8‐Bromoguanosine 3′:5′‐cyclic monophosphate decreases intracellular free calcium concentrations in cultured vascular smooth muscle cells from rat aorta

摘要

>The effects of 8-bromoguanosine 3′:5′-cyclic monophosphate (8-Br cGMP) on intracellular free calcium concentrations ([Ca2+]_i) in cultured rat aortic vascular smooth muscle cells (VSMCs) loaded with fura-2 were recorded microfluorometrically. Irrespective of whether VSMCs were at rest (in 5 mM K+ PSS), under Ca2+ depletion (in Ca2+-free medium for 10 min) and K+ depolarization (in high K+ PSS), [Ca2+]_i was actively reduced and reached a new and lower steady-state level with the application of 8-Br cGMP. This may be the first and direct evidence that cGMP, a putative mediator of various vasodilators, actively reduces [Ca2+]_i in VSMCs.