The slow tonic responses of the anterior byssus retractor of Mytilus edulis to rapid cooling were investigated by simultaneously recording tension and resting potential changes after soaking the muscle in banthine, a powerful neuromuscular blocking agent. The quantitative relations between the amount of cooling and the amount of associated depolarization necessary for contraction at various concentrations of potentiating potassium can be expressed in a family of curves. The plateaus of the curves for sea water and for potassium-free sea water were beneath the depolarization value necessary for contraction, so that it is clear that no amount of cooling with sea water alone or with potassium-free sea water would ever be effective. When the muscle is treated with subthreshold amounts of potassium and rapidly cooled in various concentrations of sodium ion and calcium ion, respectively, the sodium and calcium do not affect the amount of depolarization. Acetylcholine, in subthreshold amounts, has a potentiating effect, but, unlike potassium and cooling, acts through the nervous apparatus. Mytilus muscle will respond to cooling with tonic contraction whenever a critical threshold amount of depolarization is achieved. Cooling alone cannot trigger the contraction since it cannot bring about sufficient depolarization. Cooling can result in contraction, however, if used in conjunction with some other subthreshold depolarizing agent. Cooling affects the contractile mechanism by first causing membrane breakdown and depolarization.
Article|
September 20 1958
THE EFFECT OF IONS UPON THE RESPONSE OF SMOOTH MUSCLE TO COOLING
Rita Guttman,
Rita Guttman
From the Department of Biology, Brooklyn College; Department of Physiology, State University of New York, Downstate Medical Center at New York City; and the Marine Biological Laboratory, Woods Hole, Massachusetts
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Samuel M. Ross
Samuel M. Ross
From the Department of Biology, Brooklyn College; Department of Physiology, State University of New York, Downstate Medical Center at New York City; and the Marine Biological Laboratory, Woods Hole, Massachusetts
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Rita Guttman
From the Department of Biology, Brooklyn College; Department of Physiology, State University of New York, Downstate Medical Center at New York City; and the Marine Biological Laboratory, Woods Hole, Massachusetts
Samuel M. Ross
From the Department of Biology, Brooklyn College; Department of Physiology, State University of New York, Downstate Medical Center at New York City; and the Marine Biological Laboratory, Woods Hole, Massachusetts
Received:
January 15 1958
Online ISSN: 1540-7748
Print ISSN: 0022-1295
Copyright, 1959, by The Rockefeller Institute
1958
J Gen Physiol (1958) 42 (1): 1–8.
Article history
Received:
January 15 1958
Citation
Rita Guttman, Samuel M. Ross; THE EFFECT OF IONS UPON THE RESPONSE OF SMOOTH MUSCLE TO COOLING . J Gen Physiol 20 September 1958; 42 (1): 1–8. doi: https://doi.org/10.1085/jgp.42.1.1
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