title: Interaction of purines and related compounds with photoaffinity-labelled benzodiazepine receptors in rat brain membranes.
abstract: The interaction of purine-receptor agonists and antagonists with [3H]Ro15-1788 binding sites in rat brain membranes was examined before and after UV-photoaffinity labelling of a proportion of the sites with flunitrazepam. Whereas photoaffinity labelling of the receptors reduced benzodiazepine agonist affinity but not benzodiazepine antagonist affinity, the IC50S of adenosine-receptor agonists, partial agonists and antagonists were unaltered by the conformational changes in the benzodiazepine receptors which are thought to be induced by the photolabelling process. The affinity of dipyridamole, a potent adenosine uptake blocker and potent displacer of [3H]diazepam binding, was drastically reduced by photolabelling.
mesh_terms: D000345:Affinity Labels; D000818:Animals; D001570:Benzodiazepinones / Q000378:metabolism*; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003292:Convulsants / Q000378:metabolism*; D005442:Flumazenil; D066298:In Vitro Techniques; D011687:Purines / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011963:Receptors, GABA-A; D013574:Synaptosomes / Q000378:metabolism; D013806:Theophylline / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D000345:Affinity Labels; D001570:Benzodiazepinones; D003292:Convulsants; D011687:Purines; D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; D005442:Flumazenil; D013806:Theophylline