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

Abstract

Prostaglandin E₁ (PGE₁), 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, PGE₁ was coated with a 0.2-µg lipid microsphere produced by beans; this was designated lipo-PGE₁. This coating protects PGE₁ from being rapidly metabolized. In this study, the effectiveness of the intravenous administration of lipo-PGE₁ was compared with that of PGE₁ 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 PGE₁ and lipo-PGE₁, no obvious differences in the effects on SBP and CBF were observed in this study.