Figure 1.

Capsaicin depressed the C-wave recorded from the whole nerve trunk of the aortic depressor nerve (ADN). The ADN electroneurogram (ENG) had an early arriving A-wave and a late broad, C-wave (panel A). This representative ADN was estimated to be 21 mm in length. Application of a pledget soaked in saline (Control), 1 μM CAP (green, broken) and then 10 μM CAP (red) for ten min at each condition resulted in progressive depression and then elimination of the slow conducting (0.5 m/sec) C-wave while the fast conducting, A-wave was preserved. Note that the y-axis is broken to better display the C-wave. Amplitude units are arbitrary since the degree of electrical isolation varied from nerve to nerve and was affected by saline shunting and the length of free nerve ending. For semi-quantitative comparisons across nerves, segments of the ENG were full wave rectified and digitally integrated to represent the amplitude of the entire wave (panel B, lower).