Kiss T, Vehovszky A, Hiripi L, Kovács A, Vörös L
Balaton Limnological Research Institute of the Hungarian Academy of Sciences, P.O. Box 35, H-8237 Tihany, Hungary.
Comp Biochem Physiol C Toxicol Pharmacol. 2002 Feb;131(2):167-76. doi: 10.1016/s1532-0456(01)00290-3.
The effect of anatoxin (ANTX), the crude extract (AlgTX) and purified fraction (F1) isolated from cyanobacterium C. raciborskii was studied on the neurones of two snail species. ANTX and AlgTX exerted excitatory, inhibitory and biphasic effects on the spontaneous activity of identified neurones. Both ANTX and AlgTX elicited an inward current, which could be decreased by curare or amiloride. On the contrary, F1 had no direct effect on the spontaneous activity; it was not able to induce conductance changes of the neuronal membrane, but it did antagonise the acetylcholine (ACh)-induced inward current. We concluded that ANTX affects the neuronal membrane of neurones acting on ACh receptors. The AlgTX had similar effects, and therefore the extract of C. raciborskii may contain an ANTX-like component. The purified fraction prolonged and decreased the ACh-elicited response, but had no direct membrane effect. We suggest, therefore, that both AlgTX and the purified fraction F1 interact with the ACh receptor, but they have different binding sites on the neuronal ACh receptor-ion channel complex. The possible neurotoxic effects of the C. raciborskii extract and F1 are demonstrated for the first time; the molecular mechanism of their action, however, remains to be elucidated.
研究了从蓝藻拉氏尖头藻（C. raciborskii）中分离出的类毒素（ANTX）、粗提物（AlgTX）和纯化组分（F1）对两种蜗牛神经元的影响。ANTX和AlgTX对已鉴定神经元的自发活动产生兴奋、抑制和双相作用。ANTX和AlgTX均引发内向电流，箭毒或阿米洛利可使其减小。相反，F1对自发活动无直接影响；它不能诱导神经元膜的电导变化，但能拮抗乙酰胆碱（ACh）诱导的内向电流。我们得出结论，ANTX作用于ACh受体，影响神经元的细胞膜。AlgTX有类似作用，因此拉氏尖头藻提取物可能含有类似ANTX的成分。纯化组分延长并减弱了ACh引发的反应，但对膜无直接作用。因此，我们认为AlgTX和纯化组分F1均与ACh受体相互作用，但它们在神经元ACh受体 - 离子通道复合物上有不同的结合位点。首次证明了拉氏尖头藻提取物和F1可能的神经毒性作用；然而，其作用的分子机制仍有待阐明。
