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A melatonin binding site modulates the alpha 2-adrenoceptor.

L G Mårtensson·R G Andersson
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Abstract

The melanophores of the cuckoo wrasse (Labrus ossifagus L., a teleost fish) can aggregate and disperse their pigment granules. This migration is controlled by sympathetic nerves and a postsynaptic alpha 2-adrenoceptor. Melatonin was discovered because of its ability to aggregate pigment granules, hence we used the cuckoo wrasse melanophore as a model for studying the effect of melatonin at a cellular level. We found that melatonin had no aggregating effect; instead the hormone enhanced the actions of several alpha 2-agonists, such as noradrenaline, medetomedine and clonidine. When the melanophores were pre-aggregated in vitro by use of the alpha 2-agonist B-HT 920, the aggregation was not augmented after the addition of melatonin. Instead the pre-aggregated granules were dispersed. This suggests that melatonin has affinity for an alpha 2-adrenoceptor site that can modulate the effect of alpha 2-adrenoceptor agonists.

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Adrenergic alpha-AgonistsAdrenergic alpha-AntagonistsAnimalsAzepinesBinding SitesCell AggregationDrug SynergismFishesMelanophoresMelatoninNorepinephrinePigments, BiologicalReceptors, Adrenergic, alpha-2SerotoninSkinSympathetic Nervous SystemJournal ArticleResearch Support, Non-U.S. Gov't

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BibTeXRIS

L G Mårtensson, R G Andersson. 1996. A melatonin binding site modulates the alpha 2-adrenoceptor.. https://doi.org/10.1016/0024-3205(95)02318-6

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