Delgado M J, Céspedes M V, De Pedro N, Alonso-Bedate M, Alonso-Gómez A L
Departamento de Biología Animal II (Fisiología Animal), Facultad de Biología, Universidad Complutense, 28040, Madrid, Spain.
Neurosci Lett. 2001 Mar 16;300(3):129-32. doi: 10.1016/s0304-3940(01)01560-9.
Concentration of dopamine (DA) and its metabolite, 3,4-dihydroxyphenylacetic acid is quantified by high-pressure liquid chromatography with a coulometric detection system in the eye of Xenopus laevis through ontogeny and in adults at two times during photocycle (midday and midnight). Ocular dopaminergic activity remains low during pre- and prometamorphosis and significantly rises in postmetamorphic froglets. This increase is more pronounced at midnight than at midday. The dualism of DA content versus DA release in Xenopus ocular tissue is studied in an eyecup culture system. On a 24-h cycle of DA release from adult Xenopus eyecups the highest DA release by eyecups is produced during daytime, and significantly decreases in darkness. From these results it can be concluded that in spite of the early development of the retinal dopaminergic system in the ontogeny of Xenopus, the final maturation must occur during the metamorphic climax. Endogenous DA release is significantly inhibited by light offset, which explains the higher ocular DA content found at midnight as compared to midday in postmetamorphic froglets and adults.
通过使用库仑检测系统的高压液相色谱法，对非洲爪蟾个体发育过程中以及成年个体在光周期的两个时间点（中午和午夜）眼睛中的多巴胺（DA）及其代谢物3,4 - 二羟基苯乙酸的浓度进行了定量分析。在变态前和变态初期，眼部多巴胺能活性保持较低水平，而在变态后的幼蛙中显著升高。这种升高在午夜比中午更为明显。在眼杯培养系统中研究了非洲爪蟾眼部组织中DA含量与DA释放的二元性。在成年非洲爪蟾眼杯24小时的DA释放周期中，眼杯在白天释放的DA量最高，在黑暗中则显著减少。从这些结果可以得出结论，尽管非洲爪蟾个体发育过程中视网膜多巴胺能系统发育较早，但最终成熟必须发生在变态高峰期。光照结束会显著抑制内源性DA释放，这解释了与中午相比，在变态后的幼蛙和成年个体中午夜时眼部DA含量更高的原因。
