Figure 6.
Chronic SNC80 and ARM390 both reduce δ receptor-mediated inhibition of Ca2+ channels in DRGs. The inhibitory effect of SNC80 (1 µm) on voltage-dependent Ca2+ channels was measured in medium-large DRG neurons. A, B, Exemplar currents from SNC80-responsive (A) or -nonresponsive (B) DRGs. (1, baseline depolarization; 2, SNC80-induced inhibition). Calibration: 10 ms, 20 mA on the x- and y-axes, respectively. C, SNC80 inhibited Ca2+ currents in ipsilateral DRGs from CFA (V, 33 ± 11%), but not naive (N, −0.13 ± 0.87%) animals. Both chronic SNC80 (S) and ARM390 (A) treatments reduced this effect to levels seen in naive DRGs (11.7 ± 5.3 and 0.12 ± 2.4%, respectively). Cumulative data from 6–14 cells are presented showing percentage SNC80 inhibition of Ca2+ currents; *p < 0.05, ***p < 0.001.