The effects of ketamine on Ca2+ movements in A7r5 vascular smooth muscle cells.
To investigate the effects of ketamine on Ca2+ movement to and from intracellular Ca2+ stores and across plasma membranes, 45Ca2+ fluxes were studied in permeabilized and intact A7r5 smooth muscle cells, an established cell line derived from embryonic rat aorta. Monolayers of A7r5 cells were loaded with 45Ca2+, and the radioactivity in the collected medium and the residual activity were measured by liquid scintillation counting. Ketamine had no effect on 45Ca2+ uptake and passive leak of the nonmitochondrial Ca2+ pool in permeabilized A7r5 cells. Ketamine 1 mM had no inhibitory effect on the inositol 1,4,5-trisphosphate (InsP3, 1 microM)-induced Ca2+ release from the intracellular stores. In intact A7r5 cells, ketamine did not alter the Ca2+ extrusion from these cells under resting conditions. Addition of 10 nM vasopressin resulted in a transient Ca2+ release from the intracellular stores. Ketamine inhibited this vasopressin-induced Ca2+ release, but did not enhance Ca2+ extrusion through the plasma membrane in the period after the vasopressin effect. These results indicate that ketamine inhibits agonist-induced Ca2+ release from intracellular stores, but has no effect on Ca(2+)-uptake into intracellular stores or on Ca2+ extrusion through the plasma membrane in A7r5 smooth muscle cells.
Department of Anesthesiology and Critical Care Medicine, Kagoshima University School of Medicine, Japan. kan@med4.kufm.kagoshima-u.ac.jp
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Kanmura
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Missiaen
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Casteels
D000778:Anesthetics, Dissociative / Q000494:pharmacology*; D000818:Animals; D001011:Aorta; D002118:Calcium / Q000493:pharmacokinetics*; D002120:Calcium Channel Agonists / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects; D002132:Calcium Radioisotopes; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate / Q000493:pharmacokinetics; D007649:Ketamine / Q000494:pharmacology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014667:Vasopressins / Q000494:pharmacology
D000778:Anesthetics, Dissociative; D002120:Calcium Channel Agonists; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D002132:Calcium Radioisotopes; D014662:Vasoconstrictor Agents; D014667:Vasopressins; D007649:Ketamine; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium