In vivo evidence for a lack of central effect of ebastine, an antihistaminic agent, in rats: a microdialysis study.

The effects of ebastine and its active metabolite carebastine on brain dopamine uptake and the accessibility to brain were compared with those for a classical antihistaminic agent chlorpheniramine by using the microdialysis technique. Both carebastine and chlorpheniramine potently inhibited brain [(3)H]dopamine uptake and increased the extracellular concentration of dopamine in the striatum after local perfusion via microdialysis probes, although systemic injection of ebastine but not chlorpheniramine did not change the dopamine level. These findings suggest that neither ebastine nor carebastine affects central dopamine metabolism because of a limited access to brain, in spite of having a potent inhibitory action on neuronal dopamine uptake.