Sperm increase inositol 1,4,5-trisphosphate mass in Xenopus laevis eggs preinjected with calcium buffers or heparin.
Sperm increase inositol 1,4,5-trisphosphate mass in Xenopus laevis eggs preinjected with calcium buffers or heparin.
复制标题
精子增加预先注射钙缓冲液或肝素的非洲爪蟾卵中肌醇 1,4,5-三磷酸的质量。
作者：
B. Stith;R. Espinoza;D. Roberts;T. Smart
虽然已知所有受精事件都是由于细胞内钙离子([Ca~(2+)]i)的升高，但精子如何引起受精卵[Ca~(2+)]_i的升高还不清楚。我们报道了精子可以增加非洲爪哇卵子中的肌醇1，4，5-三磷酸，而预先注入钙缓冲液以防止受精后[Ca~(2+)]_i的升高(包括最初的升高和随后的升高)。在缓冲[Ca~(2+)]i至远低于基础水平后，IP3的产生没有被阻止，而IP3的代谢可能被抑制。此外，肝素(一种肌醇1，4，5-三磷酸作用和受精反应的抑制剂)不能阻止受精后IP3的正常增加。产生不同水平的多精受精的条件与IP3的增加有关，类似于单精子受精后的情况。这些数据表明了受精事件的特定顺序：精子在受精时利用最初产生的肌醇1，4，5-三磷酸来产生[Ca2+]i增加。
Although it is known that all fertilization events are due to elevated intracellular calcium ([Ca2+]i), it is not known how sperm induce an increase in zygote [Ca2+]i. We report that sperm can increase inositol 1,4,5-trisphosphate in Xenopus laevis eggs that have been preinjected with calcium buffers to prevent the increase in [Ca2+]i (both the initial increase and the subsequent wave) after fertilization. After buffering [Ca2+]i to levels well below basal, IP3 production was not blocked, whereas IP3 metabolism may be inhibited. Also, heparin (an inhibitor of inositol 1,4,5-trisphosphate action and the fertilization response) does not prevent a normal increase in IP3 after fertilization. Conditions that produce various levels of polyspermy are associated with IP3 increases similar to those noted after monospermic fertilization. These data suggest a specific order of fertilization events: sperm utilize an initial production of inositol 1,4,5-trisphosphate to produce the [Ca2+]i increase at fertilization.