Gulati A, Rebello S
Department of Pharmacodynamics, University of Illinois, Chicago 60612.
Life Sci. 1991;48(12):1207-15. doi: 10.1016/0024-3205(91)90460-s.
The binding of [125I] sarafotoxin 6b (SRT 6b) and [125I] endothelin-1 (ET-1) to endothelin (ET) receptors of neuronal membranes prepared from cerebral cortex and ventrolateral medulla of 8 week old spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats was determined. [125I] SRT 6b bound to the membranes of cerebral cortex and ventrolateral medulla at a single high affinity site. The binding of [125I] SRT 6b in the cerebral cortex was found to be similar in SHR and WKY rats. However, in the ventrolateral medulla [125I] SRT 6b binding was found to be significantly lower in SHR as compared to WKY rats. The decreased binding was due to decrease (48%) in the Bmax values in SHR rats as compared to WKY rats. The Kd values were similar in SHR and WKY rats. [125I] ET-1 also bound to the membranes of cerebral cortex and ventrolateral medulla at a single high affinity site. The binding of [125I] ET-1 in the cerebral cortex was found to be similar in SHR and WKY rats. However, in the ventrolateral medulla [125I] ET-1 binding was found to be significantly lower in SHR as compared to WKY rats. The decreased binding was due to 36% decrease in the Bmax values in SHR rats as compared to WKY rats. The Kd values were similar in SHR and WKY rats. It is concluded that the population of ET receptors is less in the ventrolateral medulla of SHR rats and may be contributing to the regulation of blood pressure.
测定了8周龄自发性高血压（SHR）大鼠和正常血压的Wistar-Kyoto（WKY）大鼠大脑皮层和延髓腹外侧制备的神经细胞膜上[125I] 毒胡萝卜素6b（SRT 6b）和[125I] 内皮素-1（ET-1）与内皮素（ET）受体的结合情况。[125I] SRT 6b在大脑皮层和延髓腹外侧的膜上以单一高亲和力位点结合。发现SHR大鼠和WKY大鼠大脑皮层中[125I] SRT 6b的结合情况相似。然而，与WKY大鼠相比，SHR大鼠延髓腹外侧中[125I] SRT 6b的结合显著降低。结合减少是由于与WKY大鼠相比，SHR大鼠的Bmax值降低了48%。SHR大鼠和WKY大鼠的Kd值相似。[125I] ET-1也在大脑皮层和延髓腹外侧的膜上以单一高亲和力位点结合。发现SHR大鼠和WKY大鼠大脑皮层中[125I] ET-1的结合情况相似。然而，与WKY大鼠相比，SHR大鼠延髓腹外侧中[125I] ET-1的结合显著降低。结合减少是由于与WKY大鼠相比，SHR大鼠的Bmax值降低了36%。SHR大鼠和WKY大鼠的Kd值相似。得出的结论是，SHR大鼠延髓腹外侧的ET受体数量较少，可能参与血压调节。
