Differential expression of connexins in trigeminal ganglion neurons and satellite glial cells in response to chronic or acute joint inflammation

Trigeminal nerve activation in response to inflammatory stimuli has been shown to increase neuron-glia communication via gap junctions in trigeminal ganglion. The goal of this stud), was to identify changes in the expression of gap junction proteins, connexins (Cxs), in trigeminal ganglia in response to acute or chronic joint inflammation. Although mRNA for Cxs 26, 36, 40 and 43 was detected under basal conditions, protein expression Of Only CXS 26, 36 and 40 increased following capsaicin or complete Freunds adjuvant (CFA) injection into the temporomandibular joint (TMI). While Cx26 plaque formation between neurons and satellite glia was transiently increased following capsaicin injections, CX26 plaque.forination between neurons and satellite glia was sustained in response to CFA. Interestingly, levels of Cx36 and Cx4o were only elevated in neurons following capsaicin or CFA injections, but the temporal response was similar to that observedfor 0:26. In contrast, CX43 expression was not increased in neurons or satellite glial cells in response to CF-A or capsaicin. Thus, trigentinal ganglion neurons and satellite glia can differentially regulate Cx expression in response to the type and duration of inflammatory stinuili, which likely facilitates increased neuron-glia communication during acute and chronic inflainination and pain in the TAIJ.