19726200 |
Maksay G, Vincze Z, Nemes P: Synthesis of heteroaromatic tropeines and heterogeneous binding to glycine receptors. Bioorg Med Chem. 2008 Feb 15;16(4):2086-92. Epub 2007 Nov 4. Heteroaromatic carboxylic esters of (nor) tropine were synthesized. Tropine esters displaced [(3) H] strychnine binding to glycine receptors of rat spinal cord with low Hill slopes. Two-site displacement resulted in nanomolar IC (50,1) and micromolar IC (50,2) values, and IC (50,2)/IC (50,1) ratios up to 615 depending on the heteroaromatic rings and N-methyl substitution. Nortropeines displayed high affinity and low heterogeneity. IC (50,1) and IC (50,2) values of tropeines did not correlate suggesting different binding modes/sites. Glycine potentiated only the nanomolar displacement reflecting positive allosteric interactions and potentiation of ionophore function. Affinities of three (nor) tropeines were different for glycine receptors but identical for 5-HT (3) receptors. |
83(1,1,1,3) |