[Analysis of the effect of bicarbonate on taste receptor sensitivity to organic acids]

Addition of NaHCO3 or NaOH to the solutions of lactic or pyruvic acids decreased threshold concentrations of H+ ions and increased intensity of afferent impulsation in the cat chroda tympani nerve. In spite of the fact that the concentrations of both lactate and pyruvate anions with the presence of NaOH and NaHCO3 are the same at equal pH values the observed changes of the receptors responses were more intensive if NaHCO3 had been added. Therefore the influence of NaHCO3 on the perception of organic acids depends not only on its buffer properties but, probably, on direct action of CO2 appearing as the result of interaction of NaHCO3 and acids, as well. This assumption was confirmed by the data on high sensitivity of the cat tongue receptors for the carbon dioxide.