Harder D R, Contney S J, Willems W J, Stekiel W J
Am J Physiol. 1981 Jun;240(6):H837-42. doi: 10.1152/ajpheart.1981.240.6.H837.
Comparative in situ (innervation and circulation intact) and in vitro measurements of transmembrane potential (Em) were made in vascular smooth muscle cells (VSM) of small (300-500 micrometers) veins of an externalized intestinal mesenteric loop in 13- to 15-wk-old anesthetized spontaneously hypertensive rats (SHR) and Wistar-Kyoto normotensive controls (WKY). During suffusion with physiological salt solution (PSS), the mean in situ Em in SHR was significantly lower (-34 +/- 0.8 mV) than in WKY (-49 +/- 1.3 mV). In situ neural blockade with 1 microgram/ml tetrodotoxin (TTX) in PSS hyperpolarized venous Em in SHR (-45 +/- 1.7 mV) but not in WKY. In vitro Em in SHR (-51 +/- 1.0 mV) and WKY (-54 +/- 1.1 mV), though significantly elevated above respective in situ values, did not differ significantly from each other and were not altered by TTX. Increasing norepinephrine (NE) concentrations in the PSS gradedly depolarized the venous VSM of WKY in situ to a plateau Em of -32 +/- 0.9 mV at 6 microM (1 micrograms/ml) NE but had no significant depolarizing effect on the less-polarized venous VSM of SHR. However, after addition of 1 micrograms/ml TTX to the PSS, the in situ Em in SHR followed a depolarizing NE dose-response curve similar to that observed in WKY (with or without TTX). These results support the hypothesis that the neurogenic vasoconstrictor component of VSM tone is significantly elevated in mesenteric veins of the SHR model of essential hypertension.
在13至15周龄麻醉的自发性高血压大鼠（SHR）和Wistar-Kyoto正常血压对照大鼠（WKY）的外置肠系膜环小静脉（300 - 500微米）的血管平滑肌细胞（VSM）中，进行了跨膜电位（Em）的比较性原位（神经支配和循环完整）和体外测量。在用生理盐溶液（PSS）灌注期间，SHR的平均原位Em（-34±0.8 mV）显著低于WKY（-49±1.3 mV）。在PSS中用1微克/毫升河豚毒素（TTX）进行原位神经阻滞使SHR的静脉Em超极化（-45±1.7 mV），但对WKY无此作用。SHR（-51±1.0 mV）和WKY（-54±1.1 mV）的体外Em虽然明显高于各自的原位值，但彼此之间无显著差异，且不受TTX影响。增加PSS中去甲肾上腺素（NE）的浓度可使WKY的静脉VSM原位逐渐去极化至6微摩尔（1微克/毫升）NE时的平台Em为-32±0.9 mV，但对极化程度较低的SHR静脉VSM无显著去极化作用。然而，在PSS中加入1微克/毫升TTX后，SHR的原位Em呈现出与WKY（有或无TTX）中观察到的相似的去极化NE剂量反应曲线。这些结果支持了以下假设：在原发性高血压SHR模型的肠系膜静脉中，VSM张力的神经源性血管收缩成分显著升高。
