Localization of the central pressor action of bradykinin to the cerebral third ventricle

Bradykinin injected into the lateral ventricle produces a rise in blood pressure. Cream plugs selectively localized to discrete regions of the ventricular system were used to block drug access to periventricular sites. Third ventricular plugs blocked the pressor response to lateral ventricular injections of 5 micrograms bradykinin (27 +/- 5 before vs. 5 +/- 5 mmHg after plug, n = 7) and 100 ng angiotensin II (22 +/- 3 before vs. 4 +/- 2 mmHg after plug, n = 5). Third ventricular plugs also suppressed the drinking response to angiotensin II (3.7 +/- 0.6 before vs. 0.9 +/- 0.6 ml after plug, n = 5). However, plugs that occluded the fourth ventricle failed to suppress the central bradykinin pressor response (27 +/- 8 before vs. 35 +/- 9 mmHg after plug, n = 5). The data suggest that the central bradykinin pressor response has a site of action similar to that of angiotensin II in the ventral third ventricle.