Bisogno T, Ventriglia M, Milone A, Mosca M, Cimino G, Di Marzo V
Istituto per la Chimica di Molecole di Interesse Biologico, C.N.R., Napoli, Italy.
Biochim Biophys Acta. 1997 Apr 21;1345(3):338-48. doi: 10.1016/s0005-2760(97)00009-x.
Cannabinoid receptors have been described in sea urchin sperm and shown to mediate inhibition of sperm acrosome reaction. Anandamide (arachidonoyl-ethanolamide), the mammalian physiological ligand at the cannabinoid CB1 receptor, has been subsequently found to effect this inhibition. Here we present data showing that ovaries from the sea urchin Paracentrotus lividus contain anandamide and two related acyl-ethanolamides, as well as enzymatic activities potentially responsible for their biosynthesis and degradation. Pilot experiments carried out with either ovaries or spermatozoa, extracted from both P. lividus and Arbacea lixula and radiolabelled with [14C]ethanolamine, showed that in sexually mature ovaries of both species significant levels of radioactivity were incorporated into a lipid component with the same chromatographic behaviour as anandamide. Lipid extracts from P. lividus ovaries were purified and analysed by gas chromatography/mass spectrometry which showed the presence of low but measurable amounts of anandamide, palmitoyl- and stearoyl-ethanolamides. The extracts were also found to contain lipid components with the same chromatographic behaviour as the N-acyl-phosphatidyl-ethanolamines, the phospholipid precursors of acyl-ethanolamides in mammalian tissues, and capable of releasing anandamide, palmitoyl- and stearoyl-ethanolamides upon digestion with S. chromofuscus phospholipase D. Accordingly, whole homogenates from P. lividus contained an enzymatic activity capable of converting synthetic [3H]N-arachidonoyl-phosphatidyl-ethanolamine into [3H]anandamide. Finally, mature ovaries of P. lividus were shown also to contain an amidohydrolase activity which catalyses the hydrolysis of anandamide and palmitoyl-ethanolamide to ethanolamine. This enzyme displayed subcellular distribution, pH/temperature dependency profiles and sensitivity to inhibitors similar but not identical to those of the previously described 'anandamide amidohydrolase' from mammalian tissues. These data support the hypothesis, formulated in previous studies, that anandamide or related metabolites may be oocyte-derived cannabimimetic regulators of sea urchin fertility.
大麻素受体已在海胆精子中被发现，并被证明可介导对精子顶体反应的抑制作用。随后发现，作为大麻素CB1受体的哺乳动物生理配体，花生四烯酸乙醇胺（anandamide）可产生这种抑制作用。在此，我们展示的数据表明，地中海海胆（Paracentrotus lividus）的卵巢中含有花生四烯酸乙醇胺以及两种相关的酰基乙醇胺，同时还具有可能负责其生物合成和降解的酶活性。用从地中海海胆和阿里西亚海胆（Arbacea lixula）中提取并用[14C]乙醇胺进行放射性标记的卵巢或精子进行的初步实验表明，在这两种物种性成熟的卵巢中，大量放射性物质被整合到一种脂质成分中，其色谱行为与花生四烯酸乙醇胺相同。对地中海海胆卵巢的脂质提取物进行纯化，并通过气相色谱/质谱分析，结果显示存在少量但可测量的花生四烯酸乙醇胺、棕榈酰乙醇胺和硬脂酰乙醇胺。提取物中还发现含有与N-酰基磷脂酰乙醇胺色谱行为相同的脂质成分，N-酰基磷脂酰乙醇胺是哺乳动物组织中酰基乙醇胺的磷脂前体，在用嗜铬栖热放线菌磷脂酶D消化后能够释放出花生四烯酸乙醇胺、棕榈酰乙醇胺和硬脂酰乙醇胺。相应地，地中海海胆的全匀浆含有一种能够将合成的[3H]N-花生四烯酰磷脂酰乙醇胺转化为[3H]花生四烯酸乙醇胺的酶活性。最后，研究表明地中海海胆成熟的卵巢还含有一种酰胺水解酶活性，该酶可催化花生四烯酸乙醇胺和棕榈酰乙醇胺水解为乙醇胺。这种酶的亚细胞分布、pH/温度依赖性图谱以及对抑制剂的敏感性与先前描述的来自哺乳动物组织的“花生四烯酸乙醇胺酰胺水解酶”相似但不完全相同。这些数据支持了先前研究中提出的假设，即花生四烯酸乙醇胺或相关代谢物可能是卵母细胞衍生的海胆生育拟大麻素调节剂。
