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1.
beta-Endorphin: characteristics of binding sites in the rat brain.   总被引:3,自引:0,他引:3  
Stereospecific binding of human β-endorphin to rat membrane preparations is described for the first time using [3H-Tyr27]-βh-endorphin as the ligand. The binding is time dependent and saturable with respect to βh-endorphin with an apparent dissociation constant of 0.3 nM. Sodium ion (100 mM) elevates this value to 2.5 nM but has no effect on the total number of binding sites present in the membrane preparation. The ability of certain β-endorphin analogs, opiate agonists as well as antagonists to inhibit the binding of βh-endorphin, is presented.  相似文献   

2.
A factor from human plasma having opiate-like activity was characterized in the present study. In addition to its ability to inhibit the binding of [3H]-methionine-enkephalin to opiate receptors, it also cross-reacted with two β-endorphin specific anti-sera. Compared with β-endorphin, the plasma factor had a shorter action on inhibiting the contraction of the guinea pig ileum. By gel-filtration chromatography, the size of this factor was intermediate between that of β-endorphin and methionine-enkephalin.  相似文献   

3.
Beta-endorphin (beta-EP) and peptide E were compared in respect to their binding potency in the rat brain membrane by radioreceptor binding assay using tritiated human beta-EP, [D-Ala2,D-Leu5]-enkephalin (DADLE), dihydromorphine (DHM) and ethylketocyclazocine (EKC) as primary ligands. When the potency of beta h-EP was chosen to be 100%, peptide E was equipotent with beta-EP in displacing DHM (95%) and EKC (103%) less potent for competing with beta h-EP (60%) and least active (7%) for displacing DADLE. It may be concluded that peptide E binds preferentially with the opiate mu and kappa receptors in the rat brain membrane.  相似文献   

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