Premium
Muscarinic cholinergic receptors regulate oscillation of intracellular Ca 2+ in steroid‐producing adrenocortical carcinoma cells
Author(s) -
Sharthiya Harsh,
Surachaicharn Nuntida,
Shams Yara,
Arshad Mohammad,
Kopf Phillip G.,
Malaiyandi Latha M.,
Dineley Kirk E.
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.672.4
Subject(s) - endocrinology , medicine , carbachol , aldosterone , angiotensin ii , chemistry , muscarinic acetylcholine receptor , calcium in biology , cholinergic , muscarinic agonist , calcium , biology , receptor , stimulation
Elevated circulating aldosterone levels are associated with hypertension, thrombosis formation, cardiac hypertrophy, and congestive heart failure. Aldosterone secretion is regulated by angiotensin II (Ang II), potassium, and adrenocorticotropic hormone (ACTH). Calcium is required for the stimulation of aldosterone secretion by these steroidogenic stimuli. Despite the importance of calcium in steroidogenesis, the relationship between intracellular Ca 2+ homeostasis and steroid production by the adrenal cortex remains incompletely understood. We used the Ca 2+ ‐sensitive fluorophore Fluo‐4 to study whole‐cell calcium in human adrenocortical carcinoma (HAC15) cells. We found that oscillation in intracellular Ca 2+ could be triggered in a subset of cells by the cholinergic agonist carbachol. The oscillations were characterized by a relatively rapid periodicity, and often returned completely to baseline before spiking again. Removal of calcium from the extracellular perfusate suggested that oscillations resulted from repetitive release and recapture of calcium stored internally in the endoplasmic reticulum. Carbachol‐triggered oscillations were inhibited by muscarinic antagonists including atropine, pirenzepine, and darifenacin. Because darifenacin nearly completely abolished the carbachol effect, we concluded that regulation by M3 receptors is most important for the oscillations. Nicotinic cholinergic receptors were ruled out because nicotine did not alter intracellular calcium levels. Angiotensin II increased intracellular Ca 2+ , however these changes were relatively large and sustained, and not oscillatory in nature. Further experiments will investigate the relationship between muscarinic receptor activity and aldosterone production stimulated by angiotensin II. Support or Funding Information Supported by funds from Midwestern University