Inhibition of brain [3H]cimetidine binding by improgan-like antinociceptive drugs
                                
                                    
                                        作者:Rebecca Stadel、Amanda B. Carpenter、Julia W. Nalwalk、Iwan J.P. de Esch、Elwin Janssen、Lindsay B. Hough                                    
                                    
                                        DOI:10.1016/j.ejphar.2010.01.026
                                    
                                    
                                        日期:2010.4
                                    
                                    [H-3]cimetidine, a radiolabeled histamine H-2 receptor antagonist, binds with high affinity to an unknown hemoprotein in the brain which is not the histamine H-2 receptor. Improgan, a close chemical congener of cimetidine, is a highly effective pain-relieving drug following CNS administration, yet its mechanism of action remains unknown. To test the hypothesis that the [H-3]cimetidine-binding site is the improgan antinociceptive target, improgan, cimetidine, and 8 other chemical congeners were studied as potential inhibitors of [H-3]cimetidine binding in membrane fractions from the rat brain. All compounds produced a concentration-dependent inhibition of [H-3]cimetidine binding over a 500-fold range of potencies (K-i values were 14.5 to >8000 nM). However, antinociceptive potencies in rats did not significantly correlate with [H-3] cimetidine-binding affinities (r=0.018, p=0.97, n=10). These results suggest that the [H-3]cimetidine-binding site is not the analgesic target for improgan-like drugs. (C) 2010 Elsevier B.V. All rights reserved.