ABSTRACT
The central nervous system, with the brain as its head ganglion, has developed as the great controller and coordinator of the various physiological functions of the body and of the behavioural patterns by which animals meet the many needs which must be satisfied for survival. Biochemical differences in the brain represent a major way of classifying and distinguishing functional subsystems. The first step in the discovery of a new brain chemical is usually the development of a method for detecting, reliably identifying and quantifying the presence of the chemical in the brain. Neurotransmitters are synthesized in the brain by a series of enzymatic steps. This can be illustrated by the amino acid tyrosine. Tyrosine is a constituent of many foods. Neurochemical toxins are structurally similar to established neurotransmitters, but which are unstable at brain pH and temperature, when they spontaneously auto-oxidize and form toxic compounds such as hydrogen peroxide.
