Different effects of tropisetron and ondansetron in learning and memory paradigms.
The effects of the 5-HT3 receptor antagonists tropisetron (ICS 205-930) and ondansetron on memory and performance impairments induced by scopolamine were tested in a passive avoidance procedure and in the Morris water maze task. Pretreatment with ondansetron (0.01 and 1 microgram/kg i.p.) but not with tropisetron (1, 10, and 30 micrograms/kg i.p.) reversed scopolamine-induced memory deficits in the step-through passive avoidance task. When the effects of these 5-HT3 receptor antagonists on cognition were assessed in the Morris water maze, ondansetron (0.01, 1, and 10 micrograms/kg i.p.) did not antagonize scopolamine-induced spatial navigation deficits. On the contrary, pretreatment with tropisetron (10 and 30 micrograms/kg, and to some extent also with 1 microgram/kg i.p.) counteracted the learning and memory impairment due to scopolamine treatment. The findings suggest that it could be worthwhile to investigate whether or not different subtypes of the 5-HT3 receptor may underlie the different effects on cognition displayed by compounds that belong to the same pharmacological class.
Pitsikas
N
N
Department of Biology, Boehringer Ingelheim Italia, Milano, Italy.
Borsini
F
F
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D007211:Indoles / Q000494:pharmacology*; D007858:Learning / Q000187:drug effects*; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects*; D018727:Muscarinic Antagonists / Q000633:toxicity; D017294:Ondansetron / Q000494:pharmacology*; D051381:Rats; D011985:Receptors, Serotonin / Q000378:metabolism*; D044406:Receptors, Serotonin, 5-HT3; D012601:Scopolamine / Q000633:toxicity; D012702:Serotonin Antagonists / Q000494:pharmacology*; D000077526:Tropisetron
D007211:Indoles; D018727:Muscarinic Antagonists; D011985:Receptors, Serotonin; D044406:Receptors, Serotonin, 5-HT3; D012702:Serotonin Antagonists; D017294:Ondansetron; D000077526:Tropisetron; D012601:Scopolamine