title: Possible involvement of GABAergic mechanism in protective effect of melatonin against sleep deprivation-induced behaviour modification and oxidative damage in mice.
abstract: Sleep is an important physiological process responsible for the maintenance of physical, mental and emotional health of a living being. Sleep deprivation is considered risky for several pathological diseases such as anxiety and motor and cognitive dysfunctions. Sleep deprivation has recently been reported to cause oxidative damage. This study has been designed to explore the possible involvement of the GABAergic mechanism in protective effects of melatonin against 72-h sleep deprivation-induced behaviour modification and oxidative damage in mice. Mice were sleep-deprived for a period of 72 h using the grid over water suspended method. Animals were divided into groups of 6-8 animals each. Melatonin (5 and 10 mg/kg), flumazenil (0.5 mg/kg), picrotoxin (0.5 mg/kg) and muscimol (0.05 mg/kg) were administered for 5 days starting 2 days before 72-h sleep deprivation. Various behavioural tests (plus maze, zero maze, mirror chamber, actophotometer) and body weight assessment followed by oxidative stress parameters (malondialdehyde level, glutathione, catalase, nitrite and protein) were carried out. The 72-h sleep deprivation caused significant anxiety-like behaviour, weight loss, impaired locomotor activity and oxidative damage as compared with naïve (without sleep deprivation). Treatment with melatonin (5 mg/kg and 10 mg/kg, ip) significantly improved locomotor activity, weight loss and antianxiety effect as compared with control (sleep-deprived). Biochemically, melatonin treatment significantly restored reduced glutathione, catalase activity, attenuated lipid peroxidation and nitrite level as compared with control animals (72-h sleep-deprived). Flumazenil (0.5 mg/kg) and picrotoxin (0.5 mg/kg) pretreatments with a lower dose of melatonin (5 mg/kg) significantly antagonized the protective effect of melatonin. However, muscimol (0.05 mg/kg) pretreatment with melatonin (5 mg/kg, ip) potentiated the protective effect of melatonin which was significant as compared with their effect per se. This study suggests that GABAergic modulation is involved in the protective action of melatonin against sleep deprivation-induced anxiety-like behaviour and associated oxidative damage.
authors.affiliation: Pharmacology Division, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh 160014, India. kumaruips@yahoo.com
authors.forename: Anil
authors.initials: A
authors.lastname: Kumar
authors.forename: Anant
authors.initials: A
authors.lastname: Singh
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology*; D001007:Anxiety / Q000209:etiology / Q000517:prevention & control; D001522:Behavior, Animal / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D005442:Flumazenil / Q000494:pharmacology; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D018757:GABA Modulators / Q000008:administration & dosage / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008550:Melatonin / Q000008:administration & dosage / Q000494:pharmacology*; D051379:Mice; D009043:Motor Activity / Q000187:drug effects; D009118:Muscimol / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects*; D010852:Picrotoxin / Q000494:pharmacology; D012892:Sleep Deprivation / Q000150:complications*
chemical_list: D000975:Antioxidants; D005442:Flumazenil; D018755:GABA Agonists; D018756:GABA Antagonists; D018757:GABA Modulators; D008550:Melatonin; D009118:Muscimol; D010852:Picrotoxin