Nerve cells sensitive to spicy compounds help detect harmful bacteria in the gut

Capsaicin-sensitive vagal afferents are crucial for the activation of neurons in the nucleus of the solitary tract in response to pathogenic bacteria.

• Selective lesions of capsaicin-sensitive vagal afferents affect c-Fos expression in the nucleus of the solitary tract after bacterial inoculation.
• Activation of nucleus of the solitary tract neurons by intraluminal pathogenic bacteria requires intact capsaicin-sensitive vagal afferents.
• Tumor necrosis factor alpha (TNFα) and lipopolysaccharide (LPS) can directly activate cultured vagal afferent neurons.
• Nearly all TNFα and LPS responsive neurons in culture are sensitive to capsaicin.
• The afferent arm of the parasympathetic neuroimmune reflex can sense the release of inflammatory mediators in intestinal tissue.

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