Induction of rhythmic contraction in canine tracheal smooth muscle.
Na(+)-K+ ATPase activity of the canine tracheal smooth muscle membrane is responsible for the electrogenic pumping of Na+ and K+ ions. It has been shown that this activity results in muscle relaxation. Based on the results of the current study, we suggest that prolonged electrical stimulation induces increased Na(+)-K+ ATPase activity in isolated tracheal smooth muscle. Tracheal smooth muscle pretreated with prolonged electrical stimulation developed graded mechanical activity when subsequently treated with histamine, serotonin, acetylcholine, or 80 mM K+. This increased isometric tension was interrupted by rhythmic activity, which was elicited by histamine or serotonin but not by acetylcholine or 80 mM K+ stimulation. The spontaneous phasic activity was not inhibited by atropine or propranolol but was totally inhibited by 10(-6) M ouabain. These results suggested that the relaxation phase of rhythmic contraction in response to histamine and serotonin stimulation could be the result of stimulated Na(+)-K+ ATPase activity.
Kong
S K
SK
Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
Stephens
N L
NL
D000818:Animals; D004285:Dogs; D004558:Electric Stimulation; D004789:Enzyme Activation; D006632:Histamine / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D010042:Ouabain / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D014132:Trachea / Q000187:drug effects / Q000502:physiology*
D012701:Serotonin; D010042:Ouabain; D006632:Histamine; D000254:Sodium-Potassium-Exchanging ATPase