The effect of atropine on cadmium- and nickel-induced constriction of vascular smooth muscle of the dogfish shark ventral aorta

We investigated the effect of blockade of muscarinic, cholinergic receptors by atropine on the Cd 2+- and Ni 2+-induced vasoconstriction of rings of endothelium-free, vascular smooth muscle from the ventral aorta of the dogfish shark Squalus acanthias. Atropine reduced the Cd 2+-induced vasoconstriction by approximately 50%, but did not alter the Ni 2+-induced vasoconstriction, suggesting that the vasoactivity of these two metals may be, at least partially, via different pathways. In addition, this is the first demonstration that one component of Cd 2+ vaso-toxicity may be via stimulation of muscarinic receptors.