A Non-spinal Neural Circuit for Transmitting Information of Bladder Conditions

Area of Science:

• Neuroscience
• Physiology
• Urology

Background:

• The bladder's role in fluid balance and homeostasis is critical.
• The neural network governing bladder homeostasis is poorly understood compared to the urination reflex.

Purpose of the Study:

• To identify and characterize a novel non-spinal bladder-brain neural network.
• To investigate the functional connectivity and role of this network in bladder homeostasis and inflammation.

Main Methods:

• Vagal nodose ganglion tracing and herpes simplex virus (HSV) tracing from the bladder.
• Chemogenetic activation, functional magnetic resonance imaging (fMRI), and c-Fos staining.
• Utilized a cystitis model to assess the network's role in inflammation.

Main Results:

• Identified a vagal network projecting from the nodose ganglion to the bladder and brainstem.
• Confirmed functional connectivity within this vagal network using chemogenetics and fMRI.
• The network excludes the primary motor cortex (M1), indicating a role beyond conscious urination control.
• Demonstrated the network's involvement in transmitting bladder inflammation signals in a cystitis model.

Conclusions:

• A non-spinal bladder-brain network, primarily involving the vagus nerve, has been identified.
• This network is distinct from the neural circuits controlling urination and appears crucial for bladder homeostasis.
• The identified network plays a role in sensing and potentially transmitting bladder inflammation.