title: The window of opportunity for administration of magnesium therapy following focal brain injury is 24 h but is task dependent in the rat.
abstract: The present study was conducted to establish the window of opportunity for the administration of a regimen of MgCl2 pharmacotherapy following focal injury to the brain. Rats were subjected to unilateral electrolytic lesions of the sensorimotor cortex (SMC) and administered a regimen of MgCl2 (1.0 mmol/kg) or 0.9% saline (1.0 ml/kg) beginning either 15 min, 8 h or 24 h after injury. Subsequent injections were administered 24 and 72 h after the initial treatment. Behavioral testing assessed recovery of function on several sensorimotor behaviors for 24 days following injury. The results of the present study suggest that treatment with a regimen of MgCl2 significantly facilitated recovery of function on the forelimb-->forelimb and vibrissae-->forelimb placing tests when administered 15 min, 8 h or 24 h after injury compared with saline-treated rats. Recovery of locomotor placing was significantly facilitated at 15 min and 8 h but not at 24 h compared with saline-treated rats. In addition, the ability of MgCl2 to limit neuronal loss in the ipsilateral ventral posterior lateral (VPL) nucleus of the thalamus was seen at only the 15-min treatment interval. These results suggest that the window of opportunity for MgCl2 pharmacotherapy is 24 h, task dependent and is much shorter for protecting neurons in the VPL.
authors.affiliation: Brain Injury Laboratory, Department of Psychology and Program in Neuroscience, Rawl #218, East Carolina University, Greenville, NC 27858, USA. hoanem@mail.ecu.edu
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hoane
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Barth
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D001930:Brain Injuries / Q000188:drug therapy* / Q000473:pathology / Q000523:psychology*; D002452:Cell Count; D002540:Cerebral Cortex / Q000473:pathology; D005552:Forelimb / Q000502:physiology; D008124:Locomotion / Q000502:physiology; D008274:Magnesium / Q000627:therapeutic use*; D008297:Male; D011597:Psychomotor Performance / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D020651:Ventral Thalamic Nuclei / Q000293:injuries / Q000473:pathology; D014738:Vibrissae / Q000502:physiology
chemical_list: D008274:Magnesium