Blood flow and functional responses correlate in the ovine neural lobe

Regional neurohypophyseal and cerebral blood flow were measured in 5 awake unstressed female sheep with radiolabelled microspheres before and after the intracarotid infusion of a 3% NaCl solution. Plasma arginine vasopressin (AVP) levels were concurrently measured by radioimmunoassay. Following intracarotid sodium chloride infusion, neural lobe (but not median eminence) blood flow significantly increased, as did plasma AVP levels. Directed thirst and water-seeking behavior was observed, accompanied by a global increase in cortical blood flow. We conclude that the neuroendocrine response and the behavioral display induced by intracarotid sodium chloride infusion are accompanied by increases in blood flow in selected brain regions.