Peripheral benzodiazepine binding sites: effect of PK 11195, 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide. I. In vitro studies.
[3H] RO5-4864 binding sites have been characterized in kidney, heart, brain, adrenals and platelets in the rat. In all these organs the following order of potency in the RO5-4864 displacement was found: RO5-4864 greater than diazepam greater than clonazepam indicating that they correspond to the "peripheral type" of benzodiazepine binding sites. PK 11195, an isoquinoline carboxamide derivative, displaces [3H] RO5-4864 from its binding sites in all the organs. PK 11195 was as potent as RO5-4864 in the platelets, heart, adrenals, kidney and several brain regions (midbrain, hypothalamus, medulla + pons and hippocampus. However it was 5 to 10 times more effective in cortex and striatum. In conclusion PK 11195 might represent a new tool to elucidate the physiological relevance of "peripheral type" benzodiazepine binding sites and might help to discriminate the hypothetical subclasses of these binding sites.
D000311:Adrenal Glands / Q000378:metabolism; D000818:Animals; D001570:Benzodiazepinones / Q000378:metabolism*; D001792:Blood Platelets / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D002998:Clonazepam / Q000378:metabolism; D003975:Diazepam / Q000378:metabolism; D066298:In Vitro Techniques; D007546:Isoquinolines / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011963:Receptors, GABA-A; D014018:Tissue Distribution
D001570:Benzodiazepinones; D007546:Isoquinolines; D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; C028513:4'-chlorodiazepam; D002998:Clonazepam; D003975:Diazepam; C037850:PK 11195