Effect of acute and long-term treatment with 17-beta-estradiol on the vasomotor responses in the rat aorta
| Autor: | H L, Andersen, J U, Weis, B, Fjalland, N, Korsgaard |
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| Rok vydání: | 1999 |
| Předmět: |
Serotonin
Time Factors Muscle Relaxation Vasodilator Agents Aorta Thoracic In Vitro Techniques Nitric Oxide Rats Sprague-Dawley Phenylephrine Animals Vasoconstrictor Agents Enzyme Inhibitors Dose-Response Relationship Drug Estradiol Drug Synergism Free Radical Scavengers Acetylcholine Rats Vasodilation Vasomotor System NG-Nitroarginine Methyl Ester Papers Potassium Calcium Female Endothelium Vascular hormones hormone substitutes and hormone antagonists Muscle Contraction |
| Zdroj: | British journal of pharmacology. 126(1) |
| ISSN: | 0007-1188 |
| Popis: | 1. This study sought to evaluate whether the effects of acute and long-term treatment with 17-beta-estradiol on the vasomotor responses in rat aortic rings are mediated through the same mechanism. 2. Ovariectomized rats were treated daily with either 17-beta-estradiol-3-benzoate (100 microg kg(-1)) or vehicle for 1 week. 3. The effect of long-term 17-beta-estradiol treatment on the responses to cumulative doses of phenylephrine, 5-HT, calcium, potassium and 17-beta-estradiol was determined in aortic rings. In the same rings, the effect of acute exposure to 17-beta-estradiol (5 and 10 microM) on the dose response curves for phenylephrine, 5-HT, calcium, potassium and acetylcholine were estimated. The measurements were made in rings with and without intact endothelium. The tone-related basal release of nitric oxide (NO) was measured in rings with intact endothelium. 4. Long-term 17-beta-estradiol treatment reduced the maximum developed contraction to all contracting agents studied. This effect was abolished in endothelium denuded vessels. Acute 17-beta-estradiol treatment also reduced maximal contraction. This effect, however, was independent of the endothelium. 5. Long-term 17-beta-estradiol treatment significantly increased the ability of the rings to dilate in response to acetylcholine whereas acute exposure to 17-beta-estradiol had no effect. The tone-related release of NO was significantly increased after long-term exposure to 17-beta-estradiol. 6. In conclusion, this study indicate that the acute and long-term effects of 17-beta-estradiol in the rat aorta are mediated through different mechanisms. The long-term effect is mediated through the endothelium most likely by increasing NO release. In contrast, the acute effect of 17-beta-estradiol seems to be through an effect on the vascular smooth muscle cells. |
| Databáze: | OpenAIRE |
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