title: Hippocampal oxytocin mediates apomorphine-induced penile erection and yawning.
abstract: Repeated episodes of penile erection and yawning can be induced in male rats either by low doses of the dopaminergic agonist apomorphine or by oxytocin given systematically or into a lateral ventricle (ICV), respectively, or after microinjection of the two substances directly in the paraventricular nucleus (PVN) of the hypothalamus. These behavioral responses are prevented in a dose-dependent manner by the ICV administration of the potent oxytocin antagonist d(CH2)5Tyr(Me)-Orn8-vasotocin. In contrast, the PVN injection of d(CH2)5Tyr(Me)-Orn8-vasotocin (1-30 ng), while effective in preventing oxytocin effect, was unable to prevent apomorphine response. On the other hand, apomorphine-, but not oxytocin-induced penile erection and yawning was prevented by electrolytic lesion of the medial septum (MS). Such a lesion decreased oxytocin content by about 45% in the hippocampus. The above results suggest that the hypothalamic-hippocampal oxytocinergic pathway mediates apomorphine-induced penile erection and yawning and that oxytocin is involved at different levels in the CNS for the control of these behavioral responses.
authors.affiliation: B. B. Brodie Department of Neurosciences, University of Cagliari, Italy.
authors.forename: M R
authors.initials: MR
authors.lastname: Melis
authors.forename: R
authors.initials: R
authors.lastname: Stancampiano
authors.forename: A
authors.initials: A
authors.lastname: Argiolas
mesh_terms: D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001921:Brain / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D007267:Injections; D007276:Injections, Intraventricular; D008297:Male; D010121:Oxytocin / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D010286:Paraventricular Hypothalamic Nucleus; D010410:Penile Erection / Q000187:drug effects*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D015000:Yawning / Q000187:drug effects*
chemical_list: D010121:Oxytocin; C042951:oxytocin,1-(beta-mercapto-(beta, beta-cyclopentamethylene)propionic acid)-Tyr(OMe)(2)-Orn(8)-; D001058:Apomorphine