Cochlear blood flow following temporary occlusion of the cerebellar arteries

In order to induce acute transient local blood flow impairment in the guinea pig cochlea, terminal vessels arising from the proximal and middle third of the basilar artery and from the rostral part of the collateral vertebral artery near their junction were occluded by temporary (1-2 min) compression. Clear identification of the anterior inferior cerebellar artery was impeded due to great variation in branching of the cerebellar arteries. To quantify the effect of the vascular occlusion on the cochlear microcirculation, laser Doppler flowmetry was used. Successive compression of the cerebellar arteries resulted in individually differentiated effects on the Doppler signal from the cochlea. In about half of the experiments there was a decrease in the laser signal to 25-55% of the initial level, while in the other cases no clear decrease occurred. Proximal obstruction of the basilar artery was found to reduce the cochlear blood flow up to 10-25% of its initial level, indicating that the Doppler signal primarily reflects microcirculation within the membranous cochlea. The findings are discussed with regard to their significance as an animal model for acute transient cochlear hypoxia.