Similarities and differences in female and male rat voiding

Streng, Tomi; Santti, Risto; Talo, A.

doi:10.1002/nau.10004

Cited by 48 publications

(54 citation statements)

References 15 publications

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“…For UFR measurements, a discontinuous-like pattern of urine flow was detected, and this characteristic of UFR recordings was similar to that in previous studies by Streng et al (30,32,33). However, the pattern of EUS-EMG in our study completely differed from that of Streng et al This is because the approach used for EUS-EMG recording by Streng et al (30,32) was a monopolar suction electrode method, and that in our study, the approach was a bipolar wire electrode method.…”

Section: Discussionsupporting

confidence: 88%

Influence of serotonergic mechanisms on the urine flow rate in male rats

Fan

Chen

Hsieh

et al. 2014

American Journal of Physiology-Regulatory, Integrative and Comp

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This study extensively examined the role of a 5-HT 1A receptor in controlling voiding function in anesthetized male rats. A simultaneous recording of the intravesical pressure (IVP), external urethral sphincter (EUS)-electromyography (EMG), and urine flow rate (UFR) during continuous cystometry was used. 8-Hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT), a 5-HT 1A receptor agonist, significantly improved the voiding efficiency, as detected by increases in the evoked contraction amplitude, EUS burst period, and silent period, and decreases in the volume threshold, pressure threshold, and residual volume. Interestingly, the UFR during voiding was reduced by 8-OH-DPAT, as evidenced by decreases in the maximal UFR and mean UFRs of the voiding period, spike duration, and interspike interval. Conversely, treating rats with WAY-100635, a 5-HT1A antagonist, produced effects opposite to those produced by 8-OH-DPAT. These findings suggest that 8-OH-DPAT improved the voiding efficiency by enhancing the detrusor contractile ability and prolonging EUS burst period, which would compensate for the lower UFR, resulting from urethral smooth muscle contractions and longer EUS silent periods during voiding. The present study contributes to our understanding of the role of 5-HT1A receptors in controlling the urine flow rate in male rats. intravesical pressure; external urethral sphincter-electromyography; 8-hydroxy-2-(di-n-propylamino)-tetralin; WAY-100635; voiding efficiency SEROTONIN (5-HYDROXYTRYPTAMINE, 5-HT) comprises 14 structurally different 5-HT receptors in mammalian species, including seven subfamilies (5-HT 1 to 5-HT 7 ) (28). A number of 5-HT receptor subfamilies, particularly 5-HT 1A receptors, located at nerve terminals are involved in the function of the lower urinary tract (LUT) (38). Indeed, these 5-HT receptors-related nerve terminals are distributed in areas of the spinal cord containing afferent and efferent components of LUT neural control centers (8,15,19,24,38). Thus, 5-HT receptors appear to modulate all of the pathways involved in the control of reflex bladder and urethral sphincter activity, including the parasympathetic, sympathetic, and somatic pathways (13).The 5-HT 1A receptor is one of the most extensively investigated agents in functions of the LUT in various animal pharmacological experiments, including rats, guinea pigs, and cats (28). However, contradictory results have generated various interpretations of the functions of this receptor subtype in different animal species. Because the rat model has now gained greater popularity as the main species for investigating functions of the LUT, the effects of a 5-HT 1A receptor agonist on regulating urine storage and micturition reflexes have been extensively investigated in female rats (14, 20 -22, 35). However, few studies have explored these pharmacological effects in male animals. Moreover, our recent studies demonstrated that 8-OH-DPAT, a 5-HT 1A receptor agonist, elevated the urethral pressure (resistance) during the voiding reflex in male rats (1...

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Section: Discussionsupporting

confidence: 88%

Influence of serotonergic mechanisms on the urine flow rate in male rats

Fan

Chen

Hsieh

et al. 2014

American Journal of Physiology-Regulatory, Integrative and Comp

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“…As a result, physiological transmural urethral pressure is difficult to measure (23). The pressure range chosen in this study was based on measured maximal voiding pressures for a female rat (35). Second, the urethra consists of musculature arranged in two directions: circumferential and longitudinal.…”

Section: Discussionmentioning

confidence: 99%

Ex vivo biomechanical properties of the female urethra in a rat model of birth trauma

Prantil

Jankowski

Kaiho³

et al. 2007

American Journal of Physiology-Renal Physiology

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Prantil RL, Jankowski RJ, Kaiho Y, de Groat WC, Chancellor MB, Yoshimura N, Vorp DA. Ex vivo biomechanical properties of the female urethra in a rat model of birth trauma. Am J Physiol Renal Physiol 292: F1229 -F1237, 2007. First published December 26, 2006; doi:10.1152/ajprenal.00292.2006.-Stress urinary incontinence (SUI) is the involuntary release of urine during sudden increases in abdominal pressures. SUI is common in women after vaginal delivery or pelvic trauma and may alter the biomechanical properties of the urethra. Thus we hypothesize that injury due to vaginal distension (VD) decreases urethral basal tone and passive stiffness. This study aimed to assess the biomechanical properties of the urethra after VD in the baseline state, where basal muscle tone and extracellular matrix (ECM) are present, and in the passive state, where inactive muscle and ECM are present. Female rat urethras were isolated in a rat model of acute SUI induced by simulated birth trauma. Our established ex vivo system was utilized, wherein we applied intraluminal static pressures ranging from 0 to 20 mmHg. Outer diameter was measured via a laser micrometer. Measurements were recorded via computer. Urethral thickness was assessed histologically. Stress-strain responses of the urethra were altered by VD. Quantification of biomechanical parameters indicated that VD decreased baseline stiffness. The passive peak incremental elastic modulus of the distal segment in VD urethras was less than for controls (1.84 Ϯ 0.67 vs. 1.19 Ϯ 0.70 ϫ 10 6 dyne/cm 2 , respectively; P ϭ 0.016). An increase was noted in passive lowpressure compliance values in proximal VD urethras compared with controls (9.44 Ϯ 2.43 vs. 4.62 Ϯ 0.60 mmHg Ϫ1 , respectively; P ϭ 0.04). Biomechanical analyses suggest that VD alters urethral basal tone, proximal urethral compliance, and distal stiffness. Lack of basal smooth muscle tone, in combination with these changes in the proximal and distal urethra, may contribute to SUI induced by VD. stress urinary incontinence; sphincter; collagen COSTS FOR URINARY INCONTINENCE exceed $16 billion annually, and stress urinary incontinence (SUI) is the most common type of urinary incontinence among middle-aged women (25,26). SUI is associated with weakened and overstretched muscles and connective tissues, which lead to reduced muscle tension in the urethral sphincter complex. This results in the inability of the urethra to close tightly during increased abdominal pressure. Particularly in younger women, neuromuscular injury during vaginal birth often causes disorders involving sphincteric mechanisms (30). The incidence of intrinsic sphincter deficiency was recently found to be greater than previously thought (18), and previous clinical studies suggested that impaired urethral closure mechanisms contribute to intrinsic sphincter deficiency in SUI.Decreased electromyographic activity of the striated urethral sphincter muscle has been detected in middle-aged women with SUI (37). Using a rat model of birth trauma, Resplande et al. (28) ...

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“…HFOs are a common feature of voiding in anesthetized rats, where they occur between two bladder pressure peaks (14,34,60), and urine flows for the short time during these pressure oscillations (60). We did not record EUS EMG activity in unanesthetized rats, but the bladder pressure response during voiding was different from that seen in anesthetized rats.…”

Section: Discussionmentioning

confidence: 99%

Abdominal muscle activity during voiding in female rats with normal or irritated bladder

Cruz¹,

Downie²

2006

American Journal of Physiology-Regulatory, Integrative and Comp

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Cruz, Yolanda, and John W. Downie. Abdominal muscle activity during voiding in female rats with normal or irritated bladder. Am J Physiol Regul Integr Comp Physiol 290: R1436 -R1445, 2006. First published December 22, 2005 doi:10.1152/ajpregu.00556.2005The aims of the present study were to determine in female rats whether abdominal muscle discharges during normal voiding and to describe the effect of bladder irritation on this visceromotor activity. The sensory pathway of this reflex was also determined. Electromyograms (EMGs) indicated that in awake rats, the abdominal muscle was consistently activated during spontaneous voiding and during voiding induced by saline infusion. Similarly, in anesthetized animals, the muscle discharged during urine expulsion. The abdominal EMG activity was not abolished by hypogastric (Hgnx) or sensory pudendal neurectomy (SPdnx). SPdnx dramatically decreased the intercontraction interval and voided volume. Acetic acid infusion reduced the intercontraction interval and increased bladder contraction duration. It also reduced the pressure threshold for evoking the abdominal EMG response and increased the EMG duration and amplitude. Although SPdnx and Hgnx modified some urodynamic parameters, they did not reverse the acetic acid effect on EMG activity. Thus the afferents activating the visceromotor reflex during normal voiding and the increased reflex in response to acetic acid are probably both carried by the pelvic nerve. Abdominal muscle activity induced by bladder distension has been considered to be a pain marker. However, we conclude that in female rats, the abdominal muscle is reflexively activated during physiological urine expulsion. On the other hand, bladder irritation is marked by an exaggeration of this abdominal visceromotor reflex. urethral sphincter; acetic acid; sensory pudendal nerve; hypogastric nerve MICTURITION REQUIRES THE coordinated activity of the bladder, the urethra, and the external urethral sphincter (EUS). This coordination is mediated by multiple reflex pathways organized in the brain and spinal cord. Some reflexes promote urine storage, whereas others facilitate voiding.In rats, several motor reflex pathways are activated during voiding. Striated muscles such as EUS, external anal sphincter, pubococcygeous, cremaster, bulbocavernosus, and ischiocavernosus discharge simultaneously with the bladder contraction (14, 50, 60 -62). Burst activity of the striated sphincter during voiding is necessary for efficient bladder emptying muscle (32,61). Perineal activity may contribute to expulsion of urine (14).The striated muscle reflexes of micturition can be modulated by nociceptive pathways. Thus, although muscles such as external anal sphincter and EUS are activated by the innocuous stimulus of normal voiding in rats, the activity is increased during voiding in animals with mild lower urinary tract irritation (62).Contraction of abdominal musculature in response to visceral noxious stimulation has been considered to be a pseudoaffective response indicating pa...

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Similarities and differences in female and male rat voiding

Cited by 48 publications

References 15 publications

Influence of serotonergic mechanisms on the urine flow rate in male rats

Influence of serotonergic mechanisms on the urine flow rate in male rats

Ex vivo biomechanical properties of the female urethra in a rat model of birth trauma

Abdominal muscle activity during voiding in female rats with normal or irritated bladder

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