Neurotensin-containing endocrine cells and neurotensin receptor mRNA-expressing epithelial cells in the chicken thymus.

Distribution of neurotensin-containing cells and neurotensin receptor-expressing cells was examined in the chicken thymus using a combination of in situ hybridization histochemistry for neurotensin receptor mRNA and immunohistochemistry for neurotensin. Neurotensin receptor mRNA-expressing cells and neurotensin-immunoreactive cells were localized in the medulla. Neurotensin receptor mRNA-expressing cells showed a round or elongated shape, while neurotensin-immunoreactive cells revealed round, ovoid, spindle or reticular shapes. Neurotensin-immunoreactive cells were much more numerous than those displaying labeling for the neurotensin receptor mRNA in males and females. Furthermore, electron microscopic immunohistochemistry for neurotensin showed that immunoreactive cells contained a large number of round or spherical granules which were 250-350 nm in diameter. This evidence indicates that neurotensin is localized in endocrine cells, and that neurotensin receptor mRNA is expressed in epithelial cells. It further suggests the possibility of microenvironmental interaction of neurotensin between endocrine cells and epithelial cells within the chicken thymus.