However, it is unlikely that the effect of MAK involves the 5-HT1A mechanisms, because we observed no serotonin syndrome-like behaviors (such as flat body posture, hind limb abduction, and forepaw treading) that are induced primarily by an agonism at 5-HT1 receptor subtypes [31] in the MAK-treated rats. Here, HTR1A is linked to serotonin syndrome.