The glossopharyngeal nerve as a novel pathway in immune-to-brain communication: relevance to neuroimmune surveillance of the oral cavity.

Glossopharyngeal afferents may be the neural channel by which immune challenge of the posterior oral cavity conveys information to the brain. If this is the case, then bilateral transection of the glossopharyngeal nerves (GLOx) should disrupt this communication. Injection of lipopolysaccharide (LPS) or interleukin (IL)-1beta into the soft palate (ISP) of sham-operated rats induced a dose-related febrile response. GLOx significantly attenuated the febrile response induced by ISP injection of both LPS and IL-1beta. In contrast, GLOx did not affect the febrile response when LPS or IL-1beta were injected intraperitoneally, indicating that the effect of GLOx is not systemic. These results provide experimental evidence for a novel neural pathway for immune-to-brain communication.