Gap junction morphology of retinal horizontal cells is sensitive to pH alterations in vitro.
Isolated goldfish retinae were incubated in NaHCO3-reduced solutions, a treatment known to lower intracellular pH and to decrease gap-junction-mediated coupling between cells. The morphology of the gap junctions of horizontal cells examined by means of freeze-fracture replicas and ultrathin sections displays alterations after such treatment. The gap-junctional particles aggregate into dense clusters or crystalline arrays, whereas controls (pH 7.5) display a loose arrangement of particles. Incubation in NaHCO3-reduced solution leads to the appearance, in ultrathin sections, of prominent, electron-dense material beneath the gap-junctional membranes. Both effects, the increasing density of particles and the appearance of electron-dense material, are reversible. The application of dopamine, which uncouples horizontal cells, and its antagonist haloperidol produce less clear-cut effects on particle density in vitro.
Schmitz
Y
Y
Pathologisches Institut der Universität, Tübingen, Federal Republic of Germany.
Wolburg
H
H
D000818:Animals; D004298:Dopamine / Q000494:pharmacology; D005614:Freeze Fracturing; D006054:Goldfish; D006220:Haloperidol / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007365:Intercellular Junctions / Q000187:drug effects / Q000648:ultrastructure*; D008854:Microscopy, Electron; D012160:Retina / Q000648:ultrastructure*
D006220:Haloperidol; D004298:Dopamine