Umemura K, Takiguchi Y, Nakashima M, Nozue M
Department of Pharmacology, Hamamatsu University School of Medicine, Japan.
Ann Otol Rhinol Laryngol. 1990 Jun;99(6 Pt 1):491-5. doi: 10.1177/000348949009900615.
The present study was undertaken to clarify the effect of arachidonic acid (AA) on the inner ear blood flow of rats as measured with a laser Doppler flowmeter. With the rats under anesthesia with sodium pentobarbital, the middle ear was approached ventrally and a laser Doppler probe was positioned over the lateral wall of the cochlea. Drugs were administered via the subclavicular artery. The dose range of each drug was determined so as not to affect the systemic blood pressure. The AA (20 to 70 micrograms) increased the inner ear blood flow dose-dependently; this effect was abolished by indomethacin (5 mg orally). Both prostaglandin E2 (PGE2; 1 to 50 ng) and CS-570, a PGI2 analogue (12.8 to 25.6 ng) caused a dose-dependent increase in the inner ear blood flow. The response of PGI2 was shorter than that of PGE2. On the other hand, a stable thromboxane A2 (STA2; 30 to 80 ng) decreased the inner ear blood flow dose-dependently. Administration of PGF2 alpha (0.2 to 3 micrograms) showed no effect on the inner ear blood flow. These results indicated that the effect of AA was mediated mainly via PGI2 and PGE2.
本研究旨在阐明花生四烯酸（AA）对用激光多普勒血流仪测量的大鼠内耳血流量的影响。在戊巴比妥钠麻醉的大鼠身上，从腹侧接近中耳，并将激光多普勒探头置于耳蜗外侧壁上。药物通过锁骨下动脉给药。确定每种药物的剂量范围，以使其不影响全身血压。AA（20至70微克）剂量依赖性地增加内耳血流量；吲哚美辛（口服5毫克）可消除这种作用。前列腺素E2（PGE2；1至50纳克）和前列环素2类似物CS-570（12.8至25.6纳克）均导致内耳血流量剂量依赖性增加。前列环素2的反应比前列腺素E2的反应持续时间短。另一方面，稳定的血栓素A2（STA2；30至80纳克）剂量依赖性地减少内耳血流量。给予前列腺素F2α（0.2至3微克）对内耳血流量无影响。这些结果表明，AA的作用主要通过前列环素2和前列腺素E2介导。
