Sim M K, Singh M
Br J Pharmacol. 1987 Jan;90(1):147-50. doi: 10.1111/j.1476-5381.1987.tb16834.x.
The responses to noradrenaline (NA) of the aortae of various hypertensive rats, namely the spontaneously hypertensive rat (SHR), the low blood pressure SHR (LBP-SHR), and the left renal artery stenosed LBP-SHR (LRAS-LBR-SHR), were compared to those of the normotensive Wistar-Kyoto rats (WKY). The aortae of the hypertensive rats were significantly more responsive (P less than 0.05) to 10(-8) M NA. However, the reverse was true for higher doses of NA. The ED50 values for the aortae of WKY, LBP-SHR, SHR and LRAS-LBP-SHR were 20, 8.5, 7.8 and 8 nM respectively. The NA-contracted aortae of the LRAS-LBP-SHR were significantly less responsive (P less than 0.05) to the relaxant action of histamine and acetylcholine (ACh) compared to those of the WKY. This observation was not made in the aortae of the LBP-SHR. The maximal relaxation (% of the maximal contraction induced by 10(-8) M NA) observed in the aortae of WKY, LBP-SHR and LRAS-LBP-SHR were, respectively, 72 +/- 2, 66 +/- 6, 39 +/- 7 for ACh and 50 +/- 3, 36 +/- 4, 27 +/- 3 for histamine. In aortae where the endothelium had been removed by collagenase treatment, histamine induced a dose-related contraction. The rank order of this dose-related contraction was WKY greater than LBP-SHR greater than SHR greater than LRAS-LBP-SHR with the corresponding maximal tension (g) 0.89 +/- 0.04, 0.59 +/- 0.04, 0.36 +/- 0.04, 0.19 +/- 0.05. 5 The results suggested that elevation of blood pressure above the normal (due either to intrinsic or extrinsic factors), as seen in SHR and LRAS-LBP-SHR, results in a decreased response of the aortae to ACh and histamine. This effect was seen in both the endothelium mediated relaxation and the nonendothelium mediated contraction.
将各种高血压大鼠（即自发性高血压大鼠（SHR）、低血压SHR（LBP - SHR）和左肾动脉狭窄的LBP - SHR（LRAS - LBP - SHR））的主动脉对去甲肾上腺素（NA）的反应与正常血压的Wistar - Kyoto大鼠（WKY）进行比较。高血压大鼠的主动脉对10(-8) M NA的反应明显更强（P小于0.05）。然而，对于更高剂量的NA，情况则相反。WKY、LBP - SHR、SHR和LRAS - LBP - SHR主动脉的半数有效剂量（ED50）值分别为20、8.5、7.8和8 nM。与WKY相比，LRAS - LBP - SHR的NA收缩主动脉对组胺和乙酰胆碱（ACh）的舒张作用反应明显较弱（P小于0.05）。在LBP - SHR的主动脉中未观察到这种现象。WKY、LBP - SHR和LRAS - LBP - SHR主动脉中观察到的最大舒张（相对于10(-8) M NA诱导的最大收缩的百分比），对于ACh分别为72±2、66±6、39±7，对于组胺分别为50±3、36±4、27±3。在通过胶原酶处理去除内皮的主动脉中，组胺诱导剂量相关的收缩。这种剂量相关收缩的顺序为WKY大于LBP - SHR大于SHR大于LRAS - LBP - SHR，相应的最大张力（g）为0.89±0.04、0.59±0.04、0.36±0.04、0.19±0.05。结果表明，如在SHR和LRAS - LBP - SHR中所见，血压升高至正常以上（由于内在或外在因素）会导致主动脉对ACh和组胺的反应降低。这种效应在内皮介导的舒张和非内皮介导的收缩中均可见。
