Fig. 1

Systemic LPS prevents mAIH-induced long-term facilitation (LTF) of inspiratory hypoglossal and phrenic motor output. a Representative integrated inspiratory phrenic (Phr) and hypoglossal (xii) neurograms before, during and for 90 min after exposures to mAIH in sham-vehicle (i and ii) or LPS-treated rats (iii and iv). Top two traces (i and ii) are from one rat, demonstrating respiratory LTF of phrenic and hypoglossal motor output. Bottom two (iii and iv) traces are from a separate rat illustrating lack of LTF following systemic LPS treatment. b Mean values expressed as a percentage change from baseline (baseline = 0), showing that mAIH triggers LTF in sham-vehicle-treated rats. In rats pre-treated with systemic LPS, LTF was absent. Values are normalized means ± SE. *Significant difference compared to baseline; ^#significant difference compared to LPS-treated group at the indicated time points: for all, p < 0.05. mAIH, moderate acute intermittent hypoxia; Hx1, Hx2, Hx3, hypoxic episodes 1, 2, and 3; Phr, phrenic; xii, hypoglossal; pLTF, phrenic long-term facilitation; xiiLTF, hypoglossal long-term facilitation