Genazzani A A, Galione A
University Department of Pharmacology, Oxford, U.K.
Biochem J. 1996 May 1;315 ( Pt 3)(Pt 3):721-5. doi: 10.1042/bj3150721.
Nicotinic acid-adenine dinucleotide phosphate (NAADP) is a novel intracellular Ca2+ releasing agent recently described in sea-urchin eggs and egg homogenates. Ca2+ release by NAADP is independent of that induced by either inositol trisphosphate (InsP3) or cyclic adenosine dinucleotide phosphate (cADPR). We now report that in sea urchin egg homogenates, NAADP releases Ca2+ from a Ca2+ pool that is distinct from those that are sensitive to InsP3 and cADPR. This organelle has distinct Ca2+ uptake characteristics: it is insensitive to thapsigargin and cyclopiazoic acid, but maintenance of the pool shows some requirement for ATP. Although the different Ca2+ pools have different characteristics, there appears to be some degree of overlap or cross-talk between the NAADP- and cADPR/InsP3-sensitive Ca2+ pools. Ca(2+)-induced Ca2+ release is unlikely to account for the apparent overlap between stores, since NAADP-induced Ca2+ release, in contrast with that stimulated by cADPR, is not potentiated by bivalent cations.
烟酰胺腺嘌呤二核苷酸磷酸（NAADP）是一种最近在海胆卵和卵匀浆中发现的新型细胞内钙离子释放剂。NAADP诱导的钙离子释放独立于由肌醇三磷酸（InsP3）或环磷酸腺苷二磷酸核糖（cADPR）诱导的钙离子释放。我们现在报道，在海胆卵匀浆中，NAADP从一个与对InsP3和cADPR敏感的钙离子池不同的钙离子池中释放钙离子。这个细胞器具有独特的钙离子摄取特性：它对毒胡萝卜素和环匹阿尼酸不敏感，但该钙离子池的维持对ATP有一定需求。尽管不同的钙离子池具有不同的特性，但在NAADP敏感的钙离子池与cADPR/InsP3敏感的钙离子池之间似乎存在一定程度的重叠或相互作用。钙离子诱导的钙离子释放不太可能解释储存库之间明显的重叠，因为与cADPR刺激的情况相反，NAADP诱导的钙离子释放不会被二价阳离子增强。
