Source(s) of activator calcium for noradrenaline-induced vasoconstriction in the perfused rabbit isolated ovarian vascular bed: a role for tyrosine kinase.
The effects of Ca2+ withdrawal and agents affecting Ca2+ translocation on alpha1-adrenoceptor-mediated vasoconstrictor responses in the perfused rabbit ovarian vascular bed were studied. Noradrenaline-induced vasoconstriction was lost in a Ca(2+)-free Krebs' solution, and the rate of loss of the response was accelerated by EGTA (2 mM). Noradrenaline-induced vasoconstriction and SDZ NVI 085-induced vasoconstriction were concentration-dependently inhibited by verapamil and nifedipine. These agents were, however, more effective against KCl-induced responses. Cyclopiazonic acid, an intracellular Ca(2+) depletor, concentration-dependently inhibited noradrenaline-induced responses and abolished the response in Ca(2+)-free Krebs' solution. GF 109203X and polymyxin B, inhibitors of protein kinase C (PKC), had no significant effect on noradrenaline-induced responses. Tyrosine kinase inhibitors, genistein and erbstatin, inhibited noradrenaline-induced vasoconstriction in the perfused rabbit ovarian vascular bed. The results would suggest that both extracellular Ca2+ and intracellular Ca2+ participate in noradrenaline-induced vasoconstrictor responses in the perfused rabbit ovarian vascular bed. The results would also suggest that tyrosine kinase and not protein kinase C activation has a role in such effects.
Yousif
M H
MH
Department of Pharmacology, Faculty of Medicine, Kuwait University, Safat.
Williams
K I
KI
Oriowo
M A
MA
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D007211:Indoles / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology*; D010053:Ovary / Q000098:blood supply / Q000187:drug effects*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011817:Rabbits; D015424:Reperfusion; D014661:Vasoconstriction / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007211:Indoles; D014665:Vasodilator Agents; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D002118:Calcium; D009638:Norepinephrine; C000543:cyclopiazonic acid