Salbutamol enhances isotonic contractile properties of rat diaphragm muscle.
Salbutamol enhances isotonic contractile properties of rat diaphragm muscle.
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沙丁胺醇增强大鼠膈肌的等张收缩特性。
DOI：
10.1152/jappl.1998.85.2.525
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Sieck,GC
中科院分区：
文献类型：
--
作者：
VanDerHeijden,HF;Zhan,WZ;Prakash,YS;Dekhuijzen,PN;Sieck,GC
本文观察了β_2-肾上腺素能受体激动剂沙丁胺醇（Slb）对大鼠膈肌等长和等张收缩特性的影响。在Diamus切除术前，心内给予负荷剂量25 μg/kg Slb，以确保充分扩散。然后在体外组织室中使用0.05 μM Slb进行研究。cAMP水平通过放射免疫测定法测定。与对照（Ct 1）相比，Slb处理后cAMP水平升高。在SLB处理的大鼠中，等长收缩和最大强直力分别增加了40%和20%。Slb处理后最大缩短速度增加了1.15%，最大功率输出增加了1.25%。在重复等渗激活期间，Slb处理的Diamus的疲劳速率更快，但Slb处理的Diamus和Ct 1 Diamus疲劳至相同的最大功率输出。尽管如此，在重复等张收缩期间的耐力时间在Slb治疗的Diamus中短了约10%。这些结果与Slb刺激β-肾上腺素受体增强Diamus收缩性的假设一致，并且Slb的这些作用可能至少部分由升高的cAMP介导。
The effects of the β2-adrenoceptor agonist salbutamol (Slb) on isometric and isotonic contractile properties of the rat diaphragm muscle (Diamus) were examined. A loading dose of 25 μg/kg Slb was administered intracardially before Diamusexcision to ensure adequate diffusion. Studies were then performed with 0.05 μM Slb in the in vitro tissue chamber. cAMP levels were determined by radioimmunoassay. Compared with controls (Ctl), cAMP levels were elevated after Slb treatment. In Slb-treated rats, isometric twitch and maximum tetanic force were increased by ∼40 and ∼20%, respectively. Maximum shortening velocity increased by ∼15% after Slb treatment, and maximum power output increased by ∼25%. During repeated isotonic activation, the rate of fatigue was faster in the Slb-treated Diamus, but both Slb-treated and Ctl Diamusfatigued to the same maximum power output. Still, endurance time during repetitive isotonic contractions was ∼10% shorter in the Slb-treated Diamus. These results are consistent with the hypothesis that β-adrenoceptor stimulation by Slb enhances Diamuscontractility and that these effects of Slb are likely mediated, at least in part, by elevated cAMP.