Melatonin exerts its analgesic actions not by binding to opioid receptor subtypes but by increasing the release of beta-endorphin an endogenous opioid
| Autor: | Shaik Shavali, Begonia Y Ho, Piyarat Govitrapong, Saiphon Sawlom, Sirirat Klongpanichapak, Manuchair Ebadi, Amornpan Ajjimaporn |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
endocrine system
medicine.medical_specialty Time Factors Enkephalin medicine.drug_class Neuropeptide FF receptor Enzyme-Linked Immunosorbent Assay (+)-Naloxone Pharmacology Tritium Melatonin receptor Binding Competitive Pineal Gland Melatonin Mice Radioligand Assay Opioid receptor Internal medicine medicine Animals Drug Interactions Cells Cultured Endogenous opioid Analgesics Dose-Response Relationship Drug Chemistry Naloxone General Neuroscience beta-Endorphin Brain Enkephalin Ala(2)-MePhe(4)-Gly(5) Rats Analgesics Opioid Nociceptin receptor Endocrinology Opioid Peptides Receptors Opioid Cattle Enkephalin D-Penicillamine (2 5) hormones hormone substitutes and hormone antagonists medicine.drug Subcellular Fractions |
| Zdroj: | Brain research bulletin. 64(6) |
| ISSN: | 0361-9230 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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