Fig. 8

Inflammatory mediator-induced changes in the excitability of small-sized dural afferent neurons. A. a, Typical voltage traces in response to depolarizing current injections in vehicle-treated (left) and IM-treated (right) small-sized DiI-positive neurons. Four representative raw traces were elicited by one-fold threshold (1 T; 150 pA) to four-fold threshold depolarizing current injections. b, Changes in the number of action potentials elicited by depolarizing current injections (1 T–4 T) in vehicle-treated (open circles) and IM-treated (closed circles) small-sized DiI-positive neurons. The points and error bars represent the mean and SEM from 12 vehicle-treated and 13 IM-treated small-sized DiI-positive neurons. *; p < 0.05, **; p < 0.01 (unpaired t-test). B. a, Typical voltage traces in response to depolarizing current injections in vehicle-treated (left) and IM-treated (right) medium-sized DiI-positive neurons. Four representative raw traces were elicited by one-fold threshold (1 T; 100 pA) to four-fold threshold depolarizing current injections. b, Changes in the number of action potentials elicited by depolarizing current injections (1 T–4 T) in vehicle-treated (open circles) and IM-treated (closed circles) medium-sized DiI-positive neurons. The points and error bars represent the mean and SEM from 10 vehicle-treated and 12 IM-treated medium-sized DiI-positive neurons. n.s; not significant (unpaired t-test). C. a, Typical voltage traces in response to depolarizing current injections in IM-treated small-sized DiI-positive neurons in the absence (left) and presence (right) of 10 μM riluzole. Four representative raw traces were elicited by one-fold threshold (1 T; 120 pA) to four-fold threshold depolarizing current injections. b, Changes in the number of action potentials elicited by depolarizing current injections (1 T–4 T) in IM-treated small-sized DiI-positive neurons in the absence (left) and presence (right) of 10 μM riluzole. The points and error bars represent the mean and SEM from eight IM-treated small-sized DiI-positive neurons. *; p < 0.05, **; p < 0.01 (paired t-test). D. a, Typical action potentials elicited by brief depolarizing current injections (3 ms duration, 500 pA) in the absence (black) and presence (gray) of 10 μM riluzole in medium-sized DiI-positive neurons. Note that riluzole (10 μM) did not affect afterhyperpolarization (AHP) of action potentials. b, Riluzole (10 μM)-induced changes in the amplitude of AHP (left) and decay time constant of AHP (right) in IM-treated small-sized DiI-positive neurons. The columns and error bars represent the mean and SEM from six IM-treated small-sized DiI-positive neurons. n.s; not significant (paired t-test)