Neuropeptide Y alters stress-induced changes in trace element concentrations of brain in chronically immobilized rats

Effects of 85 dB noise exposure on macro and trace element levels in plasma and brain areas of rats

In this study, our hypothesis was that workplace noise can alter brain element levels like immobilization and light-dark cycle shift, and we aimed to investigate the effects of workplace noise on element levels of brain areas as well as changes in blood of chronically noise-exposed rats. Twenty-four rats were randomly divided into three groups. The first group was the control. The second group (noise exposed) was subjected to daily 8 h 85 dB workplace noise for 15 days, and the third group (noise exposed plus normal condition) was also subjected to the same noise exposure and then returned to normal condition for 15 days. In noise-exposed group, Na, K, Ca, Mg , Fe, Cu, and Zn levels in plasma significantly increased when compared with controls (p = 0.03 for Na; p = 0.005 for K and Mg; p = 0.002 for Ca and Fe; p = 0.01 for Cu and Zn). In this group, Fe level of temporal lobe significantly increased (p = 0.021) while Mg level significantly increased in frontal (p = 0.021) and temporal (p = 0.001) lobes when compared with controls. In the noise-exposed plus normal condition group, plasma Na, K, Fe, Cu, and Zn levels were greatly similar to controls. But, plasma Ca and Mg levels significantly decreased when compared with controls (p = 0.002 and p = 0.007) and noise-exposed group (p = 0.002 and p = 0.001). Fe level of temporal lobe significantly increased when compared with controls (p = 0.001) and noise exposed group (p = 0.001). These alterations may be attributed to impaired intake of water and micronutrients or their excretions, emerging by acoustic stress.

Effects of chronic light/dark cycle on iron zinc and copper levels in different brain regions of rats

In this study, we aimed to investigate whether chronic shift in light/dark cycle alters brain trace element concentrations. For this purpose, 20 male Wistar albino adult rats were weighed and randomly divided into three groups. The first group (n = 6) was the control and had been subjected to 12/12-h light/dark cycle for 30 days. The second group (n = 7) was subjected to 6/18-h light/dark cycle for 15 days, and the third group (n = 7) was also subjected to 6/18-h light/dark cycle for 15 days and then returned to normal 12/12-h light/dark cycle for 15 days. When light/dark cycle protocols were completed, tissue specimens of the frontal lobe, temporal lobe, and brain stem were collected. Iron (Fe), zinc (Zn), and copper (Cu) concentrations of the frontal lobe, temporal lobe, and brain stem were determined by an atomic absorption spectrophotometer. When compared with controls, Fe levels of the temporal lobe significantly increased in 6/18-h light/dark cycle group (p < 0.05), whereas it was statistically unchanged in rats which were exposed to 6/18-h light/dark cycle then returned to the normal 12/12-h light/dark cycle period. Our results show that chronic shift in light/dark cycle affects trace element concentrations of the brain, especially Fe level in the temporal lobe, and these changes are reversible.