Ca2+-mediated neuronal death in rat brain neuronal cultures by veratridine: protection by flunarizine.
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.
Pauwels
P J
PJ
Department of Biochemical Pharmacology, Janssen Research Foundation, Beerse, Belgium.
Van Assouw
H P
HP
Leysen
J E
JE
Janssen
P A
PA
D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D002478:Cells, Cultured; D003986:Dibenzocycloheptenes / Q000494:pharmacology; D016291:Dizocilpine Maleate; D004305:Dose-Response Relationship, Drug; D005444:Flunarizine / Q000494:pharmacology*; D005971:Glutamates / Q000494:pharmacology; D007608:Kainic Acid / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D016202:N-Methylaspartate; D009474:Neurons / Q000187:drug effects*; D051381:Rats; D015222:Sodium Channels / Q000187:drug effects; D013779:Tetrodotoxin / Q000633:toxicity; D014701:Veratridine / Q000037:antagonists & inhibitors / Q000633:toxicity*; D014702:Veratrine / Q000031:analogs & derivatives*
D003986:Dibenzocycloheptenes; D005971:Glutamates; D015222:Sodium Channels; D001224:Aspartic Acid; D013779:Tetrodotoxin; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D014701:Veratridine; D007770:L-Lactate Dehydrogenase; D014702:Veratrine; D005444:Flunarizine; D007608:Kainic Acid; D002118:Calcium