Figure 5.

Effects of ganglionic α,β-methyleneadenosine 5′-triphosphate application on spinal wide-dynamic-range (WDR) neuronal responses to electrical test stimulation. (A) Experimental setup for in vivo extracellular recording of WDR neurons and drug application to L4 DRG (inset) in wild-type mice. (B) Example recording shows a WDR neuronal response to high-threshold electrical test stimulation (3.0 mA, 2 ms) at the sciatic nerve before and after ganglionic application of α,β-MeATP (100 μM). A- and C-fiber components (number of action potentials) were separated based on latency. (C and D) Quantification of A-component (C) and C-component (D) response to electrical test stimulation before and 5 minutes after ganglionic application of α,β-MeATP (100 μM) with and without A317491 pretreatment (100 μM, n = 5 mice per group). A317491 (1 mM, 200 μL) was applied to a bath of ~1 mL ACSF 2 minutes before the agonist was added. Data are expressed as mean ± SEM. *P < 0.05, **P < 0.01 vs predrug (paired t test). α,β-MeATP, α,β-methyleneadenosine 5′-triphosphate; DRG, dorsal root ganglia; WDR, wide-dynamic range.