Influence of intracerebroventricularly and intracisternally administered vasopressin on the hypothalamic self-stimulation rate of the rat.

Lysine-vasopressin (LVP) at different concentrations (2 ng, 200 pg) was injected into the lateral ventricle and cisterna magna. The effect on hypothalamic self-stimulation was studied in rats. LVP (2 ng) decreased the self-stimulation rate after intracerebroventricular and cisternal application. Injection of 200 pg LVP diminished the self-stimulation rate after cisternal administration only. The findings suggest that the site of peptide administration is of decisive importance to vasopressin-induced effects. Both biochemical factors and the interaction between behaviour and vegetative nervous system should be taken into consideration when interpreting changes in self-stimulation as induced by vasopressin applied to the CSF space.