Neuroendocrine basis of lunar-synchronized spawning migration in grass puffer

为了建立河豚与月亮同步产卵迁移的神经内分泌控制的分子基础，我们评估了不同神经激素及其受体在下丘脑和松果体中基因表达的变化。在下丘脑，这些基因的表达在产卵期显著增加，并表现出与褪黑素受体基因表达变化相关的日变化和昼夜变化。在松果体中，褪黑素受体基因表现出独特的节律性表达，具有14小时的周期性和月变化。在产卵场和水族馆中对产卵行为的观察表明，产卵节律是由内源维持的，可能是在松果体的圆月时钟的控制下。

To establish molecular basis of neuroendocrine control of lunar-synchronized spawning migration in grass puffer, we assessed changes in magnitudes of gene expression for various neurohormones and their receptors in the hypothalamus and pineal gland. In the hypothalamus, the expressions of those genes significantly increased during the spawning period and showed diurnal and circadian variations in association with changes in expression of melatonin receptor gene. In the pineal gland, melatonin receptor gene showed unique rhythmic expressions with 14 hours cyclicity and monthly variations. Observations of spawning behavior in spawning grounds and in aquarium revealed that the spawning rhythm is endogenously maintained possibly under the control of the circalunar clock in the pineal gland.