Abstract
We investigated chemical blood flow regulation in the brainstem and inner ear in rats. To evaluate the efficiency of chemical regulation, we observed the response of brainstem blood flow (BBF) and cochlear blood flow (CoBF) to hypercapnia and hypoxia using laser-Doppler flowmetry. Both BBF and CoBF increased in response to hypercapnia, showing a decrease in total vascular resistance. The result supposed the existence of chemical regulation in both the brainstem and inner ear. BBF and CoBF were maintained in response to hypoxia and consequent hypotension, also showing decrease in total vascular resistance. The brainstem showed stronger vascular response than the inner ear, and we concluded that chemical blood flow regulation in the brainstem was more efficient than that in the inner ear.
