Hallucinogens mechanism

For many years it was believed that the brain mechanisms underlying the effects of psychedelic hallucinogens and dissociative anesthetics were separate and distinct. Indeed, there has been considerable debate about which represents the best drag model of schizophrenia. However, recent data show that the two classes of psychotomimetic drags share a common final pathway involving an increase in the release of the excitatory neurotransmitter glutamate. 

Nichols, DE. Differences between the mechanisms of action of MDMA, MBDB, and the classical hallucinogens. Identification of a new therapeutic class Entactogens. J Psychoactive Drugs 18 305-313, 1986. 

Appel, J.B. White, F.J. and Holohean, A.M. Analyzing mechanisms of hallucinogenic drug action with drug discrimination procedures. Neurosci Biobehav Rev 6 529-536, 1982. 

The answer is c. (Hardman, pp 574—575.) Phencyclidine is a hallucinogenic compound with no opioid activity Its mechanism of action is amphetamine-like. A withdrawal syndrome has not been described for this drug in human subjects. In overdose, the treatment of choice for the psychotic activity is the antipsychotic drug haloperidol. 

In this chapter, we have reviewed the effects of indolealkylamine and phen-ylalkylamine hallucinogens on respondent (classical or Pavlovian) and operant (instrumental) behavior. Both the classically conditioned NMR and bar pressing or licking that is simultaneously reinforced with food or water and suppressed by punishment appear to be particularly sensitive to low doses of LSD- or mescaline-like agents. To date, however, neither of these behaviors has provided substantial amounts of information regarding specific, underlying neuronal mechanisms. 

Sloviter, R. S., Drust, E. G., Dammiano, B. P., and Conner, J. D. (1981) A common mechanism for lysergic acid, indolealkylamine and phenethylamine hallucinogens Serotonergic mediation of behavioral effects in rats. J. Pharmacol. Exp. Ther., 214 231-238. 

The major focus of the present volume is to provide an up-to-date account of current research on the mechanisms of action of hallucinogenic drugs. The approach is a multidisciplinary one that, hopefully, avoids many of the pitfalls inherent in a dependency on any single experimental methodology. 

Yamamoto, T., and Ueki, S. (1981) The role of central serotonergic mechanisms on head-twitch and backward locomotion induced by hallucinogenic drugs. Pharmacol. Biochem. Behav., 14 89-95. 

This chapter considers the effects of indolealkylamine (LSD-like) and phenyl-alkylamine (mescaline-like) hallucinogens on learned behavior. We concentrate on those approaches that have shed the most light on underlying neuronal mechanisms or that show promise of becoming useful (in vivo) animal models of hallucinogenic drug action. Thus we are selective rather than exhaustive, a luxury made possible in part because several more empirically oriented reviews have been published recently (14,16,34,35). 

The neurotransmitter serotonin (21) has been implicated as playing a role in the mechanism of action of the hallucinogenic indolealkylamines however, the importance of other neurotransmitters cannot be ruled out at this time. Studies targeted specifically toward the elucidation of the mechanism of action of indolealkylamines are considered in other chapters, and this review is limited to a discussion of structure-activity relationships. 

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