Autor: |
Volkov, E., Frosin, V., Poletaev, G. |
Zdroj: |
Neurophysiology; May1985, Vol. 17 Issue 3, p258-264, 7p |
Abstrakt: |
The resting membrane potential of fibers of the rat diaphragm was measured by a microelectrode technique 3 h after division of the phrenic nerve and incubation in culture medium for 5 days after denervation. The membrane potential was recorded in synaptic regions of fibers close to (2-3 mm) and distant from (9-11 mm) the site of nerve division. The membrane potential of the synaptic region of the close fibers 3 h after denervation became smaller, whereas that of the synaptic region of distant fibers did not change relative to the control. Placing the muscle 3 h after denervation into medium with carbamylcholine (1·10 M), cGMP (1·10 M), or dibutyryl-cGMP (1·10 M) led to hyperpolarization of the synaptic region of the close fibers but did not change the resting potential in the synaptic region of the distant fibers, and abolished differences between them. Five days after division of the nerve, incubation of the muscle in a solution with the above-mentioned substances did not affect the resting membrane potential. Nonquantal release of acetylcholine from motor nerve endings, assessed by the amplitude of hyperpolarization of the postsynaptic membrane, induced by application of curarine against the background of acetylcholine esterase inhibition, 3 h after denervation was identical in the synaptic region of the close and distant fibers and did not differ from the control. It is postulated that the postdenervation fall of membrane potential of rat muscle fibers is not due to disturbance of nonquantal secretion of acetylcholine from motor nerve endings. [ABSTRACT FROM AUTHOR] |
Databáze: |
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