Voltage clamp analysis of acetylcholine produced end-plate current fluctuations at frog neuromuscular junction

摘要: 1. Acetylcholine produced end-plate current (e.p.c.) noise is shown to be the results of statistical fluctuations in ionic conductance voltage clamped end-plates Rana pipiens. 2. These e.p.c. are characterized by their spectra which conform a relation predicted from simple model channel gating behaviour. 3. The rate constant closing α determined and found depend on membrane potential V according = BeAV (B 0·17 msec−1±0·04 S.E., A 0·0058 mV−1±0·0009 S.E. at 8° C) vary with temperature T Q10 2·77, −70 mV. B this expression both therefore produce dependent for α. 4. Nerve-evoked e.p.c.s spontaneous miniature decay exponentially time depends V. magnitude dependence exactly that α. 5. γ single open has been estimated not detectibly potential, mean current. 0·32±0·0045 ( S.E.) × 10−10 mhos. Some variation values occurs muscle muscle. 6. It concluded relaxation kinetics ACh sensitive channels limiting step synaptic constant. independent how it (ACh fluctuations, e.p.c., m.e.p.c.), consistent hypothesis individual rapidly specific remains an distributed duration. 7. agree predictions dipole-conformation change model.