Lateralization of the respiratory control following unilateral cerebral ischemia-reperfusion injury

Cerebral control of respiration has been extensively studied but at present, no evidence of cerebral laterality or dominance for respiration exists. We examined the ventilatory changes following temporary (20 min) occlusion of the right or left common carotid artery in rabbits. The corresponding groups of sham-operated rabbits were used as controls. The partial pressure of end-tidal carbon dioxide (PE T_{C O2}) was measured with a microstream capnograph before the operation as well as at 6 h, and days 1, 4, 9 and 15 postoperation and was used to indicate the ventilatory status. The results showed that following temporary occlusion of the left common carotid artery, subjects began hypoventilation and had a progressive rise in PE T_{C O2} on day 9 postoperation compared to the sham-operated group. However, animals that underwent occlusion of the right common carotid artery hyperventilated from as early as 6 h postoperation to days 1 and 4, an effect that ceased up to day 9 postoperation. It was concluded that respiration might be under differential regulation by the two cerebral hemispheres. While the left hemispheric ischemia-reperfusion injury induced hypoventilation that of the right hemisphere resulted in hyperventilation.