EFFECTS OF NORADRENERGIC STIMULATION OF THE MEDIAL AND LATERAL HYPOTHALAMUS ON CARDIOVASCULAR-RESPONSES

Microinjections of noradrenaline into the medial hypothalamus of anaesthetized normotensive rats elicited hypotensive and hypertensive effects. Noradrenergic stimulation of the dorsomedial nucleus of the hypothalamus caused a drop in arterial pressure and heart rate, which was abolished by previous injection of phentolamine but not by previous injection of propranolol. Noradrenaline injected into the ventromedial nucleus caused an increase in blood pressure and heart rate, which was blocked by propranolol but not by phentolamine. Microinjection of noradrenaline into the lateral hypothalamic area elicited tachycardia and a hypertensive response, both abolished by phentolamine, but not by propranolol. © 1979 The Italian Pharmacological Society.