Tinikul Yotsawan, Joffre Mercier A, Soonklang Nantawan, Sobhon Prasert
Department of Anatomy, Faculty of Science, Mahidol University, Ratchathewi, Bangkok, Thailand.
Gen Comp Endocrinol. 2008 Sep 15;158(3):250-8. doi: 10.1016/j.ygcen.2008.07.009. Epub 2008 Aug 5.
Serotonin or 5-hydroxytryptamine (5-HT) and dopamine (DA) are the two key neurotransmitters that control gonadal development in decapod crustaceans. This study investigated changes in the levels of 5-HT and DA in the CNS and ovary during different phases of the ovarian cycle of the freshwater prawn, Macrobrachium rosenbergii. The levels of 5-HT and DA were quantified by using High Performance Liquid Chromatography with electrochemical detection (HPLC-ECD). Moreover, changes of vitellogenin (Vg) concentrations in the hemolymph after treatment with 5-HT and DA (at doses of 2.5 x 10(-6) and 2.5 x 10(-7)mol per prawn) were also examined. 5-HT exhibited a gradual increase in concentration in the brain and thoracic ganglia from ovarian stage I (0.12+/-0.01 nmol/mg, 0.22+/-0.01 nmol/mg, respectively) to reach a maximum (0.66+/-0.03 nmol/mg, 1.48+/-0.03 nmol/mg, respectively) at ovarian stage IV. In contrast, DA in the brain and thoracic ganglia showed the highest concentrations at ovarian stage II (0.20+/-0.01 nmol/mg, 1.27+/-0.06 nmol/mg, respectively) and then decreased to the lowest concentrations (0.06+/-0.01 nmol/mg, 0.28+/-0.04 nmol/mg, respectively) at ovarian stage IV. The ovarian concentration of 5-HT was 0.53+/-0.11 nmol/mg at ovarian stage I and gradually increased to 1.63+/-0.16 nmol/mg at ovarian stage IV. In contrast, the concentration of DA was highest at ovarian stage I (29.05+/-1.31 nmol/mg), and lowest at the ovarian stage IV (11.43+/-0.74 nmol/mg). Injecting 5-HT into prawns significantly increased Vg concentration in the hemolymph at ovarian stage IV compared to control groups, and injecting DA into prawns had the opposite effect. The inverse relationship between 5-HT and DA levels in neural ganglia and ovaries, and their opposing effects on hemolymph Vg levels suggest that these two transmitters play opposite regulatory roles in controlling ovarian maturation and oocyte development in this species.
血清素或5-羟色胺（5-HT）和多巴胺（DA）是控制十足目甲壳类动物性腺发育的两种关键神经递质。本研究调查了淡水虾罗氏沼虾卵巢周期不同阶段中枢神经系统和卵巢中5-HT和DA水平的变化。采用高效液相色谱-电化学检测法（HPLC-ECD）对5-HT和DA的水平进行定量。此外，还检测了用5-HT和DA（每只虾剂量为2.5×10⁻⁶和2.5×10⁻⁷mol）处理后血淋巴中卵黄蛋白原（Vg）浓度的变化。5-HT在卵巢I期时脑和胸神经节中的浓度逐渐升高（分别为0.12±0.01 nmol/mg、0.22±0.01 nmol/mg），在卵巢IV期达到最高值（分别为0.66±0.03 nmol/mg、1.48±0.03 nmol/mg）。相比之下，脑和胸神经节中的DA在卵巢II期浓度最高（分别为0.20±0.01 nmol/mg、1.27±0.06 nmol/mg），然后在卵巢IV期降至最低浓度（分别为0.06±0.01 nmol/mg、0.28±0.04 nmol/mg）。卵巢中5-HT的浓度在卵巢I期为0.53±0.11 nmol/mg，并在卵巢IV期逐渐增加至1.63±0.16 nmol/mg。相比之下，DA的浓度在卵巢I期最高（29.05±1.31 nmol/mg），在卵巢IV期最低（11.43±0.74 nmol/mg）。与对照组相比，向虾体内注射5-HT可显著提高卵巢IV期血淋巴中Vg的浓度，而向虾体内注射DA则产生相反的效果。神经节和卵巢中5-HT和DA水平的负相关关系，以及它们对血淋巴Vg水平的相反作用表明，这两种神经递质在控制该物种卵巢成熟和卵母细胞发育中发挥着相反的调节作用。
