Effects of menstrual cycle and urinary tract instrumentation on uroflowmetry

Does pharmacological activation of 5-HT1A receptors improve urine flow rate in female rats?

The role of 5-HT1A receptors in regulating voiding functions remains unclear, particularly regarding the urine flow rate (UFR) during voiding. This study examined the effects of 5-HT1A receptors on regulating urethral functions in female rats and investigated underlying modulatory mechanisms. Intravesical pressure (IVP), external urethral sphincter-electromyography (EUS-EMG), and UFR were simultaneously recorded during continuous transvesical infusion to examine the effects of a 5-HT1A receptor agonist (8-OH-DPAT) and antagonist (WAY-100635) on bladder and urethral functions. In addition, this study evaluated the independent roles of urethral striated and smooth muscles in the UFR in rats after a neuromuscular blockade (NMB) treatment and bilateral hypogastric nerve transection. Our results revealed that 8-OH-DPAT significantly increased the maximal UFR but reduced the mean UFR. This discrepancy may be because 8-OH-DPAT markedly increased the maximal UFR during the initial segment of the flow duration and subsequently induced an approximately zero level of long oscillatory waves during the remaining flow duration. Thus the mean UFR was reduced because of the prolonged approximately zero level of the UFR. However, paralyzing the EUS with an NMB agent, 8-OH-DPAT, significantly increased the maximal and mean UFRs because the prolonged zero level of the oscillatory UFR did not continue. These results support the hypothesis that the increased UFR in female rats during voiding is due to the induction of urethral smooth muscle relaxation by 8-OH-DPAT. This paper provides a detailed understanding of the role of 5-HT1A receptors in controlling the UFR in female rats.

Urodynamic and morphometric characteristics of the lower urogenital tracts of female Beagle littermates during the sexually immature period and first and second estrous cycles

OBJECTIVE

To compare values of lower urogenital tract urodynamic and morphometric variables determined during the prepubertal (sexually immature) period and first and second estrous cycles in healthy female Beagle littermates to determine functional and anatomic changes of the lower urogenital tract during those periods.

ANIMALS

5 female Beagle littermates.

PROCEDURES

Urethral pressure profilometry, diuresis cystometry, and vaginourethrography were performed when dogs were 3.5, 4.5, 5, 6, 7, 8, 8.5, and 9 months old and during proestrus; estrus; early, middle, and late diestrus; and early and late anestrus of the first and second estrous cycles.

RESULTS

At the end of the prepubertal period, values of urodynamic and morphometric variables increased significantly, compared with values at earlier times. Maximum bladder capacity developed when dogs were 9 months old. In all dogs, the bladder was intermittently located in an intrapelvic position during the prepubertal period; the bladder was intra-abdominal from the time dogs were 9 months old until the end of the study. Urethral pressure decreased significantly during estrus and early diestrus of the first and second estrous cycles. Bladder capacity increased significantly during diestrus of both estrous cycles. Urethral and vaginal lengths were significantly longer during proestrus and estrus than they were during anestrus.

CONCLUSIONS AND CLINICAL RELEVANCE

Values of lower urogenital tract urodynamic and morphometric variables were influenced by age and phases of the estrous cycle of immature and young adult Beagles in this study. Age of dog and phase of estrous cycle should be considered when interpreting urodynamic and vaginourethrography data.

The influence of ejaculation and abstinence on urinary flow rates

AIMS

To investigate the relationship between urinary flow rate and ejaculation in healthy young men.

METHODS

Young men were voluntarily enrolled in the study. All subjects were healthy, and sexually active, without neurological diseases, genital, or urethral surgery and they were not under any medications. Subjects were evaluated with ultrasound, uroflowmetry, and post-void residual urine (PVR) measurement. All subjects were followed for 22 days (T) with daily uroflowmetry, and were instructed to ejaculate only on specific days (0, 6 and 22) during the study period. On days 0, 6 and 22 uroflow measurements were performed between 2 and 6  hr following ejaculation. Uroflowmetry parameters before and after ejaculation and during abstinence were compared. Data presented a non-normal distribution and the non-parametric Wilcoxon-match-paired test and Kruskal-Wallis test were used for statistical analysis.

RESULTS

18 subjects (mean age 27.4 years) completed the study. A total of 414 uroflow charts were collected. A statistical significant increase in Qmax was observed after ejaculation (T-1 Qmax: 22.7  ±  5.4 vs. T0 Qmax: 25.7 ± 8, P = 0.002; T5 Qmax 23.2  ±  5.4 vs. T6 Qmax 25.4  ±  8, P = 0.031; T21 Qmax 21  ±  4.8 vs. T22 Qmax 24.5  ±  7.9, P = 0.031). Sexual abstinence resulted in a progressive, statistically significant decline in Qmax rates (T0 Qmax 25.7  ±  8 vs. T5 23.2 ± 5.4 P = 0.035; T6 Qmax 25.4  ±  8 vs. T21 Qmax 21  ±  4.8, P = 0.01). PVR did not change during the study period.

CONCLUSIONS

Our results suggest that in young healthy men micturition might be influenced by ejaculation. Our findings, if confirmed in larger series of patients with LUTS, should support that sexual status and activity could represent an important confounding factor in the interpretation of uroflowmetry traces.

Establishing a Mean Postvoid Residual Volume in Asymptomatic Perimenopausal and Postmenopausal Women

OBJECTIVE

To estimate mean postvoid residual (PVR) volumes among perimenopausal and postmenopausal women without significant lower urinary tract or pelvic organ prolapse symptoms.

METHODS

Patients presenting for well-women encounters were offered study participation. Women with a history of urinary incontinence greater than twice per week, urinary retention, symptomatic pelvic organ prolapse, or neurologic disorders were excluded. Pelvic relaxation, if present, was characterized according to the pelvic organ prolapse quantification system. Within 10 minutes of spontaneously voiding, PVR volume was assessed with bladder ultrasonography.

RESULTS

A total of 96 patients were enrolled; mean age was 60+/-11 years. The majority (80%) were postmenopausal; 30% had a previous hysterectomy. Most women (92%) had some degree of prolapse; the median stage was one, most commonly involving the anterior compartment (70%). The median PVR volume was 19 mL (range 0-145 mL); the mean PVR volume was 24+/-29 mL. Only 15% of patients had a PVR volume greater than 50 mL, and 95% had a PVR volume 100 mL or less. Only age 65 years or older was associated with a higher mean PVR volume; hormone therapy, vaginal atrophy, parity, and stage of asymptomatic prolapse did not affect PVR volumes.

CONCLUSION

Most asymptomatic perimenopausal and postmenopausal women had a PVR volume less than 50 mL, which was unaffected by multiple factors that were thought to potentially affect bladder function. Establishing "normal" volumes in this population may aid in developing recommendations regarding appropriate bladder function and retention criteria for women who are symptomatic or those who have had pelvic floor surgery.

Influence of estradiol on micturition thresholds in the rat: involvement of the hypogastric nerve

Studies have shown that the severity of bladder hyperreflexia induced by acute bladder inflammation varies with the ovarian cycle. These results suggest that the hyperreflexia is modulated by ovarian hormones. Other studies have suggested that such modulation involves the bladder's sympathetic innervation. These hypotheses were tested by assessing the development of bladder hyperreflexia in urethane-anesthetized rats subjected to different hormonal manipulations with or without bilateral hypogastric neurectomy (HYPX). The groups included sham ovariectomy (sham OVX), ovariectomy (OVX), OVX with estradiol replacement (OVX+E), OVX+HYPX, and OVX+HYPX+E. Assessments were performed using repeated cystometrograms (CMGs) to measure micturition thresholds (MT) before and hourly for 3 h after intravesicular treatment with 50% turpentine oil (or olive oil in an OVX+E control group). In the uninflamed bladder, treatment with estradiol increased MTs in the OVX+E group compared with the OVX group. As expected, bladder inflammation induced bladder hyperreflexia in sham OVX rats (studied in estrus). This hyperreflexia was eliminated by OVX and restored by either estradiol replacement or HYPX. Combining estradiol replacement and HYPX (i.e., OVX+E+HYPX) did not increase the severity of bladder hyperreflexia compared with either manipulation alone. These results indicate that the bladder hyperreflexia that is induced by bladder inflammation requires the presence of estradiol and suggest that this hormonal modulation is exerted via the sympathetic control of the bladder, possibly via an increase of beta-adrenergic inhibitory actions on the detrusor muscle. Similar mechanisms may contribute to bladder disorders in postmenopausal women.

Influence of the estrous cycle on urodynamic and morphometric measurements of the lower portion of the urogenital tract in dogs

OBJECTIVES

To compare the values of the urodynamic parameters of the lower portion of the urinary tract and vaginourethral measurements obtained during the phases of the estrous cycle in dogs and determine possible functional or anatomic modifications of the lower portion of the urinary tract associated with those phases.

ANIMALS

7 adult female Beagles.

PROCEDURE

Urethral pressure profilometry, diuresis cystometry, and vaginourethrography were performed in each dog during proestrus; estrus; early, mid, and late diestrus; and early and late anestrus. The maximum urethral pressure (MUP), maximum urethral closure pressure (MUCP), urethral functional and anatomic profile lengths (UFPL and UAPL, respectively), integrated pressure, threshold pressure, threshold volume, compliance, urethral length, and vaginal length and width were measured.

RESULTS

For all measurements, significant interindividual variation was detected. Integrated and threshold pressures, APL, and each morphometric value significantly increased from late anestrus to proestrus. Compared with other phases, MUP, MUCP, and integrated pressure values were significantly lower in estrus and early diestrus; UAPL and UFPL values were significantly lower in late diestrus. At each cycle phase in old dogs, MUP, MUCP, threshold pressure, and vaginal length and width were significantly lower (except in proestrus for vaginal measurements) and threshold volume and compliance values were significantly higher, compared with middle-aged dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Urodynamic and morphometric measurements of the lower portion of the urogenital tract are affected by the changes in hormonal balance that occur during the estrous cycle. In sexually intact female dogs, estrous phase determination is important for the interpretation of urodynamic data.

Does urinary incontinence occurrence depend on the menstrual cycle phase?

BACKGROUND

The aim was to study an eventual co-variation of menstrual cycle progression and urinary incontinence (UI) occurrence in 20-54-year-old-women, who have regular menstrual cycles, which are not influenced by exogenous sex hormones.

METHODS

An age-stratified random sample of of 3900 women, aged 20-59 years, answered a questionnaire on UI. The present analysis included 821 women, who reported regular menstrual cycles un-intervened by sex hormone intake.

RESULTS

Five percent of the women reported episodes of UI the day before they answered the questionnaire. Urinary incontinence was unassociated with menstrual cycle characteristics, such as time position from day one in the menstrual cycle, presence and amount of bleeding and the number of sanitary towels or tampons used. There was however, a borderline significant association (P = 0.08) with day 11-15 before the expected next menstrual bleeding.

CONCLUSIONS

The present data allow for limited co-variation, if any, to exist in UI occurrence with the natural menstrual cycle phases, including the menstruation itself. A hypothesis of a moderate UI increase associated with ovulation however, merits attention.

Estrous influences on micturition thresholds of the female rat before and after bladder inflammation

Recent evidence suggests that lower urinary tract functions may be influenced by reproductive status, particularly under pathophysiological conditions. This study used repeated cystometrograms via a transurethral catheter to investigate the influence of estrous stage on micturition thresholds before and after turpentine-induced bladder inflammation in urethane-anesthetized female rats. Whereas there were no estrous influences on micturition threshold in the uninflamed bladder, micturition thresholds after bladder inflammation were significantly lower in rats in proestrus or estrus than in rats in metestrus or diestrus. Furthermore, the risk that the initial urethral catheterization and preinflammation cystometrogram would produce hematuria was significantly lower in estrus than in the other stages. These estrous influences are not readily explicable by levels of ovarian hormones at the time of testing and may relate instead to dynamic interactions between these hormones and other neuroactive molecules. In addition, the results here have relevance to interpretations of cystometrographic findings in the clinic and basic research.