Figure 7.

Effects of 5 × 10⁻⁶ m methoctramine on pre- and postsynaptic responses. A, seven superimposed extracellular recordings from the distal region of a single endplate before (Control) and after application of methoctramine. B, the normalized (to the control = 1.0) values (means ± s.e.m.) from 6 endplates of quantal contents, minimal latencies, mean modal values of the latency histograms and the P₉₀ parameter in proximal, central and distal regions of the synapse in the presence of methoctramine. C, same as in B but in the presence of a combination of 1 × 10⁻⁵ m pirenzepine with 5 × 10⁻⁶ m methoctramine. D, histograms of uniquantal postsynaptic current amplitudes in control and in the presence of a combination of methoctramine and pirenzepine.