Influence of a GABAB and GABAC receptor antagonist on sleep-waking cycle in the rat

This study tested the influence of CGP 36742, a both gamma-aminobutyric acid(B) (GABA(B)) and GABA(C) receptor antagonist, on sleep and waking. The compound was injected intraperitoneally at 1, 10, 30, 100, 300 and 500 mg/kg to rats which were recorded during 6h. Only at 500 mg/kg, total waking was increased during third and fourth hours and total duration of recording by a specific enhancement of quiet waking (without hippocampal theta activity). Slow wave sleep was decreased at 100, 300, 500 mg/kg during the third and fourth hours, and during total recording time at 500 mg/kg. Paradoxical sleep was not affected. While it was not possible to distinguish already known GABA(B) and GABA(C)-identical influence on waking and slow wave sleep, their previously shown opposite effect on paradoxical sleep seemed to nullify each other. (c) 2006 Elsevier B.V. All rights reserved.