Family of colecistokinetic peptides

Abstract

Introduction. Cholecystokinin (CCK) is a peptide hormone that, together with secretin and gastrin, forms the triad of intestinal hormones. Due to the receptors, which are expressed in different tissues, and to the diversity of the subgroups of the cholecystokinin family peptides that activates them, CCK acts on different organs and systems.Aim of the study. Identification and study of the biochemical and physiological effects of the subgroups of the CCK peptides family and of their role in maintaining homeostasis and viability of the human organism. Materials and methods. A bibliographic study of the specialized literature present in the databases PubMed, MeSH, Internet Archive, IUPHAR/BPS, from 2010-2020 was performed, using the search words cholecystokinin, CCK receptors, expression of CCK receptors, cholecystokinin-like peptides, physiology of the Gastrointestinal Tract. Results. There are two types of CCK receptors: CCK-A (CCK1 "Alimentary") and CCK-B (CCK2 "Brain"). CCK-A receptors are located in the gall bladder where stimulates its contractions, in the intestinal parietal mucosa where via somatostatin inhibits gastric acid secretion, in the nervous system where directly or indirectly, through dopaminergic processes, it modulates the behavior in general and eating behavior in particular. CCK-B receptors are predominantly in the CNS where they modulate anxiety, analgesia and neuroleptic activities. CCK-B receptors also have been identified in the pancreas where they stimulate the secretion of enzymes. It has been shown that pancreas-responsible neurons release CCK-8 and CCK-5, which subsequently produce effects. Moreover, CCK via acetylcholine activates parasympathetic neurons, therefore increasing blood supply to the stomach and increasing motility. At the thyroid level, CCK-8 stimulates normal growth and C-cell proliferation. Conclusions. The expression of CCK at the level of different organs determines a wide range of various effects, involved in normal metabolic and physiological processes, which ensures the maintenance of homeostasis and viability of organs and tissues. Knowledge of the pleiotropic effects of the CCK family peptides and the receptors involved in their development opens new possibilities for addressing the nutritional disorders and functional diseases of the gastrointestinal tract, as well as of intervention in some processes in the nervous system associated with chronic pain, anxiety and depression.