A comparative study of voiding in rat and guinea pig: simultaneous measurement of flow rate and pressure

Asselt, Els van; Groen, Jan; Mastrigt, Ron van

doi:10.1152/ajpregu.1995.269.1.r98

Cited by 34 publications

(47 citation statements)

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“…An ultrasonic flow probe (Probe #ME2PXN; Transonic Systems, Ithaca, NY), connected to a flow meter (TS410; Transonic Systems) was used to measure the UFR. The flow probe was placed around the most distal part of the urethra (31,39).…”

Section: Methodsmentioning

confidence: 99%

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: Methodsmentioning

confidence: 99%

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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show abstract

“…An ultrasonic flow probe (Probe #ME2PXN; Transonic Systems, Ithaca, NY, USA) connected to a flow meter (TS410; Transonic Systems) was used to measure the UFR. The flow probe was placed around the most distal part of the urethra [14][15][16].…”

Section: Simultaneous Recording Of Ivp Eus-emg and Ufrmentioning

confidence: 99%

Chronic pudendal neuromodulation using an implantable microstimulator improves voiding function in diabetic rats

et al. 2016

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Abtract Objective. Few studies have investigated the feasibility of using chronic pudendal neuromodulation for improving voiding function in patients with diabetes who are also experiencing urinary retention. The present study investigated the effects of chronic electrical stimulation (ES) of the sensory branch of the pudendal nerve on voiding function in diabetic rats. Approach. A custom-made implantable microstimulation system was designed and manufactured for chronic implantation in normal control (NC) and diabetic rats. After three or six weeks of pudendal neuromodulation, the intravesical pressure, external urethral sphincter electromyograms (EUS-EMGs), and urine flow rate (UFR) of all rats were simultaneously recorded to assess the effects of chronic pudendal ES on voiding function. Morphological changes in pudendal axons were assessed through hematoxylin and eosin (H&E) staining. Results. Abnormal cystometric measurements, including an increased volume threshold, contraction amplitude, and residual volume (RV) as well as a decreased burst period (BP) indicated voiding dysfunction in the diabetic rats with sham ES for three or six weeks. However, real ES for three or six weeks reversed these abnormal results; these parameters became similar to those of the NC rats and, consequently, voiding efficiency (VE) increased significantly from 17%–45% to 51%–57%. The cross-sectional area and axonal density of the pudendal nerve decreased in all the diabetic rats with sham ES for six weeks; however, these values increased significantly after real ES for six weeks. Significance. This study demonstrated the feasibility of using chronic pudendal neuromodulation for improving voiding function in diabetic rats. These results may facilitate the development of an advanced neural prosthesis for restoring bladder function in clinical settings.

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“…However, in rats, cocontraction of the bladder and sphincter is not considered to be dyssynergic because bladder emptying occurs. During the sustained phase of bladder contraction, the EUS bursts at 6 -10 Hz and the intraluminal bladder pressure shows high-frequency oscillations (HFO) (24,28,47,48). The HFOs correlate temporally with the burst activity of the EUS (14, 23) and are abolished when a ligature of the bladder neck separates the bladder pressure from the urethral pressure (5).…”

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confidence: 99%

Sexually dimorphic micturition in rats: relationship of perineal muscle activity to voiding pattern

Cruz

Downie²

2005

American Journal of Physiology-Regulatory, Integrative and Comp

102

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Cruz, Yolanda, and John W. Downie. Sexually dimorphic micturition in rats: relationship of perineal muscle activity to voiding pattern. Am J Physiol Regul Integr Comp Physiol 289: R1307-R1318, 2005. First published June 30, 2005; doi:10.1152/ajpregu.00088.2005In the present study we examined the possibility that striated muscle activity may underlie sexually dimorphic micturition in rats. Micturition dynamics, the gross anatomy of the external urethral sphincter, and the participation of the striated perineal muscles in micturition were compared in urethane-anesthetized adult male and female rats. Bladder contraction characteristics, particularly the magnitude of bladder high-frequency pressure waves during voiding, differed between sexes. Dissections indicated that the sphincter was more extensive and thicker in males than in females. Electromyography showed that in both sexes the sphincter discharged in bursts that correlated with the rising phase of high-frequency bladder pressure oscillations. Regional differences in discharge pattern were seen in the sphincters of males, with the proximal part of the sphincter showing components activated during bladder filling. Bulbospongiosus, ischiocavernosus, and cremaster muscles also were activated during bladder contraction in males. In both sexes transection of the motor branch of the lumbosacral plexus eliminated the bladder high-frequency oscillations and reduced voided volume. Neurectomy did not affect bladder pressure but reduced voiding efficiency by 45% in males. In females the bladder pressure was dramatically decreased, but voiding efficiency only decreased by 24%. Our findings suggest that, in rats, striated perineal muscles contribute to the sexually dimorphic micturition. Activity of the dimorphic perineal muscles may regulate genital and urinary urethra expulsive functions, helping to expel seminal plug and fluids through the long urethra in the male. electromyography; bulbospongiosus muscle; cremaster muscle; motor nerve transection IN MAMMALS, lower urinary tract function consists of storage of urine in the bladder with brief periods of voiding of urine. These processes involve spinal and supraspinal reflexes (3,4,31). Storage and release of urine requires coordination between the urinary bladder and the external urethral sphincter (EUS). During urine storage, the bladder is inactive but the sphincter shows tonic contraction (42) that helps to support urinary continence (1). During voiding in species such as humans and cats, sphincter activity stops as the bladder contracts so that voiding is efficient (9, 40, 50). After spinal cord injury above the lumbosacral spinal segments, concurrent contraction of bladder and EUS (bladder-sphincter dyssynergia) appears during voiding, leading to a high urethral resistance and poor bladder emptying (2, 13, 18, 37).In contrast to cats and humans, rats show simultaneous activation of the bladder and the EUS during voiding (1, 23, 24). However, in rats, cocontraction of the bladder and sphincter is not considered to ...

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A comparative study of voiding in rat and guinea pig: simultaneous measurement of flow rate and pressure

Cited by 34 publications

References 1 publication

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

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

Chronic pudendal neuromodulation using an implantable microstimulator improves voiding function in diabetic rats

Sexually dimorphic micturition in rats: relationship of perineal muscle activity to voiding pattern

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