Aminergic innervation of the gall bladder in man and dog

This study has compared the innervations of human and canine gall bladders, using immunohistochemical localization of neuron-specific enolase to visualize all intramural nerves and localization of tyrosine hydroxylase, DOPA decarboxylase and serotonin to visualize different populations of aminergic neurons. The vasculature, the wall smooth musculature and the intramural ganglion cells receive a substantial sympathetic innervation, in both species. By contrast, the mucosa appears to be supplied almost entirely by non-sympathetic fibres. On the basis of DOPA decarboxylase immunoreactivity, a large proportion of the biliary sympathetic nerves in both species may be dopaminergic. Human gall bladder also contains a population of putatively tryptaminergic, intramural neuron-like cells. However, there was no evidence for tryptaminergic innervation of effector structures in the gall bladder wall.