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- Title
Adenosine participates in regulation of smooth muscle relaxation in aortas from rats with experimental hypothyroidism.
- Authors
Banos, G.; Martinez, F.; Grimaldo, J.I.; Franco, M.
- Abstract
The contribution of adenosine receptors was evaluated in vascular relaxation in experimental hypothyroidism. Hypothyroid aortic rings contracted less than normal controls with noradrenaline, phenylephrine, and KCl; the differ-ence was maintained after incubation with 1,3-dipropyl-8-p-sulfophenylxanthine (an A1 and A2 adenosine receptor blocker). The vascular relaxation induced by acetylcholine or carbachol was similar in normal and hypothyroid aortic rings. However, adenosine, N[sup6] -cyclopentyladenosine (an A1 adenosine receptor analogue), and 5'-N-ethylcarbox-amidoadenosine (an A2 and A3 adenosine analogue) induced vasodilation that was larger in hypothyroid than in nor-mal aortas. N[subomega;]-nitro-L-arginine methyl ester shifted the dose-response curves of adenosine, N[sup6] -cyclopentyladenosine, or 5'-N-ethylcarboxamidoadenosine to the right in both normal and hypothyroid vessels. The blocker 1,3-dipropyl-8-p-sulfophenylxanthine significantly reduced adenosine-induced relaxation in the hypothyroid but not in the normal aortic vessels. These results suggest that in hypothyroid aortas, a larger adenosine-mediated vasodilation is observed probably due to an increase in receptor number or sensitivity.
- Subjects
ADENOSINES; CELL receptors; SMOOTH muscle; HYPOTHYROIDISM; AMINO acids; CELL metabolism
- Publication
Canadian Journal of Physiology & Pharmacology, 2002, Vol 80, Issue 6, p507
- ISSN
0008-4212
- Publication type
Article