Stimulation of Ejaculatory Behaviour by the 5-HT<SUB>1B</SUB> Receptor Antagonist Isamoltane in Citalopram-pretreated Male Rats

It has previously been shown that blocking 5-HT1A receptors unmasks an inhibitory action of the selective 5-hydroxytryptamine (5-HT) re-uptake inhibitor citalopram on male rat ejaculatory behaviour. This paper reports that subcutaneous (s.c.) administration of the selective 5-HT re-uptake inhibitor citalopram (10 mgkg−1) facilitated ejaculatory behaviour in male Wistar rats treated with the 5-HT1B receptor antagonist isamoltane (4 mgkg−1, s.c.), whereas neither citalopram nor isamoltane alone had any effect. It is concluded that citalopram possesses an inhibitory action on male rat ejaculatory behaviour, and that this inhibition normally is balanced by a facilitatory action mediated via 5-HT1A receptors.