[Effects of zinc sulfate on isolated vascular smooth muscles]

ZnSO4 was found to inhibit the contractions of isolated guinea pig aortic preparations induced by KCl, CaCl2 and noradrenaline (NE). ZnSO4 (0.01-0.1 mmol/L) shifted the dose-response curves for KCl, CaCl2 and NE to the right, and depressed their maximal responses with PD2' values of 3.21, 3.07 and 2.91 respectively. ZnSO4 (0.1 mmol/L) significantly antagonized KCl, CaCl2 and NE-induced contraction responses in isolated dog portal vein preparations. These results suggest that the ZnSO4 induced relaxation of vascular smooth muscle might result from its antagonistic effect on transmembrane Ca2+ channels.