Cooling-induced contraction in ileal longitudinal smooth muscle of guinea-pig.
The ileal longitudinal smooth muscle developed a transient contraction on cooling from 37 degrees C to 1 degree C in normal Ca2+ (2.5 mM) medium. The transient contraction was not inhibited by pretreatment with the Ca2+ antagonist, D-600 (1 X 10(-6)M). The contractions were sustained by cooling to 1 degree C in the presence of added Ca2+ greater than 10 mM. After the pretreatment with D-600, when the muscle incubated in normal medium with added 20 mM Ca2+ had been cooled to 1 degree C, a phasic response was only seen. However, D-600 did not inhibit the sustained contraction at 1 degree C after incubation in the presence of added 20 mM Ca2+. It is suggested that the transient and sustained contraction at 1 degree C is maintained by Ca2+ release from a cellular site, probably the cell membrane and it requires more calcium for the sustained tension.
D019297:2,4-Dinitrophenol; D000818:Animals; D001464:Barium / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D003080:Cold Temperature; D004140:Dinitrophenols / Q000494:pharmacology; D005711:Gallopamil / Q000494:pharmacology; D006168:Guinea Pigs; D007082:Ileum / Q000502:physiology; D066298:In Vitro Techniques; D007461:Iodoacetates / Q000494:pharmacology; D019807:Iodoacetic Acid; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D013324:Strontium / Q000494:pharmacology
D002121:Calcium Channel Blockers; D004140:Dinitrophenols; D007461:Iodoacetates; D001464:Barium; D005711:Gallopamil; D019297:2,4-Dinitrophenol; D002118:Calcium; D019807:Iodoacetic Acid; D013324:Strontium