Variability in H2S and CO generation in the carotid body. (A) Effects of graded hypoxia on H2S generation in the carotid bodies from SD, BN, and SH rats in the absence and presence of l-PAG (10 µM), a CSE inhibitor. (B) Effects of graded hypoxia on CO generation in the carotid bodies from SD, BN, and SH rats. (C and D) Effect of CrMP (10 µM), an HO inhibitor, on CO generation (C) and H2S generation alone or in combination with l-PAG (10 µM) (D) in BN carotid body under normoxia (Nx) or hypoxia (Hx). (E) Effect of CORM-2 (20 µM), a CO donor, on H2S generation in SH rat carotid body under Nx and Hx (PO2 ∼30 mm Hg). Data are mean ± SEM from n = 5 rats. *P < 0.05; **P < 0.01. (See also Figs. S3 and S4).