Possible mechanisms involved in the spontaneous rhythmicity in the guinea-pig tracheal smooth muscle as induced by glucose removal.
The rhythmic contraction induced by glucose removal was not eliminated by tetrodotoxin, atropine, propranolol or indomethacin, but was abolished by Ca2+ removal from the solution or administration of verapamil and was increased by Ca2+-ionophore (A-23187). The rhythmicity was eliminated by ouabain (1.7 X 10(-6) - 1.7 X 10(-5) M), and was also abolished by removal of potassium from the solution but re-appeared after re-admission of potassium. The addition of calcium or sodium to preparations incubated in calcium or sodium and glucose-free solution in the presence of ouabain did not induce rhythmicity. Our findings suggest that the rhythmicity produced by glucose removal in the guinea-pig tracheal smooth muscle is myogenic in origin and involves a depolarization-dependent calcium influx. The possibility that the rhythmicity may be related to alterations in Na-K ATPase activity was not ruled out.
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D005260:Female; D005947:Glucose / Q000502:physiology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000502:physiology*; D010042:Ouabain / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
D000001:Calcimycin; D013779:Tetrodotoxin; D010042:Ouabain; D001285:Atropine; D011433:Propranolol; D014700:Verapamil; D005947:Glucose; D007213:Indomethacin