Barium and strontium as calcium substitutes for contractile responses in the rat tail artery.
The ability of Ba2+ and Sr2+ to substitute for Ca2+ in contractile responses of the rat tail artery has been examined. Both Ba2+ and Sr2+ caused comparable contractions in Ca-depleted NA-stimulated, or K+-depolarized strips. Ba2+ and Sr2+ substitute poorly for Ca2+ at noradrenaline-sensitive membrane sites. At high concentrations, the three divalent cations stabilize the membrane in the order: Ca2+ greater than Sr2+ greater than Ba2+. The relaxation rates following high-K+ contractions were similar for all three divalent cations, suggesting a common mechanism for sequestration/extrusion.
A B
AB
Ebeigbe
C P
CP
Aloamaka
D000818:Animals; D001464:Barium / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D002451:Cell Compartmentation / Q000187:drug effects; D007473:Ion Channels / Q000187:drug effects; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D013324:Strontium / Q000494:pharmacology*; D013623:Tail / Q000098:blood supply
D007473:Ion Channels; D001464:Barium; D011188:Potassium; D002118:Calcium; D013324:Strontium