Mescaline Mexico. Europeans noted use of peyote in Native American religious ceremonies upon early contact, notably by the Huichols in Mexico. Other mescaline-containing cacti such as the San Pedro have a long history of use in South America, from Peru to Ecuador. In traditional peyote preparations, the top of the cactus is cut off, leaving the large tap root along with a ring of green photosynthesizing area to grow new heads. These heads are then dried to make disc-shaped buttons. Buttons are chewed to produce the effects or soaked in water to drink. However, the taste of the cactus is bitter,
Mescaline and activates the serotonin 5-HT receptor with a high affinity. How activating the 5-HT receptor leads to psychedelia is still unknown, but it is likely that somehow it involves excitation of neurons in the prefrontal cortex. Mescaline is also known to bind to and activate the serotonin 5-HT receptor. Difluoromescaline and trifluoromescaline are more potent than mescaline, as is its amphetamine homologue trimethoxyamphetamine. In the United States, mescaline was made illegal in 1970 by the Comprehensive Drug Abuse Prevention and Control Act, categorized as a Schedule I hallucinogen. The drug was prohibited internationally by the 1971 Convention on Psychotropic Substances.