Effects of prostaglandins on perilymphatic oxygenation. Enhancement of cochlear autoregulation by prostacyclin.
Effects of prostaglandin E1, prostacyclin, a prostacyclin analogue (OP-2507), and an inhibitor of thromboxane A2 synthetase (OKY-046) on the perilymphatic oxygen tension were measured in the feline tympanic perilymph under various respiratory conditions and blood pressure ranges. Factors influencing the capacity of the autoregulative properties of the inner ear vessels to accommodate changes in systemic blood pressure were also examined. Intravenous administration of prostacyclin, OP-2507, and OKY-046 prevented a decrease in perilymphatic oxygen tension when the systemic blood pressure decreased. Even a negative correlation of the differential coefficients between the perilymphatic oxygen tension and the systemic blood pressure was noticed during the administration of prostacyclin. Thus, prostacyclin enhanced the autoregulative property of the inner ear vessels. Furthermore, correlation studies between perilymphatic oxygen tension and cochlear blood flow demonstrated a partial dissociation, indicating the presence of autoregulation in the mean systemic blood pressure range under 80 mmHg.
Nagahara
K
K
ENT Department, Kyoto National Hospital, Japan.
Aoyama
T
T
Fukuse
S
S
Noi
O
O
D000527:Alprostadil / Q000494:pharmacology*; D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats; D003051:Cochlea / Q000098:blood supply*; D011464:Epoprostenol / Q000494:pharmacology* / Q000031:analogs & derivatives; D006706:Homeostasis / Q000187:drug effects; D007761:Labyrinthine Fluids / Q000187:drug effects*; D008689:Methacrylates / Q000494:pharmacology; D008833:Microcirculation / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects*; D010498:Perilymph / Q000187:drug effects*; D012039:Regional Blood Flow / Q000187:drug effects; D014463:Ultrasonography
D008689:Methacrylates; C049453:OP 2507; D011464:Epoprostenol; D000527:Alprostadil; C034364:ozagrel