5-HT2A/B receptor expression in the phrenic motor nucleus in a rat model of ALS (SOD1

Despite respiratory motor neuron death, ventilation is preserved in SOD1(G93A) rats. Compensatory respiratory plasticity may counterbalance the loss of these neurons. Phrenic long-term facilitation (pLTF; a form of respiratory plasticity) in naïve rats is 5-HT(2) and NADPH oxidase-dependent. Furthermore, 5-HT(2A), not 5-HT(2B), receptor-induced phrenic motor facilitation is NADPH oxidase-independent in naïve rats. pLTF is NADPH oxidase-dependent in pre-symptomatic, but not end-stage, SOD1(G93A) rats. Here, we hypothesized that in the putative phrenic motor nucleus (PMN) of SOD1(G93A) rats vs. wild-type littermates: 1) pre-symptomatic rats would have greater 5-HT(2B) receptor expression that decreases at end-stage; and 2) 5-HT(2A) receptor expression would increase from pre-symptomatic to end-stage. Putative PMN 5-HT(2A) receptor expression was reduced when comparing across (but not within) pre-symptomatic vs. end-stage groups (p