the FTY720 Multiple Sclerosis international level to reach a consensus for making reliable psychiatric diagnoses, which represents a huge progress. In this article, we explore the nature of the relationship between psychopharmacology,

psychiatric symptomatology, and higher brain functions. Psychotropic medication Psychotropic drugs, such as chlorpromazine, imipramine, or diazepam, were developed by astute researchers, at a time when several neurotransmitters had not yet been discovered and when little was known about the physiology of neurotransmitters. The modes of action of these first psychotropic drugs were discovered years after they had been successfully used clinically, and are still undergoing further study. A psychotropic drug can Inhibitors,research,lifescience,medical be described according to the way in which it influences receptors, transporters, and enzymes, ie, the cellular sites of its pharmacological actions. These drugs can be selective to a greater or lesser extent. There are the so-called “dirty” drugs that influence a large number

of brain systems. Chlorpromazine is an Inhibitors,research,lifescience,medical example of such a nonselective psychotropic drug as it acts as an antagonist of many dopaminergic, adrenergic, serotonergic, cholinergic, and hislarninergic receptors and has a membranestabilizing action. Clozapine is another example of a drug that acts on many cell-membrane receptors or transporters; it is difficult to explain why blocking Inhibitors,research,lifescience,medical all these systems with clozapine has led to the best Inhibitors,research,lifescience,medical results yet. seen in the treatment of schizophrenia. Prescribing only clozapine to a patient cannot, be said to be monotherapy, because more than 10 different modes of action may be involved in its clinical effects. On the other hand, there are psychotropic drugs with a more selective mode of action, for example, the serotonin (5-HT) transporter (5-HTT) blockers (selective serotonin reuptake inhibitors [SSRIs]). When these drugs are administered, however, physiological systems subserving many brain Inhibitors,research,lifescience,medical functions are influenced, as is apparent, from the list

of their beneficial and adverse effects. Selectivity is also relative if one considers the number of intracellular changes that, are induced following drug administration, and the number of different neuronal AV-951 circuits that are influenced. For example, an agonist, of the Mi muscarinic receptor, a drug that may be useful in dementia of the Alzheimer type, has a selective mode of action. However, this selectivity is only at the cell membrane receptor level; stimulation of this cell membrane receptor leads, through secondary and tertiary intracellular messengers,1 to the expression of more than 100 proteins 60 minutes after administration (Nitsch RM, unpublished data). In the future, clinicians will be able to explain to their patients that psychotropic drugs modify protein synthesis in the brain (demanding patients mayask for the exact list of the proteins that are modified by their medication!).