Chronic treatment with LY341495 decreases 5-HT2A receptor binding and hallucinogenic effects of LSD in mice

► Chronic LY341495 down-regulates 5-HT2A binding in mouse somatosensory cortex. ► This effect does not occur in mGlu2-KO mice. ► Chronic LY341495 decreases head-twitch behavior and cellular responses induced by LSD. ► These findings suggest that repeated blockade of mGlu2 reduces 5-HT2A-dependent effects of LSD.