Studies on the drug-receptor interactions of dimethyltrilobine iodide
Cao, Y.X.; Che, X.P.
Yao Xue Xue Bao 22(6): 462-464
1987
ISSN/ISBN: 0513-4870 PMID: 3130746 Document Number: 300671
The drug-receptor interactions of dimethyltrilobine iodide (DTI) with toad rectus abdominis N2 cholinoreceptor were studied and compared with those of curare. The DTI antagonism of ACh induced muscle contractions was completely overcome by increasing the concentration of ACh and the dose-cumulative-effect curves were parallel. The pA2 values of DTI and curare were 5.89 and 5.73 respectively. The KB's of DTI and curare were 2.90 .times. 10-6 mol and 2.84 .times. 10-6 mol respectively. When the dose ratios log(X-1) were plotted versus negative log molar values of DTI, the regression slope was -0.92 which is close to the theoretical value -1.0 of competitive antagonist. These results suggest that DTI is a competitive antagonist.