Inhibitory effect of lidocaine on the sarcoplasmic reticulum Ca2+-dependent atpase from temporalis muscle.
Myotoxic effects of local anesthetics on skeletal musclefibers involve the inhibition ofsarcoplasmic reticulum Ca2+ -dependent ATPase activity and Ca2 transport. Lidocaine is a local anesthetic frequently used to relieve the symptoms of trigeminal neuralgia. The aim of this work was to test the inhibitory and/or stimulatory effect of lidocaine on sarcoplasmic reticulum Ca2+ -dependent ATPase isolated from rabbit temporalis muscle. Ca2+ -dependent ATPase activity was determined by a colorimetric method Calcium-binding to the Ca dependent ATPase, Ca2+ transport, and phosphorylation of the enzyme by ATP were determined with radioisotopic techniques. Lidocaine inhibited the Ca2+ -dependent ATPase activity in a concentration-dependent manner. The preincubation of the sarcoplasmic reticulum membranes with lidocaine enhanced the Ca2+ dependent ATPase activity in the absence of calcium ionophore. Lidocaine also inhibited both Ca2+ uptake and enzyme phosphorylation by ATP but had no effect on Ca2+ -binding to the enzyme. We conclude that the effect of lidocaine on the sarcoplasmic reticulum Ca2+ -dependent ATPase from temporalis muscle is due to the drug's direct interaction with the enzyme and the increased permeability of the sarcoplasmic reticulum membrane to Ca.
Biophysics Department, School of Dentistry, University of Buenos Aires, Argentina.
Gabriel A
GA
Sánchez
Ana C
AC
Casadoumecq
Guillermo L
GL
Alonso
Delia
D
Takara
D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D008012:Lidocaine / Q000494:pharmacology*; D008297:Male; D011817:Rabbits; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000037:antagonists & inhibitors*; D013703:Temporal Muscle / Q000201:enzymology*
D000779:Anesthetics, Local; D008012:Lidocaine; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases