| Summary: | 碩士 === 國防醫學院 === 解剖學研究所 === 82 === Endothelin-1 (ET-1) is a very potent vasoconstrictor peptide
which is secreted by endothelial cells. The aim of this study
was to investigate the binding characteristics of the ET-1 in
cultured aortic smooth muscle cells of spontaneously
hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. Using the
method of tissue " explant " technique, the rat aortic smooth
muscle cells had successfully cultured in our laboratory. Four
groups of rats used in this studies: the 4-week-old SHR (pre-
hypertensive stage), the 24-week-old SHR (hypertensive stage),
and the age-matched WKY rats (controls). Receptor binding assay
was performed. The data, Bmax and Kd of ET-1 binding sites on
rat aortic smooth muscle cells, were analyzed by " Scatchard
plot " analysis. Our data showed that the binding affinity (Kd)
of [125I]-ET-1 were similar in 4-week-old SHR, 4-week-old WKY
rats, 24-week-old SHR and 24-week-old WKY rats. However, the
density of ET-1 binding sites in aortic smooth muscle cells in
culture was significantly higher in 24-week-old SHR (5206 ±
443 molecules per cell) than in 4-week-old SHR (3229 ± 214).
On the other hand, the maximal binding capacity (Bmax) was also
significantly higher in 24-week-old SHR than in 24-week-old WKY
rats (2223 ± 62 molecules per cell). These results suggest
that the processing of hypertension in SHR could be related to
an increased density of ET-1 binding sites (ETA-receptor) on
arterial smooth muscle cells.
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