title: Effects of nicardipine, felodipine and nifedipine on passive avoidance behavior of intact and hypoxia-exposed rats.
abstract: The effects of various doses (0.03, 0.1, 0.3 or 1 mg/kg) of the calcium channel blockers nicardipine, felodipine and nifedipine on the learning ability in intact rats and on hypoxia-induced retention deficits were examined. All animals were trained in a passive avoidance procedure. The drugs tested had been injected 30 minutes before the learning trial started. Some animals were exposed to a hypoxic condition immediately after the learning trial response had been acquired. A passive avoidance retention test was performed 24 hours later. It was found that hypoxia strongly impaired the retention of the passive avoidance response. Nicardipine, felodipine and nifedipine did not influence the passive avoidance behavior in the intact animals, but significantly improved the retention deficits in the animals exposed to hypoxia. The effects of the substances tested were dose-dependent. These findings support the hypothesis that perturbations in calcium homeostasis can contribute to the memory deficits associated with hypoxic conditions.
authors.affiliation: Department of Pharmacology, School of Medicine, University of Rijeka, Croatia.
authors.forename: G
authors.initials: G
authors.lastname: Zupan
authors.forename: J
authors.initials: J
authors.lastname: Mrsić
authors.forename: A
authors.initials: A
authors.lastname: Simonić
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D001921:Brain / Q000187:drug effects; D002118:Calcium / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004558:Electric Stimulation; D015736:Felodipine / Q000494:pharmacology; D005260:Female; D002534:Hypoxia, Brain / Q000503:physiopathology*; D009529:Nicardipine / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002121:Calcium Channel Blockers; D009529:Nicardipine; D009543:Nifedipine; D015736:Felodipine; D002118:Calcium