Experimental Cerebral Infarction Following Occlusion of Middle Cerebral Artery

Acute experimental occlusions of the left middle cerebral artery of cats were accomplished by applying the Heifets zlip through the retro-orbital extradural approach with operating microscope. The most striking neurologic signs were disturbance of consciousness, paresis of the right limbs(especially fore limb), and tonic deviation of the head neck toward the side of the occluded artery. The size and severity of the infarcts generally were related to the severity of the neuro logic disorders. 4 cats died within 48 hours of the occlusion of artery and 5 cats improved somewhat after the initial stage. However, the disturbance of the consciousness and the motor weakness persisted until the end of the period of observation. The severity of persistence of the neurological deficits may depend upon the effectiveness of reperfusion through collateral channels and the variability of anatomical pattern of the cerebral structures. A disturbances of consciousness may be related to the generalized decreases of neuronal activity or to focal neuronal dysfunction. Ischemic edema secondary to brain ischema increases the intracranial pressure and aggravates the impairment of neurological deficits. Finally cerebral herniation may produce the irreversible brainstem damage and death. Therefore, early reperfusion of ischemic brain before ischemic edema develops may improve the neurological deficts and prevent the occurrence of the secon-dary neuronal dysfunction.