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Title: Pharmacology and function of melatonin receptors

The hormone melatonin is secreted primarily from the pineal gland, with highest levels occurring during the dark period of a circadian cycle. This hormone, through an action in the brain, appears to be involved in the regulation of various neural and endocrine processes that are cued by the daily change in photoperiod. This article reviews the pharmacological characteristics and function of melatonin receptors in the central nervous system, and the role of melatonin in mediating physiological functions in mammals. Melatonin and melatonin agonists, at picomolar concentrations, inhibit the release of dopamine from retina through activation of a site that is pharmacologically different from a serotonin receptor. These inhibitory effects are antagonized by the novel melatonin receptor antagonist luzindole (N-0774), which suggests that melatonin activates a presynaptic melatonin receptor. In chicken and rabbit retina, the pharmacological characteristics of the presynaptic melatonin receptor and the site labeled by 2-(125I)iodomelatonin are identical. It is proposed that 2-(125I)iodomelatonin binding sites (e.g., chicken brain) that possess the pharmacological characteristics of the retinal melatonin receptor site (order of affinities: 2-iodomelatonin greater than 6-chloromelatonin greater than or equal to melatonin greater than or equal to 6,7-di-chloro-2-methylmelatonin greater than 6-hydroxymelatonin greater than or equal to 6-methoxymelatonin greater thanmore » N-acetyltryptamine greater than or equal to luzindole greater than N-acetyl-5-hydroxytryptamine greater than 5-methoxytryptamine much greater than 5-hydroxytryptamine) be classified as ML-1 (melatonin 1). The 2-(125I)iodomelatonin binding site of hamster brain membranes possesses different binding and pharmacological characteristics from the retinal melatonin receptor site and should be classified as ML-2. 64 references.« less
Authors:
Publication Date:
OSTI Identifier:
6758413
Resource Type:
Journal Article
Resource Relation:
Journal Name: FASEB J.; (United States); Journal Volume: 2:12
Research Org:
Northwestern Univ. Medical School, Chicago, IL (USA)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; MELATONIN; RECEPTORS; BIOLOGICAL FUNCTIONS; BRAIN; CELL MEMBRANES; CENTRAL NERVOUS SYSTEM; CHICKENS; DOPAMINE; HAMSTERS; IODINE 125; RABBITS; RETINA; REVIEWS; STRUCTURE-ACTIVITY RELATIONSHIPS; TRACER TECHNIQUES; AMINES; ANIMALS; AROMATICS; AUTONOMIC NERVOUS SYSTEM AGENTS; AZAARENES; AZOLES; BETA DECAY RADIOISOTOPES; BIRDS; BODY; BODY AREAS; CARDIOTONICS; CARDIOVASCULAR AGENTS; CELL CONSTITUENTS; DAYS LIVING RADIOISOTOPES; DOCUMENT TYPES; DRUGS; ELECTRON CAPTURE RADIOISOTOPES; EYES; FACE; FOWL; FUNCTIONS; HEAD; HETEROCYCLIC COMPOUNDS; HYDROXY COMPOUNDS; INDOLES; INTERMEDIATE MASS NUCLEI; IODINE ISOTOPES; ISOTOPE APPLICATIONS; ISOTOPES; MAMMALS; MEMBRANE PROTEINS; MEMBRANES; NERVOUS SYSTEM; NEUROREGULATORS; NUCLEI; ODD-EVEN NUCLEI; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; ORGANS; PHENOLS; POLYPHENOLS; PROTEINS; PYRROLES; RADIOISOTOPES; RODENTS; SENSE ORGANS; SYMPATHOMIMETICS; TRYPTAMINES; VERTEBRATES 550201* -- Biochemistry-- Tracer Techniques