Catecholamines (CAs) and
granin peptides are costored in dense-core vesicles within the chromaffin cells of the adrenal medulla and in other endocrine organs and neurons.
Granins play a major functional and structural role in chromaffin cells but are ubiquitous
proteins, which are present also in secretory cells of the nervous, endocrine, and immune systems, where they regulate a number of cellular functions. Furthermore, recent studies also demonstrate that
granin-derived
peptides can functionally interact with CA to modulate key physiological functions such as lipolysis and blood pressure. In this chapter, we will provide a brief update on the interaction between CA and
granins at the cellular and organ levels. We will first discuss recent data on the regulation of exocytosis of CA and
peptides from the chromaffin cells by the sympathetic nervous system with a specific reference to the prominent role played by splanchnic nerve-derived pituitary
adenylate cyclase-activating
peptide (
PACAP). Secondly, we will discuss the role of
granins in the storage and regulation of exocytosis in large dense-core vesicles. Finally, we will provide an up-to-date review of the roles played by two
granin-derived
peptides, the
chromogranin A-derived
peptide catestatin and the VGF-derived
peptide TLQP-21, on lipolysis and
obesity. In conclusion, the knowledge gathered from recent findings on the role played by
proteins/
peptides in the sympathetic/target cell synapses, discussed in this chapter, would contribute to and provide novel mechanistic support for an increased appreciation of the physiological role of CA in human pathophysiology.