Fig. 3.

Nicotine facilitates neuronal excitably in LS. (A–C) Recordings were obtained from the same neuron in the absence and the presence of 3 µM nicotine and upon wash-out. The waveforms of MP during depolarizing (40 pA) and hyperpolarizing (−300 pA) current steps are superimposed. The red and blue dashed lines mark MP at ±0 mV and −130 mV, respectively. (D–F) Values before (black traces) and after the application of 3 µM nicotine (red) and upon the wash-out (blue). The analyzed parameters are: (D) the peak MP response to hyperpolarizing currents ranging from −20 pA to −300 pA in 20-pA increments; (E) the amplitude of the first AP upon depolarization by current steps (20–300 pA); (F) the number of APs per second. Note that, under control conditions, no AP was triggered at 20 pA (black). (G–I) The phenotype of both AP (left) and RAP (right) in a train, in the absence (black) or presence of 3 µM nicotine (red), and during wash-out (blue). Note the transition of a single AP with prominent ADP (under control conditions) into double spikes in the presence of nicotine. Scale bars for A–C and G–I are identical.