Blockade of thalamic GABAB receptors decreases EEG synchronization.

The gamma-aminobutyric acid (GABA)B receptor antagonists 2-OH-saclofen and CGP 35348 were injected in the thalamus of freely moving cats via a microdialysis probe while recording the sleep-walking cycle. The results obtained with the two antagonists were similar: wakefulness and the total sleep time were not affected by the blockade of GABAB receptors, but deep slow wave sleep and the mean power of slow waves (< 10 Hz) were decreased, while light slow wave sleep was increased. These data suggest an involvement of thalamic GABAB receptors in the regulation of EEG slow waves.