1988 Volume 156 Issue Suppl Pages 1-9
By the occlusion of arteries in the ventral surface of the medulla, the blood supply to the central chemoreceptor for respiration was examined in anesthetized, paralyzed and peripheral chemodenervated cats. Phrenic nerve activities (P.N.A.), as an index of the respiratory center output, increased with an injection (3 ml/min, 10 sec) of hypercapnic blood (PCO2=104.5 mmHg) into the vertebral artery (VA injection response). The VA injection responses during occlusion of arteries in the ventral surface of the medulla were classified into three groups: 1) The response disappeared by the bilateral occlusion of the anterior inferior cerebellar arteries (AICA) in 8 out of 29 cats. 2) The response disappeared by the occlusion of both AICA and the posterior inferior cerebellar arteries (PICA) in 9 cats. 3) The response did not disappear in spite of the additional occlusion of several branches from the basilar artery in 11 cats, although the response had diminished. These different results may be due to the complexity of the central chemosensitive structure or of the central vascular system. However, among arteries the AICA blood flow seemed to be most preferentially related to the VA injection response. Thus, at least a part of the central chemosensitive structure may be located in the area perfused by the AICA.