Lithocholylcholine, a bile acid/acetylcholine hybrid, is a muscarinic receptor antagonist.

Article Details


Cheng K, Khurana S, Chen Y, Kennedy RH, Zimniak P, Raufman JP

Lithocholylcholine, a bile acid/acetylcholine hybrid, is a muscarinic receptor antagonist.

J Pharmacol Exp Ther. 2002 Oct;303(1):29-35.

PubMed ID
12235229 [ View in PubMed

Previous work from our laboratory indicates that bile acids, specifically lithocholic acid conjugates, interact with muscarinic receptors on gastric chief cells. Structural similarities between acetylcholine and lithocholyltaurine suggest a potential molecular basis for their interaction with the same receptor. We synthesized a hybrid molecule consisting of the steroid nucleus of lithocholyltaurine and the choline moiety of acetylcholine. The new molecule, lithocholylcholine, is hydrolyzed by acetyl-cholinesterase. Lithocholylcholine inhibited binding of a cholinergic radioligand to Chinese hamster ovary cells expressing each of the five muscarinic receptor subtypes. The binding affinities (K(i); micromolar) of lithocholylcholine for these receptors were: M3 (1.0) > M1 (2.7) > M2 (4.1) = M4 (4.9) > M5 (6.2). Lithocholylcholine inhibited intracellular signaling pathways mediated by interaction with M1, M2, and M3 muscarinic receptors. Regarding M3 receptors, lithocholylcholine was 10-fold more potent than lithocholyltaurine in terms of binding affinity and inhibition of acetylcholine-induced increases in inositol phosphate formation and mitogen-activated protein kinase phosphorylation. In a functional assay, lithocholylcholine inhibited acetylcholine-induced relaxation of rat aortic rings. These observations indicate that lithocholylcholine is a muscarinic receptor antagonist and provide further evidence that bile acids may have gastrointestinal signaling functions that extend beyond their effects on sterol metabolism, lipid absorption, and cholesterol elimination. Hybrid molecules created from bile acids and acetylcholine may be used to develop selective muscarinic receptor ligands.

DrugBank Data that Cites this Article

Binding Properties
DrugTargetPropertyMeasurementpHTemperature (°C)
AcetylcholineMuscarinic acetylcholine receptor M2Ki (nM)340N/AN/ADetails
AcetylcholineMuscarinic acetylcholine receptor M3Ki (nM)4200N/AN/ADetails
AcetylcholineMuscarinic acetylcholine receptor M4Ki (nM)5400N/AN/ADetails
CarbamoylcholineMuscarinic acetylcholine receptor M2Ki (nM)>10000N/AN/ADetails
CarbamoylcholineMuscarinic acetylcholine receptor M3Ki (nM)>10000N/AN/ADetails