[Cochlear ischemia and changes in compound action potentials in the guinea pig].
To determine the degree of decrease in cochlear blood flow (CoBF) which causes compound action potentials (CAPs) to disappear, a cochlear ischemic model was created by compressing the internal auditory artery in guinea pig. CoBF was measured with a laser Doppler flowmeter, and CAPs were recorded with an electrode placed on the round window membrane. The amplitude and latency of the N1 wave of CAPs changed as CoBF decreased. When CoBF diminished to as much as 70% below the original level, N1 disappeared. In this study, we also observed the N1 recovery process following CoBF reperfusion after 20 minutes of cochlear ischemia. N1 recovery in the group with an incomplete decrease in CoBF was better than in the group with a complete decrease in CoBF. These findings suggest that both the degree of compromise of CoBF and the duration of ischemia are important factors affecting the recovery of auditory function.
Tang
A
A
Department of Otolaryngology, University of the Ryukyus, Okinawa.
Ura
M
M
Yamauchi
M
M
Noda
Y
Y
D000818:Animals; D003051:Cochlea / Q000098:blood supply* / Q000503:physiopathology; D003055:Cochlear Microphonic Potentials; D006168:Guinea Pigs; D007511:Ischemia / Q000503:physiopathology*; D012039:Regional Blood Flow