Effects of valproate in a model nervous system (buccal ganglia of Helix pomatia): II. Epileptogenic actions.
High concentrations of valproate (VPA; greater than 20 mM) depolarized identified neuronal individuals in the buccal ganglia of Helix pomatia and transiently induced paroxysmal depolarization shifts (PDS). Threshold concentration of VPA for the induction of PDS was decreased (a) by increased seizure susceptibility, (b) by increased concentrations of derivatives of VPA, and (c) by increased H+ concentrations. Intrasomatic injection of VPA did not induce PDS. The epileptogenic action of VPA is believed to be exerted from the extracellular side of the cell membrane.
Altrup
U
U
Institut für Experimentelle Epilepsieforschung, Münster, Germany.
Reith
H
H
Speckmann
E J
EJ
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004827:Epilepsy / Q000139:chemically induced / Q000209:etiology*; D005045:Etomidate; D005110:Extracellular Space / Q000378:metabolism; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology; D005724:Ganglia / Q000187:drug effects / Q000502:physiology; D006372:Helix, Snails / Q000187:drug effects / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D008959:Models, Neurological; D009420:Nervous System / Q000187:drug effects*; D009424:Nervous System Physiological Phenomena; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D010433:Pentylenetetrazole; D014635:Valproic Acid / Q000494:pharmacology*
D005229:Fatty Acids, Monounsaturated; C014168:2-propyl-2-pentenoic acid; D014635:Valproic Acid; D010433:Pentylenetetrazole; D005045:Etomidate