[Effect of intracerebroventricular neurotensin injection on blood pressure in rat].

Injection of neurotensin (NT) (10 and 20 micrograms/rat) into the lateral cerebroventricle (icv) could induce a rise or a drop of blood pressure and a slowing down of heart rate in urethane anaesthetized male rats (1.2 g/kg). The central pressor and depressor response to NT could be respectively blocked by pretreatment with alpha 1-receptor blocker prazosin (1.5 micrograms/3 microliters, icv) and M receptor blocker atropine (2.5 micrograms/3 microliters, icv). No significant changes in central cardiovascular responses to NT were observed following pretreatment with either H1 receptor blocker chlorpheniramin (50 micrograms/3 microliters, icv) or H2 receptor blocker cimetidine (250 micrograms/3 microliters, icv). In view of the above results it appears that NT, catecholamine and acetylcholine are all involved in central regulation of blood pressure.