Adenosine decreases intracellular free calcium concentrations in cultured vascular smooth muscle cells from rat aorta

[摘要]

Using an intracellularly trapped dye, quin 2, effects of adenosine on intracellular free calcium concentrations ([Ca²⁺]_i) were recorded, microfluorometrically, using rat aortic medial vascular smooth muscle cells (VSMCs) in primary culture. Regardless of whether cells were at rest (in 5 mM K⁺), at K⁺-depolarization (in 55 mM K⁺) or at Ca²⁺ depletion (in Ca²⁺-free media), adenosine induced a rapid reduction of [Ca²⁺]_i, following which there was a gradual increase to pre-exposure levels, in cells at rest and in the case of Ca²⁺ depletion. Only when the cells were depolarized (55 mM K⁺) did adenosine induce a new steady [Ca²⁺]_i level, lower than the pre-exposure value. These findings indicate that decrease in [Ca²⁺]_i by adenosine is one possible mechanism involved in the adenosine-mediated vasodilatation, and that adenosine decreases [Ca²⁺]_i by direct extrusion, by sequestration, or by inhibiting the influx of Ca²⁺ into VSMCs.

[学科分类] 生物化学/生物物理

[关键词] Adenosine;Quin 2;(Vascular smooth muscle cell;Rat aorta);[Ca2+]i;intracellular free Ca2+ concentration;PSS;physiological saline solution;VSMCs;vascular smooth muscle cells