Vasopressin stimulates inositol phospholipid metabolism in rat medulla oblongata in vivo

Abstract

We have investigated whether microinjections of arginine-vasopressin (AVP) into the nucleus tractus solitarii (NTS) of rats results in the stimulation of inositol phospholipid metabolism, a biochemical event related to the activation of V1-type receptors. We found that AVP, but not the related peptides oxytocin or deamino-D-AVP, increases the incorporation of [3H]myoinositol into lipids and the accumulation of labelled inositol phosphates in the dorsomedial medulla oblongata of lithium-treated rats. These effects were abolished by local pretreatment with D-(CH2)5-Tyr(Me)-AVP, a specific antagonist of V1-receptors. It is concluded that the effects of AVP in the NTS of rats are likely to be due to an action on specific receptors (V1-like) and subsequent activation of polyphosphoinositide turnover