Calcium sparklets in arterial smooth muscle.

摘要: Voltage-dependent, L-type Ca2+ channels (LTCC) play an essential role in arterial smooth muscle contraction and, consequently, the regulation of diameter, tissue perfusion and blood pressure. However, spatial organization functional LTCC myocytes is incompletely understood. Total internal reflection fluorescence swept-field confocal microscopy revealed that opening a single or cluster produces local elevations [Ca2+]i called sparklets. In myocytes, sparklets are produced by Cav1.2 channels. The sparklet activity bimodal. low mode, rare stochastic openings solitary produce limited influx ('low sparklets'). contrast, discrete clusters associated with protein kinase Ca (PKCa) operate sustained, high-activity mode resulting substantial ('persistent varies regionally within myocyte depending on relative activities nearby PKCa opposing phosphates 2A 2B. Low- persistent modulate global muscle, suggesting this signal may important vascular function.