Licorice Ameliorates imbalance between reactive oxygen species and antioxidant enzymes in the brain of sleep deprived rats

@#Sleep deprivation can be described as inadequate quantity or quality of sleep characterized by insufficient sleep duration, delayed sleep onset, and occurrence of napping episodes during the day. Sleep deprivation in animals and obstructive sleep apnea syndrome in human was reported to be associated with increased oxidative stress. Glycyrrizha glabra (licorice) is a medicinal plant known to be a highly efficacious medicinal herb with several pharmacological effects. Hence, the aim of this study was to demonstrate whether or not licorice root extract will regulate the imbalance between the reactive oxygen species and production of antioxidant enzymes in the brain of sleep deprived rats. Twenty - five 6-week-old male Wistar rats were randomly divided into five groups to undergo sleep deprivation and recovery for 5 days each. Group I (Control): Group II: sleep deprivation (SD); Group III: sleep deprivation and recovery (SD+SR) all received distill water (10ml/kg) orally; Group IV: sleep deprivation and licorice (SD+Lic), Group V: sleep deprivation, recovery with licorice (SD+SR+Lic) both received licorice (150mg/kg) orally once daily. MDA concentration among rats in Groups II (51%), III (46.7%) and IV (31.3%) were significantly higher when compared with control. Rats in Group III (20.5%), Group IV (24.6%) and Group V (30.8%) showed increased significant change in GSH concentration when compared with Group II. The concentration of CAT among rats in Group II was significantly lower than those rats in Group III (43.8%), Group IV (53.8%) and Group V (72.9%). These results clearly show that sleep deprivation significantly affects the oxidative status of rats. In conclusion, licorice root extract has ameliorative effect on the imbalance between the reactive oxygen species and production of antioxidant enzymes in the brain of sleep deprived rats.

Glucocorticoid receptor activation selectively influence performance of Wistar rats in Y-maze.

Glucocorticoid receptors (GR) are ubiquitously expressed in metazoans. Different and contrasting phenotypes have been reported upon their activation. This study investigated the behavioral phenotypes characteristic of GR stimulation in male Wistar rats. Rats in each of the four groups of rats received one of the following treatments: distilled water (control) or one of three doses of dexamethasone (treatment) injected intraperitoneally for 7 days. The Rats were afterwards subjected to the Y maze, the elevated plus maze (EPM), the Morris water maze (MWM), and the novel object recognition (NOR) test. At the end of the study, the animals were anesthetized and neural activity from the prefrontal cortex recorded. Blood was collected via cardiac puncture to evaluate the levels of plasma insulin and glucose, and the prefrontal cortexes excised to determine the levels of insulin, markers of oxidative stress, and calcium in the homogenate. This study showed that treatment with dexamethasone significantly reduced the total and percentage alternation in the Y maze, but had no significant effect on object recognition in the NOR test, long-term and short-term spatial memory in the MWM, or anxiety-like behavior in the EPM. Plasma and brain insulin and calcium levels were elevated moderately following treatment with the lowest dose of dexamethasone. All doses of dexamethasone decreased brain superoxide dismutase and increased lactate dehydrogenase levels. No significant change in neural activity was observed. This study shows that activation of glucocorticoid receptors differentially affects different behavioral paradigms and provides evidence for a role for glucocorticoids in mediating insulin function in the brain.