Speakman C T, Hoyle C H, Kamm M M, Henry M M, Nicholls R J, Burnstock G
Sir Alan Parks Physiology Unit, St. Mark's Hospital, London, UK.
Dig Dis Sci. 1993 Nov;38(11):1961-9. doi: 10.1007/BF01297070.
Physiological and histological studies have shown that the internal and sphincter is abnormal in idiopathic fecal incontinence. We have recently demonstrated that the in vitro contractile response of the internal anal sphincter to the sympathetic neurotransmitter noradrenaline is decreased in incontinence. In this study we have further defined this reduced sensitivity and provided more information about the intrinsic innervation in both the normal and the incontinent sphincter muscle. Muscle strips from 12 incontinent patients undergoing post and repair and from 11 controls undergoing rectal excision for low rectal carcinoma were studied. Responses to noradrenaline were recorded initially alone and then in the presence of phentolamine, an alpha-adrenoceptor blocker. In the presence of phentolamine, noradrenaline caused relaxation: there was no significant difference in the relaxation-response curves and the EC50 was the same in the two groups. These results demonstrate that the previously documented reduced sensitivity to noradrenaline is due to an altered sensitivity of the alpha-adrenoceptors. Electrical field stimulation produced relaxations in all muscle strips, but only in the controls was the magnitude of the relaxation significantly increased in the presence of phentolamine. This indicates that there is an alpha-adrenergic excitatory component of the response to electrical field stimulation of the intramural nerves, which was present in tissues from control patients but which was absent in tissues from patients with idiopathic fecal incontinence.
生理学和组织学研究表明，特发性大便失禁患者的内括约肌存在异常。我们最近证实，大便失禁患者的肛门内括约肌对交感神经递质去甲肾上腺素的体外收缩反应降低。在本研究中，我们进一步明确了这种敏感性降低的情况，并提供了更多关于正常和失禁括约肌固有神经支配的信息。研究了12例接受后路修复的大便失禁患者和11例因低位直肠癌接受直肠切除的对照患者的肌肉条。最初单独记录对去甲肾上腺素的反应，然后在存在α-肾上腺素能受体阻滞剂酚妥拉明的情况下记录反应。在酚妥拉明存在的情况下，去甲肾上腺素引起松弛：两组的松弛反应曲线无显著差异，EC50相同。这些结果表明，先前记录的对去甲肾上腺素敏感性降低是由于α-肾上腺素能受体敏感性改变所致。电场刺激使所有肌肉条松弛，但只有对照组在酚妥拉明存在时松弛幅度显著增加。这表明，对壁内神经电场刺激的反应存在α-肾上腺素能兴奋成分，该成分存在于对照患者的组织中，但在特发性大便失禁患者的组织中不存在。
