Modulation of adrenal chromaffin cell intracellular calcium by angiotensin, bradykinin and endothelin.

Studies were undertaken to compare and contrast the effects of the vasoactive peptides, angiotensins II and III, bradykinin and endothelin, on mobilization of intracellular calcium in isolated, cultured bovine adrenal medullary (chromaffin) cells. Calcium mobilization was studied using the Fura-2 technique. The potency for elevating intracellular calcium, compared on a molar basis, was bradykinin greater than angiotensin III greater than angiotensin II much greater than endothelin. When nicotine and angiotensin II were added together, a synergism was evident with prolonged elevation of intracellular calcium. However, concomitant addition of angiotensin II and endothelin was barely additive. Yet, combined addition of endothelin and depolarizing potassium chloride yielded a very marked synergism in calcium mobilization. We conclude that the multiplicity of vasoactive peptide receptors on chromaffin cells exert interactive modulation on calcium mobilization in these cells and this property may have functional significance.