Fig. 3.

PDE inhibitor–induced increases in cGMP, but not cAMP, stimulate MB in RPTCs. cAMP (A) and cGMP (B) levels were measured in RPTCs by enzyme-linked immunosorbent assay 20 minutes after treatment with dimethylsulfoxide, cilostamide (25 nM), trequinsin (30 nM), rolipram (0.5 μM), or sildenafil (10 nM). (C) FCCP-uncoupled mitochondrial respiration was measured using the Seahorse XF-96 instrument after 24-hour treatment with 8-Br-cAMP or 8-Br-cGMP. (D) RPTCs were exposed to 8-Br-cAMP (10 μM) or 8-Br-cGMP (10 μM) for 24 hours and evaluated for changes in mRNA expression of PGC-1α, ND6, and NDUFβ8 relative to dimethylsulfoxide controls. Data are presented as the mean ± S.E.M. (n ≥ 3). *P < 0.05 vs. vehicle control.