BROWNLEE G, HARRY J
Br J Pharmacol Chemother. 1963 Dec;21(3):544-54. doi: 10.1111/j.1476-5381.1963.tb02022.x.
A circular and a longitudinal muscle strip were prepared from adjacent parts of a guinea-pig ileum and a direct pharmacological comparison made under identical conditions. The longitudinal preparation was sensitive to acetylcholine, methacholine, carbachol, 5-hydroxytryptamine, histamine and nicotine, while the circular preparation was insensitive to 5-hydroxytryptamine, histamine and nicotine, and responded to the choline esters only in high concentrations. Incubation of the preparations with the anticholinesterase, mipafox (NN-diisopropylphosphodiamidic fluoride), sensitized both preparations to the action of acetylcholine; potentiation of the contraction of the longitudinal muscle was 16-times; that of the circular one 4,000-times. The longitudinal muscle was more sensitive than the circular muscle to acetylcholine whether both were treated with mipafox or not. Bradykinin and substance P both stimulated the longitudinal but not the circular muscle, an effect not modified after mipafox. Hyoscine antagonized the responses of the circular muscle strip, treated with mipafox, to acetylcholine and to histamine, but on the longitudinal muscle strip the response to histamine was not affected, the response to acetylcholine being competitively antagonized. Morphine, in the same concentrations on both circular and longitudinal muscle strips, antagonized the stimulant actions of nicotine and to a lesser extent of 5-hydroxytryptamine, but the responses to histamine on the longitudinal muscle strip were not antagonized by morphine which was in contrast to its action on the circular muscle strip. These observations showed that the main differences in the responses of the circular and longitudinal muscle of the guinea-pig ileum to drugs were in the intrinsic properties of the smooth muscle cells. In addition cholinesterase may protect the circular muscle cells. Finally the circular muscle strip preparation proved to be a useful tool to study the action of drugs on the nervous plexuses of the ileum of the guinea-pig.
从豚鼠回肠相邻部位制备环形和纵行肌条，并在相同条件下进行直接药理学比较。纵行肌条对乙酰胆碱、醋甲胆碱、卡巴胆碱、5-羟色胺、组胺和尼古丁敏感，而环形肌条对5-羟色胺、组胺和尼古丁不敏感，仅在高浓度时对胆碱酯类有反应。用抗胆碱酯酶米帕明（NN-二异丙基磷二酰胺氟化物）孵育这些肌条，可使两者对乙酰胆碱的作用敏感化；纵行肌收缩增强16倍，环形肌增强4000倍。无论是否用米帕明处理，纵行肌对乙酰胆碱的敏感性均高于环形肌。缓激肽和P物质均刺激纵行肌而非环形肌，米帕明处理后此效应无改变。东莨菪碱拮抗经米帕明处理的环形肌条对乙酰胆碱和组胺的反应，但对纵行肌条，对组胺的反应不受影响，对乙酰胆碱的反应则被竞争性拮抗。吗啡在相同浓度下作用于环形和纵行肌条时，拮抗尼古丁的兴奋作用，对5-羟色胺的拮抗作用较弱，但对纵行肌条对组胺的反应无拮抗作用，这与它对环形肌条的作用相反。这些观察结果表明，豚鼠回肠环形肌和纵行肌对药物反应的主要差异在于平滑肌细胞的内在特性。此外，胆碱酯酶可能对环形肌细胞起保护作用。最后，环形肌条制备被证明是研究药物对豚鼠回肠神经丛作用的有用工具。
