ABSTRACT
With the development and applications of immunological, histochemical and new techniques in biochemistry and molecular biology there has been a systematic study of peptides in nervous and non-nervous tissues. The structure, distribution and the functions of many of these peptides are in progress. Neuroactive peptides have been found to act in at least three different pathways in the body. Certain colocalizations atypical of normal physiologic conditions have been demonstrated after disruption of normal afferent and efferent connections and in altered hormonal environments. The chapter discusses the distribution of peptides in the brain, their neuronal pathways in a number of brain areas, possible functions in these areas and relationships with other, non-peptide neurotransmitters. Gastrointestinal peptides are given particular attention; they are also found in the brain and it has been hypothesized that they play a neurotransmitter role.
