Binding sites for a peripheral type benzodiazepine antagonist ([3H]PK 11195) in human iris

Peripheral-type benzodiazepine binding sites have been characterized on sections of 8 normal human iris/ciliary-body preparations. Saturability was determined at 25 degrees C with [3H] PK 11195 (1 nM) a specific ligand of peripheral type sites. The studies revealed a single class of binding sites fo...

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Published inNeuropharmacology Vol. 26; no. 6; p. 549
Main Authors Valtier, D, Malgouris, C, Gilbert, J C, Guicheney, P, Uzan, A, Gueremy, C, Le Fur, G, Saraux, H, Meyer, P
Format Journal Article
LanguageEnglish
Published England 01.06.1987
Subjects
Aged
Benzodiazepines - antagonists & inhibitors
Benzodiazepines - metabolism
Binding, Competitive
Ciliary Body - metabolism
Humans
In Vitro Techniques
Iris - metabolism
Isoquinolines - metabolism
Kinetics
Receptors, GABA-A - metabolism
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Summary:Peripheral-type benzodiazepine binding sites have been characterized on sections of 8 normal human iris/ciliary-body preparations. Saturability was determined at 25 degrees C with [3H] PK 11195 (1 nM) a specific ligand of peripheral type sites. The studies revealed a single class of binding sites for PK 11195 with a nanomolar range affinity (KD = 1.45 nM) and a maximal capacity (Bmax) of 35.5 fmol/mg protein. The displacement potency order of the benzodiazepines tested suggest that these sites belong to the peripheral type: PK 11211 (IC50 = 12 nM) greater than Ro 5-4864 (IC50 = 770 nM) greater than clonazepam (IC50 = 20,000 nM). The present data demonstrate that high affinity binding sites for peripheral type benzodiazepines are present in human iris/ciliary-body. This tissue is therefore a suitable tool for evaluation of the putative functional role of these binding sites.
ISSN:0028-3908
DOI:10.1016/0028-3908(87)90146-8