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Neuropharmacology. 1996 Jan;35(1):45-55.

gamma-Butyrolactone-induced absence-like seizures increase nuclear CRE- and AP-1 DNA-binding activities in mouse brain.

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Department of Pharmacology, College of Pharmacy, Nihon University, Chiba, Japan.


We examined the involvement of the GABAB receptor and the coordinated induction of nuclear transcriptional factors in experimental generalized absence seizures induced by gamma-butyrolactone (GBL) in mice. Although administration of GBL 50 mg/kg did not show any effects on behavior or ECoG pattern, higher doses of GBL (70 and 100 mg/kg, i.p.) induced behavioral changes associated with 3-6-Hz spike and wave discharges in the mice. CGP 35348, a GABAB receptor antagonist, suppressed both the GBL-induced absence seizures and the spike and wave discharges. The antiepileptic effects of CGP 35348 (200 mg/kg, i.p.) were stronger than those of ethosuximide (200 mg/kg, i.p.). Sodium valproate (100 mg/kg, i.p.) attenuated the early phase but not the late phase of the GBL-induced absence seizures. Gel-mobility assay demonstrated that administration of an effective dose of GBL for eliciting spike and wave discharges dose-dependently increased nuclear cyclic AMP-responsive element (CRE)- and activator protein 1 (AP-1) DNA-binding activities in mouse whole brain. The increases in nuclear CRE- and AP-1 DNA-binding were antagonized by CGP 35348 in a dose-dependent fashion. In addition, GABAB receptor binding assay revealed that GBL or antiepileptic drugs did not displace [3H]baclofen binding in cerebral cortical membranes. In contrast, gamma-hydroxybutyrate (GHB), an active metabolite of GBL, inhibited [3H]baclofen binding in a concentration-dependent manner. These results suggest that GABAB receptor-mediated synaptic responses are involved in GBL-induced generalized absence seizures and that the increases in nuclear CRE- and AP-1 DNA-binding activities are correlated with the GBL-induced generalized absence seizures.

[Indexed for MEDLINE]

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