ATP release by angiotensin II from segments and cultured smooth muscle cells of guinea-pig taenia coli.

Effects of angiotensin II on ATP release were evaluated in segments and cultured smooth muscle cells from the guinea-pig taenia coli. In the segments, angiotensin II (0.3-3 microM) elicited release of ATP which was blocked by losartan and SC-52458, non-peptide angiotensin II type-1 receptor (AT1)-antagonists, but not by PD-123319, an AT2-antagonist. In superfused cultured cells, 10 microM angiotensin II likewise elicited release of ATP. Again the response was blocked by losartan and SC-52458 but not by PD-123319. These findings suggest that angiotensin II releases ATP from the smooth muscles by activation of angiotensin II-, presumably AT1-, receptors.