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Article10.1096/fasebj.22.1_supplement.913.1

ULTRASTRUCTURAL BASIS OF ASYNCHRONOUS URIDINE 5′‐TRIPHOSPHATE (UTP)‐INDUCED CA(2+) WAVES IN RAT BASILAR ARTERY

Harley T. Syyong,Clarice HH Yang,Gina Trinh,Kuo‐Hsing Kuo,Cornelis van Breemen-2008-03-01-The FASEB Journal
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TL;DRAbstract

A common form of Ca2+ signaling in smooth muscle cells is Ca2+ oscillations. We observed that uridine 5′‐triphosphate (UTP) elicits cyclic, dose‐dependent increases in intracellular Ca2+ which underlie tonic force generation in rat basilar artery, similar to those observed in conduit arteries. We also observed subplasmalemmal junctions between the plasma membrane (PM) and sarcoplasmic reticulum (SR), known as PM‐SR junctions. Pharmacological dissociation of these junctions abolishes maintenance of Ca2+ waves, but does not affect Ca2+ release. The maintenance of Ca2+ waves is dependent on extracellular Ca2+ entry, which is mediated by L‐type voltage‐gated calcium channels (L‐VGCCs), non‐selective cation channels (NSCCs), and by the plasma membrane Na+/Ca2+ exchanger (NCX) working in reverse‐mode. Blockade of inositol 1,4,5‐triphosphate receptors (IP3Rs), but not ryanodine receptors, abolishes ongoing Ca2+ waves. These findings suggest that Ca2+ waves in rat basilar artery underlie tonic

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A common form of Ca2+ signaling in smooth muscle cells is Ca2+ oscillations. We observed that uridine 5′‐triphosphate (UTP) elicits cyclic, dose‐dependent increases in intracellular Ca2+ which underlie tonic force generation in rat basilar artery, similar to those observed in conduit arteries. We also observed subplasmalemmal junctions between the plasma membrane (PM) and sarcoplasmic reticulum (SR), known as PM‐SR junctions. Pharmacological dissociation of these junctions abolishes maintenance of Ca2+ waves, but does not affect Ca2+ release. The maintenance of Ca2+ waves is dependent on extracellular Ca2+ entry, which is mediated by L‐type voltage‐gated calcium channels (L‐VGCCs), non‐selective cation channels (NSCCs), and by the plasma membrane Na+/Ca2+ exchanger (NCX) working in reverse‐mode. Blockade of inositol 1,4,5‐triphosphate receptors (IP3Rs), but not ryanodine receptors, abolishes ongoing Ca2+ waves. These findings suggest that Ca2+ waves in rat basilar artery underlie tonic

Keywords

Ryanodine receptorBiophysicsExtracellularEndoplasmic reticulumChemistryCalciumBasilar arteryIntracellular

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