ß-Adrenergic-mediated vasodilation in young men and women: cyclooxygenase restrains nitric oxide synthase.
Am J Physiol Heart Circ Physiol
; 310(6): H756-64, 2016 Mar 15.
Article
em En
| MEDLINE
| ID: mdl-26747505
ABSTRACT
We tested the hypothesis that women exhibit greater vasodilator responses to ß-adrenoceptor stimulation compared with men. We further hypothesized women exhibit a greater contribution of nitric oxide synthase and cyclooxygenase to ß-adrenergic-mediated vasodilation compared with men. Forearm blood flow (Doppler ultrasound) was measured in young men (n = 29, 26 ± 1 yr) and women (n = 33, 25 ± 1 yr) during intra-arterial infusion of isoproterenol (ß-adrenergic agonist). In subset of subjects, isoproterenol responses were examined before and after local inhibition of nitric oxide synthase [N(G)-monomethyl-l-arginine (l-NMMA); 6 male/10 female] and/or cyclooxygenase (ketorolac; 5 male/5 female). Vascular conductance (blood flow ÷ mean arterial pressure) was calculated to assess vasodilation. Vascular conductance increased with isoproterenol infusion (P < 0.01), and this effect was not different between men and women (P = 0.41). l-NMMA infusion had no effect on isoproterenol-mediated dilation in men (P > 0.99) or women (P = 0.21). In contrast, ketorolac infusion markedly increased isoproterenol-mediated responses in both men (P < 0.01) and women (P = 0.04) and this rise was lost with subsequent l-NMMA infusion (men, P < 0.01; women, P < 0.05). ß-Adrenergic vasodilation is not different between men and women and sex differences in the independent contribution of nitric oxide synthase and cyclooxygenase to ß-mediated vasodilation are not present. However, these data are the first to demonstrate ß-adrenoceptor activation of cyclooxygenase suppresses nitric oxide synthase signaling in human forearm microcirculation and may have important implications for neurovascular control in both health and disease.
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MEDLINE
Assunto principal:
Vasodilatação
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Inibidores de Ciclo-Oxigenase
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Agonistas Adrenérgicos beta
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Óxido Nítrico Sintase
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ômega-N-Metilarginina
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Cetorolaco
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Inibidores Enzimáticos
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Isoproterenol
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article