Effects of 5-HT2 receptor antagonist on cycloheximide-induced amnesia in mice.
A role played by serotonergic neuronal system in cycloheximide (CXM)-induced amnesia was studied in mice using a step-down passive avoidance task. CXM (30 mg/kg SC) given immediately after training caused impairment of memory. Nonselective serotonin (5-HT) antagonist methysergide and selective 5-HT2 antagonist ritanserin significantly attenuated impairment of memory caused by CXM. 5-HT1 antagonist (+/-)-pindolol had no effect on CXM-induced amnesia. The antiamnesic effect of ritanserin on CXM-induced amnesia was antagonized by 5-HT (ICV), but not by nonselective 5-HT agonist 5-methoxy-N,N-dimethyltryptamine and 5-HT1A selective agonist 8-hydroxy-2-(di-n-propylamino)tetralin at the dose level which did not cause the memory disruption. Scopolamine antagonized the antiamnesic effects of methysergide and ritanserin on CXM-induced amnesia. These results suggest that 5-HT2 receptors and cholinergic neuronal system may play an important role in memory formation.
Nabeshima
T
T
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences Meijo University, Nagoya, Japan.
Itoh
K
K
Kawashima
K
K
Kameyama
T
T
D000647:Amnesia / Q000139:chemically induced / Q000378:metabolism*; D000818:Animals; D003513:Cycloheximide / Q000494:pharmacology*; D008297:Male; D008784:Methysergide / Q000494:pharmacology*; D051379:Mice; D010880:Piperidines / Q000494:pharmacology*; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology*; D016713:Ritanserin; D012601:Scopolamine / Q000494:pharmacology*
D010880:Piperidines; D011985:Receptors, Serotonin; D016713:Ritanserin; D003513:Cycloheximide; D012601:Scopolamine; D008784:Methysergide