title: Rapid onset and calcium independence of the gap junction uncoupling induced by heptanol in cultured heart cells.
abstract: The kinetics of the reversible interruption of gap junction communication by the aliphatic alcohol heptanol and the possible mediation of an increase of the cytosolic Ca2+ concentration have been investigated in pairs of myocytes dissociated from neonatal rat ventricles and cultured for 2-3 days. Junctional communication was estimated by measuring either the cell-to-cell electrical conductance with a double whole-cell voltage-clamp method, or the rate constant of dye diffusion with the fluorescence recovery after photo-bleaching (gap FRAP) technique. Electrical coupling was seen to be abruptly interrupted (in less than 0.5 s) by heptanol (1-3 mM). The cytosolic Ca2+ concentration was not affected, even at a saturating heptanol concentration. Heptanol removal allowed a gradual re-opening of gap junctional channels, as shown by the recovery curve of the cell-to-cell conductance, which is 90% complete within 90 s. These data are consistent with a direct interaction of heptanol with channel proteins or with their lipid environment.
authors.affiliation: Laboratoire de Physiologie Cellulaire, Unité de Recherche Associée au CNRS no. 1869, Poitiers, France.
authors.forename: B
authors.initials: B
authors.lastname: Bastide
authors.forename: J C
authors.initials: JC
authors.lastname: Hervé
authors.forename: L
authors.initials: L
authors.lastname: Cronier
authors.forename: J
authors.initials: J
authors.lastname: Délèze
mesh_terms: D015761:4-Aminopyridine / Q000494:pharmacology; D000438:Alcohols / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology*; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D004594:Electrophysiology; D017629:Gap Junctions / Q000502:physiology*; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D019850:Heptanol; D007700:Kinetics; D009206:Myocardium / Q000378:metabolism; D018408:Patch-Clamp Techniques; D051381:Rats
chemical_list: D000438:Alcohols; D019850:Heptanol; D015761:4-Aminopyridine; D002118:Calcium