Osanai, S; Rozanov, C; Mokashi, A; Buerk, DG; Lahiri, S*

Brain Research [BRAIN RES.], vol. 764, no. 1-2, pp. 221-224, Aug 1997

To test the hypothesis whether CO2-HCO3- buffer is essential for the expression of chemoreception and to distinguish between pHi and pHo interaction with pCO in the carotid chemosensory response, we superfused-perfused in vitro cat carotid bodies using HEPES-Tyrode's solution with and without CO2-HCO3-, and compared the responses at the same pHo in the absence and presence of light. In the absence of light, pCO (>138 Torr) stimulated the carotid body chemoreceptors in CO2-HCO3- buffer at pHo of 7.40, whereas pCO (69-550 Torr) did not stimulate the neural discharge in HEPES buffer at the pHo of 7.4-7.1 but did so below pHo 7.1. In the presence of light, all the responses were diminished proportionately.