Effects of a depressor on cochlear blood flow and perilymphatic oxygen tension.
To clarify the characteristics of the blood circulation in the cochlea, we investigated the relationship between cochlear blood flow and perilymphatic oxygen tension in guinea pigs with trimetaphan camsilate induced hypotension. Cochlear blood flow was measured by laser Doppler flowmetry, and perilymphatic oxygen tension by a polarographic method. Cochlear blood flow generally paralleled systemic blood pressure, while perilymphatic oxygen tension showed a slower response to the decrease of systemic blood pressure. Although there were individual differences in the changes of systemic blood pressure, cochlear blood flow and perilymphatic oxygen tension, they were found to be dose dependent. Since hypotension induced by trimetaphan camsilate is fairly reproducible in the dose range of this experiment, this drug can be used as a ganglion blocking agent in experiments on cochlear blood flow and perilymphatic oxygen tension during systemic hypotension. The change of perilymphatic oxygen tension with a slower response could be considered to be a factor in the homeostasis in the inner ear fluid.
Kawakami
M
M
Department of Otolaryngology, Osaka Medical College, Japan.
Makimoto
K
K
Fukuse
S
S
Takahashi
H
H
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D003051:Cochlea / Q000098:blood supply* / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D007022:Hypotension / Q000139:chemically induced / Q000503:physiopathology*; D007834:Lasers; D010100:Oxygen / Q000032:analysis* / Q000502:physiology; D010498:Perilymph / Q000737:chemistry* / Q000187:drug effects; D012039:Regional Blood Flow / Q000187:drug effects; D014294:Trimethaphan / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000494:pharmacology*
D014665:Vasodilator Agents; D014294:Trimethaphan; C017774:trimethaphan camsylate; D010100:Oxygen