How does the stimulus define exocytosis in adrenal chromaffin cells?

• Published in: Pflügers Archiv Vol. 470; no. 1; pp. 155 - 167
• Main Authors: Marengo, Fernando D., Cárdenas, Ana M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2018; Springer Nature B.V
• Subjects: Actomyosin; Adrenal glands; Adrenal medulla; Adrenal Medulla - metabolism; Adrenal Medulla - secretion; Animals; Biomedical and Life Sciences; Biomedicine; Calcium channels; Calcium Channels - metabolism; Catecholamines; Cell Biology; Chromaffin cells; Chromaffin granules; Chromaffin Granules - metabolism; Exocytosis; Firing rate; Human Physiology; Humans; Invited Review; Molecular Medicine; N-Ethylmaleimide-sensitive protein; Neurosciences; Proteins; Receptors; Secretion; Secretory vesicles; SNAP receptors; Splanchnic nerve; Synaptotagmin; Vesicular Transport Proteins - metabolism; Chromaffin cells; Catecholamines; Voltage-dependent Ca; channels; Vesicle pools; Exocytosis; Voltage-dependent Ca2+ channels
• ISSN: 0031-6768; 1432-2013
• DOI: 10.1007/s00424-017-2052-5

The extent and type of hormones and active peptides secreted by the chromaffin cells of the adrenal medulla have to be adjusted to physiological requirements. The chromaffin cell secretory activity is controlled by the splanchnic nerve firing frequency, which goes from approximately 0.5 Hz in basal conditions to more than 15 Hz in stress. Thus, these neuroendocrine cells maintain a tonic release of catecholamines under resting conditions, massively discharge intravesicular transmitters in response to stress, or adequately respond to moderate stimuli. In order to adjust the secretory response to the stimulus, the adrenal chromaffin cells have an appropriate organization of Ca
2+
channels, secretory granules pools, and sets of proteins dedicated to selectively control different steps of the secretion process, such as the traffic, docking, priming and fusion of the chromaffin granules. Among the molecules implicated in such events are the soluble
N
-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, Ca
2+
sensors like Munc13 and synaptotagmin-1, chaperon proteins such as Munc18, and the actomyosin complex. In the present review, we discuss how these different actors contribute to the extent and maintenance of the stimulus-dependent exocytosis in the adrenal chromaffin cells.