Adrenergic inhibition of neurally evoked secretion in ground squirrel intestine.
Adrenergic inhibition of neurally evoked secretion in ground squirrel intestine.
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DOI：
10.1016/0014-2999(90)90243-y
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发表时间：
1990-05
影响因子：
5
通讯作者：
H. Carey;M. Zafirova
中科院分区：
文献类型：
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作者：
H. Carey;M. Zafirova
在松鼠空肠上研究了去甲肾上腺素在神经刺激的粘膜反应中的作用。电场刺激通透室中的空肠片可引起河豚毒素敏感的短路电流增加(42±6μA/cm~2)，并在刺激期间下降，然后在刺激终止后再次升高。电流的初始增加被布美他尼抑制，在无氯溶液中显著降低，提示电刺激时神经递质对电刺激产生氯的分泌有刺激作用。阿托品将神经诱发的分泌反应降低到对照组的35%。用酚妥拉明或育亨宾阻断α-2-肾上腺素受体，或用灯盏花素阻止去甲肾上腺素的释放，增强了阿托品抵抗部分的反应，并消除了刺激后电流的升高。神经诱发反应不受哌唑嗪或心得安的影响。在粘膜下神经丛和肌间神经丛的神经纤维中检测到儿茶酚胺免疫反应，而在两者的细胞体中均未检测到儿茶酚胺免疫反应。结果提示，电刺激地鼠空肠可引起由乙酰胆碱和其他分泌递质(S)介导的氯离子分泌，同时被粘膜肾上腺素能纤维释放的去甲肾上腺素所抑制。
The role of norepinephrine in the mucosal response to neural stimulation was examined in the ground squirrel jejunum. Electrical field stimulation of jejunal sheets in flux chambers evoked a tetrodotoxin-sensitive increase in short-circuit current (42±6μA/cm2) that declined during the stimulus period, followed by a second rise in current after the stimulus was terminated. The initial increase in current was inhibited by bumetanide and significantly reduced in chloride-free solutions, suggesting neurotransmitter stimulation of electrogenic chloride secretion during electrical stimulation. Atropine reduced the neurally evoked secretory response to 35% of control values. Blockade ofα2-adrenoceptors with phentolamine or yohimbine, or prevention of norepinephrine release with bretylium enhanced the atropine-resistant portion of the response and abolished the post-stimulus rise in current. The neurally evoked response was not affected by prazosin or propranolol. Catecholamine immunoreactivity was detected in nerve fibers of submucosal and myenteric plexuses but none was found in cell bodies of either plexus. The results suggest that electrical stimulation of the ground squirrel jejunum evokes active chloride secretion that is mediated by acetylcholine and other secretory transmitter(s), and simultaneously inhibited by norepinephrine released from adrenergic fibers in the mucosa.