Involvement of substance P in noncholinergic excitation of rabbit colonic muscle.
Involvement of substance P in noncholinergic excitation of rabbit colonic muscle.
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P物质参与兔结肠肌的非胆碱能兴奋。
DOI：
10.1152/ajpgi.1989.256.1.g246
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Ho,FJ
中科院分区：
文献类型：
--
作者：
Koelbel,CB;Mayer,EA;ReeveJr,JR;SnapeJr,WJ;Patel,A;Ho,FJ
神经激肽是哺乳动物胃肠道中的非胆碱能兴奋性神经递质。为了表征结肠肌对神经激肽的肌源性和神经源性反应，我们研究了近端和远端结肠肌条对P物质（SP）、神经激肽A（NKA）和神经激肽B（NKB）的机械反应和[3 H]乙酰胆碱的释放。所有神经激肽引起剂量依赖性变力反应。SP是80倍更有力的远端相比，近端纵向肌肉。近端纵肌的效价排序为NKA大于SP = NKB，远端肌肉NKA = SP = NKB。对SP脱敏或用SP拮抗剂预处理抑制对SP的机械反应和对电刺激的阿托品抵抗性变力性关闭反应。只有纵向肌肉从远端结肠有一个阿托品和六甲铵敏感的正性肌力成分SP。相反，所有三种肽释放[3 H]乙酰胆碱从纵向肌条与[3 H]胆碱预孵育是等效的。这些结果表明：1）SP是一种有效的兔结肠激动剂，具有近端-远端生物学效价梯度; 2）远端结肠的肌源性反应似乎是通过NK-1受体介导的; 3）SP是远端纵肌关闭反应的非胆碱能成分的主要介质。
Neurokinins have been implicated as noncholinergic excitatory neurotransmitters in the mammalian gastrointestinal tract. To characterize the myogenic and neurogenic response of colonic muscle to neurokinins we studied the mechanical response of muscle strips from proximal and distal colon and the release of [3H]acetylcholine in response to substance P (SP), neurokinin A (NKA) and neurokinin B (NKB). All neurokinins caused a dose-dependent inotropic response. SP was 80 times more potent in distal compared with proximal longitudinal muscle. The rank order of potencies in proximal longitudinal muscle was NKA greater than SP = NKB and in distal muscle NKA = SP = NKB. Desensitization to SP or pretreatment with a SP antagonist inhibited the mechanical response to SP and the atropine-resistant inotropic off response to electrical stimulation. Only longitudinal muscle from distal colon had an atropine- and hexamethonium-sensitive inotropic component to SP. In contrast, all three peptides were equipotent in releasing [3H]acetylcholine from longitudinal muscle strips preincubated with [3H]choline. These results suggest the following: 1) SP is a potent agonist of rabbit colon with a proximal distal gradient in biological potency; 2) the myogenic response of the distal colon appears to be mediated through a NK-1 receptor; and 3) SP is a major mediator of the noncholinergic component of the off response in distal longitudinal muscle.