Fig. 2.

Representative compound action potentials (CAP) from the left aortic depressor nerve (ADN) of male and female rats. Bipolar, constant-voltage stimulation (arrowhead) of the ADN in a male (A) and a female (B) rat showed clear differences in the magnitude and timing of the CAP evoked from low-threshold myelinated baroreceptor (BR) afferent fibers. The CAP corresponding to the faster-conducting A-type fibers was discernable at stimulation intensities as low as 0.1 V. The leftmost dotted line separates the stimulus artifact from the leading edge of the CAP for A-type fibers which extends through to the 10-m/s demarcation (dashed line). The CAP corresponding to the slower-conducting Ah-type fibers was bounded by the 10-m/s and 2-m/s demarcation lines. The CAP for the Ah-type BR fibers was apparent at low stimulus intensities (∼0.5 V) in female rats, but in male rats no such Ah-type volley was observed. Each trace is an average of 25 recordings at a stimulus rate of 1 Hz.