Mårtensson L G, Andersson R G
Department of Pharmacology, Faculty of Health Sciences, University of Linköping, Sweden.
Life Sci. 1996;58(6):525-33. doi: 10.1016/0024-3205(95)02318-6.
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.
杜父鱼（Labrus ossifagus L.，一种硬骨鱼）的黑素细胞能够聚集和分散其色素颗粒。这种迁移受交感神经和突触后α2-肾上腺素能受体控制。褪黑素因其聚集色素颗粒的能力而被发现，因此我们将杜父鱼黑素细胞作为在细胞水平研究褪黑素作用的模型。我们发现褪黑素没有聚集作用；相反，该激素增强了几种α2-激动剂的作用，如去甲肾上腺素、美托咪定和可乐定。当黑素细胞在体外通过使用α2-激动剂B-HT 920进行预聚集后，添加褪黑素后聚集并未增强。相反，预聚集的颗粒发生了分散。这表明褪黑素对一个α2-肾上腺素能受体位点具有亲和力，该位点可调节α2-肾上腺素能受体激动剂的作用。
