Role of Orexin 1 Receptor Blocker SB-334867 On Changes Of Triglyceride And Cholesterol Metabolisminduced By Paradoxical Sleep Deprivation In Adult Male Rats

Background: Sleep deprivation (SD) is a growing hazard through its effects on metabolism. Orexin is involved in the regulation of both sleep and metabolism. Work on orexin receptors may explain the mechanisms of some hazardous effects of SD. Aim: To test the role of the orexin-1 receptor (OX1R)blocker, SB-334867 in changes of triglycerides and cholesterol metabolisminduced by SD. Method: 72 adult albino rats arranged in 4 equal groups: control, SD, SD-OX1R blocked &SD-DMSO groups. The 3 SD groups are subjected to 8 days of paradoxical SD using the modified multiple platform method. The OX1R blocked group was injected intraperitoneallydaily with a single dose (3 mg/kg/day) of SB-334867 dissolved in 2 ml DMSO and diluted 1:1000. The SD-DMSO group was injected by 2 ml of DMSO diluted 1:1000. Triglycerides and cholesterol levels were measured. Results: Blood triglyceride levels dropped in all groups subjected to SD after the 1stday while the blood cholesterol level dropped in all groups subjected to SD at the 7th or 8th day. In SD-OX1R blocked group showed less drop in blood triglycerides than the other SD groups but the statistically non-significant change in cholesterol level. Conclusion: SD leads to earlier and more drop-in blood triglyceridesthan the drop in cholesterol levels. This can be explained by high metabolism during SD with dependence on triglyceride more than cholesterol. OX1R blocker partially reduces the drop of triglyceride, not cholesterol level indicating that orexin may be involved in the control of triglyceride metabolism but not cholesterol.