Figure 1.
Individual examples of reflex responses to C-fibre activation. Individual EMG recordings from the biceps femoris. The responses were elicited by electrical stimulation (2 ms pulses, 3×threshold) within the sural nerve territory at the time indicated by the arrows. In the following figures, the responses were analysed within a time-window from 150–600 ms following the stimulus (horizontal bar). The upper traces were recorded during the control period, the middle and lower traces were recorded 2 and 10 min following sufentanil 1 μg kg−1. A1, intact animal pre-treated with saline. Following the expected depression, sufentanil elicited facilitations of the reflex. A2, intact animal pre-treated with (+)-HA966 10 mg kg−1. (+)-HA966 enhanced the depressive effects of sufentanil and inhibited the facilitations. B1, obex-transected animal pre-treated with saline. Compared to intact animal, the sufentanil-induced depression increased. B2, obex-transected animal pre-treated with (+)-HA966 10 mg kg−1. (+)-HA966 enhanced the depressive effects of sufentanil.