Characterisation of Melatonin Binding Sites in the Eye of the Japanese Quail (Coturnix japonica)
| Autor: | Debra J. Skene, K. James, Josephine Arendt, V. Lucini, B. Stankov |
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| Rok vydání: | 1995 |
| Předmět: |
Male
medicine.medical_specialty Indoles Guanine Receptors Melatonin Receptors Cell Surface Coturnix In Vitro Techniques Biology Retina Iodine Radioisotopes Melatonin Radioligand Assay chemistry.chemical_compound Endocrinology biology.animal Internal medicine medicine Radioligand Animals Binding site Pigment Epithelium of Eye Binding Sites Choroid Nucleotides Quail Epithelium Kinetics medicine.anatomical_structure chemistry Melatonin binding Animal Science and Zoology sense organs Signal transduction medicine.drug |
| Zdroj: | General and Comparative Endocrinology. 100:188-196 |
| ISSN: | 0016-6480 |
| DOI: | 10.1006/gcen.1995.1148 |
| Popis: | Melatonin binding sites were examined in the quail eye using 2-[ 125 I]iodomelatonin. Radioreceptor assays indicated similar binding sites in membrane preparations of neural retina (NR) and choroidretinal pigment epithelium (C-RPE) eye components. In both tissues binding of the radioligand was specific, saturale and of high affinity [ K d values NR 50.8 ± 19.5 p M , C-RPE 98.2 ± 35.4 p M , mean ± SEM ( n = 4)] and low capacity ( B max values NR 12.4 ± 2.7 fmol/mg protein. C-RPE 21.5 ± 3.2 fmol/mg protein). Kinetic studies demonstrated that association of 2-[ 125 I]iodomelatonin was rapid and further that this binding was reversible upon the addition of 1 μ M melatonin. The order of pharmacological potencies of various indoles tested in 2-[ 125 I]iodomelatonin displacement studies was melatonin > 6-chloromelatonin > 64-hydroxymelatonin > N -acetylscrotonin ⪢ 5-methoxytryptophol > 5-hydroxytryptamine > 5-methoxytryptamine (5-hydroxytryptamine > 5-methoxytryptophol for C-RPE). Studies with guanine nucleotides indicated that the signal transduction mechanism of the binding site may involve a G-protein linkage. This melatonin binding site displays several pharmacological similarities with those investigated in the retina of other species and with those previously characterised in the quail brain. |
| Databáze: | OpenAIRE |
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