Dorsal root activity evoked by stimulation of vagina–cervix–uterus junction in the rat

Abstract

In the present study, we characterized the evoked electrical activity from T13 to S2 dorsal roots (DRs) during glass probe-stimulation of the vagina–cervix–uterus junction (VCUJ) of female Wistar rats. The results showed that gentle stimulation of VCUJ evoked high-amplitude electrical activity in L3 and L6 DRs. Hypogastric or pelvic nerve transection failed to abolish this activity. L6–S1 spinal trunk transection abolished the high-amplitude electrical activity evoked in L6 DR, while transection of the lumbosacral trunk blocked the high-amplitude electrical activity evoked in L3 DR. These data suggest that during copulation, penile intromission likely activates the low-threshold sensory receptors of the VCUJ, thereby evoking sensory neural activity that enters the spinal cord via L3 and L6 dorsal roots, whose axons travel through the lumbosacral trunk and pudendal nerve.