We investigated the potential ability of p-fluoro-hexahydro-sila-difenidol (p-F-HHSiD) to discriminate between M1 and M3 muscarinic receptor subtypes using Chinese hamster ovary cells stably transfected with the genes encoding the two receptors. Both radioligand binding and functional assays were utilized for this purpose. In contrast to initial reports of a 14-fold selectivity of this antagonist for M3 versus M1 receptors, we have detected a qualitatively similar selectivity that was markedly smaller in magnitude.
Bibliographical noteFunding Information:
This work was supported in part by a grant NS-25743 from the National Institutes of Health and contract DAAL-03-88K-0078 from the U. S. Army Research Office.
- CHO cells
- Muscarinic receptors
- Receptor subtypes