IntroductionPeptic ulcer disease and its complications still remain a hot issue in modern gastroenterology and one of the constantly important targets for pharmacologic research [1][2][3]. It is commonly acknowledged that nonsteroidal anti-inflammatory drugs (NSAIDs), being the most commonly prescribed group of drugs worldwide for the management of pain and inflammation, play an important role in provoking gastrointestinal tract ulceration, bleeding and perforation [1,4,5]. This mediates the necessity of the effective gastroprotective measures in patients, who are at risk of gastric ulceration, in particular chronic NSAIDs users. Nowadays for this purpose proton pump inhibitors and H 2 -antagonists are commonly used, but due to side effects of these drugs the search for new compounds with gastroprotective properties, suitable for longterm use, remains actual [1,2]. Contemporary literature gives accumulating evidence that a number of oligopeptides play an important role in the regulation of the function of gastrointestinal tract and their synthetic analogues were reported to be effective in the prevention and treatment of gastric ulceration [1,[5][6][7][8][9][10][11][12].That is why the purpose of this review was to summarize the current data on the oligopeptides with documented gastroprotective properties and their possible mechanisms of action.
DiscussionDue to the modern outlook, regulatory peptides are considered to be phylogenetically the oldest form of bioregulation [13][14][15][16][17][18][19][20][21]. Thus, the mechanisms of peptidergic regulation of homeostasis open huge perspectives for the creation of the essentially new methods for the prevention and treatment of different diseases [13][14][15][16]. Interestingly, deep studies of the mechanisms of action of regulatory peptides showed that in many cases life-sustaining processes are regulated not by the total peptide molecules but their short-chained derivatives -oligopeptides that are produced in the course of limited proteolysis from proteins-precursors (cytokines, thymic peptides, immunoglobulins) [13,14,18,20,21].The term "oligopeptide" refers to proteins, composed of not more than 20 amino acid residues [22]. For example, it was shown that the inhibition of pancreatic juice secretion by 28-amino acidscontaining hormone ghrelin is realized by its biologically active part -pentapeptide with the sequence of amino acids Gly-Ser-Ser (n-octanoyl)-Phe [23].The advantages of the short peptides above their long-chain derivatives are high biological activity, that often many fold exceeds the activity of the peptide-precursor, high tissue specificity, lack of species specificity and lack of immunogenicity [13,14,[15][16][17][18]20,21]. It was established that low-weighing oligopeptides realize their effect on the cellular, chromosomal, genomic and molecular levels [13][14][15][16][17][18][19][20][21]. The interaction with DNA was proposed to be the key moment of the realization of the biological effect of the short peptides [17][18][19]21]. This concept is s...
