Macroscopic electrical propagation in the guinea pig urinary bladder

Abstract

There is little knowledge about macroscopic electrical propagation in the wall of the urinary bladder. Recording simultaneously from a large number of extracellular electrodes is one technology that could be used to study the patterns of macroscopic electrical propagations. The urinary bladders from 14 guinea pigs were isolated and placed in an organ bath. A 16 × 4-electrode array was positioned at various sites on the serosal bladder surface, and recordings were performed at different intravesical volumes. In four experiments, carbachol (CCH; 10−6 M), nifedipine (10 mM), or tetrodotoxin (TTX; 10−6 M) was added to the superfusing fluid. After the experiments, the extracellular signals were analyzed and propagation maps were constructed. Electrical waves were detected at all sites on the bladder surface and propagated for a limited distance before terminating spontaneously. The majority of waves (>90%) propagated in the axial direction (i.e., from dome to base or vice versa). An increase in vesicle volume significantly decreased the conduction velocity (from 4.9 ± 1.5 to 2.7 ± 0.7 cm/s; P < 0.05). CCH increased, nifedipine decreased, while TTX had little effect on electrical activities. In addition, a new electrical phenomenon, termed a “patch,” was discovered whereby a simultaneous electrical deflection was detected across an area of the bladder surface. Two types of electrical activities were detected on the bladder surface: 1) electrical waves propagating preferentially in the axial direction and 2) electrical patches. The propagating electrical waves could form the basis for local spontaneous contractions in the bladder during the filling phase.

Physiological and pathophysiological implications of micromotion activity in urinary bladder function

“…It was hypothesized that these electrical waves/patches may form the basis for microcontractions/microelongations (Hammad et al . ). As this method is fundamentally two‐dimensional, as is video filming, it is not currently known whether all micromotion activity is co‐planar with the bladder surface ( x‐ and y‐ vectors) or whether micromotions may also occur in a perpendicular direction ( z‐ vector; Fig.…”

Identification of uterine pacemaker regions at the myometrial–placental interface in the rat

“…2009). In contrast, the small intestine and bladder generate excitatory potentials at distinct but anatomically variable sites throughout the tissue (Lammers & Stephen, ; Hammad et al . 2014).…”

A pilot study of cardiac electrophysiology catheters to map and pace bladder electrical activity

“…Animal studies have established a link between increased interstitial cell gap junction expression and bladder overactivity The details of this process on a macroscopic level in the bladder has yet to be elucidated. However, a recent study measuring electrical activity across the bladder in guinea pigs with a multi electrode array, uncovered microvolt signals traveling from base to dome and isolated areas of spontaneous electrical activity …”