Postvagotomy changes in neurogenic plasma extravasation in rat bronchi

Area of Science:

• Neuroscience
• Respiratory Physiology
• Inflammation Research

Background:

• Neurogenic plasma extravasation in the bronchi is mediated by sensory nerves.
• Vagotomy can alter neurogenic inflammation in the airways.
• The role of substance P in vagotomized airways requires further investigation.

Purpose of the Study:

• To investigate the effect of unilateral midcervical vagotomy on capsaicin-induced plasma extravasation in rat bronchi.
• To determine if substance P can intensify neurogenic plasma extravasation in partially denervated bronchi.

Main Methods:

• Sprague-Dawley rats underwent unilateral midcervical vagotomy.
• Plasma extravasation was induced by capsaicin or substance P at various time points post-vagotomy.
• Extravasation was measured in the mainstem and secondary bronchi ipsilateral and contralateral to the vagotomy.

Main Results:

• Capsaicin-evoked plasma extravasation in secondary bronchi significantly decreased 1-14 days post-vagotomy.
• Differences in extravasation between bronchi sides were significant 3-14 days post-vagotomy.
• Substance P-induced extravasation was not decreased by vagotomy, and caused mucosal edema and goblet cell degranulation.

Conclusions:

• Secondary bronchi are primarily desensitized to capsaicin after unilateral cervical vagotomy.
• Desensitization occurs within 1 day post-vagotomy, reducing neurogenic inflammation.
• Substance P receptors remain functional post-vagotomy, but substance P levels may be insufficient to elicit a strong response.