PH-DEPENDENCE OF JUNCTIONAL CONDUCTANCE

Current views on the molecular mechanisms of the pH-dependence of gap junctions are mainly based on the experimental fact that extracellular ly applied CO2 or other weak acids rapidly and reversibly block juncti onal conductance and also decrease intracellular pH. The data are pres ented suggesting that the mechanism of the uncoupling action of weak a cids may not be restricted to the intracellular acidification. Hypothe ses concerning possible protonation sites in the connexin molecules ar e also considered.