[Features of the ultrastructure of the brain tissue of Meriones unguiculatus after cerebral ischemia and postischemic recirculation].

The authors studied the ultrastructure of the brain tissue in "symptom negative" clawed jirds (M. unguiculatus) in the presence of permanent and transient circulatory ischemia caused by ligation of the right common carotid artery and by a 3-minute occlusion of the left common carotid artery which was unattended by any clinical manifestations signifying cerebral ischemia. The formation of oedema and dystrophic changes in the right hemisphere differed from that in the left one. Permanent ischemia was associated with the typical picture of hypoxic damage to the neural tissue with the development of cytotoxic oedema. Transient ischemia was predominantly characterized by an impairment of the blood-brain barrier with the development of marked vasogenic oedema. The study made it possible to closely follow the differences in the formation of an early stage of brain damage in permanent and transient ischemia and to establish the possibility of the damaging effect of blood recirculation in the hemisphere previously affected with ischemia.