Intracranial pressure changes following middle cerebral artery occlusion in rats.

Prolonged recording of intracranial pressure (ICP) was performed on rats subjected to middle cerebral artery (MCA) occlusion. ICP was repeatedly recorded before and after occlusion of the vessel via a narrow catheter placed in the cisterna magna. MCA occlusion was followed by an increase in ICP, and a pressure peak occurred after 12-24 h in all animals. Subsequently, essentially two patterns of ICP changes were observed. These seemed to be related to the severity of neurological deficits and extension of the infarct area. In the most severely affected animals, raised ICP was noted throughout the 1st week after MCA occlusion; in rats with reversible neurological deficits, ICP returned to normal values after the first peak at 12-24 h. The present investigation shows that prolonged ICP recording is feasible in MCA-occluded rats. The MCA occlusion model in rats is well characterized. Thus, ICP registration can be used in conjunction with other methods for evaluating treatment against increased ICP.