Ondansetron, an antagonist of 5-HT3 receptors, antagonizes the anti-exploratory effect of caerulein, an agonist of CCK receptors, in the elevated plus-maze

• Published in: Psychopharmacologia 1993, Vol.110 (1-2), p.213-218
• Main Authors: VASAR, E, PEURANEN, E, ÖÖPIK, T, HARRO, J, MÄNNISTÖ, P. T
• Format: Article
• Language: English
• Subjects: Animals; Anxiety - psychology; Biological and medical sciences; Ceruletide - antagonists & inhibitors; Ceruletide - pharmacology; Dose-Response Relationship, Drug; Exploratory Behavior - drug effects; Female; Medical sciences; Motor Activity - drug effects; Neuropharmacology; Ondansetron - pharmacology; Pharmacology. Drug treatments; Psycholeptics: tranquillizer, neuroleptic; Psychology. Psychoanalysis. Psychiatry; Psychopharmacology; Rats; Receptors, Cholecystokinin - agonists; Serotonin Antagonists - pharmacology
• ISSN: 0033-3158; 1432-2072
• DOI: 10.1007/BF02246976

Systemic treatment with caerulein (0.25-5 micrograms/kg SC), non-selective agonist of cholecystokinin (CCK) receptors, dose-dependently suppressed the exploratory behaviour of rats in an elevated plus-maze without producing remarkable changes in the locomotor activity of animals in an open field test. Ondansetron, a selective antagonist of 5-HT3 receptors, increased the number of open arm entries in the plus-maze test only at a dose 10 micrograms/kg. The other doses of ondansetron (0.1, 1 and 100 micrograms/kg IP) did not significantly change either the locomotor activity or the exploratory behaviour of rats. Pretreatment of rats with ondansetron (at 10 micrograms/kg, but not at 0.1, 1 or 100 micrograms/kg) completely reversed the anti-exploratory effect of caerulein (5 micrograms/kg). The concomitant treatment with caerulein and ondansetron did not cause any major change in the locomotor activity of animals in open field. Consequently, we propose that 5-HT-ergic mechanisms are involved not only in the regulation of CCK release in the cerebral cortex and nucleus accumbens, but also in the modulation of the anti-exploratory effect of caerulein, a CCK agonist, in the elevated plus-maze.