The hypertensive response to injection of physostigmine into the hypothalamus of the unanesthetized rat.

Microinjection of physostigmine (3-30 nmoles) into the posterior hypothalamic nucleus of freely-moving, unanesthetized rats elicited a dose-related hypertensive response. This effect was significantly reduced by prior central injection of hemicholinium-3. The direct acting cholinergic agonist, carbachol, also evoked an elevation of blood pressure following intrahypothalamic injection; however, this response was unaffected by prior administration of hemicholinium-3.