MATERIAL and METHODS: Eighteen rats were anesthetized and the right femoral artery was cannulated. Mean arterial pressures, heart rates, arterial carbon dioxide tension, arterial oxygen tension, and blood pH were recorded. When the free cerebrospinal fluid flow was seen, 0.1 ml normal saline (Group SIC, n=6) or 9 μg/kg diluted dexmedetomidine in 0.1 ml volume (Group DIC, n=6) was administered into the cisterna magna of rats. After 24 hours, the whole body blood was collected for measurement of plasma lipid peroxidation (LPO) levels. The hippocampal formations used for histopathological examination and measurement of tissue LPO levels.

RESULTS: There was a statistically significant difference between the DIC/SIC groups and DIC/CONTROL groups regarding the brain LPO levels (p=0.002, p<0.001, respectively). Plasma LPO levels were statistically different between the CONTROL/DIC groups, CONTROL/SIC groups, DIC/ SIC groups (p=0.002, p=0.047, p=0.025, respectively), The picnotic neuron counts were different between the CONTROL/SIC groups, CONTROL/ DIC groups, DIC/SIC groups (p<0.001, p=0.001, p=0.024, respectively).

CONCLUSION: In conclusion, dexmedetomidine had a toxic effect on cerebral neurons when it was administered centrally into the cerebrospinal fluid by the intracisternal route. Keywords : Dexmedetomidine, Intracisternal, Intrathecal, Hippocampus, Brain, Cerebral neuron