Single channel properties of synaptic acetylcholine receptors in dystrophic fibers

摘要

AbstractNeuromuscular transmission in dystrophic mice has been extensively studied through analysis of nerve‐evoked endplate potentials. In the present study, single channel ACh‐induced activity recorded from endplates of fast twitch muscle fibers frommdxanddydystrophic mice, was compared with activity recorded from wild‐type fiber endplates to ascertain whether expression of these phenotypes leads to changes in ACh receptor properties and synaptic transmission. An 89 pS class of ACh‐induced events predominated in recordings from wild‐type and both strains of dystrophic mice. The mean open times for this class of events was well described by two exponential components, one with a voltage‐independent time constant of ∼ 0.3 ms and the other with a time constant of 2–5 ms which increased e‐fold with ∼ 120 mV of hyperpolarization. The expression of themdxor thedyphenotype was not associated with significant differences in the conductance, distribution of open durations, or the voltage‐dependence of the mean open time for this class of ACh‐induced events. © 19