Vassallo D V, Vasquez E C, Cabral A M
Depto. Ciências Fisiológicas, Universidade Federal do Espirito Santo, Vitória, Brasil.
Pharmacol Res Commun. 1988 Jan;20(1):61-72. doi: 10.1016/s0031-6989(88)80607-6.
Previous studies suggested that left ventricle papillary muscles from neurogenic hypertensive rats with 15 days of sino-aortic denervation (SAD) develop intense depression of their inotropic state. Considering that these animals have an increased cardiac sympathetic tonus that could produce the observed depression of the contractile response we did the present study simulating a cardiac sympathetic hyperactivity pretreating rats, during 15 days, with isoproterenol (IPA, 0.1 mg/kg, i.p., divided in 3 daily doses). Because SAD rats also develop hypertension, the effect of blood pressure overload was studied in rats with 15 days of renovascular hypertension (RHR), Goldblatt 1K1C, to compare, separated, the effects of sympathetic hyperactivity and hemodynamic overload. Results showed that RHR had muscles that developed larger force than their controls (C: 7.31 +/- 0.34 g/mm2, RHR: 12.8 +/- 0.40 g/mm2), meanwhile IPA pretreated rats had muscles developing less force than their respective controls (C: 13.8 +/- 0.37 g/mm2, IPA: 8.61 +/- 0.24 g/mm2). These results are according to the proposition that the contractile state depression is related to the sympathetic hyperactivity, as suggested by the IPA pre-treated group and because the animals with isolated pressure overload showed a better contractile performance when compared to their uninephrectomized controls.
先前的研究表明，进行了15天窦主动脉去神经支配（SAD）的神经源性高血压大鼠的左心室乳头肌出现了明显的收缩力状态抑制。考虑到这些动物的心脏交感神经张力增加，可能会导致观察到的收缩反应抑制，我们进行了本研究，通过用异丙肾上腺素（IPA，0.1mg/kg，腹腔注射，分3次每日剂量）预处理大鼠15天来模拟心脏交感神经过度活跃。由于SAD大鼠也会出现高血压，因此在患有15天肾血管性高血压（RHR）的Goldblatt 1K1C大鼠中研究了血压过载的影响，以分别比较交感神经过度活跃和血流动力学过载的影响。结果显示，RHR大鼠的乳头肌产生的力量比其对照组更大（对照组：7.31±0.34g/mm²，RHR组：12.8±0.40g/mm²），而IPA预处理的大鼠的乳头肌产生的力量比其各自的对照组更小（对照组：13.8±0.37g/mm²，IPA组：8.61±0.24g/mm²）。这些结果符合这样的观点，即收缩状态抑制与交感神经过度活跃有关，如IPA预处理组所示，并且与单纯压力过载的动物相比，其单侧肾切除的对照组表现出更好的收缩性能。
