ABSTRACT
The brain is a highly complex and specialized organ, and this complexity can be seen in its cellular composition. The cellular specialization of the brain, and of the other components of the central nervous system (CNS) and peripheral nervous system (PNS), inevitably reflects, and is ideally suited to, its function. This cellular specificity is built on a foundation of biochemical factors, processes and mechanisms; thus, there is also a neurochemical specificity in brain function. This is primarily but not solely associated with neurons, which are differentiated by the neurotransmitters they secrete and the receptors they express. It is this neurochemistry with which this chapter is mainly concerned.
