Is the transient nature of the secretory response of chromaffin cells due to inactivation of calcium channels?

• Published in: FEBS letters 1985-03, Vol.182 (1), p.115-118
• Main Authors: Burgoyne, Robert D., Cheek, Timothy R.
• Format: Article
• Language: English
• Subjects: Adrenals. Interrenals; Adrenomedullary hormones. Regulation; Animals; Biological and medical sciences; Calcium - metabolism; Calcium - pharmacology; Carbachol - pharmacology; Cattle; Chromaffin Granules - drug effects; Chromaffin Granules - metabolism; Chromaffin System - metabolism; Egtazic Acid - pharmacology; Fundamental and applied biological sciences. Psychology; Ion Channels - metabolism; Potassium - pharmacology; Verapamil - pharmacology; Vertebrates: endocrinology
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(85)81166-2

Catecholamine release from chromaffin cells in response to carbamylcholine and high K + is transient. Monitoring intracellular free calcium ([Ca 2+] i) using quin2 demonstrated a transient rise in [Ca 2+] i in response to carbamylcholine. The termination of secretion due to carbamylcholine is probably a consequence of the return of [Ca 2+] i to resting levels as the nicotinic receptors desensitise. Depolarisation with 55 mM K + led to a long-lasting rise in [Ca 2+] i which persisted after the secretory response had terminated. The maintained rise in [Ca 2+] i appeared to be due to continued opening of verapamil-sensitive Ca 2+ channels. These results suggest that inactivation of voltage-dependent Ca 2+ channels does not account for the transient nature of the secretory response in chromaffin cells. Chromaffin cell Calcium Calcium channel Secretion Quin2