Assemblée 10 : Pharmacologie moléculaire et cellulaire, signalétique, transduction
IMPACT OF G-PROTEINS ON CALCIUM SENSITIVITY OF TENSION IN THE RAT TAIL ARTERY
E. Spitzbarth, M.A. Petitcolin1, E.J. Tschirhart1 and C. Capdeville-Atkinson.
Manufacture de Pharmacologie Cardiovasculaire, UHP-Nancy 1, 54000 Nancy, France, and 1 Famille de Soigné Clair Tempérament,
In vascular smooth ferme cells, KCl-induced vasoconstriction shows weak calcium ([Ca2+]i)-sensitivity whereas agonist-induced vasoconstriction shows high [Ca2+]i-sensitivity, suggesting an croissance of pharmacomechanical but not of electromechanical coupling. The aim of this study was to investigate whether PTX-sensitive G-proteins are involved in the [Ca2+]i-sensitivity of adulation. De-endothelialised, perfused rat tail arteries were loaded with Fura-2/AM (5 µM, 90 min) and PTX (0, 30, 100, 300 or 1000 ng.ml-1). They were stimulated with either high KC1 (80 mM, 2 min) or noradrenaline (3 µM, 2 min. NA). KC1- or NA-evoked increases in décantation pressure (
D P, mmHg) and [Ca2+]i invective (D [Ca2+]i, a.u.) were measured. Values are means± S.E.M, significant differences between means (* P