[Passive Ca2+ fluxes across the membrane of sarcoplasmatic reticulum of skeletal muscles. The effect of calcium channel blockers].
It was found that the initial rate of passive KC1-stimulated Ca2+ influx into sarcoplasmic reticulum (SR) vesicles follows the saturation kinetics at Ca2+ concentrations of 8-10 mM. The inhibitory effect of Ca2+ channel blockers (La3+, Mn2+, Co2+, Cd2+, Mg2+) on passive Ca2+ influx into SR vesicles is competitive with respect to Ca2+. These blockers also inhibit the initial fast phase of Ca2+ efflux from Ca2+-loaded SR vesicles. Verapamil (0.1-0.5 mM) added to the incubation mixture has no effect on passive Ca2+ fluxes across the SR vesicle membrane or on Ca2+ binding and ATP-dependent Ca2+ accumulation. However, preincubation of SR vesicles with verapamil (18 hours, 4 degrees C) or its introduction into the medium for SR vesicle isolation leads to the inhibition of passive Ca2+ fluxes.
Diadiusha
G P
GP
Tugaĭ
V A
VA
Zemlianaia
N N
NN
Zakharchenko
A N
AN
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D007700:Kinetics; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
D002121:Calcium Channel Blockers; D002118:Calcium
Issledovanie passivnykh potokov Ca2+ cherez membranu sarkoplazmaticheskogo retikuluma skeletnykh myshts. Vliianie blokatorov kal'tsievykh kanalov.