α-和β-肾上腺素能受体阻断对大鼠离体心脏神经诱发内源性去甲肾上腺素释放的影响。
Effects of alpha- and beta-adrenoceptor blockade on the neurally evoked overflow of endogenous noradrenaline from the rat isolated heart.
作者信息
Dart A M, Dietz R, Hieronymus K, Kübler W, Mayer E, Schömig A, Strasser R
出版信息
Br J Pharmacol. 1984 Mar;81(3):475-8. doi: 10.1111/j.1476-5381.1984.tb10100.x.
beta-Adrenoceptor blockade by propranolol (4 X 10(-6)M) was without effect on the overflow of endogenous noradrenaline from the isolated heart of the rat induced by stimulation of sympathetic nerves for 1 min at 1 and at 4 Hz. The increase in heart rate in response to such stimulation was abolished by propranolol treatment. alpha 2-Adrenoceptor blockade by yohimbine (10(-6)M) induced approximately a two fold increase in the overflow of endogenous noradrenaline induced by stimulation of sympathetic nerves for 1 min at 1 and at 4 Hz. A combination of yohimbine (10(-6)M) and desipramine (10(-7)M) induced a more than 3 fold increase in the overflow of endogenous noradrenaline produced by sympathetic nerve stimulation at 1 and at 4 Hz. Heart rate increases produced by such stimulation were intensified. These results provide no evidence for the feedback stimulation of presynaptic beta-adrenoceptors in this preparation. The action of alpha-2-blockade was equipotent at stimulation frequencies of 1 and 4 Hz.
普萘洛尔（4×10⁻⁶M）对大鼠离体心脏交感神经刺激1分钟（频率为1赫兹和4赫兹）所诱导的内源性去甲肾上腺素溢出无影响。普萘洛尔处理可消除此类刺激引起的心率增加。育亨宾（10⁻⁶M）对α₂肾上腺素能受体的阻断作用，使交感神经刺激1分钟（频率为1赫兹和4赫兹）所诱导的内源性去甲肾上腺素溢出增加约两倍。育亨宾（10⁻⁶M）与地昔帕明（10⁻⁷M）联合使用，使交感神经刺激（频率为1赫兹和4赫兹）所产生的内源性去甲肾上腺素溢出增加超过三倍。此类刺激引起的心率增加增强。这些结果并未为此制剂中突触前β肾上腺素能受体的反馈刺激提供证据。α₂阻断作用在1赫兹和4赫兹的刺激频率下效力相当。
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