Catinot M P, Bastide B, Suarez-Kurtz G, Mounier Y
Laboratoire de Plasticité Neuromusculaire, SN4, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
Eur J Pharmacol. 1998 Dec 4;362(2-3):221-7. doi: 10.1016/s0014-2999(98)00756-0.
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.
