Different effects of norepinephrine and KCl on the cytosolic Ca2+-tension relationship in vascular smooth muscle of rat aorta.
Norepinephrine and KCl induced a concentration-dependent increase in the cytosolic Ca2+ level [( Ca2+]cyt) measured either by intracellular fura 2-Ca2+ fluorescence or by 45Ca2+ uptake. Muscle contraction in isolated rat aortic strips was also increased although a greater contraction was induced by norepinephrine than by KCl at the same [Ca2+]cyt. This result suggests that the contraction of vascular smooth muscle is regulated by [Ca2+]cyt and also by other factor(s).
Karaki
H
H
Department of Veterinary Pharmacology, Faculty of Agriculture, University of Tokyo, Japan.
Sato
K
K
Ozaki
H
H
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D009638:Norepinephrine / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D011189:Potassium Chloride; D002118:Calcium; D009638:Norepinephrine