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 pHi 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.
Dixon
D B
DB
Department of Ophthalmology, Beckman Vision Center, UCSF School of Medicine, San Francisco, CA 94143-0730, USA.
Takahashi
K
K
Bieda
M
M
Copenhagen
D R
DR
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002397:Catfishes / Q000502:physiology*; D003035:Cobalt / Q000494:pharmacology; D004553:Electric Conductivity; D004594:Electrophysiology; D017629:Gap Junctions / Q000187:drug effects* / Q000502:physiology; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D018408:Patch-Clamp Techniques; D011803:Quinine / Q000494:pharmacology*; D012160:Retina / Q000166:cytology / Q000187:drug effects* / Q000502:physiology
D003035:Cobalt; D000584:Amiloride; D011803:Quinine; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid