Adjacent segments of the septate axon of the crayfish Procambarus are electrotonically coupled by junction located in the septa between them (see Pappas et al. 1970. J. Cell Biol. 49:173). The coupling resistance at the septa was changed by several experimental treatments. Mechanical injury to an axon increased coupling resistance (more than 7-fold); no recovery of coupling resistance was observed, although the resting potential and resistance of the injured axon could return to near normal levels. Immersion in salines with Na propionate substituted for NaCl increased coupling resistance (mean: 6.1-fold). On return of the preparation to normal saline, coupling resistance recovered virtually completely. Immersion in low Ca++ solutions moderately increased coupling resistance (3.5-fold or less), but return to normal saline was followed by large increases in coupling resistance (5–100-fold). 60 nM Ca++ is near the maximum concentration that leads to increased coupling resistance on return to normal saline. Large increases in coupling resistance are associated with separation of junctional membranes (Pappas et al. 1970. Ibid.); calculations show that the separated membranes greatly increase in resistance. Increase in coupling resistance is probably an important response to injury. Mechanisms underlying changes reported here may be relevant to normal physiological processes of coupling and decoupling.
Article|
April 01 1971
EXPERIMENTAL ALTERATION OF COUPLING RESISTANCE AT AN ELECTROTONIC SYNAPSE
Y. Asada,
Y. Asada
From the Department of Anatomy and the Rose Fitzgerald Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Yeshiva University, New York 10461.
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M. V. L. Bennett
M. V. L. Bennett
From the Department of Anatomy and the Rose Fitzgerald Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Yeshiva University, New York 10461.
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Y. Asada
From the Department of Anatomy and the Rose Fitzgerald Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Yeshiva University, New York 10461.
M. V. L. Bennett
From the Department of Anatomy and the Rose Fitzgerald Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Yeshiva University, New York 10461.
Dr. Asada's present address is the Department of Neuropsychiatry, Osaka University Medical School, Asahi-Machi, Abenoku, Osaka, Japan.
Received:
July 06 1970
Revision Received:
October 19 1970
Online ISSN: 1540-8140
Print ISSN: 0021-9525
Copyright © 1971 by The Rockefeller University Press
1971
J Cell Biol (1971) 49 (1): 159–172.
Article history
Received:
July 06 1970
Revision Received:
October 19 1970
Citation
Y. Asada, M. V. L. Bennett; EXPERIMENTAL ALTERATION OF COUPLING RESISTANCE AT AN ELECTROTONIC SYNAPSE . J Cell Biol 1 April 1971; 49 (1): 159–172. doi: https://doi.org/10.1083/jcb.49.1.159
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