A second class of drugs with hallucinogenic properties often referred to as psychedelic or dissociative anesthetics includes arykyclohexy lamines, whose

most important representatives are PCP and ketamine. These agents primarily act as antagonists of the vV-mcthyl-D-aspartate (NMDA) subtype of the glutamate receptor. Finally, a third Inhibitors,research,lifescience,medical class of drugs, the so-called “entactogens,” produce psychedelic-like effects, but virtually no hallucinations. They arc closely related structurally to hallucinogenic phenylethylamines and stimulant amphetamines and include phenyttsopropy lamines, such as 3,4-methylenedioxymethamphetaminc (MDMA), 3,4-methylenedioxyethylamphctamine (MDE), and related compounds. Figure 1. Chemical structures of some important representatives of hallucinogens. Classic serotonergic hallucinogens include indolamines, such as the semisynthetic lysergic acid diethylamide (LSD) and psilocybin/psilocin (the active principle of the sacred Aztec … This review summarizes Inhibitors,research,lifescience,medical recent experiments to elucidate

the neurobiological basis of the ABT-263 mw psychological effects of psilocybin, ketamine, and MDMA, each representing one of the three classes of psychedelics. Functional brain imaging with positron emission Inhibitors,research,lifescience,medical tomography (PET) was used Inhibitors,research,lifescience,medical to identify the brain regions or functional interactions among the neurotransmitter systems involved in the action of these drugs. Furthermore, receptor mechanisms of hallucinogenic and related drugs have been investigated by exploring the effects of specific receptor antagonists on drug-induced psychological alterations and information-processing functions, such as sensorimotor gating as indexed by prepulse inhibition (PPI)

of the startle reflex. The premise of the present review is that many Inhibitors,research,lifescience,medical of the shared psychedelic effects of serotonergic hallucinogens and NMDA antagonists can be understood as an effect downstream of a common neurotransmitter system or final pathway. First, both serotonergic hallucinogens and NMDA antagonists produce sufficient overlapping psychologial isothipendyl alterations despite different primary modes of action. Second, there is converging evidence from brain imaging, behavioral, and electrophysiological studies that both serotonergic hallucinogens and NMDA antagonists disrupt information processing within corticostriato-thalamic pathways implicated in the pathogenesis of psychotic disorders. Since entactogens such as MD.M.A are expected to produce only mild psychedelic symptoms, it will be of interest to know to what extent MDMA-induced neurobiological alterations differ from those seen in the states induced by hallucinogens and NMDA antagonists.