Figure 12

Small intensely fluorescent (SIF) cells in the atria. (a) TH-IR SIF cells were grouped into clusters of 3–8 and expressed stronger TH-IR labeling than TH-IR neurons in the ICG. (a’,a’’) Two optical sections showed two separate SIF cell clusters in the dotted boxes in a indicating the intense labeling and small diameter (< 10 μm) of SIF cells. Zoom 1.5X (a), Zoom 2X (a’,a’’). Scale bar: 20 μm.