The Correlation of Age with Endothelin Binding sites in Rat Smooth Muscle Cells
| Autor: | Chin Yi-Hua, 秦義華 |
|---|---|
| Rok vydání: | 1996 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 84 Endothelin-1 (ET-1), an endothelium-derived peptide, was demonstrated in vitro to have potent vasocontractile properties and proliferative effects. Therefore, the direct effect of ET-1 on smooth muscle cells mediated via its specific receptor may play an important role in hypertension and atherosclerosis. Our previous study demonstrated that the density of ET-1 binding sites on aortic smooth muscle cells is higher in 24-week-old SHR than in 4-week-old SHR and WKY rats. It implies age-related change in ET-1 binding sites. The present study was designed to examine whether the number of endothelin-1 binding sites in aortic smooth muscle cells of the rats varies with age. The systolic blood pressure (SBP) of 4, 8, 12, 16, 24-week-old of SHR, WKY and SD rats were measured by a tail-cuff sphygmomanometer. The SBP increased with advancing age in three different rat strains, especially it was higher in SHR. Smooth muscle membrane fractions obtained from the rats were subjected to receptor binding assay using [125I]ET-1 as ligand. The maximum binding value (Bmax, means density) and dissociation constant (Kd) of ET-1 binding sites were determined from a Scatchard analysis. Over the age span studied, Bmax increased with increasing age in three different rat strains with no change in affinity. The density of ET-1 binding sites was significantly higher in SHR than in age- matched WKY and SD rats, and the density was not different between WKY and SD rats in any corresponding age. These results suggest that SBP increased with advancing age could be related to an increased density of ET-1 binding sites on smooth muscle cells in three rat strains. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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