The function of cAMP and Ca2+ in motility of human sperm

环核苷酸和Ca2+在海洋无脊椎动物精子的趋化信号传导中起关键作用。虽然这些信使分子也被用于哺乳动物精子的趋化性，但我们的知识要么是零碎的，要么是有争议的。我们拟研究cAMP和Ca2+在人精子运动和趋化性中的作用。利用动力学技术和笼化化合物，我们将研究由精子鞭毛中cAMP或Ca2+的快速增加引起的运动反应。我们将研究假定的化学引诱剂和腺苷酸环化酶激活剂刺激精子的cAMP反应。此外，我们将通过使用荧光电位探针和Ca2+染料来检查假定的化学引诱剂或cAMP提高细胞内Ca2+浓度的机制。我们早期的研究表明，哺乳动物精子能够通过两个活跃的过程被引导到受精部位的卵母细胞；趋化性和热趋化性。这些过程背后的分子机制尚不清楚。我们的目标是揭示这些机制中的分子步骤并确定它们的顺序。为此，我们将应用快速混合技术来寻找潜在第二信使水平的变化，这些变化发生在人类精子对趋化剂浓度变化（趋化性）或温度变化（热趋化性）的游动反应的时间尺度内。我们还将尝试识别细胞用于热趋向性的精子热感器。所获得的信息有望为我们对哺乳动物生殖的理解提供新的视角，并对诊断和治疗人类生育具有潜在的未来意义。

Cyclic nucleotides and Ca2+ play key roles in chemotactic signaling of sperm from marine invertebrates. While these messenger molecules have also been invoked in chemotaxis of mammalian sperm, our knowledge is either fragmentary or controversial. We propose here to study the function of cAMP and Ca2+ in motility and chemotaxis of human sperm. Using kinetic techniques and caged compounds, we will examine the motor response evoked by a rapid step increase of either cAMP or Ca2+ in the sperm flagellum. We will study the cAMP response of sperm stimulated with putative chemoattractants and activators of adenylyl cyclases. Furthermore, we will examine the mechanisms by which either putative chemoattractants or cAMP elevate intracellular Ca2+ concentration using fluorescent potentiometric probes and Ca2+ dyes.Our earlier studies demonstrated that mammalian spermatozoa are capable of being guided to the oocyte at the fertilization site by two active processes; chemotaxis and thermotaxis. The molecular mechanisms underlying these processes are obscure. Our aim is to reveal molecular steps in these mechanisms and to determine their sequence. To this end we will apply rapid-mixing techniques to look for changes in the levels of potential second messengers, which occur within the time scale of the swimming response of human spermatozoa to a change in chemoattractant concentration (for chemotaxis) or to a temperature shift (for thermotaxis). We will also try to identify the sperm thermosensors used by the cell for thermotaxis. The information gained is expected to contribute new perspectives to our understanding of mammalian reproduction and to have potential future implications to diagnosing and treating human fertility.