Antiepileptic and network inhibitory actions of Q5 (2-methyl-4-oxo-3H-quinazoline-3-acetyl piperidine) have recently been described in hippocampal slices. Here we present evidence on the in vivo antiabsence effect of Q5. All doses of Q5 tested (0.3 mg/kg, 0.9 mg/kg, 2.8 mg/kg) decreased the number, but not the duration and the frequency of absence spike-wave discharges (SWDs) in freely moving WAG/Rij rats. In vivo network inhibitory action of Q5 was monitored by following c-fos expression in different brain areas of Wistar rats. Significant depletion of c-fos expression was observed after single or repeated injections of Q5 (2.8 mg/kg and 2x2.8 mg/kg) in various brain areas, including hypothalamic paraventricular nucleus, medial amygdaloid nucleus, piriform cortex, somatosensory cortex, periventricular thalamic nucleus and periaqueductal central gray. Thus, our in vivo results demonstrate that in addition to the prevention of absence seizures, Q5 effectively suppresses neuronal activation in various stress- and pain-sensitive brain areas.