Macroscopic electrical propagation in the guinea pig urinary bladder.

Area of Science:

• Physiology
• Electrophysiology
• Urology

Background:

• Macroscopic electrical propagation in the urinary bladder wall is poorly understood.
• Extracellular electrode arrays offer a method to study these electrical patterns.

Purpose of the Study:

• To investigate macroscopic electrical propagation patterns in the guinea pig urinary bladder wall.
• To characterize the influence of intravesical volume and pharmacological agents on bladder electrical activity.

Main Methods:

• Isolated guinea pig bladders were studied using a 16x4 extracellular electrode array.
• Recordings were made at varying intravesical volumes, with and without carbachol, nifedipine, or tetrodotoxin.
• Propagation maps were constructed from extracellular signal analysis.

Main Results:

• Electrical waves were detected across the bladder surface, predominantly propagating axially (dome-to-base or vice versa).
• Increased intravesical volume significantly reduced conduction velocity (4.9 to 2.7 cm/s).
• Carbachol enhanced, nifedipine reduced, and tetrodotoxin had minimal effect on electrical activity. A novel phenomenon, 'electrical patches,' was also identified.

Conclusions:

• The urinary bladder exhibits distinct electrical wave propagation and patch phenomena.
• Axial electrical waves may underlie spontaneous bladder contractions during filling.
• Bladder volume and specific drugs modulate bladder wall electrical activity.