Effect of rivastigmine on scopolamine-induced memory impairment in rats.
The effect of rivastigmine on memory impairments induced in rats by scopolamine (0.5 mg/kg) was assessed in the Morris water maze and passive avoidance tests and compared with that of tacrine (2.5-17.7 mg/kg). Rivastigmine, (0.5-2.5 mg/kg) inhibited cholinesterase in the cortex and hippocampus by 21-60% and antagonised the deficits in working and reference memory. Tacrine (12.5 and 17.7 mg/kg) produced significantly less inhibition of cholinesterase in the hippocampus but more in the striatum than rivastigmine (0.75 and 1.5 mg/kg) and only antagonised the deficit in reference memory. Rivastigmine (1.5 and 2.5 mg/kg) or tacrine (12.5 mg/kg), injected immediately after completion of the acquisition trial in the passive avoidance test, antagonised the deficit induced by scopolamine (1 mg/kg) in memory retention. The inability of higher doses of the cholinesterase inhibitors to antagonise memory deficits induced by scopolamine may be related to excessive cholinergic stimulation in the central nervous system.
Bejar
C
C
Department of Pharmacology, Hebrew University, Hadassah Medical Centre, Ein Kerem, Jerusalem, Israel.
Wang
R H
RH
Weinstock
M
M
D000818:Animals; D002219:Carbamates / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D004359:Drug Therapy, Combination; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D008568:Memory / Q000187:drug effects*; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D048448:Phenylcarbamates; D051381:Rats; D017207:Rats, Sprague-Dawley; D000068836:Rivastigmine; D012601:Scopolamine / Q000494:pharmacology*; D013619:Tacrine / Q000494:pharmacology
D002219:Carbamates; D002800:Cholinesterase Inhibitors; D018727:Muscarinic Antagonists; D048448:Phenylcarbamates; D013619:Tacrine; D012601:Scopolamine; D000068836:Rivastigmine