Izzard A S, Bund S J, Heagerty A M
Department of Medicine, Manchester Royal Infirmary, UK.
Hypertension. 1996 Oct;28(4):604-8. doi: 10.1161/01.hyp.28.4.604.
We investigated the morphological (wall-lumen ratio) and contractile characteristics of distal mesenteric arteries from spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) controls at a distending pressure of 63% of the mean aortic pressure of each rat using a pressure arteriograph. The wall-lumen ratios obtained were compared with those obtained at a pressure of 100 mm Hg. Experiments were carried out at 5 and 20 weeks. Mean aortic pressure of SHR was significantly increased at 5 weeks compared with that of WKY and was further increased by 20 weeks. At 63% of mean aortic pressure, no difference in the wall-lumen ratio of the arteries was observed between strains at 5 weeks; at 20 weeks, the wall-lumen ratio of SHR arteries was significantly increased compared that in WKY arteries. The wall-lumen ratio of SHR vessels did not differ at 63% mean aortic pressure compared with 100 mm Hg at either 5 or 20 weeks, whereas this parameter was significantly reduced in WKY vessels at 100 mm Hg compared with 63% mean aortic pressure at 5 and 20 weeks. In the presence of spontaneous myogenic tone, there was a borderline reduction in the lumen diameter of SHR vessels compared with WKY vessels and with increasing norepinephrine concentrations at 5 weeks. At 20 weeks, lumen diameter between strains did not differ in the presence of myogenic tone nor with increasing norepinephrine concentrations. Similar results were obtained when vessels from both rat strains were pressurized to 80 mm Hg. Thus, the increased wall-lumen ratio in the distal mesenteric arteries from adult SHR compared with those from WKY is not associated with an increased contractility under isobaric conditions when studied at physiological distending pressure.
我们使用压力动脉造影仪，在相当于每只大鼠平均主动脉压63%的扩张压力下，研究了自发性高血压大鼠（SHR）和Wistar-Kyoto（WKY）对照大鼠肠系膜远端动脉的形态学特征（壁腔比）和收缩特性。将获得的壁腔比与在100 mmHg压力下获得的壁腔比进行比较。实验在5周和20周时进行。与WKY相比，SHR的平均主动脉压在5周时显著升高，并在20周时进一步升高。在平均主动脉压的63%时，5周时两品系动脉的壁腔比未观察到差异；在20周时，SHR动脉的壁腔比与WKY动脉相比显著增加。在5周和20周时，SHR血管在平均主动脉压63%时的壁腔比与100 mmHg时相比无差异，而在100 mmHg时，WKY血管的该参数与平均主动脉压63%时相比在5周和20周时显著降低。在存在自发性肌源性张力的情况下，与WKY血管相比，5周时SHR血管的管腔直径有临界性减小，且随着去甲肾上腺素浓度增加而减小。在20周时，在存在肌源性张力的情况下以及随着去甲肾上腺素浓度增加，两品系之间的管腔直径无差异。当将两种大鼠品系的血管加压至80 mmHg时，获得了类似的结果。因此，与WKY相比，成年SHR肠系膜远端动脉壁腔比增加，在生理扩张压力下等压条件下研究时，与收缩性增加无关。
