Carbachol and KCl-induced changes in intracellular free calcium concentration in isolated, fura-2 loaded smooth-muscle cells from the anterior byssus retractor muscle of Mytilus edulis.
Intracellular free calcium concentration [( Ca2+]1) was measured in suspensions of fura-2 loaded smooth-muscle cells isolated from the anterior byssus retractor muscle of Mytilus edulis. Successive application of 5mM carbachol (CCh) and 100mM KCl to the cells transiently elevated [Ca2+]1 from the resting value of 124 +/- 4.5nM (mean +/- S.E., n = 14) to 295 +/- 15.3 and 383 +/- 20.5 nM, respectively. The response to CCh was concentration-dependent with an ED50 of 10(-5) M. Under the microscope, 67 +/- 3.0 and 83 +/- 1.3 % of fura-2 loaded cells contracted on the addition of 5mM CCh and 100mM KCl, respectively. In Ca2+ -free sea water, the CCh induced change in [Ca2+]1 was partially suppressed whereas that induced by KCl was completely abolished, suggesting an agonist-evoked release of stored Ca2+.
Ishii
N
N
University Laboratory of Physiology, Oxford, U.K.
Simpson
A W
AW
Ashley
C C
CC
D000818:Animals; D001572:Benzofurans; D049872:Bivalvia; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D002217:Carbachol / Q000494:pharmacology*; D003593:Cytoplasm / Q000502:physiology; D016257:Fura-2; D066298:In Vitro Techniques; D009130:Muscle, Smooth / Q000502:physiology*; D011189:Potassium Chloride / Q000494:pharmacology*
D001572:Benzofurans; D002110:Caffeine; D011189:Potassium Chloride; D002217:Carbachol; D002118:Calcium; D016257:Fura-2