Figure 1. ACh responses that are reversibly blocked by αBgt and slowly desensitize in mammalian SCG neurons.

A, whole-cell currents evoked by rapid focal application of 500 μM ACh onto the soma of an isolated rat SCG neuron (-60 mV) in the absence (Control) and presence (αBgt) of 50 nM αBgt. B, net αBgt-sensitive ACh-evoked current, determined by subtracting the current induced by ACh in the presence of 50 nM αBgt from that recorded in the absence of the toxin; traces taken from A. The continuous line represents the best fit to the data and is the sum of two exponential functions with τ₁= 162 ms and τ₂= 1.3 s, in this case. C, family of currents evoked by 500 μM ACh recorded from a single SCG neuron at -60 mV in the absence (Control), presence (αBgt) and following washout (Wash) of 50 nM αBgt. D, ACh-evoked whole-cell current amplitudes recorded before, during and after removal of 50 nM αBgt (horizontal bar). Values have been normalized to the maximal response from the same cell, and plotted as a function of time.