Annals of Otology Rhinology & Laryngology · 1981 · 127 citations · 17 references
MedicinePharmacologyPhysiologyNeurotologyOtologySensory PhysiologyInner Ear FunctionMembrane PermeabilityOtotoxicityBlood-labyrinth BarrierDiffusion-limited TransportInner Ear Fluid HomeostasisInner Ear LabyrinthInner Ear PhysiologyOtotoxicity MechanismsPharmacologic OtotoxicityTracer Studies
The blood‑labyrinth barrier differs chemically from perilymph and may play a role in inner ear disorders. The study aimed to manipulate physiological, metabolic, and pharmacologic conditions in experimental animals to characterize the barrier’s regulatory properties. Experimental manipulation of these conditions in animals was employed to probe the barrier’s regulatory mechanisms. Tracer studies revealed slow uptake of sodium, calcium, and albumin into perilymph, limited transport of kanamycin and furosemide, transient reduction of sodium transport by ethacrynic acid, and delayed perilymph elevation following urea administration.
The blood-labyrinth barrier is a concept that has evolved based on marked difference in chemical composition between perilymph and blood. Studies reported here have been designed to manipulate physiologic, metabolic, and pharmacologic conditions in experimental animals in order to determine the characteristics of this regulatory mechanism. Tracer studies of uptake of sodium, calcium, and albumin from blood into perilymph showed that these substances penetrate into inner ear fluids quite slowly. Injections of ototoxic substances (kanamycin, furosemide) show limited transport of these agents into perilymph. Another ototoxic agent, ethacrynic acid, was found to transiently reduce the transport of sodium into perilymph. Administration of an osmotic agent (urea) resulted in a parallel but delayed elevation of perilymph concentration. The possible role of alteration of blood-labyrinth barrier in inner ear disorders has been discussed.
17