Evaluation of drug-muscarinic receptor affinities using cell membrane chromatography and radioligand binding assay in guinea pig jejunum membrane.

To study if cell membrane chromatography (CMC) could reflect drug-receptor interaction and evaluate the affinity and competitive binding to muscarinic acetylcholine receptor (mAChR).The cell membrane stationary phase (CMSP) was prepared by immobilizing guinea pig jejunum cell membrane on the surface of a silica carrier, and was used for the rapid on-line chromatographic evaluation of ligand binding affinities to mAChR. The affinity to mAChR was also evaluated from radioligand binding assays (RBA) using the same jejunum membrane preparation.The capacity factor (k') profiles in guinea pig jejunum CMSP were: (-)QNB (15.4)>(+)QNB (11.5)>atropine (5.35)>pirenzepine (5.26)>4-DAMP (4.45)>AF-DX116 (4.18)>pilocarpine (3.93)>acetylcholine (1.31). These results compared with the affinity rank orders obtained from radioligand binding assays indicated that there was a positive correlation (r²= 0.8525, P<0.0001) between both data sets.The CMC method can be used to evaluate drug-receptor affinities for drug candidates. [ABSTRACT FROM AUTHOR]