Figure 7.

Comparison of current activation threshold of DRG nociceptive neurons in response to stimulation of the dorsal roots, between control and cancer rats.

(A) Current activation threshold of DRG nociceptive neurons in response to stimulation of the dorsal roots. Current threshold was defined using the rheobase/chronaxie curve (threshold duration), which was determined as the minimum stimulus current to the dorsal root sufficient to evoke an AP with pulses of 0.02 ms, 0.1 ms, 0.2 ms, 0.4 ms, and 0.6 ms duration. C-fibre neurons (a), Aδ-fibre neurons (b), and Aβ-fibre neurons (c) show a lower rheobase in cancer rats compared with controls. *p < 0.05, **p < 0.01; (B) Representative recordings of the repetitive discharge characteristics of DRG neurons evoked by dorsal root stimulation by current pulses of 1 mA, 0.4 m. DRG = dorsal root ganglia; AP: action potential.