Abstract
We studied autoregulation in the brainstem and the inner ear. Using laser-Doppler flowmetry, we measured brainstem blood flow (BBF) and cochlear blood flow (CoBF) with BP alteration in rats. With induced hypotension by exsanguination above the critical BP level, BBF tended to be preserved supposing the existence of autoregulation. Although CoBF was slightly decreased, a nonlinear relationship to BP also suggested the effect of autoregulation. When BP was raised by reinfusion, after a large temporary increase and recovery, BBF and CoBF showed small increases, and the fact also suggested the existence of autoregulation. The latency of recovery from a temporary increase in BBF was shorter than that in CoBF. These results supposed that both the brainstem and the inner ear showed autoregulation of blood flow, and the efficiency of regulation in the brainstem was superior to that in the inner ear.
