The Dispersed Neuroendocrine Cells: The Structure, Function, Regulation and Effects of Xenobiotics on this System

Abstract

A B S T R A~Cells which express morphological and functional markers originally described in neurons and neural crest: derived endocrine cells are now known to originate from both ectodermal and endodermal progenitors. These cells are organized to secrete peptides, amines, and other regulatory products in response to neurogenic orchemical stimulation. Individual products may function in endocrine, paracrine, neurotransmitter, or neuromodulatory roles. Multiple products are often produced by individual cells and stored in the same secretory granules. The hormonal profiles of particular types of neuroendocrine cells can, to varying degrees, be changed by environmental signals during development or in adult life. These changes are caused both by transcriptional and post-transcriptional mechanisms. Hormonal profiles are also altered during'the development and progression of neoplasia. Signals which stimulate hormone secretion produce a number of ancillary effects, including activation and induction of enzymes which replenish hormone stores, activation of cellular on-. cogenes, and stimulation of cell proliferation. The effects of environmental signals on neuroendocrine cells are mediated by intracellular transduction pathways which involve cyclic AMP, phosphatidylinositol, calcium, and receptor protein kinase activity. These effects can be potentiated, inhibited, or qualitatively altered by exogenous agents.

Chromaffin Cells of the Adrenal Gland in the Beagle Dog

“…TH antibody staining is a commonly applied immunohistochemistry method to identify chromaffin cells. It is responsible for converting tyrosine to dihydroxyphenylalanine (L‐DOPA), which is subsequently converted to dopamine and then to norepinephrine and epinephrine (Tischler, ). The extra‐ and intra‐medullary chromaffin cells are all TH antibody positive, but the chromaffin cells in the cortex and capsule stained more positive than those in the medulla.…”

Merkel‐like cells in Malassez epithelium in the periodontal ligament of cats: an immunohistochemical, confocal‐laser scanning and immuno electron‐microscopic investigation

“…CGRP, SP and VIP are potent vasoregulators and induce local blood flow increase (22), promote cell proliferation and cell growth (23, 24), exert influence on immune cells in the PDL and possibly may guide immune cells towards ME (9). Thus, the neuroendocrine cells in ME demonstrate potentials for paracrine or endocrine functions in addition to neuromodulatory roles in the PDL similarly to neuroendocrine cells in different anatomical locations (25).…”

Superficial neuroendocrine carcinoma of the esophagus

“…The term 'neuroendocrine' does not imply embryological origin from the neuroectoderm but, rather, connotes a shared phenotype characterized by the simultaneous expression of multiple genes encoding a wide variety of neuronal and endocrine traits. 11 Neuroendocrine carcinoma is thought to be derived from the diffuse epithelial endocrine system (diffuse neuroendocrine system (DNES). Recently the distribution of the DNES has been noted to include all organs and tissues.…”