2-phenylmelatonin has been researched along with 6-chloromelatonin* in 2 studies
2 other study(ies) available for 2-phenylmelatonin and 6-chloromelatonin
| Article | Year |
|---|---|
Melatonin exerts its analgesic actions not by binding to opioid receptor subtypes but by increasing the release of beta-endorphin an endogenous opioid.
The occurrence of systematic diurnal variations in pain thresholds has been demonstrated in human. Salivary melatonin levels change following acute pain when other factors that could explain the change have been removed or controlled. Melatonin-induced analgesia is blocked by naloxone or pinealectomy. By using selective radioligands [3H]-DAMGO, [3H]-DPDPE, [3-U69593, and 3H]-nociceptin, we have shown that the bovine pinealocytes contain delta and mu, but not kappa or ORL1 opioid receptor subtypes. In the present study, by using melatonin receptor agonists (6-chloromelatonin or 2-iodo-N-butanoyl-5-methoxytryptamine) or melatonin receptor antagonist (2-phenylmelatonin), we have shown that these agents do not compete with opioid receptor subtypes. However, we observed a time-dependent release of beta-endorphin an endogenous opioid peptide, by melatonin from mouse pituitary cells in culture. Hence, it is suggested that melatonin exerts its analgesic actions not by binding to opioid receptor subtypes but by binding to its own receptors and increasing the release of beta-endorphin. Topics: Analgesics; Analgesics, Opioid; Animals; beta-Endorphin; Binding, Competitive; Brain; Cattle; Cells, Cultured; Dose-Response Relationship, Drug; Drug Interactions; Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; Enkephalin, D-Penicillamine (2,5)-; Enzyme-Linked Immunosorbent Assay; Melatonin; Mice; Naloxone; Nociceptin; Opioid Peptides; Pineal Gland; Radioligand Assay; Rats; Receptors, Opioid; Subcellular Fractions; Time Factors; Tritium | 2005 |
Characterization of melatonin binding sites in the brain and retina of the frog Rana perezi.
The aim of this study was to characterize 2-[125I]iodomelatonin binding sites in the neural retina and central nervous system (telencephalon, diencephalon, and optic tectum) of the anuran amphibian Rana perezi. Saturation and kinetic studies and pharmacological characterization revealed the existence of a unique melatonin-binding site that belongs to the Mel 1 receptor subtype. The affinity of this site is similar in all tissues studied (Kd, 10.5-12.8 pM), but the density varied from diencephalon and optic tectum, which exhibit the highest density, to telencephalon with the lowest. Neural retina showed an intermediate receptor density. This melatonin-binding site fulfills the requirements of a real hormone receptor; the binding is saturable, reversible, and inhibited by different melatonin agonists and antagonists. The affinity order of ligands is: 2-phenyl-melatonin = 2-I-melatonin > 6-Cl-melatonin = melatoninz >> luzindole. Additionally, specific binding is decreased by non-hydrolysable GTP analogue, sodium, and by pretreatment of membranes with pertussis toxin. All these results suggest the existence of a widely distributed and pharmacologically homogeneous melatonin receptor of the subfamily Mel 1 in the nervous system of Rana perezi coupled to a Gi/o protein. Topics: Animals; Binding Sites; Binding, Competitive; Brain; Cell Membrane; Diencephalon; Guanosine 5'-O-(3-Thiotriphosphate); Intracellular Membranes; Kinetics; Magnesium; Melatonin; Pertussis Toxin; Radioligand Assay; Ranidae; Receptors, Melatonin; Retina; Sodium; Subcellular Fractions; Superior Colliculi; Telencephalon; Tetrahydronaphthalenes; Tryptamines | 2004 |