Psychedelic drugs like LSD act on similar systems of the brain as other drugs but differ in which parts they affect, helping to explain why they produce such dramatically different experiences among users, according to researchers at Mount Sinai School of Medicine.

Medical News Today reported Feb. 4 that researcher Stuart C. Sealfon, M.D., and colleagues compared hallucinogens and non-hallucinogenic drugs that act upon the serotonin 2A receptor in the brain. They found that both types of drugs activate the serotonin receptors, but in different ways.

"The big mystery has been why drugs like lisuride, which are similar in chemical structure to hallucinogens and switch on the exact same serotonin 2A receptor, do not have a similar impact on mood and behavior," said Sealfon. "Our tests in mice revealed that once the hallucinogenic drugs turn on the serotonin 2A receptor, they also go on to activate another neurological pathway, whereas lisuride does not take any further action."

Research conducted with scientists at Columbia University also found that hallucinogens only act on cells in the cerebral cortex, not on cells traveling there.

The study was published in the Feb. 1, 2007 issue of the journal Neuron.