The mechanisms by which various drugs work in the CNS have not always been well understood. Over the past three decades, however, dramatic progress has been made in the methodology of the pharmacology of the CNS. It is now possible to study the action of a drug on individual cells and ion channels, even in single synapses. Information obtained from these studies is based on several major developments in studies of central nervous system.
First, it is clear that nearly all drugs with CNS effects act on specific receptors that modulate synaptic transmission. With very few agents such as general anesthetics and alcohol may have nonspecific actions on membranes (although these exceptions are not fully accepted), but even these are not associated with mediation of the actions result in demonstrable alterations in synaptic transmission.
Second, drugs are among the most important tools to study all aspects of the physiology of the CNS, the mechanism of seizures in the setting of long-term memory. As described below, agonists that mimic natural transmitters (and in many cases are more selective than the endogenous substances) and antagonists are extremely useful in such studies. Natural Toxins: Tools for Characterizing ion channels, describes some of these substances.
Third, unraveling the actions of drugs of known clinical effectiveness has led to some of the most fruitful hypotheses on the mechanisms of disease. For example, information on the action of antipsychotic drugs on dopamine receptors has provided the basis of assumptions regarding the pathophysiology of schizophrenia. Studies on the effects of a variety of agonists and antagonists of-aminobutyric acid (GABA) has led to new concepts in the pathophysiology of several diseases, including anxiety and epilepsy.
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