Magnesium sulphate reduces cell volume in physiological conditions but not in the cytotoxic oedema during global brain ischemia.
OBJECTIVE
To establish the effect of MgSO4 on brain cellular volume during physiological and global ischemia using impedanciometric method.


METHODS
Impedanciometric measure in the brain before and during global brain ischemia, with or without intravenous infusion of MgSO4.


METHODS
Male Sprague-Dawley rats were anaesthetized (thiobarbital, 60 mg kg-1 i.p.). Ringer solution (n=9) or MgSO4 (n=8; 1 mmol Kg-1) where i.v. isovolumetrically administered. Sub-cortical impedance was recorded before and after the infusion of ringer or MgSO4 and during global cerebral ischemia induced by a cardiopulmonary arrest.


RESULTS
In non-ischemic conditions, MgSO4 infusion induced higher voltage values than those of ringer infusion (Wilcoxon, Z=2.49; p=0.01). During global cerebral ischemia, the MgSO4 infused animals showed a fast drop of voltages (82%) in the first 5 minutes, 4-fold the values of ringer infused animals (p<0.0001). In the following 15 minutes no differences were found between ringer and MgSO4 infused animals.


CONCLUSIONS
The results suggest that MgSO4 significantly reduced brain cell volume in physiological conditions but not in global brain ischemia.
Chacón
Andrea
A
Departamento de Ciencias Fisiológicas, Facultad de Ciencias de la Salud, Universidad de Carabobo, Valencia, Venezuela.
Lisott
Elena
E
Eblen-Zajjur
Antonio
A
D000818:Animals; D001929:Brain Edema / Q000209:etiology / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D002545:Brain Ischemia / Q000150:complications* / Q000503:physiopathology; D048429:Cell Size / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D017097:Electric Impedance; D008278:Magnesium Sulfate / Q000627:therapeutic use*; D008297:Male; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley
D018696:Neuroprotective Agents; D008278:Magnesium Sulfate