THE DISTRIBUTION AND COLOCALIZATION OF NEUROPEPTIDES AND CATECHOLAMINES IN NERVES SUPPLYING THE GALL-BLADDER OF THE TOAD, BUFO-MARINUS

The indirect immunofluorescence technique was used to determine the di stribution of peptide-containing axons in the gall bladder of the cane toad, Bufo marinus. In addition, the adrenergic innervation of the ga ll bladder was examined by use of immunoreactivity to the catecholamin e-synthesizing enzyme, tyrosine hydroxylase, and glyoxylic acid-induce d fluorescence. On the basis of peptide coexistence, two intrinsic pop ulations of neurones and their projecting fibres could be distinguishe d substance P neurones and vasoactive intestine peptide neurones. Neit her of these two types of neurones contained any other colocalized neu ropeptides. Four populations of nerve fibres arising from cell bodies outside the gall bladder were identified: nerves containing colocalize d galanin, somatostatin and vasoactive intestinal peptide; nerves cont aining colocalized calcitonin gene-related peptide and substance P; ad renergic nerves containing neuropeptide Y; and nerves containing only adrenaline.