The direct vascular effect of pneumadin (PN) was determined by studying the changes in intracellular free calcium ([Ca2+]i) levels in cultured rat aortic smooth muscle cells maintained between the second and fifth passages. PN evoked a rapid, concentration-dependent, biphasic increase in [Ca2+]i. The [Ca2+]i level rose from a basal value of 108 nM to a… (More)