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Activity of the external urethral sphincter evoked by genital stimulation in male rats
Author(s) -
Juárez Raúl,
Zempoalteca René,
Pacheco Pablo,
Lucio Rosa Angélica,
Medel Alfonso,
Cruz Yolanda
Publication year - 2016
Publication title -
neurourology and urodynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 90
eISSN - 1520-6777
pISSN - 0733-2467
DOI - 10.1002/nau.22850
Subject(s) - medicine , glans , urethral sphincter , external anal sphincter , levator ani , stimulation , foreskin , urology , distension , urethra , anatomy , striated muscles , electromyography , pelvic floor , penis , surgery , anal canal , physical medicine and rehabilitation , rectum , genetics , biology , cell culture
Aims To determine whether the external urethral sphincter (EUS) fasciculi of male rats respond to the mechanical stimulation of genital structures and to characterize the pattern of the electromyographic (EMG) activity of the three regions of the EUS: the cranial (CrEUS), the medial (MeEUS) and the caudal (CaEUS). Methods Electromyographic signals were recorded from the CrEUS, MeEUS and CaEUS regions of the male rat's EUS, before, during and after the mechanical stimulation of the urogenital structures. Results The CrEUS, MeEUS and CaEUS regions responded when brushing and squeezing the foreskin and glans as well as to penile and prostatic urethral distension. The CaEUS EMG amplitude ( P < 0.01) and frequency ( P < 0.05) were lower in comparison to the CrEUS and MeEUS responses to the mechanical stimulation. In addition, the CaEUS was characterized by a short or no afterdischarge. In contrast, the CrEUS and MeEUS responded by presenting a long discharge after the penile or prostatic urethral distension. Conclusions The activity of the EUS is modulated by both, cutaneous and visceral genitourinary stimuli, with motor units being activated by mechanoreceptors located in the foreskin, glans, bladder, and urethra. The CrEUS, MeEUS and CaEUS have differential EMG patterns, indicating that the EUS consists of three anatomically and functionally different regions. Precise coordination in the muscular activity of these regions may be crucial for the control of male expulsive urethral functions, i.e., during voiding and ejaculation. Neurourol. Urodynam. 35:914–919, 2016 . © 2015 Wiley Periodicals, Inc.