Choline is a full agonist in inducing activation of neuronal nitric oxide synthase via the muscarinic M₁ receptor

The present study was designed to characterize the interaction of choline with the M₁ subtype of the muscarinic acetylcholine receptor. Using Chinese hamster ovary cells transfected with neuronal nitric oxide synthase and the cloned human M₁ receptor (CHO hM₁/nNOS cells), we investigated choline's effects on production of nitric oxide and elevation of intracellular [Ca²⁺]. Choline showed the properties of a full agonist in inducing the sustained plateau of increased intracellular [Ca²⁺], although it was only a partial agonist in inducing the larger, transient [Ca²⁺] peak. Choline was also found to act as a full agonist in stimulating the production of nitric oxide. These results have implications for efforts in the clinical treatment of dementia. Copyright (C) 2000 S. Karger AG, Basel.