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Ethanol disrupts carbamylcholine-stimulated release of arachidonic acid from Chinese hamster ovary cells expressing different subtypes of human muscarinic receptor. Alcohol Clin Exp Res 1998 Apr;22(2):409-15

Date

05/15/1998

Pubmed ID

9581647

DOI

10.1111/j.1530-0277.1998.tb03667.x

Scopus ID

2-s2.0-0031981772 (requires institutional sign-in at Scopus site)

Abstract

Ethanol disrupts signal transduction mediated by a variety of G-protein coupled receptors. We examined the effects of ethanol on arachidonic acid release mediated by muscarinic acetylcholine receptors. Chinese hamster ovary (CHO) cells transfected with the different subtypes of human muscarinic receptors (M1 to M5) were incubated with [3H]arachidonic acid ([3H]AA) for 18 hr, washed, and exposed to the cholinergic agonist carbamylcholine for 15 min. Carbamylcholine induced [3H]AA release from CHO cells expressing M1, M3, or M5, but not M2 or M4, muscarinic receptors. Dose response curves revealed that carbamylcholine stimulated [3H]AA release by up to 12-fold with an ECo of approximately 0.4 microM; maximal responses were obtained with 10 microM carbamylcholine. Exposure of M1-, M3-, or M5-expressing cells to ethanol for 5 min before stimulating with carbamylcholine reduced [3H]AA release by 40 to 65%; 50% of the maximal inhibition was obtained with an ethanol concentration of 30 to 50 mM. Ethanol did not affect basal [3H]AA release measured in the absence of carbamylcholine. Dose response curves suggest that ethanol acts as a noncompetitive inhibitor of muscarinic receptor-induced [3H]AA release insofar as maximal [3H]AA release was depressed in the presence of ethanol with no apparent change in the EC50 for stimulation by carbamylcholine. Exposure of CHO cells to 38 mM ethanol for 48 hr increased [3H]AA release induced by carbamylcholine without affecting basal [3H]AA release or altering the EC50 for carbamylcholine. These results indicate that ethanol acutely inhibits muscarinic receptor signaling through the arachidonic acid pathway in a noncompetitive manner, but chronically enhances muscarinic signaling through the same pathway.

Author List

Stair SM, May LG, Puhl HL, Phelps SH, Williams CL, Aronstam RS

Author

Carol L. Williams PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Arachidonic Acid
CHO Cells
Carbachol
Cricetinae
Dose-Response Relationship, Drug
Ethanol
Gene Expression
Humans
Muscarinic Agonists
Receptors, Muscarinic
Signal Transduction