Membrane constants and distribution of acetylcholine (ACh) receptors were determined for multiply innervated fibers of the anterior latissimus dorsi (ALD) and singly innervated fibers of the posterior latissimus dorsi (PLD) muscles of 3–6 month old chickens. The values of the various membrane constants were: length constant, 1.78 mm (mean) in ALD, 0.68 mm in PLD; time constant, 35 msec in ALD, 3.7 msec in PLD; transverse membrane resistance, 4388 Ω cm2 in ALD, 561 Ω cm2 in PLD; and membrane capacitance, 8.2 µF/cm2 in ALD, 7.0 µF/cm2 in PLD. Peaks of ACh sensitivity occurred at intervals of ca. 740 µ on ALD fibers with a low sensitivity remaining between peaks. Only one peak of ACh sensitivity was detected on PLD fibers. The maximum ACh sensitivity found was 5 ± 4 mv/ncoul for fibers of the ALD and 77 ± 60 mv/ncoul for fibers of the PLD. The distance over which this sensitivity fell to 0.1 was ca. 225 µ in the ALD and 140 µ in the PLD. The membranes of these two muscle fiber types differ widely regarding some electrical properties and the disposition of ACh-sensitive receptor sites.
Article|
May 01 1969
Electrical Properties and Acetylcholine Sensitivity of Singly and Multiply Innervated Avian Muscle Fibers
M. R. Fedde
M. R. Fedde
From the Department of Physiology, College of Medicine, University of Utah, Salt Lake City, Utah 84112, and the Neuromuscular Laboratory, Department of Physiological Sciences, Kansas State University, Manhattan, Kansas 66502.
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M. R. Fedde
From the Department of Physiology, College of Medicine, University of Utah, Salt Lake City, Utah 84112, and the Neuromuscular Laboratory, Department of Physiological Sciences, Kansas State University, Manhattan, Kansas 66502.
Dr. Fedde's present address is Department of Physiological Sciences, Burt Hall, Kansas State University, Manhattan, Kansas 66502
Received:
October 21 1968
Online ISSN: 1540-7748
Print ISSN: 0022-1295
Copyright © 1969 by The Rockefeller University Press
1969
J Gen Physiol (1969) 53 (5): 624–637.
Article history
Received:
October 21 1968
Citation
M. R. Fedde; Electrical Properties and Acetylcholine Sensitivity of Singly and Multiply Innervated Avian Muscle Fibers . J Gen Physiol 1 May 1969; 53 (5): 624–637. doi: https://doi.org/10.1085/jgp.53.5.624
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