The vascular and epithelial serotonergic innervation of the actinopterygian gill filament with special reference to the trout, Salmo gairdneri

Antibodies against serotonin and 5-methoxytryptamine reveal indolaminergic neurons innervating the proximal part of the efferent arterial vasculature, the filament epithelia, the central venous sinus, and certain other serotonergic cells of the teleost gill filament. In the same area, acetylcholinesterase-positive and indoleaminergic neurons have already been described. We propose that these populations of neurons belong to a single neuronal …