title: Effect of isradipine, a dihydropyridine-calcium antagonist on i.v. self-administration of morphine in rats.
abstract: The effect of dihydropyridine calcium channel antagonist isradipine (PN 200-110) on morphine reinforcement has been investigated using i.v. self-administration test in rats. Rats were given the opportunity to self-administer a solution of morphine (1 mg/ml, i.v.) in a 1 hr limited access paradigm (FR = 1). Within 5-7 days rats had learned to self-administer approximately 1 mg of morphine in 1 hr as evidenced by a plateau of responding. The administration of isradipine (1.2, 2.5 and 5.0 mg/kg s.c.) 90 min before the morphine self-administration session, induced dose-dependent increase in the number of morphine self-infusions with respect to basal values. This response pattern was very similar to the one observed when morphine solution was substituted by saline in trained rats not treated with isradipine. The results indicate that isradipine inhibits partially the reinforcing properties of morphine in self-administration test.
authors.affiliation: St.-Petersburg Pavlov Medical University, Russia.
authors.forename: A
authors.initials: A
authors.lastname: Kuzmin
authors.forename: M C
authors.initials: MC
authors.lastname: Martellotta
authors.forename: W
authors.initials: W
authors.lastname: Fratta
authors.forename: G L
authors.initials: GL
authors.lastname: Gessa
authors.forename: E
authors.initials: E
authors.lastname: Zvartau
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D007275:Injections, Intravenous; D017275:Isradipine / Q000494:pharmacology*; D008297:Male; D009020:Morphine / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012646:Self Administration
chemical_list: D002121:Calcium Channel Blockers; D009020:Morphine; D017275:Isradipine