Acute pancreatitis affects the metabolism of catecholamine neurotransmitters in rats

Abstract

Abnormalities of mental status represent a severe complication and an important cause of death in acute pancreatitis (AP), which is characterized by a pattern of neurological signs and symptoms. As some of the symptoms of AP are also affected by catecholamine neurotransmitters, they cannot be ruled out of the pathophysiology of AP; however, little research has been performed exploring this hypothesis. Our study aimed to elucidate whether AP affects the metabolism of catecholamine neurotransmitters in rats. A total of 300 male SD rats were randomly divided into five groups: control, 6H, 24H, 48H and 72H experimental groups. AP was induced in rats by an injection of a sodium taurocholate solution via a cannulated bile-pancreatic duct. In the striatum, hippocampus and cerebellum, catecholamine neurotransmitters were tested using high performance liquid chromatography equipped with a electrochemical detector, and the activities and protein concentration levels of monoamine oxidase A (MAO-A) and tyrosine hydroxylase (TH) were also evaluated using ELISA and Western blotting analyses. In the hippocampus, the dopamine (DA) concentrations increased in the 48-h and 72-h groups. The 3,4-dihydroxyphenylacetic acid (DOPAC) concentration of the 72-h group also increased. The MAO-A and TH activity of the 6-h and 24-h groups decreased, respectively. The TH activities of the 48-h groups also decreased. The MAO-A and TH protein concentration of the 6-h and 24-h groups decreased. In the corpus striatum, the homovanillic acid concentration of the 72-h group and norepinephrine concentrations of the 24-h and 48-h groups increased, respectively. The MAO-A and TH activities of the 6-h and 24-h groups decreased. The MAO-A and TH protein concentrations of the 6-h and 24-h groups decreased. In the prefrontal cortex (left prefrontal lobe), the DA and DOPAC concentrations of the 48-h group increased. The MAO-A and TH activities of the 6-h, 24-h and 48-h groups decreased. The MAO-A and TH protein concentrations of the 6-h and 24-h groups also decreased. The other catecholamine concentration and enzyme activities fluctuated, but there was no statistically significant difference compared with the control group. Catecholamine neurotransmitter metabolic systems are widely affected in AP, and these fluctuations may play an important role in determining the symptomatology of AP.

Keywords: acute pancreatitis; catecholamine neurotransmitter; monoamine oxidase; tyrosine hydroxylase.