Immunohistochemical Localization of Neurotensin in a Subpopulation of Noradrenergic Chromaffin Cells of the Adrenal Gland of the Flat Snake (Waglerophis merremii)

The distribution of neurotensin (NT)-like immunoreactivity (LI) in the adrenal gland of the snake Waglerophis merremii has been examined immunohistochernically. Double staining, combining NT with tyrosine hydroxylase (TH) or calcitonin gene-related peptide (CGRP) antibodies and TH with CGRP antibodies. was also carried out. Results were analyzed by conventional and by confocal fluorescence microscopy. Immunostaining revealed a subpopulation of chromaffin cells containing NT-LI within the dorsal noradrenergic ribbon. In addition, there were some NT-immunoreactive (IR) fibers in this region. NT immunoreactivity was not present within adrenergic chromaffin cells or in cortical tissue. Double staining revealed CGRP-IR fibers innervating most of the chromaffin adrenergic cells. Within the dorsal noradrenergic ribbon, two groups of chromaffin TH-IR cells were present, one receiving a dense CGRP-IR innervation and another without contact with CGRP-IR terminals. The latter chromaffin cells displayed NT-LI. These results show, for the first time, the presence of a neuropeptide in chromaffin noradrenergic cells of a reptilian adrenal gland and open up the possibility that other peptides may also be present in these cells.