Comparison of the effects of xenon and halothane on voltage-dependent Ca(2+) fluxes in rabbit T-tubule membranes.
The effects of xenon and halothane on depolarization-induced (45)Ca(2+) fluxes mediated by voltage-dependent Ca(2+) channels were investigated in transverse tubule membrane vesicles from rabbit skeletal muscle. Halothane, in the concentration range of 0.5-2 mM, caused a significant inhibition of (45)Ca(2+) fluxes. Xenon tested in the range of 60%-100% did not affect the (45)Ca(2+) fluxes. Radioligand binding studies indicated that xenon and halothane have different effects on the specific binding of [(3)H]Isradipine to transverse tubule membranes. Halothane caused a significant inhibition on the specific binding of [(3)H]Isradipine. In controls and in presence of 0.5 mM halothane, B(max) values were 26.9 pmole/mg and 15.1 pmole/mg, and K(D) values were 238 pM and 247 pM, respectively. On the other hand, there was no effect of xenon (60%-100%) on the characteristics of [(3)H]Isradipine binding. In conclusion, results indicate that xenon and halothane differ in their effects on the function of voltage-dependent Ca(2+) channels and on the specific binding of [(3)H]Isradipine in skeletal muscle membranes.
Oz
Murat
M
National Institute on Drug Abuse/IRP, Cellular Neurobiology Section, 5500 Nathan Shock Drive, Baltimore MD 21224, USA. moz@intra.nida.nih.gov
Dinc
Meral
M
Tchugunova
Yulia
Y
Dunn
Susan M J
SM
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D006221:Halothane / Q000494:pharmacology*; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000187:drug effects* / Q000378:metabolism; D015640:Ion Channel Gating; D017275:Isradipine / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000648:ultrastructure; D011817:Rabbits; D011869:Radioligand Assay; D014978:Xenon / Q000494:pharmacology*
D018685:Anesthetics, Inhalation; D015220:Calcium Channels; D014978:Xenon; D002118:Calcium; D006221:Halothane; D017275:Isradipine