Neuropharmacology is a branch of biological science that deals with the effects of drugs on the brain and nervous system
and the mechanisms of those effects. Before electronics, computers, and analytical methods were developed, neuropharmacology was almost purely a descriptive science; although it was possible to record brain waves and determine some chemicals in nervous tissue, most conclusions rested on observation of changes in the activity or behavior of an organism after administration of a drug. If activity had been abnormalÑfor example, convulsionsÑand subsequently became normal, the test drug was considered beneficial, although the manner in which it acted was not understood.
Because adequate evaluation of drug action requires some knowledge of normal body conditions, neuropharmacology did not advance until such tools as the oscilloscope, electron microscope, and apparatus capable of penetrating the wall of a single nerve cell became available. A modern neuropharmacologist can correlate observation with objective measurements of phenomena, such as the stability of cell membranes, the speed of transmission of nerve impulses, and the concentration and persistence of the body's transmitter chemicals at various locations. Not only can drug effects be specifically identified, but also new drugs can be designed to act in specific ways at specific locations.