UTP and ATP increase extracellular signal-regulated kinase 1/2 phosphorylation in bovine chromaffin cells through epidermal growth factor receptor transactivation.

Adenosine triphosphate (ATP) is coreleased with catecholamines from adrenal medullary chromaffin cells in response to sympathetic nervous system stimulation and may regulate these cells in an autocrine or paracrine manner. Increases in extracellular signal-regulated kinase (ERK) 1/2 phosphorylation were observed in response to ATP stimulation of bovine chromaffin cells. The signaling pathway involved in ATP-mediated ERK1/2 phosphorylation was investigated via Western blot analysis.

Tyrosine hydroxylase phosphorylation increases in response to ATP and neuropeptide Y co-stimulation of ERK2 phosphorylation.

ATP and neuropeptide Y (NPY) are examples of agents co-secreted with catecholamines from neuronal and neuroendocrine cells which may regulate the function of the cells from which they are released. For example, ATP and NPY could influence chromaffin cell activity in an autocrine or paracrine manner. The primary recognized function of chromaffin cells is the synthesis and secretion of catecholamines; therefore, we hypothesize that ATP and NPY can regulate catecholamine synthesis in chromaffin cells.