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. 2021 Mar 24;125(5):1543–1551. doi: 10.1152/jn.00088.2021

Figure 2.

Figure 2.

A: representative respiratory (tidal volume, VT) and metabolic rate (reflected in the % O2 leaving the chamber; %O2) traces from a TPH2+/+ pup following administration of vehicle (DMSO) or MDL-11,939 (MDL); scale bar = 1 s. B: raw traces of gasping in a TPH2−/− given vehicle (saline; top left), a TPH2−/− given DOI (top right), a TPH2+/+ given vehicle (DMSO; bottom left) and a TPH2+/+ given MDL (bottom right). Start of hypoxic apnea denoted by arrow. First gasp denoted by *. Dashed arrow indicates the period between the first and second gasp, used to calculate gasping frequency. Scale bar = 10 s in all panels of B. Note the delayed gasping in TPH2−/− and its hastening following DOI. MDL delayed and slowed the gasping of TPH2+/+. DOI, 2,5-dimethoxy-4-iodoamphetamine; TPH2, tryptophan hydroxylase 2; TPH2+/+ mice, wild-type mice; TPH2−/− mice, tryptophan hydroxylase 2 knockout mice; Veh, vehicle.