Experimental cerebral concussion. A histochemical study.

The activity of mitochondrial enzymes (succinic dehydrogenase and cytochrome oxidase) and enzymes associated with blood-brain barrier function (butyrylcholinesterase and alkaline phosphatase) in the CNS of rats was studied from 5 minutes to 62 hours after cerebral concussion. There was a transient increase in succinic dehydrogenase activity during the first hour after concussion in the neurons of the structures close to the impact. The alkaline phosphatase activity, strongly positive in the walls of normal blood vessels, decreased within five minutes after concussion; it virtually disappeared in 15 minutes but returned to normal level after 62 hours. These findings are in good correlation with previous electron microscopic observations. Their significance is discussed.