CFA increases excitability in large sensory neurons. (A) Representative recordings of DRG action potentials (AP) from sham and CFA-treated rats in the presence of 100 nM of tetrodotoxin (TTX). APs were triggered by a 1 ms current stimulus. The minimal (threshold) current amplitude needed to trigger APs was smaller in neurons from CFA-treated animals as illustrated by the smaller amplitude stimulus shown under each action potential. (B) Average threshold currents in sham and CFA conditions. CFA significantly decreased the amplitude of the current needed to trigger an action potential in neuronal cells exposed or not to 100 nM of TTX. Data shown as mean ± SEM (***P <0.001, CFA vs. sham; ###
P <0.001, –TTX vs. + TTX ANOVA followed by Sidak’s MCT; n = 14–22 from 3 rats in each condition).