Aminergic control of early devlopment

神经递质5-羟色胺（5-HT， 5-羟色胺）的功能在中枢神经系统和其他一些组织中被深入研究和熟知。5-羟色胺及其受体在雌性生殖组织中的存在在脊椎动物中已被零星报道，但在一些无脊椎动物中，5-羟色胺在生殖中的精确功能已被更好地描述，特别是在软体动物物种中，如蛤。在该物种中，5-HT触发成熟动物的产卵，并在将其添加到分离的卵母细胞中时诱导卵母细胞减数分裂成熟，从而模仿通常由受精精子设定的激活过程。以蛤蚌为模型，我们之前已经表明，蛤蚌的i前期卵母细胞具有5-HT受体，其激活可触发细胞内钙和cAMP的增加，并导致减数分裂完全成熟。我们的具体目标是通过研究其在哺乳动物宿主细胞（HEK-293）中转染后的信号特性和药理学特征，进一步表征克隆的蛤卵母细胞5-HT受体，并确定它是否是导致减数分裂成熟的特异性受体。其他在蛤卵细胞中表达的胺能受体将被研究，包括克隆的推测的章鱼胺受体，并测试它们影响减数分裂成熟的能力。我们还将验证5-HT引起的cAMP升高在多大程度上导致静止卵母细胞减数分裂的重新启动。我们将研究蛋白激酶A的特异性激活剂和抑制剂通过5-HT改变减数分裂再起始的能力，并建立内部cAMP水平与细胞内钙升高相关的MAPK信号通路之间的可能联系。最后，其他生物胺如章鱼胺和多巴胺在生殖调节中的可能参与将被检查。我们的研究计划将阐明胺能受体参与生殖和早期发育过程的机制。我们的工作将为理解越来越多的胺能受体的潜在作用铺平道路，这些受体的局部功能未知，但据报道，它们不仅在无脊椎动物的生殖细胞中表达，也在脊椎动物物种中表达。

The functions of the neurotransmitter serotonin (5-HT, 5-hydroxytryptamine) are intensively studied and well known in the central nervous system and some other tissues.  The presence of 5-HT and its receptors in female reproductive tissues has been sporadically reported in vertebrate animals but it is in some invertebrates that precise functions of 5-HT in reproduction have been better described, in particular in molluscan species such as surf clam.  In this species, 5-HT triggers spawning in mature animals, and induces oocyte meiotic maturation when added to isolated oocytes, thus mimicking a process of activation normally set by the fertilizing sperm.  Using surf clam as a model, we have previously shown that their prophase I-arrested oocytes possess a 5-HT receptor whose activation triggers increased intracellular calcium and cAMP, and leads to full meiotic maturation.  Our specific objectives will be to further characterize a cloned putative clam oocyte 5-HT receptor by studying its signalling properties and pharmacological profile when transfected in mammalian host cells (HEK-293), and determine whether it is the specific receptor leading to meiotic maturation.   Other aminergic receptors expressed in clam oocytes will be investigated, including a cloned putative octopamine receptor, and tested for their capacity to influence meiotic maturation.  We will also verify to what extent observed cAMP rises elicited by 5-HT are causal in reinitiating meiosis in quiescent oocytes.  We will examine the capacity of specific activators and inhibitors of protein kinase A to alter meiosis reinitiation by 5-HT and establish possible links between internal cAMP levels and the MAPK signaling pathway relative to intracellular calcium rises.  Finally, the possible involvement of other biogenic amines such as octopamine and dopamine in the regulation of reproduction will be examined.  Our research program will clarify the mechanisms by which aminergic receptors are involved in reproductive and early developmental processes.  Our work will pave the way for understanding potential roles of a growing list of aminergic receptors of unknown local function but reported to be expressed in reproductive cells of not only invertebrate but vertebrate species, as well.