THE EFFECTS OF DORSAL RAPHE ADMINISTRATION OF ELTOPRAZINE, TFMPP AND 8-OH-DPAT ON RESIDENT INTRUDER AGGRESSION IN THE RAT

To evaluate the role of somatodendritic 5-HT1A receptors in the mediat ion of aggressive behaviour, eltoprazine, TFMPP (1-(3-trifluoromethylp henyl)piperazine hydrochloride) and 8-OH-DPAT (8-hydroxy-2-(di-n-propy lamino)tetralin) were administered locally into the dorsal raphe nucle us of rats. 8-OH-DPAT (1 and 10 mug) and eltoprazine (10 and 30 mug) r educed aggression, but concomitantly reduced social interest and incre ased inactivity. TFMPP (1 and 10 mug) did not reduce aggression. As 8- OH-DPAT and to a lesser extent eltoprazine affect 5-HT1A receptors, it is proposed that a general reduction of serotonergic neurotransmissio n by activation of somatodendritic serotonergic autoreceptor leads to a non-specific reduction of aggression. As TFMPP has a significantly l ower affinity for 5-HT1A receptors than 8-OH-DPAT or eltoprazine, the lack of effect of TFMPP supports this view.