Arginine‐Vasopressin Stimulates Inositol Phospholipid Metabolism in Rat Hippocampus

: The hippocampal vasopressin receptors have been characterised by measuring the stimulated accumulation of inositol monophosphate in the presence of 10 mM LiCl after hippocampal slices were prelabelled with [3H]inositol. Arginine‐vasopressin caused a dose‐dependent increase in inositol monophosphate accumulation (ED50=7.1 nM). The response was unchanged in the absence of Ca2+ and significantly reduced in the presence of a V1,‐receptor antagonist. Equimolar oxytocin was ineffective as a stimulus. This suggests that the hippocampal receptors are of the V1 type.