Effects of micromolar concentrations of manganese, copper, and zinc on alpha1-adrenoceptor-mediating contraction in rat aorta.
To determine the influences of the Mn, Cu, and Zn on alpha1-adrenoceptor (AR)-mediated vasoconstriction, we investigated their effects on vasoconstriction produced by the alpha1-AR agonist phenylephrine in isolated rings of rat thoracic aorta. The cumulative concentration-contraction curves for phenylephrine were obtained in the absence and presence of Mn (0.3, 1, 3 microM), Cu (1, 10, 16 microM), and Zn (0.3, 1, 10 microM). Mn, Cu, and Zn each inhibited phenylephrine-mediated contraction in a dose-dependent manner. The maximal phenylephrine-induced contraction was significantly reduced by the pretreatment of the arterial rings with 10 and 16 microM Cu (p<0.05). The results suggest that variations in the plasma concentrations of metal might lead to changes in alpha1-AR-mediated constrictive response.
Yan
M
M
Cardiac Research Laboratory, National Heart Centre of Singapore, Singapore.
Liu
D L
DL
Chua
Y L
YL
Chen
C
C
Lim
Y L
YL
D058646:Adrenergic alpha-1 Receptor Agonists; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000502:physiology*; D003300:Copper / Q000008:administration & dosage*; D066298:In Vitro Techniques; D008297:Male; D008345:Manganese / Q000008:administration & dosage*; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology; D015032:Zinc / Q000008:administration & dosage*
D058646:Adrenergic alpha-1 Receptor Agonists; D018340:Receptors, Adrenergic, alpha-1; D010656:Phenylephrine; D008345:Manganese; D003300:Copper; D015032:Zinc