Haemodynamic effects of arginine-vasopressin microinjections into the nucleus tractus solitarius: a comparative study of vasopressin, a selective vasopressin receptor agonist and antagonist, and oxytocin.

Arginine-vasopressin (AVP) and related peptides were administered by microinjection into the nucleus tractus solitarius of the rat. AVP produced a rise both in mean arterial pressure and in heart rate. This effect was abolished by pretreatment with a specific antagonist of V1 receptors and was not seen either after injections of oxytocin or of the V2 agonist deamino-D-arginine-vasopressin. This study provides evidence for a specific action of vasopressin on the cardiovascular system in the nucleus of the tractus solitarius, which is mediated neither by V2 nor oxytocin receptors.