The effect of cadmium and other metals on vascular smooth muscle of the dogfish shark, Squalus acanthias

Abstract

The effect of Cd 2+ and related metals (Ni 2+, Hg 2+, Pb 2+, Co 2+, Sn 2+ Cu 2+ and Zn 2+) on vascular tension was studied using isolated rings of endothelium-free, smooth muscle from the ventral aorta of the shark, Squalus acanthias. Both Cd 2+ and Ni 2+ produced significant vasoconstriction at concentration at or above 10 −6 M (112 and 59 ppb, respectively); the other metals were either marginally constrictive (Hg 2+ and Sn 2+) or were without effect (Pb 2+, Co 2+, Cu 2+, and Zn 2+). We suggest that previously published vascular effects of Hg 2+ and Pb 2+ may have been secondary to responses of the vascular endothelium, and that the role of Ni 2+ in hypertension should be investigated further. Our data indicate that the effects of metals on this vascular smooth muscle are specific and not generic. Moreover, this system could be utilized to investigate the mechanisms of metal-induced vasoconstriction.