[Calcium release from vesicles of heavy sarcoplasmic reticulum of rabbit skeletal muscles].
The release of Ca2+ from vesicles of heavy sarcoplasmic reticulum after its accumulation due to hydrolysis of ATP, GTP, CTP, UTP or ITP has been studied using Antipyrylazo III, a metal-chromic Ca-indicator. All the studied substrates of the Ca-pump provide Ca2+ accumulation inside the heavy sarcoplasmic reticulum vesicles, the spontaneous Ca2+ outflux rate being different for different nucleoside triphosphates. It is only ATP that provides Ca-(caffeine)-induced Ca2+ release, however AMP, ADP, beta, gamma-methylene-ATP induce Ca2+ ejection in the presence of nonadenylic nucleotides. The ruthenium red (10(-7M) inhibits the induced ejection of Ca2+ from vesicles of the heavy sarcoplasmic reticulum, but does not prevent the spontaneous release of Ca2+ in the same concentrations. A conclusion is drawn that besides Ca-channels sensitive to Ca2+ and caffeine in the presence of ATP (or to AMP, ADP, beta, gamma-methylene-ATP in the presence of nonadenylic nucleotides) and possessing high sensitivity to the ruthenium red there is another pathway for Ca2+ in the heavy reticulum membranes along which its spontaneous release occurs after the substrate exhaustion. It is supposed that this release is provided by the presence of the Ca-ATPase protein.
Smirnova
M B
MB
Rubtsov
A M
AM
Boldyrev
A A
AA
D000249:Adenosine Monophosphate / Q000502:physiology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003570:Cytidine Triphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006868:Hydrolysis; D007202:Indicators and Reagents; D007293:Inosine Triphosphate / Q000378:metabolism; D009132:Muscles / Q000378:metabolism*; D009282:Naphthalenesulfonates; D011817:Rabbits; D012430:Ruthenium Red / Q000494:pharmacology; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D014544:Uridine Triphosphate / Q000378:metabolism
D007202:Indicators and Reagents; D009282:Naphthalenesulfonates; D012430:Ruthenium Red; D007293:Inosine Triphosphate; C005147:5'-adenylyl (beta,gamma-methylene)diphosphonate; D000249:Adenosine Monophosphate; D003570:Cytidine Triphosphate; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; C016238:antipyrylazo III; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D002118:Calcium; D014544:Uridine Triphosphate
Vykhod kal'tsiia iz vezikul tiazhelogo sarkoplazmaticheskogo retikuluma skeletnykh myshts krolika.