The vasopressin response to microinjections of norepinephrine into the brain of the conscious pig

Abstract

Abstract. The possibility that the amygdala influences the release of vasopressin has been raised by the observation that electrical stimulation of this area results in vasopressin release in the conscious animal. Therefore the effect on vassopressin concentrations has been studied by microinjections of norepinephrine into the amygdala of the conscious miniature pig. The studies were performed on castrated male and female pigs with chronically implanted cannulae in the brain and in the external jugular vein. Lysine vasopressin concentrations were determined using a specific sensitive radioimmunoassay. Microinjections of 1 μl 0.12 m sodium chloride were without effect. Injections of norepinephrine in the dose range 10−4–10−10m had no effect in the male animal but a significant vasopressin response could be obtained in the females.