Extrahypothalamic vasopressin in human brain.

The distribution of arginine vasopressin immunoreactivity in post-mortem human brain was examined using a radioimmunoassay. The highest concentration was found in the hypothalamus but substantial amounts of vasopressin-like immunoreactivity were also found in the locus coeruleus, periaqueductal grey, substantia nigra compacta and reticulata and in lower concentrations in the globus pallidus. The extrahypothalamic vasopressin was immunologically and chromatographically similar to hypothalamic vasopressin. The possibility arises that the high levels of vasopressin in the locus coeruleus may relate to an effect on noradrenergic transmission.