Vagal influences over mast cells.

Area of Science:

• Neurogastroenterology
• Immunology
• Cell Biology

Background:

• Intestinal mucosal mast cells (IMMC) are anatomically linked to mucosal nerves, suggesting potential communication.
• Rat mast cell protease II (RMCPII) release from IMMC can be triggered by conditioned stimuli, hinting at neural involvement.
• Previous studies indicated vagal nerve involvement in the IMMC-nerve axis, showing afferent penetration, trophic relationships, and neurochemical release.

Purpose of the Study:

• To investigate the IMMC-nerve axis in a rat model of post-inflammatory bowel disorders.
• To explore the functional connection between mast cells and extrinsic afferent nerves following parasitic infection.
• To establish Nippostrongylus brasiliensis (Nb) infection as a model for altered gut-brain communication relevant to functional bowel disorders.

Main Methods:

• Utilized a Nippostrongylus brasiliensis (Nb) infection model in rats to induce post-inflammatory changes.
• Assessed mast cell numbers and mucosal nerve remodeling (hyperinnervation) post-infection.
• Measured mesenteric afferent nerve firing in response to Nb antigen and 2-methyl-5HT challenges.

Main Results:

• Nb infection led to increased mast cell counts and mucosal nerve remodeling.
• Nb antigen challenge significantly increased mesenteric afferent nerve firing in infected rats.
• Post-infection challenge with 2-methyl-5HT confirmed intact vagal afferent innervation and functional mast cell-nerve communication.

Conclusions:

• Data suggest a functional connection between intestinal mast cells and extrinsic afferent nerves.
• Nb infection serves as a valuable model for studying altered gut-brain communication in post-inflammatory states.
• Understanding the mast cell-nerve axis is critical for developing treatments for human functional bowel disorders.