Overactive bladder and pontine reticular formation

Solifenacin/Mirabegron Induces an Acute Compliance Increase in the Filling Phase of the Capacity-Reduced Urinary Bladder: A Pressure-Volume Analysis in Rats

Aims: Pressure in the bladder, which is a high compliance organ, is only slightly elevated to a considerable filling volume during storage. Although cystometry off-line offers mean compliance, no protocol is available for real-time assays of the dynamics of bladder compliance, and the potential impact of solifenacin and mirabegron on dynamic bladder compliance has not been established.

Methods: Along with constantly infused cystometry, a pressure-volume analysis (PVA) was performed by plotting intra-vesical volume against pressure in Sprague-Dawley rats. The instant compliance was assayed as the slope of the trajectory, and the mean compliance (Cm) was determined by the slope of the line produced by regression of the data points at the end of the first, second, and third quarters of the filling phase.

Results: Under a steady-state, the PVA trajectory moved clockwise which shaped coincident enclosed loops with stable compliance. Though administering to naïve animals solifenacin, but not mirabegron (both 1 × 10⁻⁵−1 × 10⁻¹ mg/kg, i.a.) decreased the peak pressure, both of these reagents exhibited acute increments in the trajectory slope and Cm of the filling phase in a dose-dependent manner (ED₅₀ = 1.4 × 10⁻⁴ and 2.2 × 10⁻⁵ mg/kg, respectively). Resembling urine frequency/urgency in OAB patients, the voiding frequency of a capacity-reduced bladder was increased in association with decreased compliance which was ameliorated by both acute solifenacin and mirabegron injections (both 1 × 10−1 mg/kg).

Conclusion: In addition to their well-known anti-inotropic/relaxative effects, solifenacin, and mirabegron induce an acute increase in bladder compliance to ameliorate OAB-like syndromes. Together with time-domain cystometry, PVA offers a platform for investigating the physiology/pathophysiology/pharmacology of bladder compliance which is crucial for urine storage.

Caffeine as a Probable Factor for Increased Risk of OAB Development in Elderly People

OBJECTIVE

This study was conducted to compare overactive bladder (OAB) prevalence among people greater than 60 years of age who intake various doses of caffeine, as well as those who abstain from caffeine.

PATIENTS AND METHODS

A randomized observational study was carried out in Vladivostok Gerontological Hospital. A total of 1,098 retired people greater than 60 years of age (659 women and 439 men, average age 67.1 years) took part in the study. They were admitted to the in-patient department with the purpose of annual physical examination performed in accordance with the order of the Ministry of Public Health of the Russian Federation. People over age 60, who at the moment of examination were in satisfactory health condition, were included into the study. People in which OAB had been detected or who used to take antimuscarinic were excluded from the study. Assessment tools for examining the patients' lower urinary tract condition were as follows: OAB-q SF, urination diaries, and uroflowmetry.

RESULTS

In the course of the experiment conducted, we found that 1/3 of people, both men and women greater than 60 years of age, who did not previously seek medical advice due to urination troubles, had symptoms of detrusor overactivity. These symptoms were moderate and did not bother patients too much in most cases (63.4%). It was also found that most patients consumed no more than 300mg caffeine with beverages per day, with 30% and 10% of patients suffering from OAB or severe detrusor overactivity, respectively. At the same time, almost 50% of patients taking more than 300 mg of caffeine per day suffer from OAB.

CONCLUSION

48.1% of people over 60 years of age suffering from overactive detrusor symptoms consume greater than 300 mg caffeine daily, which is significantly higher than that of their peers who do not intake excessive amounts of caffeine.