Molecular Basis for Neurohormonal Control of Salmonid Spawning Migration

鲑鱼产卵洄游是一种典型的定型或本能行为，是由遗传程序控制的。然而，分子方法很少揭示鲑鱼迁徙的遗传程序。为了澄清这种遗传程序作为最终目标，我们研究了鲑鱼产卵迁移的神经内分泌机制的分子基础。由于产卵迁移是生殖行为，我们假设，产生促性腺激素释放激素（GnRH）和催产素（VT）的视前神经元在协调中枢神经系统的感觉，运动和动机功能以及脑垂体性腺轴的神经内分泌功能中起着至关重要的作用。中枢神经系统和神经内分泌系统的协调活动对繁殖的成功至关重要，也就是说，迁移和产卵行为的神经控制必须在时间和空间上一致。给你我们测定了沿着迁移途径编码神经激素和垂体激素的mRNA量的绝对变化，以阐明迁移过程中激素基因表达的变化。我们进一步分析了鲑类激素基因表达的调控机制。通过本项目获得的结果实际上支持了我们的上述假设。

Spawning migration of salmon is a typical stereotyped or instinctive behavior which is genetically programmed. However, molecular approaches are rare to reveal what is a genetic program of salmon migration. Aiming clarification of such genetic program as the final goal, we examined molecular bases of neuroendocrine mechanisms for salmon spawning migration. Since spawning migration is reproductive behavior, we hypothesized that preoptic neurons producing gonadotropin-releasing hormone (GnRH) and vasotocin (VT) have a crucial role in coordination of the sensory, motor and motivational function of the central nervous system and the neuroendocrine function of the brain-pituitary-gonadal axis. The coordinated activity of the central nervous system and the neuroendocrine system should be crucial for the success of reproduction, that is, the neural controls of migratory and spawning behavior must be temporally and spacially coincident. Herewith. we determined absolute changes in the amounts of mRNAs encoding neurohormones and pituitary hormones along migratory pathways to elucidate changes in expression of hormonal genes during migration. We further analyzed regulatory mechanisms of expression of hormonal genes in salmonids. The results obtained through the present project actually support our hypothesis mentioned above.