[On the relation between substance P and physostigmine on cardiovascular control in rabbit brain].

ABSTRACT

Using an electromagnetic flowmeter technique, the cardiac output as measured by blood flow in the aortic arch was measured during intracerebroventricular injection (icv.) of Substance P (SP) and physostigmine in 47 anesthetized rabbits. Carotid artery blood pressure and heart rate were recorded. After icv of SP (20 micrograms/20 microliters) or physostigmine (60 micrograms/20 microliters), both cardiac output and mean artery pressure were increased. Pretreatment with icv. of atropine (150 micrograms/20 microliters) did not alter the effect of SP, but the effect of physostigmine was blocked by pretreatment with SP blocker (25 micrograms/20 microliters). These findings suggest that cerebral SP is involved in cholinergic mechanisms on the central control of blood pressure.