Central adrenergic mediation of the cardiovascular effect of intraventricular bradykinin.

The lateral septal area of anaesthetized rats was perfused using a push-pull cannula and the effect of the intracerebroventricular injection of bradykinin on the release of 3H-noradrenaline from the lateral septal area studied. A significant increase in 3H-noradrenaline release concomitant to a cardiovascular response was observed after bradykinin administration, suggesting the involvement of septal noradrenergic mechanisms in the response to the peptide. Morphine, subcutaneously administered, blocked the increase in the effluent radioactivity and the cardiovascular response to bradykinin, suggesting that the bradykinin receptors in the septal area are similar to those found in the sympathetic ganglia. Intravenous injection of diphenhydramine blocked the cardiovascular response to bradykinin but not the 3H-noradrenaline release, indicating the involvement of histaminergic mechanism in a step posterior to the release of catecholamines in the septal area.