Permeability of Reissners Membrane in the Isolated Ear of the Guinea Pig

Abstract

The purpose of this work was to provide more information concerning the permeability of Reissner's membrane. Examinations were carried out using chemical compounds labelled with radioiso-topes. The following molecules were used: NaCl, KCl, NaJ, NaHCO_a, Na₂HPO₄, Na₂SO₄, albumin and colloidal gold. Experiments were carried out on 77 isolated labyrinths of the guinea pig. Isotope solution was introduced into the space of the scala vestibuli through the oval window opening. The activity of the compound in the scala media, scala vestibuli and scala tympani was determined after 4 minutes. Estimation of permeability was based on the relative activity of the compound on both sides of Reissner's membrane. It was found that small inorganic compounds penetrate Reissner's membrane but albumin and colloidal gold did not. Penetration of the small inorganic compounds demonstrated remarkable variations. Potassium and sodium had the greatest ability to penetrate, and iodine and bicarbonate the least. Orthophosphoran and sulphate showed slight penetration. The results demonstrate some similarity in permeability of Reissner's membrane and capillary vessels. Exchange of some molecules between the peri-lymph of the scala vestibuli and the endolymph of the cochlear duct confirms the theory of “the radial flow” of the labyrinth fluids, yet not proving it entirely.