Medizinische Universität Graz - Research portal

• Go directly to the nagivation.
• Go directly to the content.

• Print view.
• German.
• Contact.
• Data entry.
• Start.
• Open Access.

Selektive exokrine Hyperstimulierung des Pankreas zur Untersuchung akuter Pankreatitis

Abstract

Cholecystokinin CCK1 receptors have two affinity states, which are activated by appropriate concentrations of CCK or analogs like caerulein. Activation of high affinity sites stimulates enzyme secretion into the pancreatic ducts, while activation of low affinity sites inhibits this effect and induces acute pancreatitis in vivo. We have investigated whether the selective CCK1 agonist SR146131 would discriminate between the two affinity states of the receptor. Intraperitoneal injection of caerulein (0.25–7.5 nmol/kg) in anesthetized rats stimulated amylase output via the biliopancreatic duct in a dose-dependent manner, but enzyme secretion was completely blocked at a supramaximal dose (25 nmol/kg). SR146131 (18–180 nmol/kg) also dose-dependently stimulated amylase secretion; however, secretion did not decline even at doses of 1800 nmol/kg. The effect of SR146131 was blocked by a CCK1 antagonist dexloxiglumide, but not by the CCK2 antagonist itriglumide. A supramaximal dose of caerulein (25 nmol/kg given twice i.p. at an interval of 1 h) induced acute oedematous pancreatitis, quantified by water content of the pancreatic tissue and increases in amylase activities in the blood serum and in the pancreatic interstitial space. The effects of caerulein were prevented by dexloxiglumide, but not by itriglumide. SR146131 (60–1800 nmol/kg twice i.p.) did not induce any signs of inflammation, as all measured parameters remained at values obtained in rats without pancreatitis. Histological evaluation showed that even the highest dose of SR146141 did not induce any signs of acinar cell damage. In summary, the CCK1 agonist SR146131 stimulates pancreatic exocrine function in vivo without exhibiting inhibition at supramaximal doses. Unlike the CCK analog caerulein, SR146131 does not induce acute pancreatitis even when applied at excessive dose levels. We conclude that in contrast to CCK and caerulein, SR146131 is an agonist only at the high affinity site of the CCK1 receptor.

Project Leader:

Griesbacher Thomas

Duration:

13.12.2001-31.12.2003

Programme:

Jubiläumsfonds (ÖNB)

Type of Research

basic research

Staff

Griesbacher, Thomas, Project Leader

MUG Research Units

Division of Pharmacology

Funded by

Österreichische Nationalbank (Jubiläumsfonds), Otto Wagner Platz 3, A-1090 Wien, Austria