Peptide Neurotransmitters and Hormones

Abstract

Neuropeptides are structurally diverse class of chemical messengers that play important roles in the coordination of many physiological and behavioural events. Neuropeptides are derived from the cleavage of the larger precursor proteins at the dibasic amino acid sites by prohormone convertases. They are synthesised in the cell body, packaged in the large dense core vesicles and released in a neuronal activity‐dependent manner. The neuropeptides may function as blood‐borne hormones, or as mediators/transmitters affecting neuronal activity in the nervous system. In the target cells, neuropeptides activate the complementary G protein‐coupled receptors and elicit responses that are specific to these cells. The released peptide is subsequently inactivated by the actions of several nonspecific extracellular peptidases. Key Concepts: Neuropeptides are structurally diverse class of chemical messengers produced by nerve cells to coordinate many physiological and behavioural processes. The major neuroendocrine centre in the brain is the pituitary gland. Neuropeptides are derived from the cleavage of the larger precursor proteins by specific endoproteases that are co‐packaged in the dense core secretory granules. Receptors for neuropeptides belong mainly to the family of G protein‐coupled receptor.