Ciapa B, Maggio K
Laboratoire de Physiologie Cellulaire et Comparée, Faculté des Sciences, Université de Nice, France.
Dev Biol. 1993 Sep;159(1):114-21. doi: 10.1006/dbio.1993.1225.
Treatment of Paracentrotus lividus embryos with lithium, which is known to block the polyphosphoinositide (PPI) cycle, induces their development into vegetalized larvae. We have investigated how ionic balance and PPI metabolism were affected in such vegetalized embryos. Exposure to 80 mM lithium for 3 1/2 hr at the morula stage induced an accumulation of lithium into the embryos, concomitant with a decrease in intracellular sodium and potassium contents. Intracellular lithium was totally expelled 6 hr after removal of this ion from the external medium. We found that intracellular levels of all PPI-cycle intermediates were altered after vegetalization: PIP2 and PIP increased, while PI decreased. Finally, vegetalized embryos showed a significant depression of IP3 mass. The degree of change in inositol phosphates increased as the intracellular accumulation of lithium increased. The change in morphology (vegetalization) also correlated well with the increase in lithium accumulation. This is consistent with the hypothesis that lithium alters the PPI cycle.
用已知能阻断多磷酸肌醇（PPI）循环的锂处理紫球海胆胚胎，会诱导其发育成植物化幼虫。我们研究了在这种植物化胚胎中离子平衡和PPI代谢是如何受到影响的。在桑椹胚阶段暴露于80 mM锂3.5小时会导致锂在胚胎中积累，同时细胞内钠和钾含量降低。从外部培养基中去除该离子6小时后，细胞内的锂被完全排出。我们发现植物化后所有PPI循环中间体的细胞内水平都发生了改变：磷脂酰肌醇-4,5-二磷酸（PIP2）和磷脂酰肌醇-4-磷酸（PIP）增加，而磷脂酰肌醇（PI）减少。最后，植物化胚胎的三磷酸肌醇（IP3）总量显著降低。随着锂在细胞内积累的增加，肌醇磷酸的变化程度也增加。形态变化（植物化）也与锂积累的增加密切相关。这与锂改变PPI循环的假设一致。
