We previously showed that unilateral ibotenate lesions of the basal forebrain (BF) in rats increased NREM sleep and EEG delta power in all states in both light and dark phases of L:D 12:12 cycle, suggesting that the BF plays an important role in the maintenance of behavioural and cortical arousal [Kaur et al. (2004) SFN Abstr. 196.12]. The BF has also been implicated in adenosinergic regulation of sleep homeostasis. Therefore, in the present study we investigated whether BF ibotenate lesions affect recovery sleep and EEG after 6-h sleep deprivation (SD). Male rats were implanted with polygraphic electrodes and unilateral/bilateral guide cannulae above the nucleus basalis magnocellularis and substantia innominata. After acclimatization, a 24-h pre-injection recording was conducted followed by injection of 8µg/0.5µl ibotenate or ACSF. On 27th post-injection day animals were recorded for 30-h pre-SD baseline and then sleep deprived by gentle handling for 6 h in the second half of the light phase, followed by ...