Effects of intravenous administration of prostaglandin E1 and lipo-prostaglandin E1 on cochlear blood flow in guinea pigs

Prostaglandin E-1 (PGE(1)), a vasodilator and an inhibitor of platelet aggregation, has been used for the treatment of idiopathic sudden sensorineural hearing loss, despite the fact that its effectiveness has not been proven. Furthermore, it is rapidly metabolized in the lungs, which makes it difficult to use clinically. In an attempt to prevent this, PGE(1) was coated with a 0.2-mug lipid microsphere produced by beans; this was designated lipo-PGE(1). This coating protects PGE, from being rapidly metabolized. In this study, the effectiveness of the intravenous administration of lipo-PGE(1) was compared with that of PGE(1) by investigating the effects on systemic blood pressure (SBP) and cochlear blood flow (CBF) in guinea pigs with normal ears. The results of both drugs showed a dose-dependent decrease in SBP and the maintenance of CBF despite the decrease in SBP. However, no significant increase in CBF was observed for either drug. In comparing the effects of PGE(1) and lipo-PGE(1), no obvious differences in the effects on SBP and CBF were observed in this study.