Effect of nitric oxide on calcium-induced calcium release in coronary arterial smooth muscle.
The present study was designed to determine whether nitric oxide (NO)-induced reduction of [Ca(2+)](i) is associated with Ca(2+)-induced Ca(2+) release (CICR) in coronary arterial smooth muscle cells (CASMCs). Caffeine was used as a CICR activator to induce Ca(2+) release in these cells. The effects of NO donor, sodium nitroprusside (SNP), on caffeine-induced Ca(2+) release were examined in freshly dissociated bovine CASMCs using single cell fluorescence microscopic spectrometry. The effects of NO donor on caffeine-induced coronary vasoconstriction were examined by isometric tension recordings. Caffeine, a CICR or ryanodine receptor (RYR) activator, produced a rapid Ca(2+) release with a 330 nM increase in [Ca(2+)](i). Pretreatment of the CASMCs with SNP, CICR inhibitor tetracaine or RYR blocker ryanodine markedly decreased caffeine-induced Ca(2+) release. Addition of caffeine to the Ca(2+)-free bath solution produced a transient coronary vasoconstriction. SNP, tetracaine and ryanodine, but not guanylyl cyclase inhibitor, ODQ, significantly attenuated caffeine-induced vasoconstriction. These results suggest that CICR is functioning in CASMCs and participates in the vasoconstriction in response to caffeine-induced Ca(2+) release and that inhibition of CICR is of importance in mediating the vasodilator response of coronary arteries to NO.
Li
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Department of Pharmacology and Toxicology, Medical College of Wisconsin, 53226, Milwaukee, WI, USA
Zou
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Ge
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Campbell
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Li
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D000818:Animals; D001158:Arteries / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D003331:Coronary Vessels / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D008955:Models, Cardiovascular; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D009569:Nitric Oxide / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology; D010108:Oxyhemoglobins / Q000494:pharmacology; D012433:Ryanodine / Q000494:pharmacology; D013748:Tetracaine / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects
D010108:Oxyhemoglobins; D013748:Tetracaine; D012433:Ryanodine; D009599:Nitroprusside; D009569:Nitric Oxide; D002110:Caffeine; D002118:Calcium