Arginine vasopressin receptors in pig cerebral microvessels, cerebral cortex and hippocampus

We tested for the presence of arginine vasopressin (AVP) receptors in pig cerebral microvessels, cerebral cortex and hippocampus by specific binding methods with [3H]AVP as the ligand. The specific binding of [3H]AVP to all preparations was saturable and Scatchard analysis indicated a single class of high affinity binding sites (dissociation constant of 1-2 nM). Maximal binding capacity in cerebral microvessels was about 60% that of the cerebral cortex; and there were no apparent differences in the maximal binding capacity between cerebral cortex and hippocampus. These findings suggest the existence of AVP receptor sites in cerebral microvessels and support the hypothesis that AVP has a role in the control of the brain microcirculation.