Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/69497
Type: Artigo de periódico
Title: OPIOID NATURE OF LEARNED HELPLESSNESS AND STRESS-INDUCED ANALGESIA OBSERVED WITHOUT REEXPOSURE TO SHOCK
Author: HUNZIKER, MHL
Abstract: It has been shown that uncontrollable shocks that produce learned helplessness also produce long-term opioid analgesia if the animal is re-exposed to shock immediately before the test. The present study was conducted in order to investigate if this effect can be observed 24 h after the uncontrollable shock treatment without re-exposure to shock, and if it is opioid mediated. Long-term analgesia was found in the absence of re-exposure to shock, and was prevented by an i.p. injection of naloxone (10 mg/kg) administered 10 min before the test. The learned helplessness effect produced by the same shock treatment was prevented by the administration of 10 and 20 mg/kg of naloxone 10 min before the shuttle-box test, but not by a lower naloxone dose (5 mg/kg). These findings suggest that the shock re-exposure requirement proposed in previous studies is not crucial in determining the long-term analgesia, and that both the long-term analgesia and the learned helplessness effect produced by this shock treatment were opioid mediated.
Subject: LEARNED HELPLESSNESS
STRESS-INDUCED ANALGESIA
OPIOID ANALGESIA
UNCONTROLLABLE SHOCKS
NALOXONE
RAT
Country: Inglaterra
Editor: Rapid Science Publishers
Rights: fechado
Date Issue: 1992
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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