The role of the pubococcygeus muscle in the urethrogenital reflex of male rats.

AIM: To determine the response of the pubococcygeus muscle (Pcm) during the urethrogenital reflex (UGR). METHODS: Urethane-anesthetized male rats (n = 20) were used to describe the gross anatomy of the Pcm (n = 3), the effect of the electrical stimulation of the Pcm on the urethral pressure (n = 3), and the reflex activity of the Pcm due to the mechanical stimulation of the urethra (n = 3) and during penile and urethrogenital reflexes (n = 11). The urethral pressure (UP) was recorded as a response to penile stimulation (brushing, extension, and occlusion) and during the UGR; the electromyographic activity of the Pcm was simultaneously evaluated. The role of the Pcm was assessed by measuring urethral pressure variables before and after denervation of this muscle. RESULTS: The Pcm is innervated by the caudal branch of the somatomotor branch of the pelvic nerve. The electrically induced contraction of the Pcm increased the UP. The mechanical stimulation of the urethra during the induced micturition caused the reflex activity of the Pcm. The different penile stimuli caused bursts of activity of the Pcm. During the UGR, the Pcm exhibited a tonic activity. The transection of the caudal branch of the Smb reduced the maximal UP during the penile stimulation. The same was true regarding the duration of the UGR, the pressure that triggers the UGR, and the highest pressure observed during the UGR. CONCLUSION: Our results suggest that the activation of the Pcm is relevant for the UGR in male rats. Neurourol. Urodynam. 36:80-85, 2017. © 2015 Wiley Periodicals, Inc.

Sucrose exposure during gestation lactation and postweaning periods increases the pubococcygeus muscle reflex activity in adult male rats.

Erectile dysfunction is related to metabolic alterations produced by a high carbohydrate diet, which may affect muscle activity during penile reflex in adulthood. We determined whether sucrose water consumption during gestation lactation and postweaning affects pubococcygeus muscle (Pcm) activity during urethrogenital reflex in adult male rat offspring. Twelve female rats were mated and grouped in control mothers consumed tap water and sucrose mothers consumed sucrose water during gestation lactation. Male pups were weaned and assigned into four groups (n = 6 each): those from control mothers who continued drinking tap water (CM-CO group) or sucrose water (CM-SO group) until adult life, and those from sucrose mothers who drank tap water (SM-CO group) or continued drinking sucrose water (SM-SO group) until adult life. Body weight, Pcm activity during penile stimulation by bipolar electrodes and urethrogenital reflex were analyzed. A catheter was placed into the urethra to record variations in urethral pressure after mechanical stimulation. Two-way ANOVA followed by post hoc tests were used considering P ≤ 0.05 as a significant difference. Males from the SM-SO group showed weight gain compared to the control group (P < 0.001). Also, sucrose intake promoted high Pcm activity (P < 0.0001) but reduced urethrogenital reflex duration CM-CO vs CM-SO (P = 0.02); CM-CO vs SM-CO (P = 0.01); CM-SO vs SM-SO (P < 0.003); and SM-CO vs SM-SO (P < 0.002). Our results suggest that a combination of a sucrose-rich diet during gestation lactation and postweaning modifies Pcm activation during penile reflex. The urethrogenital reflex is a spinal ejaculatory-like reflex, these rats could have penile dysfunction equivalent to premature ejaculation in men.