AbstractAcetylcholine in the central nervous system exerts a significant influence on cardiovascular parameters and appears to be involved in some aspects of hypertension. Stimulation of central muscarinic receptors with direct‐acting cholinomimetics or with acetylcholinesterase inhibitors evokes a rise in blood pressure in unanesthetized cats, dogs, rats, and humans. Anesthetics may significantly modify this response. Concomitant with the pressor response is a potentiation of reflex bradycardia, inhibition of reflex tachycardia, and enhancement of the pressor reflex to carotid artery occlusion. Administration of atropine or intracerebroventricular injection of hemicholinium‐3 reduces blood pressure in spontaneously hypertensive rats (SHR) but not in normotensive rats. Preliminary results are presented showing that systemic or central injection of N‐(4‐diethyl‐2‐butynyl)‐ succinimide, a muscarinic receptor antagonist specific for central receptors, also reduces blood pressure in SHR but not in normotensive animals.