Machkov V V, Vlasova M A, Tarasova O S, Mikhaleva L M, Koshelev V B, Timin E N, Rodionov I M
Department of Human and Animal Physiology, Biological Faculty, Lomonosov Moscow State University, Russia.
Acta Physiol Scand. 1998 Aug;163(4):331-7. doi: 10.1046/j.1365-201X.1998.t01-1-00389.x.
The vasoconstrictor effects of noradrenaline were studied in spontaneously hypertensive rats (SHR) compared with Wistar Kyoto rats (WKY), and in Wistar rats with regional hypotension (WH) compared to control Wistar rats (WC). The abdominal aorta was ligated in WH distal to the renal arteries, lowering blood pressure in the hindquarters by 41% and tail artery wall cross-sectional area by 35% compared with WC. A cylindrical segment was dissected from the proximal part of the tail artery, cannulated at both ends and perfused with Krebs-Henseleit solution either at constant flow starting from a pressure of 120 mmHg or at a constant pressure of 120 mmHg. The cumulative dose-response relationships for noradrenaline were determined in control conditions and subsequently in the presence of gadolinium (100 microM), a non-specific blocker of mechanosensitive channels. Under constant-flow perfusion noradrenaline evoked a more prominent resistance increase in SHR compared with WKY and in WC compared with WH. Similar relations were seen in the presence of gadolinium, although responses were reduced. At constant pressure perfusion the vasoconstrictor response to noradrenaline was lower in SHR compared with WKY and in WC compared with WH. Application of gadolinium under constant-pressure perfusion reduced responses in WKY and WH, so that vasoconstriction in SHR became more pronounced than that in WKY and in WC than that in WH. It is suggested that the results can be explained by the difference in wall thickness causing different degrees of activation of the myogenic response to distension.
研究了去甲肾上腺素对自发性高血压大鼠（SHR）与Wistar Kyoto大鼠（WKY）的血管收缩作用，并比较了肾动脉以下区域低血压的Wistar大鼠（WH）与对照Wistar大鼠（WC）。在WH大鼠中，于肾动脉远端结扎腹主动脉，与WC相比，后肢血压降低41%，尾动脉壁横截面积减少35%。从尾动脉近端解剖出一段圆柱形血管，两端插管，然后以120 mmHg的压力开始以恒定流量或在120 mmHg的恒定压力下用Krebs-Henseleit溶液灌注。在对照条件下以及随后在存在机械敏感通道的非特异性阻滞剂钆（100 microM）的情况下，测定去甲肾上腺素的累积剂量-反应关系。在恒流灌注下，与WKY相比，去甲肾上腺素在SHR中引起的阻力增加更为显著，与WH相比，在WC中也是如此。在存在钆的情况下也观察到类似的关系，尽管反应有所降低。在恒压灌注下，与WKY相比，SHR对去甲肾上腺素的血管收缩反应较低，与WH相比，WC也是如此。在恒压灌注下应用钆会降低WKY和WH的反应，因此SHR中的血管收缩比WKY中更为明显，WC中的血管收缩比WH中更为明显。研究表明，这些结果可以通过壁厚差异导致对扩张的肌源性反应激活程度不同来解释。
