Figure 1. Characterization of CB chemoreceptor cell cultures from TH–GFP mouse.

A, GFP expression, anti-TH antibody labelling and brightfield images of two different CB chemoreceptor cell cultures. All GFP-positive cells in the primary cultures were labelled with the anti-TH antibody, but TH-immunostaining also detected a small number of cells not expressing GFP (arrow in left panel). B, changes in intracellular [Ca²⁺] in cells loaded with fura-2 are plotted against time. During the intervals indicated with the bottom bars, a N₂-equilibrated solution was applied to the cells. GFP-expressing chemoreceptor cells (cells 1–3) showed a reversible increase of [Ca²⁺] during hypoxia, while this stimulus was without effect in GFP-negative cells (cells 4–6).