Osanai S, Rozanov C, Mokashi A, Buerk D G, Lahiri S
Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia 19104-6085, USA.
Brain Res. 1997 Aug 1;764(1-2):221-4. doi: 10.1016/s0006-8993(97)00495-2.
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.
