ABSTRACT
The most important drugs of abuse consist of a heterogeneous group of compounds that have little in common pharmacologically except for their profound effects on Central Nervous System activity. The nerve terminal contains a number of important sites of potential interaction for drugs; combination of drugs with components at these points could profoundly alter transmission at the particular junction. Many drugs are known to interact with these storage sites, thereby displacing the transmitter and preventing subsequent binding of newly-synthesized transmitters. Drugs which act in this manner are called indirectly acting agents. The nerve terminal membrane is the site of many biochemical and physiological events and increasingly has been proposed as the primary, if not exclusive, site of action for many types of pharmacological agents. The axonal membrane contains receptors for many types of neurotropic drugs; for some, the axon proper as well as nerve terminal are regions of attachment, e.g., local anesthetics, the barbiturates, and the phenothiazines.
