Shift from Pro- to Anti-Inflammatory Phase in Pelvic Floor Muscles at Postpartum Matches Histological Signs of Regeneration in Multiparous Rabbits.

Background and Objectives: Pelvic floor muscles (PFM) play a core role in defecation and micturition. Weakening of PFM underlies urogynecological disorders such as pelvic organ prolapse and stress urinary incontinence. Vaginal delivery damages PFM. Muscle trauma implies an inflammatory response mediated by myeloid cells, essential for subsequent recovery. Molecular signaling characterizing the pro-inflammatory phase shifts M1 macrophages to M2 macrophages, which modulate muscle repair. The present study aimed to evaluate histological characteristics and the presence of M1 and M2 macrophages in bulbospongiosus (Bsm) and pubococcygeus muscles (Pcm). Materials and Methods: Muscles from young nulliparous (N) and multiparous rabbits on postpartum days three (M3) and twenty (M20) were excised and histologically processed to measure the myofiber cross-sectional area (CSA) and count the centralized myonuclei in hematoxylin-eosinstained sections. Using immunohistochemistry, M1 and M2 macrophages were estimated in muscle sections. Kruskal-Wallis or one-way ANOVA testing, followed by post hoc tests, were conducted to identify significant differences (p < 0.05). Results: The myofiber CSA of both the Bsm and Pcm of the M3 group were more extensive than those of the N and M20 groups. Centralized myonuclei estimated in sections from both muscles of M20 rabbits were higher than those of N rabbits. Such histological outcomes matched significant increases in HLA-DR immunostaining in M3 rabbits with the CD206 immunostaining in muscle sections from M20 rabbits. Conclusions: A shift from the pro- to anti-inflammatory phase in the bulbospongiosus and pubococcygeus muscles of multiparous rabbits matches with centralized myonuclei, suggesting the ongoing regeneration of muscles.

Sucrose consumption modifies the urethrogenital reflex and histological organization of the bulbospongiosus muscle in the male rat.

Disorders of the bulbospongiosus muscle (Bsm) are associated with male sexual dysfunction, such as premature ejaculation. We determined the effect of sucrose-water consumption during pregnancy-lactation and postnatal on reflex responses and morphology of Bsm fibers in adult male Wistar rat offspring. Female rats were mated and grouped into consumed tap water mothers and sucrose-water (5 %) mothers during pregnancy-lactation to obtain experimental groups. Male pups were weaned and assigned into four groups (n = 12; each group). Those from control mothers who continued drinking tap water (CM-CO group) or sucrose water (CM-SO group), and those from sucrose mothers who drank tap water (SM-CO group) or continued drinking sucrose water (SM-SO group) until adult life. In male rat offspring (n = 6 per group) was recorded the electrical activity of Bsm was recorded during penile stimulation and urethrogenital reflex (UGR). Other male rat offspring were designated for histological analysis (n = 6 per group). Sucrose consumption during prenatal stages increased the frequency of the Bsm during UGR, while pre and postnatal consumption modified muscle fiber cross-sectional area and increased the collagen content, suggesting that a combination of a diet with pre- and postnatal sucrose changes the Bsm morphophysiology possibly causing male sexual dysfunctions.

Multiparity Reduces Urethral and Vaginal Pressures Following the Bulboglandularis Muscle Stimulation in Rabbits.

Unlike male mammals showing a well-delimited external urethral sphincter, female mammals have urogenital sphincters shaped by muscles like the urethrovaginal sphincter. Childbirth-related injuries affect morphometry and function of urogenital sphincters in women, which frequently underlies pelvic floor disorders, including stress urinary incontinence and pelvic organ prolapse. The bulboglandularis muscle (Bgm) seems to shape a urogenital sphincter in rabbits. We determined herein the effect of multiparity on urethral and vaginal pressures generated by the Bgm stimulation in age-matched nulliparous and multiparous chinchilla-breed rabbits to stimulate the Bgm with trains of ascending frequencies (from 1 to 100 Hz; 4 s duration each). Subsequently, the Bgm was excised, measured in width, and weighed. Significant differences (P ≤ 0.05) were determined with Mann-Whitney U or Student t-tests or repeated measures two-way ANOVA followed by Tukey tests. Spearman's partial coefficients were calculated to investigate the correlation between the highest pressure (urethral or vaginal) and the Bgm width. Multiparity reduced the weight and the width in the Bgm origin and medial regions. Urethral and vaginal pressures increased in response to the electrical stimulation of Bgm with frequencies from 20 to 100 Hz. Multiparas showed significant reductions in both types of pressures. We detected a strong correlation (conditioned by multiparity) between the medial Bgm width and the highest vaginal pressure. Our present findings demonstrate that multiparity impairs the function of Bgm, resulting in diminished urethral and vaginal pressures. Furthermore, the significant narrowness of the Bgm was correlated with the vaginal pressure recorded.

High-sucrose diet-fed male rats show affectations in pubococcygeus reflex activation and myofiber content.

In males, the function of the pubococcygeus muscle (Pcm) shows a high androgen dependency. High sucrose intake increases testosterone levels in pubertal male rats. We aimed to analyze the Pcm reflex activity and fiber type in response to a 30 % sucrose diet. Wistar male rats were assigned into two groups: control and sugar. The Pcm electromyographic activity was recorded during the mechanical stimulation of the scrotal skin and penis. We also determined the relative levels of Glut4 expression, glycogen content, myofiber cross-sectional area (CSA), and the content of glycolytic and oxidative with NADH-TR or fast, intermediate, and slow fibers with alkaline (pH 9.4) ATPase histochemistry. The sugar group showed a short Pcm reflex activity, a higher Glut4 expression, and glycogen content; the CSA fibers showed a significant difference in the percentage of fibers with the different transversal areas. The number of nuclei was positively correlated with the CSA of the Pcm fibers. There was also a decrease in oxidative fibers but an increase in glycolytic fibers, while the content of fast muscle fibers increased to the detriment of intermediate and slow fibers. Thus, a high-sugar diet reduced Pcm reflex activity, fiber type, and dysregulation of skeletal muscle energy metabolism.

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.

Estrogens influence differentially on the pelvic floor muscles activation at somatovisceral reflexes involved in micturition of rabbits.

OBJECTIVE: To determine the estrogen-dependency of the bladder and urethral function and the coordinated activation of pelvic floor muscles (PFM) during micturition. METHODS: We allocated age-matched female rabbits to control, 1-month ovariectomized (OVX), and OVX plus 2-week estradiol benzoate (EB) groups to record cystometry, urethral pressure, and electromyograms of bulbospongiosus (Bsm), and pubococcygeus muscles (Pcm) simultaneously. We also measured serum estradiol levels and myofiber cross-sectional area. We assessed urodynamic and urethral variables, categorized the Bsm-Pcm activation patterns at storage and voiding phases, and obtained the power spectrum density of muscle activation around the voiding phase. We investigated the influence of ovarian hormones, in general, and the contribution of estrogen, particularly on the functions of the bladder, urethra, and PFM. Statistical significance was set at P < 0.05. RESULTS: Ovarian hormones influence the bladder, urethral, and PFM functions. The urodynamics analyses indicated estrogens contribute to voiding duration and, to a lesser extent, to the time between bladder contractions. Urethral pressure at closure (maximal pressure-to-maximal urethral pressure ratio) improved partially (8%, P < 0.05) in the OVX plus 2-week estradiol benzoate compared with OVX, but urethral resistance increased (∼1.9-fold, P < 0.05) compared with control rabbits. Our findings support that Pcm activity at voiding is estrogen-sensitive, albeit EB administration reduced it at storage resume, which relates to high urethral resistance. CONCLUSIONS: Ovariectomy impairs bladder and urethral pressures and Bsm and Pcm activation at micturition in anesthetized rabbits. Estrogen administration partially reverts some of these effects and influences Pcm activation.

Lumbosacral ventral root avulsion alters reflex activation of bladder, urethra, and perineal muscles during micturition in female rabbits.

AIM: To determine the effect of the lumbosacral ventral root avulsion (VRA) on the reflex activation of bladder, urethra, and activation of perineal muscles during micturition in female rabbits. METHODS: We allocated 14 virgin female rabbits to evaluate, first, the gross anatomy of lumbosacral spinal cord root (n = 5) and, second, to determine the effect of VRA on perineal muscles during micturition (n = 9). We recorded cystometrograms, urethral pressure, and electromyograms of the bulbospongiosus (Bsm) and ischiocavernosus (Ism) muscles before and after the L6-S2 VRA. Standard variables were measured from each recording and analyzed to identify significant differences (P < .05). RESULTS: We found that the L6-S2 VRA affected directly the bladder and urethral function and reduced the duration and the frequency of the bursting of Ism and Bsm muscles during voiding. The Ism and Bsm showed a phasic activation, of different frequencies, during the voiding phase and the L6-S2 VRA inhibited the co-contraction of the Ism and Bsm-bladder-urethra. CONCLUSIONS: The Ism and Bsm are activated at different frequencies to trigger the voiding phase. The L6-S2 VRA affected the activity pattern of both perineal muscles. These modifications affected the bladder and urethra function. It is possible that the restoration of the activation frequency of perineal muscles contributed for an efficient bladder contraction.

Bladder and urethral dysfunction in multiparous and mature rabbits correlates with abnormal activity of pubococcygeus and bulbospongiosus muscles.

AIMS: To evaluate the combined effect of age and multiparity on the micturition reflex, including pelvic floor muscle activation. METHODS: Young and mature nulliparous rabbits were compared to young and mature multiparas (n = 6 per group). Cystometrograms and urethral pressure (UP) were performed while simultaneously recording the electromyogram (EMG) activity of the pubococcygeus and bulbospongiosus muscles to establish their functional correlation to urological function. RESULTS: Multiparity and age significantly influence the bladder and UP affecting the voiding efficiency and intercontraction interval. Such interaction also reduced the UP threshold, timing, and duration. Other bladder and urethral variables were predominantly affected only by age. Urodynamic alterations correlated with abnormal patterns or absent EMG activity of the pubococcygeus and bulbospongiosus muscles. CONCLUSIONS: The present findings strongly suggest that multiparity and age affects specific pelvic floor muscle reflex activation during micturition, and may contribute to alterations in bladder and urethral function. This data broadens our understanding of the critical role of the appropriate activity of the individual pelvic floor muscles in micturition.

Multiparity modifies contractile properties of pelvic muscles affecting the genesis of vaginal pressure in rabbits.

AIMS: To characterize the contractile properties of the bulbospongiosus (Bsm), isquiocavernosus (Ism), and pubococcygeus muscles (Pcm), and their involvement in the genesis of vaginal pressure in nulliparous and multiparous rabbits. METHODS: Age-matched nulliparous and multiparous rabbits were used to record the isometric contractile responses of each muscle as well as the intravaginal pressure evoked by single square electrical pulses and stimulation trains of ascending frequency. To establish significant differences between groups, two-tail unpaired Student t tests were carried out. The linear correlation between intravaginal pressure and muscle contractile force was analyzed with Pearson correlation tests. For all cases, a P ≤ 0.05 was set as statistically significant. RESULTS: Multiparity decreased the contractile force of Bsm and Ism generated by high-frequency stimulation trains. The normalized force of the Pcm increased when evoked at 1, 4, and 10 Hz while this decreased at higher frequencies (20, 50, and 100 Hz). The contraction of both Bsm and Ism raised particularly the pressure on the perineal vagina while that of the Pcm increased the pressure in the pelvic vagina. Such a functional segregation is still present in multiparous rabbits albeit it was modified. CONCLUSIONS: Multiparity induces changes in the contractile responses of Bsm, Ism, and Pcm, which alterates the vaginal pressure.

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.

Coital Urinary Incontinence Induced by Impairment of the Dorsal Nerve of the Clitoris in Rats.

PURPOSE: We determined the effect of chronic bilateral neurectomy of the dorsal nerve of the clitoris on urinary parameters and sexual behavior of conscious female rats. MATERIALS AND METHODS: A total of 18 anesthetized virgin female Wistar rats were used in this study, including 11 that underwent bilateral neurectomy of the dorsal nerve of the clitoris and 7 that underwent sham surgery. Urinary parameters were determined in awake animals preoperatively, and 3 and 10 days postoperatively. Sexual behavior was tested 14 days postoperatively to determine whether the females expelled urine during sexual encounters. After male ejaculation the females were anesthetized with urethane to record external urethral sphincter electromyogram activity in response to clitoris, perigenital skin and vaginal stimulation. Neurectomy was corroborated anatomically. RESULTS: Sham surgery did not significantly modify urinary parameter values. However, bilateral neurectomy of the dorsal nerve of the clitoris significantly increased voiding frequency and voiding duration (p <0.05). It did not significantly affect the flow rate, voided volume or voiding interval. Of females that underwent bilateral neurectomy of the dorsal nerve of the clitoris 67% expelled urine just after male ejaculation. CONCLUSIONS: These results suggest that the pudendal nerve is an important neural pathway in the convergence and crosstalk of female urogenital neural circuits, and genital deafferentation may be a causal factor of coital urinary incontinence. Rats with bilateral transection of the dorsal nerve of the clitoris may serve as an animal model of coital incontinence.

Anatomic and functional properties of bulboglandularis striated muscle support its contribution as sphincter in female rabbit micturition.

PURPOSE: To determine anatomic and functional properties of the bulboglandularis muscle (Bgm) for clarifying its role in micturition in female rabbits. MATERIAL AND METHODS: Virgin female rabbits were used to describe the gross anatomy and innervation of the Bgm, to determine the effect of the Bgm contraction on urethral pressure, and to evaluate the Bgm activity during the induced-micturition. Both electromyogram and cystometrogram activity were simultaneously recorded in urethane-anesthetized rabbits. Bladder function was assessed measuring standard urodynamic variables before and after blocking the Bgm activity for approaching its contribution to micturition. The relevance of the Bgm activation for micturition was approached applying lidocaine injections. RESULTS: The Bgm was composed of circularly oriented striated fibers enveloping distal urethra and pelvic vagina. Both the venous plexus and urethra were comprised by the Bgm contraction induced by electrical stimulation. The Bgm showed bursts of tonic activity at the storage phase of micturition that gradually decreased until turning off as the onset of the voiding phase. The voided volume, the voiding efficiency, the threshold pressure, and the maximal pressure were decreased after lidocaine injection. Contrastingly, the threshold volume, the residual volume, the voiding duration, and the urethral resistance at voiding were increased. CONCLUSIONS: Present anatomical and physiological findings support that the Bgm acts as a sphincter during micturition of female rabbits. Neurourol. Urodynam. 35:689-695, 2016. © 2015 Wiley Periodicals, Inc.

Morphohistological characteristics of rabbit oviduct: a proposal for a single regionalization.

In rabbits, like other mammals, there are proposals for the oviduct regionalization. Reports consider different regions with inconsistent tissue characteristics, which make it difficult to compare results between studies. Our aim was to analyze morphohistological characteristics of the rabbit oviduct, such as thickness of epithelium, proportion of secretory or ciliated epithelial cells, presence of submucosa or crypts, shape of transverse sections, and thickness of smooth muscle layer, in order to identify regions and discriminate the possible limits between them. To do this, Masson's thricrome was used to identify tissue characteristics along the oviduct. Both qualitative and quantitative analyses were performed. Additionally, Mann-Whitney-U or Kruskall-Wallis tests were used to determine significant differences (P ≤ 0.05) for variables between oviductal regions. Five regions were well distinguished: fimbria, infundibulum, ampulla, isthmus, and utero-tubal junction. Each region had particular histological characteristics that permit its identification. Fimbria and infundibulum had more ciliated cells, the ampulla had a similar proportion of secretory and ciliated cells, and isthmus and utero-tubal junction had more secretory cells. Crypts were observed in all oviductal regions, mainly in isthmus and utero-tubal junction. Fimbria presented packages of smooth musculature. Infundibulum and ampulla showed a thin smooth muscle layer (circular orientation of fibers). Isthmus and utero-tubal junction had a thick smooth muscle layer (inner longitudinal and outer circular orientation of fibers). A single and precise regionalization of oviduct could be very useful to compare studies that analyze the influence of natural conditions or treatments for tissue components or regions.

Neuroprotection and axonal regeneration after lumbar ventral root avulsion by re-implantation and mesenchymal stem cells transplant combined therapy.

Ventral spinal root avulsion causes complete denervation of muscles in the limb and also progressive death of segmental motoneurons (MN) leading to permanent paralysis. The chances for functional recovery after ventral root avulsion are very poor owing to the loss of avulsed neurons and the long distance that surviving neurons have to re-grow axons from the spinal cord to the corresponding targets. Following unilateral avulsion of L4, L5 and L6 spinal roots in adult rats, we performed an intraspinal transplant of mesenchymal stem cells (MSC) and surgical re-implantation of the avulsed roots. Four weeks after avulsion the survival of MN in the MSC-treated animals was significantly higher than in vehicle-injected rats (45% vs. 28%). Re-implantation of the avulsed roots in the injured spinal cord allowed the regeneration of motor axons. By combining root re-implantation and MSC transplant the number of surviving MN at 28 days post-injury was higher (60%) than in re-implantation alone animals (46%). Electromyographic tests showed evidence of functional re-innervation of anterior tibialis and gastrocnemius muscles by the regenerated motor axons only in rats with the combined treatment. These results indicate that MSC are helpful in enhancing neuronal survival and increased the regenerative growth of injured axons. Surgical re-implantation and MSC grafting combined had a synergic neuroprotective effect on MN and on axonal regeneration and muscle re-innervation after spinal root avulsion.

Multiparity causes uncoordinated activity of pelvic- and perineal-striated muscles and urodynamic changes in rabbits.

Temporal and coordinated activation of pelvic- (pubococcygeous) and perineal- (bulbospongiosus and ischiocavernosus) striated muscles occurs during micturition in female rabbits. We have hypothesized that the coordinated activation of pelvic and perineal muscles is modified during the micturition of young multiparous rabbits. Young virgin and multiparous female chinchilla rabbits were used to simultaneously record cystometrograms and electromyograms of the pubococcygeous, ischocavernosus, and bulbospongiosus muscles. Bladder function was assessed using standard urodynamic variables. The temporal coordination of pelvic- and perineal-striated muscle activity was changed in multiparous rabbits. The cystometrogram recordings were different than those obtained from virgin rabbits, as seen in alterations of the threshold volume, the residual volume, the voiding duration, and the maximum pressure. In rabbits, we find that multiparity causes uncoordinated activity of pubococcygeous, ischiocavernosus, and bulbospongiosus muscles and modifies the urodynamics.

Características anatómicas y fisiológicas de los músculos pélvicos en la coneja doméstica (Oryctolagus cuniculus) / Anatomical and physiological characteristics of pelvic muscles in the female rabbit (Oryctolagus cuniculus)

In mammals, the pelvic striated muscles have been linked to the regulation of urinary functions and little is known about the involvement of this muscle in reproductive functions. The objective of this study was to use surgical and electrophysiological techniques to determine the anatomical features and innervation of iliococcygeus and pubococcygeus muscles in adult female rabbits and characterize the reflex electromyographic (EMG) activity in response to genital stimulation. Results show that the iliococcygeus and pubococcygeus are long bilateral muscles with fibers attached to the ilium bone. The muscle fibers are not attached to the pelvic viscera but they run adjacent to the vagina and rectum to be inserted into the sacral vertebrae. The iliococcygeus and pubococcygeus muscles are innervated by branches arising from S3 and S4. The reflex EMG activity was obtained during stimulation of the vaginal orifice skin and the perineal and pelvic vagina. Abdominal vaginal stimulation did not cause an EMG response. Cervical stimulation produced a temporary inhibition in the activity of the iliococcygeus and pubococcygeus. These findings extend the poor descriptions of innervation and anatomy of the striated pelvic musculature shown in the textbooks and atlas of rabbits. They also suggest that the iliococcygeus and pubococcygeous muscles can be activated by reflex action during reproductive processes such as mating and parturition.

En mamíferos, la musculatura estriada pélvica se ha relacionado con la regulación de funciones urinarias y poco se sabe de su participación en funciones reproductivas. Los objetivos del presente estudio fueron determinar las características anatómicas y la inervación de los músculos iliococcígeo y pubococcígeo de la coneja adulta, y caracterizar la actividad electromiográfica (EMG) refleja en respuesta a la estimulación genital. Para ello se utilizaron técnicas quirúrgicas y electrofisiológicas. Los resultados muestran que el iliococcígeo y pubococcígeo son músculos bilaterales que se originan en el hueso iliaco; están inervados por ramas que emergen de S3 y S4; sus fibras musculares no se adhieren a las vísceras pélvicas, sino que discurren lateral a la vagina y al recto y se insertan en las vértebras sacras. Durante la estimulación de la piel del orificio vaginal y la vagina pélvica y perineal se presentó actividad EMG refleja en ambos músculos. La estimulación de la vagina abdominal no indujo respuesta EMG. La estimulación cervical produjo inhibición temporal en la actividad del iliococcígeo y pubococcígeo. Estos resultados contribuyen a las escasas descripciones anatómicas de la musculatura pélvica de la coneja que se encuentran en libros de texto y atlas; también sugieren que los músculos pélvicos iliococcígeo y pubococcígeo podrían activarse reflejamente durante procesos reproductivos, como la cópula y el parto.

Temporal coordination of pelvic and perineal striated muscle activity during micturition in female rabbits.

PURPOSE: To determine the motor basis of urine expulsion the activity of the pelvic (pubococcygeus) and perineal (bulbospongiosus and ischiocavernosus) muscles was recorded during micturition in anesthetized female rabbits. MATERIAL AND METHODS: Virgin female chinchilla rabbits were used for simultaneously recording cystometrograms and electromyograms of the pubococcygeus, ischiocavernosus and bulbospongiosus muscles. The particular contribution of each muscle during micturition was analyzed in another set of experiments in which each was inactivated by bilateral lidocaine injection. Bladder function was assessed using standard urodynamic parameters. RESULTS: Cystometrography showed that micturition comprises 2 phases, that is storage and voiding phases. During the latter phase no high frequency oscillations were recorded. On simultaneous electromyography recordings a temporal, coordinated activation of pelvic (pubococcygeus) and perineal (bulbospongiosus and ischiocavernosus) muscles was observed. During specific blockade of each muscle some modifications in urodynamic parameters were found. CONCLUSIONS: Our findings indicate a specific role for the pelvic and perineal muscles during feminine micturition.