Effects of bestatin on the central cardiovascular regulatory mechanisms in the rat

We evaluated the effects of bestatin, the specific aminopeptidase-B and leucine aminopeptidase inhibitor, on the central cardiovascular regulatory mechanisms in Sprague-Dawley rats anesthetized with pentobarbital sodium (40 mg/kg, i.p.). Intracerebroventricular injection of bestatin (100 or 200 nmol/5 microliters) consistently elevated the basal systemic arterial pressure and heart rate. At the same time, this degradative enzyme blocker increased the sensitivity of the baroreceptor reflex responses as well as the efficacy of the modulatory actions of the medullary nucleus reticularis gigantocellularis on these reflexes. We speculate that enhancing the tonic activities of the endogenous neuropeptides in the brain by protecting them from their catabolic enzymes may affect the central cardiovascular regulatory machinery by modifying the operations of the baroreceptor feedback controls and their modulatory mechanisms.