RELATION OF CENTRALLY EVOKED PRESSOR EFFECT OF ANGIOTENSIN 2 TO CALCIUM ION

A.E.DANIELS and J.P.BUCKLEY, Relation of the centrally evoked pressor effect of angiotensin II to the calcium ion. European J. Pharmacol. 4 (1968) 152-164. Interrelationships between the centrally induced pressor effects of angiotensin II and the calcium ion were studied by administering the polypeptide intraventricularly to cats pnor to and after alteration of calcium levels in the ventricular perfusion medium. Elevated calcium concentrations had little effect on the angiotensin II response, but perfusion with acalcemic artificial cerebrospinal fluid (CSF) or with the same medium containing EDTA inhibited the pressor activity. Repetitive administration of angiotensin II by the intraventricular route did not alter the regional distribution of norepinephrine in perfused brains. Similarly, endogenous norepinephrine was not influenced by perfusing with acalcemic CSF, with or without EDTA. Since normal physiological levels of norepinephrine have been reported to be required for central angiotensin II effects, the data suggest that calcium may be another requirement for activation of the central adrenergic pressor mechanism by the peptide. © 1968.