Figure 5.

Sensory neuron and spinal cord electrophysiology. Examples are shown of inward currents to a heat ramp (top bar from 24 to 49°C) in an isolated nociceptor from a wild-type (A) and B1 receptor-deficient neuron (B). The proportion of both IB₄-positive and -negative nociceptors responding to the heat stimulus was unchanged in the mutants (C) and the mean magnitude of the inward current was also not altered (D). Application of des-Arg⁹-BK to isolated neonatal spinal cord from wild-type mice increased the C-fiber-evoked component of the VRP (F). The magnitude of the VRP returned to control values 20 min after washout of des-Arg⁹-BK. In B1-deficient mice, wind-up was significantly reduced compared with control (G). Examples of VRP wind-up from wild-type (+/+) and B1 −/− mice are shown in E. Data are means ± SEM and were analyzed by using the t test. **, P < 0.005; *, P < 0.05 compared with control.