Neural regulation of in vitro giant contractions in the rat colon
Neural regulation of in vitro giant contractions in the rat colon
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DOI：
10.1152/ajpgi.2001.281.1.g275
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发表时间：
2001-07-01
影响因子：
4.5
通讯作者：
Sarna, SK
中科院分区：
文献类型：
--
作者：
Gonzalez, A;Sarna, SK
大鼠中结肠在体外自发产生有规律的巨大收缩。我们研究了神经体液和细胞内调节这些收缩在一个标准的肌肉浴。在条和单个平滑肌细胞中测量cGMP含量。环形肌条产生自发GC。河豚毒素（TTX）、ω-芋螺毒素、N-ω-硝基-L-精氨酸（L-NNA）和多巴胺D-1受体拮抗剂Sch-23390显著增加了它们的振幅和频率。GC不受六甲双铵、阿托品和肾上腺素能（5-HT 1 - 4）、组胺能（H1 - 2）和速激肽能（NK 1 - 2）受体拮抗剂的影响，但受NK 3受体拮抗剂的增强。鸟苷酸环化酶抑制剂1H-[1，2，4] oxidazolo [4，3-a] quinoxalin-1-one（ODQ）也能增强GC，其程度与TTX和L-NNA相同，三种药物中的每一种都能阻止其他药物的作用。电场刺激、S-亚硝基-N-乙酰基-青霉胺和8-溴-cGMP可消除GC。BAY-K-8644和apamin增强GC，但它们被D-600消除。TTX、L-NNA或ODQ可降低平滑肌条中的cGMP含量，但这些处理对酶促分离的单个平滑肌细胞的cGMP含量没有影响。我们的结论是，自发收缩大鼠结肠肌条不是由胆碱能，胆碱能，或组胺能输入。肠神经元组成性释放一氧化氮维持结肠平滑肌cGMP合成，抑制体外自发性GC。
The rat middle colon spontaneously generates regularly occurring giant contractions (GCs) in vitro. We investigated the neurohumoral and intracellular regulation of these contractions in a standard muscle bath. cGMP content was measured in strips and single smooth muscle cells. The circular muscle strips generated spontaneous GCs. Their amplitude and frequency were significantly increased by tetrodotoxin (TTX), omega -conotoxin, N-omega-nitro-L-arginine (L-NNA), and the dopamine D-1 receptor antagonist Sch-23390. The GCs were unaffected by hexamethonium, atropine, and antagonists of serotonergic (5-HT1-4), histaminergic (H1-2), and tachykininergic (NK1-2) receptors but enhanced by NK3 receptor antagonism. The guanylate cyclase inhibitor 1H-[1,2,4]oxidiazolo[4,3-a] quinoxalin-1-one (ODQ) also enhanced GCs to the same extent as TTX and L-NNA, and each of the three agents prevented the effects of the others. GCs were abolished by electrical field stimulation, S-nitroso-N-acetyl-penicillamine, and 8-bromo-cGMP. BAY-K-8644 and apamin enhanced the GCs, but they were abolished by D-600. Basal cGMP content in strips was decreased by TTX, L-NNA, or ODQ, but these treatments had no effect on cGMP content of enzymatically dissociated single smooth muscle cells. We conclude that spontaneous contractions in the rat colonic muscle strips are not generated by cholinergic, serotonergic, or histaminergic input. Constitutive release of nitric oxide from enteric neurons sustains cGMP synthesis in the colonic smooth muscle to suppress spontaneous in vitro GCs.