The effects of locally applied PAF in inner ear morphology

The effect of a PAF-containing artificial perilymph (10(-7) M PAF) on the ultrastructure of the stria vascularis was investigated in acute perilymphatic perfusion experiments in guinea-pigs. We have shown previously that locally applied PAF at this concentration reversibly changes the endolymphatic potential (EP) (Ernst et al., 1989a) which suggests an interference with ion transport. Controls which were perfused with artificial perilymph as well as experimental animals were decapitated at 10, 30 and 60 min after starting the perfusion. Subsequently, the cochleae were removed and evaluated by electron microscopy. The histological findings do not correspond to those obtained with different substances modifying ion transport in the stria vascularis, e.g., ouabain, loop diuretics. There are only minor strial changes in our study. The relevance of PAF in cochlear physiology is discussed.