title: Cell volume regulation by the mouse zygote: mechanism of recovery from a volume increase.
abstract: Mouse zygotes regulate their volumes after cell swelling. This regulatory volume decrease (RVD) is rapid and complete. RVD in zygotes was inhibited by K+ or Cl- channel blockers, indicating the participation of such channels in volume recovery. The channels are separate entities, as indicated by the ability of the cation ionophore gramicidin to restore RVD when K+ channels are blocked but not when Cl- channels are blocked. Intracellular Ca2+ concentration increased with cell swelling. Nevertheless, RVD occurred normally in zygotes loaded with the Ca2+ chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, which prevented Ca2+ from increasing above its normal resting concentration. Thus an increase in intracellular Ca2+ is not necessary for zygote RVD; consistent with this, inhibitors of Ca(2+)-activated K+ channels had little or no effect on RVD. RVD in zygotes was also completely inhibited by millimolar amounts of extracellular ATP. ATP has been shown to inhibit current passed by the volume-sensitive organic osmolyte-Cl- channel in other cells, and thus zygotes may have such a channel participating in RVD.
authors.affiliation: Loeb Medical Research Institute, Ottawa Civic Hospital, Ontario, Canada.
authors.forename: D G
authors.initials: DG
authors.lastname: Séguin
authors.forename: J M
authors.initials: JM
authors.lastname: Baltz
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000241:Adenosine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001464:Barium / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000502:physiology*; D000242:Cyclic AMP / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D006016:Glycolates / Q000494:pharmacology; D006096:Gramicidin / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D008815:Mice, Inbred Strains; D009579:Nitrobenzoates / Q000494:pharmacology; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000502:physiology*; D011803:Quinine / Q000494:pharmacology; D014882:Water-Electrolyte Balance / Q000187:drug effects / Q000502:physiology*; D015053:Zygote / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
chemical_list: D018118:Chloride Channels; D006016:Glycolates; D009579:Nitrobenzoates; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D006096:Gramicidin; D001464:Barium; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; D004533:Egtazic Acid; C015765:MK 473; D000255:Adenosine Triphosphate; D011803:Quinine; D000242:Cyclic AMP; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D000241:Adenosine; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D002118:Calcium