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Distribution, content and action site of leucine-enkephalin in pulmonary artery wall of rat and rabbit

Yuan Xiangpeng, Lin Shuxin, Yuan Shilin, Qin Bingzhi, Ma Dan

Department of Pathophysiology, Fourth Military Medical University. Xi^an,Shaanxi；China(710032)；Department of Neurobiology, Fourth Military Medical University. Xi^an,Shaanxi

Abstract

Using immunohistochemical method to investigate the distribution of peptidergic fibers in the pulmonary artery wall of SD rat, L-enkephalin immunoreactive (L-ENKir)fibers were easily demonstrated. The contents of L-ENK in pulmonary artery of rat and rabbit measured by radioimmunoassay were respectively 439.18±30.52 and 29.9±1.4(pg/mg of wet tissue). Contraction of superfused strips of pulmonary artery of rabbit could be evoked by parameter I electric field stimulation. The response was blocked by #alpha#-receptor antagonist phentolamine. Alpha2-receptor antagonist Yohimbine enhanced the response in small doses(0.06-0.12#mu#mol/L), while inhibited in large (3.2#mu#mol/L). The contraction could also be enhanced when the artery strips were preincubated with naloxone. After the #alpha#-receptors were blocked with phentolamine, stronger contraction could still be evoked by parameter Ⅱ electric field stimulation and the response was not affected by naloxone. L-ENK had no effect on the contraction evoked by exogenous NE. It demonstrate that enkephalin presented in the pulmonary artery wall are released by electric field stimulation. Enkephalin may reduce the release of NE from.......

Key words: Leucine-enkephalin;Pulmonary artery;Norepinephrine;Immunohistochemistry; Radioimmunoassay;Electric field stimulation

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Citing This Article：

Yuan Xiangpeng, Lin Shuxin, Yuan Shilin, Qin Bingzhi, Ma Dan. Distribution, content and action site of leucine-enkephalin in pulmonary artery wall of rat and rabbit. Acta Physiol Sin 1994; 46 (4): (in Chinese with English abstract).