Acute cocaine results in rapid rises in intracellular free calcium concentration in canine cerebral vascular smooth muscle cells: possible relation to etiology of stroke.

Effects of cocaine on intracellular free calcium concentration ([Ca2+]i) in cultured canine cerebral vascular smooth muscle cells were studied using digital imaging microscopy and the calcium molecular fluorescent indicator, fura-2. Acute treatment of cerebral vascular smooth muscle cells with cocaine HCl, from a low concentration of 10(-9) M up to 10(-5) M, induced significant increases of [Ca2+]i. Irrespective of the changes in [Ca2+]i, the subcellular distribution of [Ca2+]i appeared heterogeneous in both normal and cocaine-treated cells. These results suggest that cocaine induces cerebral vasospasm by a rapid elevation of [Ca2+]i in vascular smooth muscle cells; these ionic events could play a crucial role in the pathogenesis of cocaine-induced cerebral ischemia and stroke.