GABAB receptor antagonists: potential new anti-absence drugs

Abstract
The availability of new antagonists of the GABAB receptor which readily cross the blood-brain barrier has made it possible to investigate the role of GABAB-receptor-mediated transmission in the control of spike-and-wave discharges (SWD) in a strain of rats (GAERS) with genetic absence epilepsy. Systemic administration of R-Baclofen, a GABAB agonist, increased the duration of SWD, or elicited SWD-like oscillations in the cortical EEG of non-epileptic control rats. Conversely, administration of CGP 35348, a GABAB antagonist, either i.p. or p.o., dose-dependently suppressed the spontaneous SWD, as well as the SWD aggravated by concomitant injection of various GABAmimetic drugs, GHB, or anticonvulsants known to exacerbate absence seizures. These results demonstrate the involvement of GABAB-mediated neurotransmission in the development of SWD in generalized non-convulsive epilepsy. GABAB antagonists may thus be considered to be potentially specific anti-absence drugs.