Effect of the new antiallergic agent olopatadine on EEG spectral powers in conscious rats

The central effect of olopatadine (((Z)-11-[3-dimethylamino)propylidene)-6, 11-dihydrodibenz[b,e]oxepin-2-acetic acid hydrochloride, CAS 140462-76-6, KW-4679) was studied in comparison with those of ketotifen and doxepin using spontaneous EEG and EEG spectral powers in conscious rats. Both ketotifen (20 mg/kg p.o.) and doxepin (20 mg/kg p.o.) caused drowsy patterns in spontaneous EEG characterized by slow waves of high amplitude at the frontal cortex, occipital cortex and amygdala, and by disappearance of the regularity in theta waves recorded from the hippocampus. In EEG spectral powers, both drugs caused a significant increase in the power densities of the delta band recorded from the frontal cortex, occipital cortex and amygdala. On the contrary, no visible changes were elicited by the treatment with olopatadine (20 mg/kg p.o.) in both spontaneous EEG and EEG spectral powers recorded from the frontal cortex, occipital cortex, hippocampus and amygdala. These results indicate that olopatadine provides no remarkable effect on the central nervous system.