ABSTRACT
Peptides, mainly but not exclusively opioid peptides, are contained within adrenal chromaffin cells, mostly within the chromaffin vesicles. Much of their understanding of the biochemistry and synthesis of these peptides is derived from studies of the adrenal medulla. Carlsson made the intriguing suggestion that peptide neurotransmitters are redundant vestiges. Although neurohormones were specifically omitted, a case was made that peptide neurotransmitters are simply left over from an evolutionary process because there is no specific negative survival value associated with them. The presence of peptide receptors allows for pharmacologic manipulation of the nervous system. The distribution of large enkephalin-containing peptides between soluble and membrane components of bovine chromaffin vesicles was examined by Hook and Liston. The immunoreactive material was localized in the core of the chromaffin vesicles as well as diffusely in the cytoplasm. Neuropeptide Y appears to be stored with epinephrine. Several proenkephalin-derived peptides were purified from bovine adrenal chromaffin vesicles and used as substrates.
