Quinine, intracellular pH and modulation of hemi-gap junctions in catfish horizontal cells

Quinine increases the conductance of hemi-gap junctions in horizontal cells. We investigated the mechanisms of alkalinization and the hypothesis that quinine-induced alkalinization produced these conductance increases. We found that quinine-induced alkalinizations were not blocked by cobalt, amiloride, or DIDS. Therefore, this suggests that the alkalinization is not likely due to net proton flux through opened hemi-gap channels nor is it likely due to an action on Cl-/HCO3- exchanger or Na+/H+ exchanger, both of which are known to regulate pH(i) in the horizontal cells, Quinine increased hemi-gap conductance even when cells were recorded with patch pipets containing up to 80 mM HEPES, We conclude that quinine-induced alkalinization cannot account solely for the hemi-gap junctional conductance increases. Copyright (C) 1996 Elsevier Science Ltd