Comparison of changes in vascular resistance between choroid and other organs following ligation of carotid artery.

The changes in the choroidal vascular resistance after carotid artery ligation were compared with those in the cerebrum and the inferior rectus muscle by evaluating the changes in the blood flow by the hydrogen clearance method. Ligation of the carotid artery produced little change in the ipsilateral cerebral blood flow, but decreased the choroidal blood flow by 16-24% and the blood flow of the inferior rectus muscle by 34-40%. Although the reduction in the arterial pressure in these organs was the same, the responses of the blood flows to the changes in the arterial pressure were different. This suggests that autoregulatory capability varies from organ to organ. It is important to study the pathogenesis of carotid artery occlusion giving special consideration to these differences among the autoregulatory capabilities of various organs.