Maggi C A, Manzini S, Meli A
Am J Physiol. 1987 Apr;252(4 Pt 1):G447-57. doi: 10.1152/ajpgi.1987.252.4.G447.
The response of the rat proximal colon to distension and drugs that interfere with intrinsic and extrinsic nerves was investigated in vivo (urethan anesthesia) and in vitro. Saline distension induced the appearance of a cyclic contractile activity that was slightly inhibited by atropine (ATRO) and enhanced by physostigmine. Hexamethonium increased the distension-induced motor activity. Topical tetrodotoxin (TTX), lidocaine, or procaine produced an increase in motility of the proximal colon. Isolated segments of the proximal colon exhibit a high-amplitude phasic contractile activity that was increased by stretching, transiently inhibited by ATRO, unaffected by hexamethonium, and increased by TTX. The effects of both ATRO and TTX were more evident at high- than low-resting tone. In the presence of ATRO plus guanethidine, field stimulation of the isolated rat proximal colon suppressed the spontaneous contractile activity of the preparations. These findings indicate that, in the proximal colon of urethan-anesthetized rats, a tonic discharge of intramural nonadrenergic noncholinergic neurons suppresses the inherent myogenic contractile activity of the smooth muscle cells. Extrinsic nervous supply plays a subsidiary role in maintaining colonic motility.
在体内（氨基甲酸乙酯麻醉）和体外研究了大鼠近端结肠对扩张以及干扰内在和外在神经的药物的反应。盐水扩张诱导出现周期性收缩活动，该活动被阿托品（ATRO）轻微抑制并被毒扁豆碱增强。六甲铵增加了扩张诱导的运动活性。局部应用河豚毒素（TTX）、利多卡因或普鲁卡因使近端结肠的运动性增加。分离的近端结肠段表现出高振幅的相性收缩活动，该活动因拉伸而增加，被ATRO短暂抑制，不受六甲铵影响，并被TTX增加。ATRO和TTX的作用在高静息张力时比低静息张力时更明显。在ATRO加胍乙啶存在的情况下，对分离的大鼠近端结肠进行场刺激可抑制制剂的自发收缩活动。这些发现表明，在氨基甲酸乙酯麻醉的大鼠近端结肠中，壁内非肾上腺素能非胆碱能神经元的紧张性放电抑制平滑肌细胞固有的肌源性收缩活动。外在神经供应在维持结肠运动中起辅助作用。
