title: Serotonin blocks vasopressin-facilitated offensive aggression: interactions within the ventrolateral hypothalamus of golden hamsters.
abstract: In golden hamsters, vasopressin (AVP) microinjected within the ventrolateral hypothalamus (VLH) facilitates offensive aggression. As serotonin is known to inhibit offensive aggression, we decided to test whether AVP-facilitated behavior is also inhibited by serotonin treatment. Testosterone-treated male golden hamsters received IP injections of fluoxetine, a serotonin reuptake inhibitor, or vehicle 1 h prior to AVP microinjections within the VLH. The animals were tested for offensive aggression in a resident-intruder model after the microinjections, and the results were compared between groups. Pretreatment with fluoxetine inhibited AVP-facilitated offensive aggression. Only one out of nine fluoxetine-treated animals attacked and bit the intruders, compared to six out of seven vehicle-treated animals. Furthermore, we also confirmed by in vitro autoradiography that the VLH contains vasopressin V(1) and serotonin 5-HT1B receptors. Therefore, it is possible that serotonin may inhibit AVP-facilitated offensive aggression by acting directly at the level of the VLH as well as at other sites.
authors.affiliation: Department of Psychiatry, University of Massachusetts Medical Center, Worcester 01655, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Delville
authors.forename: K M
authors.initials: KM
authors.lastname: Mansour
authors.forename: C F
authors.initials: CF
authors.lastname: Ferris
mesh_terms: D000374:Aggression / Q000187:drug effects*; D000818:Animals; D001345:Autoradiography; D006224:Cricetinae; D005473:Fluoxetine / Q000494:pharmacology; D007033:Hypothalamus, Middle / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008647:Mesocricetus; D008845:Microinjections; D051381:Rats; D017207:Rats, Sprague-Dawley; D017483:Receptors, Vasopressin / Q000378:metabolism; D012701:Serotonin / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology; D013238:Stereotaxic Techniques; D013739:Testosterone / Q000494:pharmacology; D014667:Vasopressins / Q000037:antagonists & inhibitors* / Q000494:pharmacology
chemical_list: D005473:Fluoxetine; D017483:Receptors, Vasopressin; D012701:Serotonin; D017366:Serotonin Receptor Agonists; D017367:Selective Serotonin Reuptake Inhibitors; D013739:Testosterone; D014667:Vasopressins