Effects Of REM Sleep Deprivation On Behavioral Depression And Brain Tryptophan Hydroxylase And Monoamine Oxidase In Rats Treated With Chronic Stresses

Objective: Antidepressant drugs need to be administered for several weeks before a therapeutic response is achieved. However, Sleep deprivation (SD) exerts antidepressant effects after only one night of deprivation, which suggests that a rapid antidepressant response is possible, but the exact mechanism behind this effect still remains unclear. Enhancements of Tryptophan hydroxylase (TPH) and Monoamine Oxidase A (MAO-A) should be responsible for it. This study is designed to investigate the effects of REM(rapid eye movement) sleep deprivation (REMSD) on Behavioral depression and brain TPH and MAO-A in rats treated with chronic mild unpredicted stresses.Materials and Methods: Sprague-Dawley rats were divided into four groups randomly: 1)normal control rats , 2)chronic stress rats 3)72hours REM sleep deprivation rats and 4) tank control rats. REM sleep deprivation was performed by flowerpot technique. Rats in chronic stress group were exposed to unpredicted mild stressors for 21 consecutive days. An open field test was repeated three times to evaluate the depressive-behavior during the experiment. Expression of TPH and Activities of MAO-A in hippocampus, frontal cortex, hypothalamus and mid-brain were measured by western-blotting and UV- spectrophotometer respectively.Results: Open field tests showed that the total activity was reduced after 21 days stresses, while 72 hours REM sleep deprivation reversed this effect. There were significant difference in TPH in hippocampus, mid-brain ,hypothalamus and front cortex respectively between chronic stress rats and 72 hours REMSD rats. There was significant difference significant difference in MAO-A between chronic stress rats and 72 hours REMSD rats.Conclusions:1. Rats showed a depressive-behaviors after 21 days stresses, while 72hours REM sleep deprivation could reverse this effect;2. Chronic mild stress produced a decline in TPH expression in the hippocampus, mid-brain , hypothalamus andfrontal cortex, while 72 hours REMSD could reverse this effect;3. Chronic mild stress produced a decline in the activities of MAO-A in the hippocampus, while 72 hours REMSD can increase the activity of MAO-A in it;4. It suggests that perhaps TPH in hippocampus ,mid-brain, hypothalamus and frontal cortex, MAO-A in hippocampus play a role in the antidepressant effect of REM sleep deprivation.