Drugs affecting the central nervous system (CNS) were among first discovered by the primitive humans and are still the group of most widely used pharmacologic agents. In addition to their uses in therapy, many CNS-active drugs are used without prescription increase the sense of well-being. The mechanisms by which the various drugs work in CNS have not always been well understood. However, a dramatic progress has been made in the methodology of pharmacology of the CNS. It is now possible to study action of a drug on individual cells and ion channels, even in the single synapses. Information obtained from these studies is based on the several major developments in studies of the central nervous system.
First, it is clear that nearly all drugs with CNS effects acts on the specific receptors that modulate synaptic transmission. With very few agents such as general anesthetics and alcohol may have the nonspecific actions on membranes (although these exceptions not fully accepted), but even these are not associated with the mediation of the actions result in the demonstrable alterations in synaptic transmission.
Second, drugs are among most important tools to study the aspects of physiology of the CNS, the mechanism of seizures in the setting of long-term memory. Agonists that mimic natural transmitters (and in many cases more selective than endogenous substances) and antagonists are extremely useful in such studies. Natural Toxins – Tools for a Characterizing ion channels, describes some of the substances.
Third, unraveling actions of drugs of known clinical effectiveness has led to some of most fruitful hypotheses on the mechanisms of the disease. For example, information on the action of the antipsychotic drugs on dopamine receptors has provided basis of assumptions regarding the pathophysiology of schizophrenia.
Studies on effects of a variety of agonists and the antagonists of-aminobutyric acid (GABA) has led new concepts in the pathophysiology of several diseases, including anxiety and epilepsy.