| Автор | Eskinder, H. |
| Автор | Gross, G. J. |
| Дата выпуска | 1988 |
| dc.description | The purpose of the present study was to determine whether 8-bromo cyclic GMP (8-Br cGMP) mimics the actions of nitroglycerin (GTN) in inhibiting alpha-1 versus alpha-2 adrenoceptor-mediated constrictor responses in canine saphenous vein. Phenylephrine (PE) and L-dobutamine were used as full and partial alpha-1 adrenoceptor agonists, respectively, and B-HT 920 was employed as a selective alpha-2 adrenoceptor agonist. The ability of 8-Br cGMP and GTN to inhibit vasoconstrictor responses to a standard agonist concentration of PE, L-dobutamine and B-HT 920 was determined. 8-Br cGMP like GTN produced a selective antagonism of alpha-2-mediated responses of B-HT 920 and had minimal effects on alpha-1-induced constrictor responses of phenylephrine. However, when a portion of the alpha-1-adrenoceptor pool was inactivated by phenoxybenzamine (POB) (5×10<sup>−8</sup> M, 1×10<sup>−7</sup> M) 8-Br cGMP like GTN produced a significant depression of responses to PE. In addition, contractions produced by L-dobutamine, a selective partial alpha-1 adrenoceptor agonist (no alpha receptor reserve), were highly sensitive to inhibition by 8-Br cGMP and GTN. These results suggest that the presence of a large alpha-1-adrenoceptor reserve to PE concealed an underlying functional antagonism to alpha-1-adrenoceptor-mediated responses by GTN and 8-Br cGMP. The similarity in the efficacy and potency of these two agents (8-Br cGMP and GTN) suggests that the effects of GTN in canine saphenous vein may be the result of an increase in the intracellular concentration of cGMP. |
| Формат | application.pdf |
| Издатель | Oxford University Press |
| Копирайт | © 1988 The European Society of Cardiology |
| Тема | Canine saphenous vein |
| Тема | nitroglycerin |
| Тема | 8-bromo cyclic GMP |
| Тема | alpha adrenoceptors |
| Тема | spare receptors |
| Тема | Nitrates Action and Efficacy |
| Название | 8-Bromo cyclic GMP mimics the actions of nitroglycerin in modulating responses produced by full and partial alpha-adrenoceptor agonists in canine saphenous vein |
| Тип | research-article |
| DOI | 10.1093/eurheartj/9.suppl_A.11 |
| Electronic ISSN | 1522-9645 |
| Print ISSN | 0195-668X |
| Журнал | European Heart Journal |
| Том | 9 |
| Первая страница | 11 |
| Последняя страница | 15 |
| Аффилиация | Department of Pharmacology and Toxicology, Medical College of WisconsinMilwaukee, Wisconsin 53226, U.S.A. |
| Выпуск | suppl_A |
