Charge Barrier of the Middle Ear and the Eustachian Tube

Abstract

The membrane potential is negative charged and it works on the filtration of substances as a charge barrier. PEI (polyethyleneimine, M. W. 1800) is a strong cationic tracer to identify the anionic sites histologically. In the present study, PEI was used in the middle ear and the eustachian tube of the guinea pigs, and histamine or PAF (platelet activating factor) were administrated in the different cases. The results showed that the particles of PEI were arranged regularly along the capillary basement membrane in the middle ear and the eustachian tube. But in the cases of addition inflammatory mediators the number of PEI particles was decreased, which may possibly be induced the condition of hyperpermeability of membrane.