title: Vigabatrin attenuates the development and expression of tolerance to morphine-induced antinociception in mice.
abstract: The efficacy of opioids is limited in chronic pain treatment, as a result of development of opioid tolerance. Based on previous demonstration of the effect of anticonvulsant drugs on morphine antinociception, the present study investigated the effects of vigabatrin (VGB) on the development and expression of morphine tolerance in mice. 101 male NMRI mice weighing 20-25 g were used in these experiments. To evaluate the VGB effects on the development or expression of morphine tolerance, animals received VGB (5, 10 or 20 mg/kg; i.p.), 30 min before morphine (50 mg/kg; s.c.) during induction period once daily for 3 days; or 30 min before challenge dose of morphine (5 mg/kg) before and after morphine-induced tolerance, respectively. The analgesic effect of VGB was evaluated at 30-time intervals (30, 60, 90 and 120 min) by tail-flick analgesiometer. The results showed that VGB at the dose of 20 mg/kg significantly attenuated the development and expression of morphine tolerance. Additionally, VGB alone did not affect the tail-flick latency times. Therefore, while VGB alone has no antinociceptive effect, it can prevent the development of morphine tolerance in mice.
authors.affiliation: Department of Psychology, Faculty of Psychology and Education, University of Tehran, Tehran, Iran.
authors.forename: Behzad
authors.initials: B
authors.lastname: Chavooshi
authors.forename: Mehdi
authors.initials: M
authors.lastname: Saberi
authors.forename: Said
authors.initials: S
authors.lastname: Pournaghash Tehrani
authors.forename: Azam
authors.initials: A
authors.lastname: Bakhtiarian
authors.forename: Abolhassan
authors.initials: A
authors.lastname: Ahmadiani
authors.forename: Abbas
authors.initials: A
authors.lastname: Haghparast
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004361:Drug Tolerance; D007279:Injections, Subcutaneous; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D010146:Pain / Q000523:psychology*; D010147:Pain Measurement / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D020888:Vigabatrin / Q000494:pharmacology*
chemical_list: D000701:Analgesics, Opioid; D000927:Anticonvulsants; D009020:Morphine; D020888:Vigabatrin