| Autor: |
Martinez-Cuesta, MA, Moreno, L, Pique, JM, Bosch, J, Rodrigo, J, Esplugues, JV |
| Zdroj: |
Gastroenterology; September 1996, Vol. 111 Issue: 3 p727-735, 9p |
| Abstrakt: |
BACKGROUND & AIMS: beta-Adrenergic relaxation seems to be mediated by nitric oxide. The aim of this study was to evaluate changes induced by portal hypertension in beta 2-adrenergic vasorelaxation. METHODS: Isolated rat mesenteric veins were relaxed by salbutamol, and nerve- mediated vasocontractions were induced by electrical field stimulation. Responses were evaluated in the presence of NG-nitro-L-arginine methyl ester (L-NAME) or tetrodotoxin. Immunocytochemical techniques were used for localization of neuronal NO synthase. RESULTS: Salbutamol-induced relaxations were decreased in rings from portal-hypertensive animals. L- NAME reduced these relaxations, but its effects were more pronounced in sham-operated rats. Tetrodotoxin decreased the effect of salbutamol only in rings from sham-operated animals. Combination of L-NAME and tetrodotoxin did not exert a greater effect than either of these agents alone. Veins from portal-hypertensive animals were more sensitive to S- nitroso-N-acetyl penicillamine. L-NAME increased vasocontractions by electrical stimulation only in rings from sham-operated rats. Veins from portal-hypertensive animals exhibited a specific degeneration of NO-containing nerve endings. CONCLUSIONS: beta 2-Adrenergic relaxation is impaired in mesenteric veins from portal-hypertensive rats, possibly as a result of a defective neuronal release of NO. (Gastroenterology 1996 Sep;111(3):727-35) |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
