Afferent neural activity from rainbow trout gills responds strongly to hypoxic perfusate or ACh, and moderately to perfusate containing Serotonin. However, the identity of the O2-responsive gill cells is unknown. I am mapping cholinergic cells and nicotinic ACh receptors in unsectioned trout gills using high-resolution 3-D fluorescence light microscopy, immunohistochemistry (IHC), and activity-dependent dyes to identify the cellular receptors in fish gills responsible for respiratory gas sensing.
