Inhibition of colon extrinsic primary afferent neurons reduces VMRs to colorectal distention. A) Arch-EGFP was targeted to colon afferents using the TRPV1-cre driver. Arch-EGFP-positive nerve terminals innervate the distal colon. B) Arch-EGFP-positive (green) nerve cell bodies are present in the L6 DRG. C) VMRs to 60 mmHg CRD were recorded in TRPV1-Arch and control littermate mice before (Baseline) and during yellow light illumination (+ Laser). D) There were noticeable decreases in VMR responses with the addition of laser in the TRPV1-Arch mice [n = 9 (5 male, 4 female)], compared to control littermate mice [n = 6 (3 male, 3 female)], but only a trend toward a significant interaction between genotype and laser (p = 0.088; two-way ANOVA). E) Of 9 TRPV1-Arch mice tested, 7 responded to yellow light stimulation. The mean of the baseline and the inhibited trials are shown. Inhibition occurred in an average of 69% of trials (inset). F) In comparing Vil-Arch (n = 8) and TRPV1-Arch (n = 7) mice that responded to yellow light, no statistical differences were detected in the extent of inhibition in responding trials [main effect of yellow light (p = 0.0001), no effect of genotype (p = 0.41), 2-way ANOVA]. G) There was also no significant difference in the percentage of inhibited trials in Vil-Arch vs. TRPV1-Arch responders (p = 0.92, unpaired t-test).