The influence of a low dose (1 microM, 2 microl) of nonselective agonist of cannabinoid CB1 receptor WIN 55.212-2 on seizure activity in different brain structures was investigated in waking guinea pigs. Changes in spontaneous local field potentials and seizure afterdischarges evoked by the electrical stimulation of the perforant path were recorded simultaneously in the hippocampus, entorhinal cortex, medial septal region, and amygdala after a preliminary intraventricular injection of WIN 55.212-2. It was found that WIN 55.212-2 blocked the stimulation-elicited seizures in 80% of tests. A repeated injection of the agonist within 30 days caused an increase in the amplitude of local field potentials and the power of the theta rhythm in all the structures under study. The infusion of kainic acid provoked the onset of status epilepticus in control animals, whereas guinea pigs injected with the agonist (daily, during 25-30 days) did not develop the status. Possible mechanisms of the protective influence of WIN 55.212-2 are discussed.