TY - JOUR
T1 - Acetylcholine receptor channels on adult mouse skeletal muscle are functionally identical in synaptic and nonsynaptic membrane
AU - Brehm, P.
AU - Kullberg, R.
PY - 1987
Y1 - 1987
N2 - It has been proposed that acetylcholine receptor channels exhibit a functionally distinct 'junctional' form at the region of synaptic contact between nerve and muscle. As a direct test of this idea, we compared acetylcholine-activated single-channel currents from synaptic membrane to those obtained from nonsynaptic sites on freshly dissociated adult mouse toe muscle. We observed, at locations along the entire length of the cell, openings by a channel with a high conductance (70 pS) and brief open time (~ 2 msec), characteristic of the classical 'junctional type' of actylcholine receptor. In 8 out of 10 synaptic and in 9 out of 19 nonsynaptic recordings, we also observed infrequent openings by a low-conductance (45-pS) channel traditionally associated only with nonsynaptic regions. In these recordings the low-conductance acetycholine receptor channel averaged only 3% of the total channel openings. Comparisons of synaptic and nonsynaptic patches indicated no trend toward an increased proportion of low-conductance channel openings with increased distance from the synapse. These findings support the view that the functional properties of the acetylcholine receptor channel do not depend on proximity to the synapse in innervated mouse skeletal muscle.
AB - It has been proposed that acetylcholine receptor channels exhibit a functionally distinct 'junctional' form at the region of synaptic contact between nerve and muscle. As a direct test of this idea, we compared acetylcholine-activated single-channel currents from synaptic membrane to those obtained from nonsynaptic sites on freshly dissociated adult mouse toe muscle. We observed, at locations along the entire length of the cell, openings by a channel with a high conductance (70 pS) and brief open time (~ 2 msec), characteristic of the classical 'junctional type' of actylcholine receptor. In 8 out of 10 synaptic and in 9 out of 19 nonsynaptic recordings, we also observed infrequent openings by a low-conductance (45-pS) channel traditionally associated only with nonsynaptic regions. In these recordings the low-conductance acetycholine receptor channel averaged only 3% of the total channel openings. Comparisons of synaptic and nonsynaptic patches indicated no trend toward an increased proportion of low-conductance channel openings with increased distance from the synapse. These findings support the view that the functional properties of the acetylcholine receptor channel do not depend on proximity to the synapse in innervated mouse skeletal muscle.
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U2 - 10.1073/pnas.84.8.2550
DO - 10.1073/pnas.84.8.2550
M3 - Article
C2 - 2436235
AN - SCOPUS:0023203878
SN - 0027-8424
VL - 84
SP - 2550
EP - 2554
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 8
ER -