Adenosine triphosphate ane phosphocreatine levels in cochlear structures. Use rate and effect of salicylates

Abstract

Guinea pigs were infected with various dosages of salicylate for varying time periods. The temporal bones were removed, frozen quickly, freeze dried, and the cochlea was dissected into essential auditory component parts and subjected to microchemical analysis for phosphocreatine (P creatine) and adenosine triphosphate (ATP) levels. It was found that high energy phosphates were not decreased by therapeutic or acutely toxic levels of salicylate. Only when chronic intoxication with salicylate was accomplished was there a reduction in ATP and P creatine. The data presented do not provide support for the widely held view that uncoupling of oxidative phosphorylation or inhibiton of enzymes involved in energy generation in the inner ear structures studied (organ of Corti, stria vascularis, Reissner's membrane, modiolar blood vessels, cochlear nerve and spiral ganglion) are the mechanisms by which salicylates cause reversible hearing loss. The study confirms the existence of a P creatine gradient opposite to the wellknown glycogen gradient in the organ of Corti and suggests a relatively uniform energy use rate of this tissue for all 4 turns (20 mmoles of phosphorus used/kg dry weight/min.).