[Changes in serotonin and noradrenaline in hepatic encephalopathy as a result of liver failure in rat].

Objective: To investigate the changes in serotonin (5-HT) and noradrenaline (NA) in hepatic encephalopathy as a result of acute and chronic liver failure in rat.

Methods: One hundred and ten Sprague-Dawley (SD) rats were randomly divided into groups of normal control (n=20), experimental group of acute liver failure (ALF) encephalopathy (n=45), and experimental group of chronic liver failure (CLF) encephalopathy (n=45). Two dosages of thioacetamide (TAA) of 500 mg/kg were gavaged with an interval of 24 hours to reproduce ALF model. To reproduce CLF model rats were fed with 0.03% TAA in drinking water for 10 weeks, and 50% of TAA dosage was added or withheld according to the change in weekly body weight measurement. Animals were sacrificed and venous blood specimens were obtained after successful replication of model, and 5-HT, NA, ammonia, parameters of liver function were determined, and liver and brain were studied pathologically.

Results: The experiment showed that the liver functions of rats in groups ALF encephalopathy and CLF encephalopathy deteriorated seriously, changes in alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), albumen (ALB), ALB/globulin (A/G), and blood ammonia were observed(P<0.05 or P<0.01). The clinical manifestations, liver and brain pathologies were identical to those of ALF and CLF encephalopathy. The values of 5-HT were increased in groups ALF encephalopathy and CLF encephalopathy [(16.06+/-1.08) micromol/L and (15.32+/-1.48) micromol/L] compared with the normal group [(2.75+/-0.26) micromol/L, both P<0.01], while the value of NA decreased in the group of CLF encephalopathy [(94.0+/-2.13) pmol/L vs.(121.2+/-14.8) pmol/L,P<0.05].

Conclusion: The levels of 5-HT are elevated in the groups of ALF encephalopathy and CLF encephalopathy. The content of NA decreases remarkably in CLF encephalopathy.