The Frequency-Dependence of Pre- and Postganglionic Nerve Stimulation of Pig and Rat Bladder.

Purpose: The urinary bladder generates phasic contractions via action potentials generated in pre- and then postganglionic neurons. Whilst the frequency-dependence of postganglionic neurons to generate contractions has been quantified, the dynamic range of preganglionic neurons is less clear and if intramural ganglia exert frequency-dependent modulation of transmission between pre- and postganglionic neurons. The phosphodiesterase type 5 inhibitor sildenafil reduces neurotransmitter release from postganglionic fibres to detrusor smooth muscle and an additional question was if there was also a preganglionic action.

Stretch- and carbachol-induced ATP release from bladder wall preparations of young and aged mice.

Aims: Bladder wall stretch increases tissue tension and releases adenosine 5'-triphosphate (ATP) as part of a transduction process to sense bladder filling. Aging is associated with bladder fibrosis to produce a stiffer bladder wall: this may augment ATP release and contribute to age-dependent urgency. Muscarinic agonists also release ATP and present a potential target for antimuscarinic agents, but its age-dependency is unknown.

The calculation and comparison of the Detrusor Contractility Parameter and Watts Factor.

Aims: To test the significance of association between a validated index of detrusor contractility, v , the Watts Factor, and the Detrusor Contractility Parameter, t ; and to test whether t depends on outflow tract resistance as indicated by Bladder Outlet Obstruction Index (BOOI).

Methods: Thirty-seven pressure-flow traces from 20 male and 17 female patients were analyzed and forms of the Watts Factor, t and BOOI were compared with v .

Results: The Detrusor Contractility Parameter, t , is significantly associated with v for both women and men without a high degree of bladder outlet obstruction.

Mild external heating and reduction in spontaneous contractions of the bladder.

Objectives: To measure the effect of external heating on bladder wall contractile function, histological structure and expression of proteins related to tissue protection and apoptosis.

Material And Methods: In vitro preparations of bladder wall and ex vivo perfused pig bladders were heated from 37 to 42°C, 46 and 50°C for 15 min. Isolated preparations were heated by radiant energy and perfused bladders were heated by altering perfusate temperature.

Estimation of bladder contractility from intravesical pressure-volume measurements.

Aims: To describe parameters from urodynamic pressure recordings that describe urinary bladder contractility through the use of principles of muscle mechanics.

Methods: Subtracted detrusor pressure and voided flow were recorded from patients undergoing filling cystometry. The isovolumetric increase of detrusor pressure, P, of a voluntary bladder contraction before voiding was used to generate a plot of (dP/dt)/P versus P.

Contractile effects and receptor analysis of adenosine-receptors in human detrusor muscle from stable and neuropathic bladders.

To measure the relative transcription of adenosine receptor subtypes and the contractile effects of adenosine and selective receptor-subtype ligands on detrusor smooth muscle from patients with neuropathic overactive (NDO) and stable bladders and also from guinea-pigs. Contractile function was measured at 37°C in vitro from detrusor smooth muscle strips. Contractions were elicited by superfusate agonists or by electrical field stimulation.