Zawilska J B
Department of Pharmacodynamics, Medical University, Lódź, Poland.
Acta Neurobiol Exp (Wars). 1992;52(4):265-74.
Vertebrate retina rhythmically produces melatonin, a hormone involved in the regulation of several intraocular processes cued by environmental lighting conditions. Calcium ions play an important role in the induction process of serotonin N-acetyltransferase (NAT), a key regulatory enzyme in melatonin biosynthetic pathway. The physiological, i.e. nocturnal, increase of NAT activity in the retina depends on transmembrane transport of Ca2+ through the L-type of voltage-sensitive calcium channels. It is suggested that Ca2+ may regulate NAT activity indirectly, by affecting the intracellular cyclic AMP content, which is, in turn, critical in the regulation of melatonin biosynthesis. The mode and mechanisms of Ca2+ action on processes governing melatonin formation in the retina are discussed.
脊椎动物的视网膜有节律地产生褪黑素，这是一种参与由环境光照条件引发的多种眼内过程调节的激素。钙离子在血清素N - 乙酰基转移酶（NAT）的诱导过程中起重要作用，NAT是褪黑素生物合成途径中的关键调节酶。视网膜中NAT活性的生理性增加，即夜间增加，取决于Ca2+通过L型电压敏感钙通道的跨膜转运。有人提出，Ca2+可能通过影响细胞内环磷酸腺苷（cAMP）含量间接调节NAT活性，而cAMP含量反过来对褪黑素生物合成的调节至关重要。本文讨论了Ca2+作用于视网膜中褪黑素形成相关过程的方式和机制。
