Pauwels P J, Van Assouw H P, Leysen J E, Janssen P A
Department of Biochemical Pharmacology, Janssen Research Foundation, Beerse, Belgium.
Mol Pharmacol. 1989 Oct;36(4):525-31.
Neuronal cell degeneration was studied in vitro in primary rat brain neuronal cultures grown in serum-free, chemically defined, CDM R12 medium, by measuring lactate dehydrogenase (LDH) released in the culture medium. A Ca2+-dependent neuronal cell degeneration was observed after prolonged and transient exposure 30 microM veratridine. The release of LDH occurred gradually and could be completely prevented by 2 mM ethylene glycol bis (beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, 0.1 microM tetrodotoxin, and 1 microM flunarizine. Flunarizine was without effect on neuronal cell loss induced by 1 mM glutamate, 1 mM kainic acid, and 5 mM KCN. The lack of effect on neurotoxicity induced by 1 mM glutamate differentiates flunarizine from N-methyl-D-aspartate antagonists such as MK-801. The latter protected at nanomolar concentrations against glutamate-induced neuronal cell death but had a maximal effect only at 0.1 mM on the veratridine-induced released LDH. It is suggested that, besides the excitatory amino acid receptor pathway, prolonged opening of the veratridine-sensitive Na+ channel can be neurotoxic. The latter can be prevented by flunarizine. The role of Na+ channel blockers as therapeutic agents in cerebral ischemia is discussed.
通过测量培养基中释放的乳酸脱氢酶（LDH），在无血清、化学成分明确的CDM R12培养基中培养的原代大鼠脑神经元培养物中对神经元细胞变性进行了体外研究。在长时间和短暂暴露于30微摩尔藜芦定后，观察到了钙离子依赖性神经元细胞变性。LDH的释放是逐渐发生的，并且可以被2毫摩尔乙二醇双（β-氨基乙基醚）-N，N，N'，N'-四乙酸、0.1微摩尔河豚毒素和1微摩尔氟桂利嗪完全阻止。氟桂利嗪对1毫摩尔谷氨酸、1毫摩尔 kainic 酸和5毫摩尔氰化钾诱导的神经元细胞损失没有影响。对1毫摩尔谷氨酸诱导的神经毒性缺乏作用使氟桂利嗪与N-甲基-D-天冬氨酸拮抗剂如MK-801区分开来。后者在纳摩尔浓度下可保护细胞免受谷氨酸诱导的神经元细胞死亡，但仅在0.1毫摩尔时对藜芦定诱导的LDH释放有最大作用。提示除兴奋性氨基酸受体途径外，藜芦定敏感的钠通道长时间开放也可能具有神经毒性。后者可被氟桂利嗪阻止。讨论了钠通道阻滞剂作为脑缺血治疗药物的作用。
