Original Article

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

Bing-xiang YUAN, Jin HOU, Lang-chong HE, Guang-de YANG


Aim: To study if cell membrane chromatography (CMC) could reflect drug-receptor
interaction and evaluate the affinity and competitive binding to muscarinic
acetylcholine receptor (mAChR).
Methods: 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.
Results: 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.
Conclusion: The CMC method can
be used to evaluate drug-receptor affinities for drug candidates.