Unique Neural Circuit Connectivity of Mouse Proximal, Middle, and Distal Colon Defines Regional Colonic Motor...

Area of Science:

• Gastroenterology
• Neuroscience
• Computational Biology

Background:

• Colonic motor patterns are complex, but the underlying neural connectivity and ganglion architecture remain unclear.
• Previous studies have described colonic motor patterns but lacked detailed structural and functional analysis of the enteric nervous system.
• Understanding the neural basis of colonic function is crucial for addressing motility disorders.

Purpose of the Study:

• To quantitatively map the structural architecture of the mouse enteric nervous system by region.
• To investigate the regional underpinnings of different colonic motor patterns using functional calcium imaging, pharmacology, and electrical stimulation.
• To establish regional differences in neural circuitry and their functional implications in the colon.

Main Methods:

• Utilized GCaMP6f/6s calcium indicators in mouse colon segments for functional imaging.
• Combined calcium imaging with assessment of colonic motor activity, immunohistochemistry, and confocal microscopy.
• Employed 3D image reconstruction and statistical analyses to quantify myenteric ganglion structure and neural connectivity.

Main Results:

• Demonstrated regionally specific myenteric ganglion size, architecture, and neural circuit connectivity in the intact colon.
• Identified region-specific neurotransmitter-receptor expression contributing to functional differences along the colon.
• Provided direct evidence of structural and functional regional differences in colonic neural circuits, with comparisons to human colon.

Conclusions:

• Myenteric ganglion architecture and functional connectivity are key to neurogenic control of patterned motor function in the mouse colon.
• Region-specific neural mechanisms underlie distinct colonic motor patterns.
• The mouse model provides a relevant platform for translating findings to human colon physiology.