Uridine triphosphate-sensitive pathway of Ca2+ release from the sarcoplasmic reticulum of rat skeletal muscle fibers.
The pyrimidine nucleotide, uridine triphosphate (UTP), was tested with skinned skeletal muscle fibers in order to investigate the UTP-sensitive pathway of Ca2+ release from the sarcoplasmic reticulum. The presence of ryanodine (200 microM), ruthenium red (10 microM) or heparin (2.5 mg/ml) did not affect the tension elicited in the presence of UTP, demonstrating that the UTP-induced Ca2+ release involved neither ryanodine nor inositol triphosphate-sensitive channels. Drugs such as compound 48/80 or cyclopiazonic acid used to inhibit Ca2+-ATPase in its reverse function appeared to be, respectively, non-specific or without any inhibitory effect on the tension induced by UTP. Finally, the UTP-induced tension as well as the trifluoperazine-induced tension were abolished in the presence of spermidine (50 mM), supporting the hypothesis that the UTP-sensitive pathway of the SR Ca2+ release might occur through the uncoupled calcium ATPase.
Catinot
M P
MP
Laboratoire de Plasticité Neuromusculaire, SN4, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
Bastide
B
B
Suarez-Kurtz
G
G
Mounier
Y
Y
D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D004396:Coloring Agents / Q000494:pharmacology; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006493:Heparin / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D012430:Ruthenium Red / Q000494:pharmacology; D012433:Ryanodine / Q000494:pharmacology; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D013095:Spermidine / Q000494:pharmacology; D014544:Uridine Triphosphate / Q000494:pharmacology*; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
D000925:Anticoagulants; D004396:Coloring Agents; D004791:Enzyme Inhibitors; D007211:Indoles; D012430:Ruthenium Red; D012433:Ryanodine; D003189:p-Methoxy-N-methylphenethylamine; D006493:Heparin; D002118:Calcium; D013095:Spermidine; D014544:Uridine Triphosphate; C000543:cyclopiazonic acid