Pathological effects of cerebral anoxia

Total Cerebral Ischemia in the Dog

“…The changes seen in the animals with brain damage were similar to those described by Courville,7,8 namely, if the animals were killed im¬ mediately or within 2-3 hours after a lethal period of cerebral anoxia, the only changes seen were cerebral edema, vascular engorge¬ ment, and small areas of petechial hemor¬ rhage. If the animals survived or were kept alive using a respirator and vasopressors after severe brain damage for at least 6-8 hours, other changes were noted, as well, including areas of gliosis and necrosis, plus decreased numbers of Purkinje cells.…”

Mechanisms Leading to Hypoventilation in Extrapyramidal Disorders, With Special Reference to Parkinson's Disease

“…On the other hand, muscular effort and activity can cause an increase in respiration. Four theories have been suggested to explain the occurrence of increased ventilation in the presence of muscular activity: ( a ) the production by the working muscles of unknown products of metabolism which stimulate the respiratory center (30–33); ( b ) a reflex mechanism, elicited by efferent impulses from active muscles and joints (34–40); ( c ) the action of the cerebral cortex on the respiratory center (41, 42); and ( d ) an increased sensitivity of the respiratory center to stimuli (41, 43, 44). It is recognized that tremor and rigidity cannot always be equated with the fairly vigorous exercise required to produce the hyperpnea precipitated by movement of a single extremity (31).…”