Cholecystokinin

  • OMIM: 118440
  • MGI: 88297

Cholecystokinin (CCK) or pancreozymin (PZ) is a peptide hormone of the gastrointestinal tract. In the brain plays an important role as a neurotransmitter. Literally translated, the name means in German Gallenblasenbeweger. Cholecystokinin is also the central nervous system involved in the triggering of satiety.

Structure

CCK is of a variable number of amino acids (for example, CCK58, CCK33, CCK8 ), which from the prohormone Procholecystokinin (95 amino acids) are processed. It is similar in structure to the gastrin. The last five C -terminal amino acids are identical to those of gastrin.

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It is ( duodenum) and in the following jejunum ( jejunum ) produced in the upper duodenum in special enteroendocrine cells, the so-called I- cells. The secretion of the hormone is stimulated by fatty acids and amino acids in the chyme.

Target organ and mode of operation

Target organs of cholecystokinin are gallbladder and pancreas. CCK stimulates pancreatic and simultaneously causing contraction of smooth muscle of the gall bladder wall and the relaxation of the sphincter thereby oddii bile flow. It stimulates the motor function of the small intestine and colon. CCK reduces the effect of gastrin in the stomach by competitive displacement of the CCKB receptor and thereby reduces the production of hydrochloric acid. Moreover, in the development of anxiety and panic as well as anxiety and panic disorders ( phobias ), it plays a role. In addition, it is responsible for the feeling of satiety by acting on the nucleus of the solitary tract ( NTS), located in the brain stem belonging to the medulla oblongata.

Cholecystokinin receptors

The effects of CCK on the various cells are mediated by membrane receptors. Similar to discovery of CCK were too low its receptors in the digestive tract detected (CCK -A receptor: A - " alimentary ", primarily in the gallbladder and pancreas). Only in 1980 could be detected for cholecystokinin receptors in the brain (CCK - B receptor: B - " Brain", mainly in the brain, but also in the stomach)

In 1992 the genes of both the CCK-A receptor and the CCK- B receptor have been discovered and cloned one after the other. This will also let the protein structure of both receptors enlighten. Both receptors belong to the superfamily of G protein- coupled receptors. They consist of seven transmembrane domains, their protein structure is identical to 48 %. However, the genetic information is located on different chromosomes ( CCKAR on Chr 4, CCKBR on Chr 11). The CCK- B receptor is genetically identical to the gastrin receptor and differs in only 5 amino acids due to a splicing variant.

Swell

  • Neuropeptide
  • Pancreas
Human Genome Organisation Mouse Genome Informatics Entrez Ensembl UniProt National Center for Biotechnology Information Smooth muscle tissue Large intestine Receptor (biochemistry)
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