The effect of pro-inflammatory cytokines on the discharge rate of vagal nerve paraganglia in the rat

Vagal paraganglia resemble the carotid body and are chemosensitive to reduction in the partial pressure of oxygen ([Formula: see text]) (O’Leary et al., 2004). We hypothesised that they may also mediate communication between the immune system and the central nervous system and more specifically respond to the pro-inflammatory cytokines: interleukin-1 beta (IL-1β) and tumour necrosis factor-α (TNF-α). We recorded axonal firing rate of isolated superfused rat glomus cells – located at the bifurcation of the superior laryngeal nerve – to IL-1β or TNF-α at concentrations of 0.5 ng/ml, 5 ng/ml and 50 ng/ml. Twenty-three successful single fibre recordings were obtained from 10 animals. IL-1β and TNF-α had no statistically significant effect on the frequency of action potentials observed (p = 0.39 and 0.42, respectively, repeated measures ANOVA). The activity of both cytokines was tested by observing translocation of P65-NFκB from cytoplasm to nucleus in cultured HELA cells. In conclusion, an immune role for SLN paraganglia has not been established.