Abstract
Digitonin solubilized muscarinic acetylcholine receptor (mAChR) of rat cerebral cortex membranes were chromatographed on the FPLC anion exchanger Mono Q. [3H]QNB (quinuclidinyl benzilate) and [3H]PZ (pirenzepine) binding activity was retarded from a NaCl free elution buffer and thereby separated from a part of the accompanying proteins. Elution of the column with a continuously increasing NaCl concentration desorbed the radioligand binding activities forming several peaks, two of which were nearly completely separated. Our data show that the mAChR in rat cerebral cortex consists of several entities with different electrical charges.