Inhibitory effect of manganese on contraction of isolated rat aorta.
The effects of MnCl2 on vascular smooth muscle contraction induced by noradrenaline (NA) and KCl were investigated. Rings segments from rat aorta were isolated and changes in isometric tension recorded. MnCl2 (10 microM and 1 mM) significantly attenuated the contractile responses to NA and KCI. There were also reductions in the contractile responses to CaCl2 in NA- and KCl-stimulated rings, after pretreatment with MnCl2. The magnitude of the phasic contraction to NA was significantly reduced in presence of MnCl2. The results suggest that MnCl2 inhibits vascular smooth muscle contraction by influencing a Ca2+-mediated mechanism.
Ettarh
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Department of Physiology, College of Medicine, University of Lagos, Idi-Araba, PMB 12003, Lagos, Nigeria. ettarh@yahoo.com
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002712:Chlorides / Q000494:pharmacology*; D017895:Manganese Compounds / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D002712:Chlorides; D017895:Manganese Compounds; D014662:Vasoconstrictor Agents; D011189:Potassium Chloride; C025340:manganese chloride; D002118:Calcium; D009638:Norepinephrine