(A) Representative traces of oxygen consumption rate (OCR) measurements from primary rat cortical microglia at 21% O2 following 18 hours of LPS (100 ng/mL) plus IFN-γ (10 ng/mL) stimulation (LPS/IFN-γ) or control (CTRL) treatment. FCCP (4 µM), pyruvate (Pyr, 10 mM) and antimycin A (AA, 1 µM) were added when indicated. (B) Quantification of basal OCR, maximal OCR, and spare respiratory capacity from the experiments described in (A). (C) Representative traces of OCR measurements from cortical microglia at 3% O2 following 18 hours of LPS/IFN-γ stimulation or CTRL treatment. Drug additions were as in (A). (D) Quantification of basal OCR, maximal OCR, and spare respiratory capacity from the experiments described in (C). (E–G) Comparison of basal OCR (E), maximal OCR (F), and spare respiratory capacity (G) from microglia (combined data of male and female) at 21% vs. 3% O2. Traces in (A) and (C) are mean ± standard deviation of three wells of cells from the same microglial preparation and are representative of 3–4 independent experiments using different preparations. Data in (B) and (D) are mean ± standard deviation, n = 3–4 microglial preparations derived from different animals. Data in (E–G) are mean ± standard deviation, n=6–8 microglial preparations derived from different animals. Each individual preparation utilized litters stemming from separate dams. #p <0.05 compared to CTRL of the same sex or the same O2. *p<0.05 for 21% vs. 3% O2.