THE 5-HT3 RECEPTOR AGONIST ATTENUATES THE ACTION OF ANTIDEPRESSANTS IN THE FORCED SWIM TEST IN RATS

Involvement of 5-hydroxytryptamine (5-HT)(3) receptors in action of an tidepressants was examined in the forced swim test in rats. Rats were forced to swim in a cylinder for 15 min on day 1 and for 5 min on day 2. Imipramine, desipramine and mianserin, administered after the 15-mi n swim session on day 1 and before the 5-min swim test on day 2, dose- dependently decreased the duration of immobility in the swim test on d ay 2. 1-(m-Chlorophenyl)-biguanide (mCPBG) attenuated the decreased du ration of immobility induced by imipramine, desipramine and mianserin, although mCPBG did not affect the duration of immobility when it was given alone. ICS205-930 dose-dependently decreased the duration of imm obility in the swim test on day 2, and the effect of ICS205-930 was at tenuated by mCPBG. These results suggest that the suppression of 5-HT3 receptor activity may contribute to the action of antidepressants. (C ) 1998 Elsevier Science B.V.