TABLE 1

Total, M₂, and M₃ muscarinic receptor density (femtomoles per milligram of solubilized protein) for different dissections of human GEJ muscles Total muscarinic receptor density was determined by total [³H]QNB binding, whereas M₂ an M₃ receptor density was determined using subtype-selective immunoprecipitation (as described under Materials and Methods). Results are reported as mean ± S.E.M. for at least duplicate determinations from two individual organs for clasp and sling fibers, whereas n = 3 donors for LEC, MEL, and MEC fibers. Statistical differences were determined using nonparametric statistics with a Mann-Whitney U test.