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首页> 外文期刊>Canadian Journal of Physiology and Pharmacology >Concentration-dependent effects of angiotensin II on sinus rate in canine isolated right atrial preparations.
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Concentration-dependent effects of angiotensin II on sinus rate in canine isolated right atrial preparations.

机译：血管紧张素II对犬离体右房制剂鼻窦速率的浓度依赖性作用。

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摘要

To investigate the concentration-response relationship of angiotensin II with respect to its chronotropic effects, the sinus rate was recorded from canine isolated right atrial preparations perfused through the sinus node artery. Nicotine (5 x 10(-5) M) injection induced an early, atropine-sensitive bradycardic response and a more delayed propranolol-sensitive tachycardic response, suggesting that the preparations contained both cholinergic and adrenergic neurons. The former response, but not the latter, was markedly reduced in preparations in which the right atrial ganglionated plexus was removed. Positive chronotropic responses were induced by angiotensin II over a wide range of concentrations (10(-12) - 5 x 10(-6) M), with a maximum increment of 29.9 +/- 9.6 beats/min. Responses to low concentrations (angiotensin II, 10(-11) M) were monophasic and were abolished by propranolol. In contrast, the responses to higher concentrations (angiotensin II, 10(-6) M) were not abolished by propranolol and were biphasic (early response, 29.9 +/- 12.1 beats/min; later response, 18.6 +/- 9.0 beats/min), the early response being blocked by losartan (AT1 antagonist) but not the later one, both being blocked by saralasin (nonselective angiotensin II antagonist). In conclusion, the data suggest that angiotensin II exerts its stimulant effects on the heart through receptors located either on cardiomyocytes or neurons, depending on the agonist concentration.
机译：为了研究血管紧张素II与其变时性作用的浓度-反应关系，从通过窦房结动脉灌注的犬右房准备中记录了窦率。尼古丁（5 x 10（-5）M）注射诱导了早期的阿托品敏感的心动过缓反应和更延迟的普萘洛尔敏感的心动过速反应，表明制剂同时含有胆碱能和肾上腺素能神经元。在去除右房神经节神经丛的制剂中，前者的反应显着降低，但后者没有显着降低。血管紧张素II在很宽的浓度范围（10（-12）-5 x 10（-6）M）中诱导正变时反应，最大增量为29.9 +/- 9.6次/分钟。对低浓度（血管紧张素II，10（-11）M）的反应是单相的，而普萘洛尔则取消了。相比之下，普萘洛尔并未消除对较高浓度（血管紧张素II，10（-6）M）的反应，而是双相的（早期反应为29.9 +/- 12.1次/分;较晚的反应为18.6 +/- 9.0次/分分钟），早期反应被氯沙坦（AT1拮抗剂）阻断，但没有较晚的反应，两者均被saralasin（非选择性血管紧张素II拮抗剂）阻断。总之，数据表明，血管紧张素II通过激动剂的浓度，通过位于心肌细胞或神经元上的受体对心脏产生刺激作用。

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