Opposite effects of intraventricular and intracisternal administration of vasopressin on blood pressure in rats.

Lysine-8-vasopressin (LVP) was injected into the lateral ventricle (ICV) or into the cisterna magna (c.m.) of ether-anesthetized rats. ICV injection of LVP decreased the blood pressure (BP), whereas c.m. administration increased it. The opposite effects of ICV versus c.m. administration of the peptide might be related to differences in brainstem versus limbic-midbrain structures in the regulation of blood pressure, and suggest that both mechanisms can be influenced by vasopressin.