Changes in brain neurotransmitters in hypothalamus related to feeding behavior in LEC rat

Abstract

In the present study, neurotransmitters related to the regulation of food intake were investigated in hypothalamus of LEC rats. The experiment was conducted using LEC and LEA (control) rats aged 4, 10 and 20 weeks. Cu concentration in hypothalamus of LEC rats aged 4 weeks was lower than that in the control, and similar to the control in 10 weeks of age. In contrast, Cu concentration of LEC rats aged 20 weeks was significantly higher (p < 0.01) than that in the control. The acetylcholine release from lateral hypothalamus of LEC rats aged 4 weeks was significantly higher (p < 0.05) than that in the control, but no significant difference of acetylcholine release was found between LEC and control rats aged 10 and 20 weeks. The metabolism of serotonin (5-HT) in hypothalamus of LEC rats was facilitated in 20 weeks of age. Furthermore, the 5-hydroxytryptophan, precursor of 5-HT in LEC rats aged 10 weeks was significantly higher (p < 0.05) than that in the control. No significant difference was found in norepinephrine (NE), dopamine (DA), 3, 4-dihydroxyphenyl acetic acid and homovanilic acid concentrations in each age of hypothalamus, except a significant decrease in NE concentration in LEC rats aged 10 weeks (p < 0.05). The daily and total food intake were suppressed in LEC rats from a young age. Furthermore, blood glucose, albumin and total cholesterol concentrations in LEC rats were lower than those in the control rats. The present study demonstrated that age dependent changes in Cu concentration and the metabolism of neurotransmitters related to the regulation of food intake occurred in hypothalamus of LEC rats. These results suggest that suppression of the food intake observed in LEC rats is not only due to hepatitis but also due to suppressive effects of feeding regulation center in central nervous system.