Intrinsic innervation of the urinary bladder

Area of Science:

• Urology
• Neuroscience
• Cell Biology

Background:

• The intrinsic innervation of the urinary bladder is crucial for its function.
• Understanding the neural pathways involved in bladder control is essential for treating urinary dysfunction.

Purpose of the Study:

• To investigate the ultrastructure of intrinsic nerve terminals in the cat urinary bladder.
• To classify different types of nerve terminals based on their morphological characteristics.
• To explore the potential functional implications of these findings for bladder control.

Main Methods:

• Total extrinsic denervation of the cat urinary bladder, including spinal nerve transection and hypogastric ganglion extirpation.
• Electron microscopy analysis of the intrinsic innervation.
• Classification of nerve terminals based on vesicle content and morphology.

Main Results:

• Four distinct types of nerve terminals were identified based on vesicle characteristics (clear, granulated, and 'peptidergic').
• Synapses were observed between nerve processes and neuronal cell bodies (perikarya), as well as between adjacent nerve processes.
• Spine synapses and desmosome-like attachments were found in the ureterovesical ganglia.
• Up to three different types of nerve fibers were observed innervating the same neuron.

Conclusions:

• The ureterovesical junction functions as a single, integrated unit coordinating bladder activity.
• The diverse intrinsic innervation suggests complex local neural circuits within the bladder wall.
• These findings provide a morphological basis for understanding bladder control and potential therapeutic targets.