(d (CH2) 51, Tyr (Me) 2, Arg8) -Vasopressin

This small molecule is a potent and selective antagonist of the vasopressin V1A receptor, blocking vasopressin and oxytocin signaling in vitro (IC50 = 5 nM and 30 nM, respectively) . In vivo, it produces sustained antivasopressor effects and demonstrates region-specific anxiolytic activity within the dorsal hippocampus, making it a valuable research tool for neuroendocrinology and behavioral studies.