Abstract
TheE isomer of 2-ene-valproic acid (Δ2(E)-VPA) is the major active metabolite of the antiepileptic drug valproate (VPA) in various species, including humans. Experimental studies on Δ2(E)-VPA and VPA indicate that Δ2(E)-VPA may be a useful antiepileptic drug itself. Δ2(E)-VPA has the same wide spectrum of anticonvulsant activity as VPA with a somewhat higher anticonvulsant potency in rodent and dog models of different seizure types. As VPA, Δ2(E)-VPA increases presynaptic γ-aminobutyric acid (GABA) levels in the brain, presumably by an effect on GABA synthesis and/or GABA degradation. Δ2(E)-VPA is a much more potent inhibitor of the human brain GABA-degrading enzyme than VPA. In high doses. Δ2(E)-VPA is more sedative in rodents than is VPA; LD50 values are about the same. In mouse and rat models for teratogenicity, Δ2(E)-VPA does not induce teratogenic effects, whereas VPA is teratogenic in these models. Pilot rat studies on liver toxicity of VPA and VPA metabolites suggest that Δ2(E)-VPA is not hepatotoxic. In view of the rare but serious hepatotoxicity and teratogenicity of VPA in humans, Δ2(E)-VPA obviously merits interest as a valuable alternative drug in antiepileptic therapy.
Similar content being viewed by others
References
Löscher W. Valproic acid. In: Frey H-H, Janz D, eds. Antiepileptic drugs. (Handbook of experimental pharmacology; vol. 74.) Heidelberg: Springer-Verlag, 1985: 507–36.
Taillandier G, Benot-Guyot J-L, Boucherie A, Broll M, Eymard P. Recherches dans la série dipropylacétique XII. Acides et alcools aliphatiques ramifiés anticonvulsivants. Eur J. Med Chem Chim Ther 1975;10:453–62.
Weissman D, Simler S, Ciesielski L, Mandel P. Variations de la teneur en GABA de certaines zones du cerveau de la souris sous l'effet de l'acide propyl-2- pentène-2-oique. CR Soc Biol (Paris) 1978;172:707–12.
Löscher W. Anticonvulsant activity of metabolites of valproic acid. Arch Int Pharmacodyn Ther 1981;249:158–63.
Nau H, Löscher W, Schäfer H. Anticonvulsant activity and embryotoxicity of valproic acid. Neurology 1984;34:400–1.
Kesterson JW, Grannemann GR, Machinist JM. The hepatotoxicity of valproic acid and its metabolites in rats. I. Toxicologic, biochemical and histopathologic studies. Hepatology 1984;4:1143–52.
Löscher W, Nau H. Pharmacological evaluation of various metabolites and analogues of valproic acid. Anticonvulsant and toxic potencies in mice. Neuropharmacology 1985;24:427–35.
Löscher W, Hönack D, Nolting B, Fassbender CP.Trans-2-en-valproate: reevaluation of its anticonvulsant efficacy in standardized seizure models in mice, rats and dogs. Epilepsy Res 1991;9:135–210.
Löscher W, Nau H, Marescaux C, Vergnes M. Comparative evaluation of anticonvulsant and toxic potencies of valproic acid and 2-en-valproic acid in different animal models of epilepsy. Eur J Pharmacol 1984; 99:211–8.
Löscher W, Jäckel R, Czuczwar SJ. Is amygdala kindling in rats a model for drug-resistant partial epilepsy? Exp Neurol 1986;93:211–26.
Hönack D, Ruudfeldt C, Löscher W. Pharmacokinetics, anticonvulsant efficacy, and adverse effects oftrans-2-en-valproate after acute and chronic administration in amygdalakindled rats. Naunyn-Schmiedebergs Arch Pharmacol 1992;345:187–96.
Löscher W, Nau H. Distribution of valproic acid and its metabolites in various brain areas of dogs and rats after acute and prolonged treatment. J Pharmacol Exp Ther 1983;226:845–54.
Nau H, Löscher W. Valproic acid: brain and plasma levels of the drug and its metabolites, anticonvulsant effects and γ-aminobutyric acid (GABA) metabolism in the mouse. J Pharmacol Exp Ther 1982;220:654–9.
Löscher W. Alterations in CSF GABA levels and seizure susceptibility developing during repeated administration of pentetrazole in dogs. Effects of γ-acetylenic GABA, valproic acid and phenobarbital. Neurochem Int 1983;5:405–12.
Löscher W, Fisher JE, Nau H, Hönack D. Marked increase in anticonvulsant activity but decrease in wetdog shake behaviour during short-term treatment of amygdala-kindled rats with valproic acid. Eur J Pharmacol 1988;150:221–32.
Nau H, Löscher W. Valproic acid and metabolites: pharmacological and toxicological studies. Epilepsia 1984;25 Suppl 1:S14–22.
Lewandowski C, Klug S, Nau H, Neubert D. Pharmacokinetic aspects of drug effectsin vivo: effects of serum protein binding on concentration and teratogenicity of valproic acid and 2-en-valproic acid in whole embryos in culture. Arch Toxicol 1986;58: 239–42.
Nau H. Transfer of valproic acid and its main active unsaturated metabolite to the gestational tissue: correlation with neural tube defect formation in the mouse. Teratology 1986;33:21–7.
Nau H, Löscher W. Pharmacologic evaluation of various metabolites and analogs of valproic acid: teratogenic potencies in mice. Fund Appl Toxicol 1986;6:669–76.
Nau H, Hendrickx AG. Valproic acid teratogenesis. ISI Atlas Sci Pharmacol 1987:52–6.
Lewis JH, Zimmermann HJ, Garrett CT, Rosenberg E. Valproate-induced hepatic steatogenesis in rats. Hepatology 1982;2:870–3.
Nau H, Merker H-J, Brendel K, Häuser I, Gansau C, Wittfoht W. Disposition, embryotoxicity and hepatotoxicity of valproic acid in the mouse as related to man. In: Levy RH, ed. Metabolism of antiepileptic drugs. New York: Raven Press, 1984:85–96.
Schäfer H, Lührs R. Responsibility of the metabolite pattern for potential side effects in the rat being treated with valproic acid, 2-propylpenten-2-oic acid and 2-propylpenten-4-oic acid. In: Levy RH, Pitlick WH, Eichelbaum M, Meijer J, eds. Metabolism of antiepileptic drugs. New York: Raven Press, 1984:73–84.
Löscher W, Nau H. Comparative transfer of valproic acid and of an active metabolite into brain and liver: possible pharmacological and toxicological consequences. Arch Int Pharmacodyn Ther 1984;270:192–202.
Nau H, Löscher W. Valproic acid and active unsatu- rated metabolite (2-en): transfer to mouse liver following human therapeutic doses. Biopharm Drug Dispos 1985;6:1–8.
Löscher W, Böhme G, Schäfer H, Kochen W. Effect of metabolites of valproic acid on the metabolism of GABA in brain nerve endings. Neuropharmacology 1981;20:1187–92.
Maitre M, Ciesielski L, Cash C, Mandel P. Comparison of the structural characteristics of the 4-aminobutyrate:2-oxoglutarate transaminases from rat and human brain, and of their affinities for certain inhibitors. Biochim Biophys Acta 1978;522:385–99.
McLean MJ, Macdonald RL. Sodium valproate, but not ethosuximide, produces use- and voltage-dependent limitation of high frequency repetitive firing of action potentials of mouse central neurons in cell culture. J Pharmacol Exp Ther 1986;237:1001–11.
Handley SL, Singh L. Neurotransmitters and shaking behaviour — more than a ‘gut-bath’ for the brain? TiPS 1986:324–8.
Horton RW, Anlezark GM, Sawaya MCB, Meldrum BS. Monoamine and GABA metabolism and the anticonvulsant action of di-n-propylacetate and ethanolamine-O-sulphate. Eur J Pharmacol 1977;41:387–97.
Hwang EC, Van Woert MH. Effect of valproic acid on serotonin metabolism. Neuropharmacology 1979;18:391–7.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Löscher, W. Pharmacological, toxicological and neurochemical effects of Δ2(E)-valproate in animals. Pharmaceutisch Weekblad Scientific Edition 14, 139–143 (1992). https://doi.org/10.1007/BF01962705
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01962705