model has been used to study relapse induced by priming14 and drug-associated cues16, but it was not integrated into a stress-induced relapse procedure. The procedure described here is used to demonstrate acute food deprivation-induced relapse to heroin seeking after punishment-imposed abstinence in male rats.

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			<td>Anafen Injection 100 mg/mL Vial/50 mL</td>
			<td>MERIAL Canada, Inc.</td>
			<td>1938126</td>
			<td>anti-inflammatory drug</td>
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			<td>Balance arm</td>
			<td>Coulbourn Instruments</td>
			<td>H29-01</td>
			<td></td>
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			<td>Cannulae (22 G, 5-up)</td>
			<td>Plastics One</td>
			<td>C313G-5up</td>
			<td></td>
		</tr>
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			<td>Environment connection board &#38; Linc cable</td>
			<td>Coulbourn Instruments</td>
			<td>H03-04</td>
			<td></td>
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			<td>Fixed speed infusion pump (3.3 RPM)</td>
			<td>Coulbourn Instruments</td>
			<td>A73-01-3.3</td>
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			<td>GE Marine Silicon</td>
			<td>GE</td>
			<td>SE-1134</td>
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			<td>Graphic State Notation 3</td>
			<td>Coulbourn Instruments</td>
			<td>GS3</td>
			<td>Software</td>
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			<td>Habitest universal Linc</td>
			<td>Coulbourn Instruments</td>
			<td>H02-08</td>
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			<td>Heroin HCl</td>
			<td>National Institute for Drug Abuse, Research Triangle Park, NC, USA</td>
			<td></td>
			<td></td>
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			<td>House light-Rat</td>
			<td>Coulbourn Instruments</td>
			<td>H11-01R</td>
			<td></td>
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			<td>Isofluorane USP 99.9% Vial/250 mL</td>
			<td>Fresenius Kabi Canada Ltd</td>
			<td>2237518</td>
			<td></td>
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			<td>Liquid Swivels, Plastic, 22 G</td>
			<td>Lomir Biomedical, Inc.</td>
			<td>RSP1</td>
			<td></td>
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			<td>Rat test cage</td>
			<td>Coulbourn Instruments</td>
			<td>H10-11R-TC</td>
			<td>Operant conditioning chambers</td>
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			<td>Retractable lever-Rat</td>
			<td>Coulbourn Instruments</td>
			<td>H23-17RA</td>
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			<td>Silastic tubing (ID 0.02, OD 0.037)</td>
			<td>Fisher Scientific (Canada)</td>
			<td>1118915A</td>
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			<td>Single high-bright cue-Rat</td>
			<td>Coulbourn Instruments</td>
			<td>H11-03R</td>
			<td></td>
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			<td>Sound attenuation boxes</td>
			<td>Concordia University</td>
			<td>Home made</td>
			<td></td>
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			<td>Stainless steal grid floor</td>
			<td>Coulbourn Instruments</td>
			<td>H10-11R-TC-SF</td>
			<td></td>
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			<td>System controller 2</td>
			<td>Coulbourn Instruments</td>
			<td>SYS CTRL 2</td>
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			<td>System power base</td>
			<td>Coulbourn Instruments</td>
			<td>H01-01</td>
			<td></td>
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			<td>Tone module 2.9 KHz</td>
			<td>Coulbourn Instruments</td>
			<td>H12-02R-2.9</td>
			<td></td>
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			<td>Tygon tubing (ID 0.02, OD 0.060)</td>
			<td>VWR</td>
			<td>63018-044</td>
			<td></td>
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a procedure to study stress-induced relapse of heroin seeking after punishment-imposed abstinence

The punishment-imposed abstinence procedure models the self-imposed abstinence that humans initiate due to the adverse consequences associated with drug-taking. This model has been implemented in experiments using different types of substances of abuse such as methamphetamine, cocaine, and alcohol. However, punishment-induced abstinence in heroin-trained animals has not been demonstrated. Furthermore, acute stress is a key trigger for relapse in humans and animal models. It was previously demonstrated that acute food deprivation robustly induced reinstatement of extinguished cocaine and heroin seeking. The procedure described here can be used to assess the effects of acute stress exposure on heroin seeking after punishment-imposed abstinence. A total of 8 rats were implanted with chronic intravenous (i.v.) catheters and trained to self-administer heroin (0.1 mg/kg/infusion) for 18 days under a seek-take chained schedule. Completing the seek link gave access to the take lever, which was paired with a heroin infusion. The seek lever was programmed with a variable interval 60 schedule of reinforcement (VI60), and the take lever was programmed with a fixed-ratio 1 reinforcement schedule (FR1). Following self-administration training, a mild foot shock was delivered on 30% of the completed seek links instead of the extension of the take lever. Footshock intensity was increased by 0.1 mA per daily session from 0.2 mA to 1.0 mA. Heroin-seeking tests were performed after 24 h of food deprivation (FD) or sated conditions. Rats under acute food deprivation condition robustly increased heroin seeking after punishment-imposed abstinence.

Male rats demonstrated an increase in seek lever presses as the schedule of reinforcement increased over the training days, and a reliable, consistent number of heroin infusions over training days (Figure 1). During punishment, rats decreased the number of seek lever presses and infusions with the increase of footshock intensity over 8 punishment days (Figure 2). Food-deprivation condition significantly increased heroin seeking after punishment-imposed abstinenc...

Watch this Scientific Journal Video about A Procedure to Study Stress-Induced Relapse of Heroin Seeking after Punishment-Imposed Abstinence at JoVE.com

A Procedure to Study Stress-Induced Relapse of Heroin Seeking after Punishment-Imposed Abstinence

A procedure that demonstrates a robust acute food deprivation-induced relapse to heroin seeking after punishment-imposed abstinence is described. A punishment-imposed abstinence model was successfully implemented using the seek and take chain schedule for heroin self-administration. Heroin-seeking tests are then performed following 24 h of food-deprivation stress.

The punishment-imposed abstinence procedure models the self-imposed abstinence that humans initiate due to the adverse consequences associated with ...

It is the first time that stress-induced relapse to heroin is shown after punishment-imposed abstinence. These methods could help us understand the neuronal mechanism underlying stress-induced relapse in humans after voluntary abstinence. By using food deprivation and punishment imposed abstinence, we are more closely mimicking the human condition and bringing ecological validity to animal models of relapse.Begin by setting the operant conditioning chambers as described in the manuscript. After recovery from the surgery, habituate the rat in the operant training chamber for 24 hours before initiating the protocol without attaching the rat to the metal spring. Place the rat housed in the operant chambers throughout the experiment.Next, attach the 5up connector to the Tygon tube and the metal spring. Start the training session on the onset of the dark phase of the reversed light cycle. For self-administration of heroin, the take lever should be available under fixed ratio one, or FR one.Program each trial to begin with the insertion of the take lever and turning the house light on. Once the rat presses the take lever one time, retract the take lever, turn on the cue light above the lever, and tone for a 20-second timeout period. Turn off the house light, and allow the delivery of 0.13 milliliters of heroin infusion at a dose of 0.1 milligram per kilogram.Then program a 30-seconds intertrial interval in which no cues are presented, the house light is turned off, and the lever is retracted. For the next trial, insert the take lever, and turn on the house light. For the self-administration with the seek take chain under FR one, program the operant training system to insert only the seek lever and turn on the house light to signal the beginning of the session with the take lever in a retracted state.Once the rat presses one time on the seek lever, the program retracts the seek lever and inserts the take lever. One press on the take lever retracts the take lever and initiates the procedure of turning on the cue light, and a 30-seconds intertrial interval, as demonstrated earlier. After the intertrial interval, program the operant training system to insert the seek lever and turn on the house light to signal the beginning of the next trial.Next, program all steps for self-administration with a seek take chain under fixed ratio one, as demonstrated earlier with introducing a variable interval of five for three days as the new schedule of reinforcement on the seek lever. Set up the software to allow the first press on the seek lever to activate variable interval five schedules. Allow the software to randomly select an interval time from a list of 0.1, five, and 10 seconds, resulting in an average of five seconds interval.After the selected interval has elapsed, the first seek lever press retracts the seek lever and extends the take lever. After following the steps for the take lever, and as the trial ends, train the rat for five days under variable interval 30 schedule for the seek link. To do so, allow the software to randomly select a time from a list of 15, 30, and 45 seconds for an average of 30 seconds.Then, train rats for three days under variable interval 60 schedules, allowing the software to randomly select a time from a list of 45, 60, and 75 seconds. For punishment-imposed abstinence, conduct punishment sessions for eight days with regular supervision to guarantee that rats do not show signs of abnormal pain or any health issues. Start punishment sessions with insertion of seek lever and turning the house light on.Program the operant training system so that after completing the seek link under variable interval 60, the seek lever retracts, the house light is turned off, and a mild foot shock is administered to the rat on 30%of the completed seek links instead of insertion of the take lever. The take lever extends on the other 70%of completed seek links as in regular self-administration trial. After programming an intertrial interval of seven minutes, set the foot shock intensity at 0.2 milliamperes, and increase by 0.1 milliamperes per punishment day until 1.0 milliamperes.Once the rat presses the take lever, repeat the fixed ratio one step for retraction of the lever, delivery of heroin infusion, and presentation of the cues followed by seven minutes intertrial interval. After the last day of the punishment-imposed abstinence, remove food hoppers from the chambers for rats that undergo food deprivation-induced relapse test, and keep food hoppers for the sated group. Provide unlimited water access in both the groups and supervise the animals'health.After 24 hours of food deprivation, proceed for a three-hour food deprivation-induced heroin-seeking test under a variable interval 60 schedule with an intertrial interval of seven minutes with no shock or heroin infusions being delivered. Following the session, return food hoppers to the food deprived rats. The next day, remove food hoppers from the chambers of the rats that were sated on the first relapse test.Allow the previously food-deprived rats unlimited access to food before and during the test. After 24-hour food deprivation, perform three-hour heroin-seeking test, as demonstrated previously. In the study, male rats demonstrated an increase in seek lever presses as the schedule of reinforcement increased.A reliable, consistent number of heroin infusions was observed over the training days. During the punishment, rats decreased the number of seek lever presses and infusions with the increase of foot shock intensity over eight punishment days. In the heroin-seeking test, the food deprivation condition significantly increased heroin-seeking after punishment-imposed abstinence, and no statistically significant effect was observed for time nor for drug seeking over time across feeding conditions It is important to take the time to train the animals to learn in the basic seek and take chain under FR one.Without this step, animals will not be able to move forward in the experiments. After implementing the model, we can now design experiments that look at the neurobiology of stress-induced relapse after voluntary abstinence.

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2.4K vistas.  Concordia University. Es la primera vez que se muestra una recaída inducida por el estrés a la heroína después de la abstinencia impuesta por el castigo. Estos métodos podrían ayudarnos a comprender el mecanismo neuronal subyacente a la recaída inducida por el estrés en humanos después de la abstinencia voluntaria. Al utilizar la privación de alimentos y la abstinencia impuesta por el castigo, estamos imitando más de cerca la condición humana y aportando validez ecológica a los modelos animales de rec...