Neuroprotective effect of exogenous melatonin on the noradrenergic neurons of adult male rats’ locus coeruleus nucleus following REM sleep deprivation

Background and Aim : Melatonin is primarily secreted by the pineal gland in dark phase of the circadian rhythm. In addition to its role as an internal sleep facilitator, melatonin acts as an antioxidant, anti-inflammatory and neuroprotective agents. Recently (how recent do you mean it’s not recent) melatonin has been introduced as a therapeutic strategy for sleep disorders. Hence, in the present study, we studied the neuroprotective effects of pre- and post-treatment of melatonin in locus coeruleus nucleus (LC) of rapid eye movement (REM) sleep deprived (REM-SD) male adult ratsMethods : Adult male rats of control, sham and trial groups were used in this study. By using flower-pot technique, short term REMSD was induced. Exogenous melatonin (ExMe) was intraperitoneally injected in two forms of pre and post treatment. The protein level of cleaved caspase-3, the number and density of tyrosine hydroxylase (TH) positive neurons and the microglia population in LC were studied by western blot and immunohistochemistry respectively. Morphological changes of LC nucleus and its neurons were also studied by using stereological analysis.Results : The number of neurons and volume of LC was reserved in animals that had received post-RSD ExMe. Apoptosis significantly was decreased comparing to RSD and Pre-RSD animals. Melatonin post-treatment of RSD rats also decreased cleavage of caspase-3 and increased reduced glutathione content in LC. Moreover, immunohistochemistry analysis showed an increase in the number of TH positive neurons and a decrease in microglia migration.Conclusion : Based on our findings antioxidant properties of exogenous melatonin could play a critical role in certain types of sleep disorders.

کلیدواژه ها:

Locus Coeruleus ، Exogenous melatonin ، REM sleep deprivation