Figure 3

Lipopolysaccharide and morphine-3-glucuronide increase the excitability of nociceptive dorsal root ganglion neurons. Current clamp recordings were performed on small (≥30 μm) to medium (≥40 μm) dorsal root ganglion (DRG) neurons (L1-6) from naïve rats. Firing of two to four action potentials (APs) was elicited by a 1 second depolarizing current injection (ranging from 0.1 to 0.6 nA depending on the cell) every 30 seconds. (A) Representative recordings demonstrating that application of 2 μg/mL lipopolysaccharide (LPS) increases the number of elicited APs and Compound 15 can reverse this effect. (B) Group data demonstrating that LPS caused a significant increase in DRG AP firing that is reversed with Compound 15. (C) Representative recordings demonstrating that application of 3 μM morphine-3-glucuronide (M3G) increases the number of elicited APs and Compound 15 can reverse this effect. (D) Group data showing that M3G caused a significant increase in DRG AP firing that is reversed by Compound 15.