Fractionated irradiation alters enteric neuroendocrine products.
Fractionated irradiation alters enteric neuroendocrine products.
复制标题
分段照射会改变肠道神经内分泌产物。
DOI：
10.1007/bf02212690
复制
发表时间：
1995
影响因子：
3.1
通讯作者：
Moulder,JE
中科院分区：
文献类型：
--
作者：
Otterson,MF;Koch,TR;Zhang,Z;Leming,SC;Moulder,JE
辐射深刻地改变了小肠和结肠的收缩活动。我们推测，肠道的某些运动改变可能继发于对平滑肌的神经输入受损或肠道内分泌肽的异常释放。对6只正常对照和6只接受1500cGy6次等分250cGy6次照射的狗的胃肠内分泌细胞内的肽能神经、胆碱能神经和内分泌细胞的产物密度进行了估计。对粘膜下层(MS)和外肌层(ME)的组织标本进行胆碱乙酰转移酶、乙酰胆碱酯酶、血管活性肠肽(VIP)、P物质(SP)、YY(PYY)和胃动素的测定。组织样本取自十二指肠、空肠、回肠、近端和远端结肠。此外，在接受1500cGy射线照射前和给药期间，用仪器记录上肠道收缩活动的四只狗分别测定了血清胃动素和PYY的水平。胆碱乙酰转移酶活性评估的内源性胆碱能活性没有变化，而远端小肠和结肠的MS层的乙酰胆碱酯酶活性增加。VIP在空肠和近端结肠的MS层以及ME层、空肠和回肠均有增加。相反，P物质在空肠和近端结肠的MS层以及空肠和回肠的ME层增加。放射暴露后十二指肠和空肠胃动素水平显著降低，而血清胃动素水平继续以移行运动复合体下降的峰值水平循环。照射后大鼠结肠PYY无明显变化，但血清PYY水平下降。神经元合成的增加和神经递质释放的抑制是VIP、P物质和乙酰胆碱酯酶组织浓度升高的潜在原因。肠道内分泌细胞对辐射的敏感性似乎存在差异。肠道调节肽和胆碱能酶活性的变化随分次剂量的腹部照射而发生，而相同的照射计划会使犬的小肠和结肠运动活动发生显著变化。因此，收缩事件的改变很可能是由肠道神经内分泌产物的变化引起的。
Radiation profoundly alters the contractile activity of the small intestine and colon. We hypothesized that some motor changes of the gut might be secondary to impaired neural input to smooth muscle or abnormal release of gut endocrine peptides. The density of products within peptidergic and cholinergic nerves and gut endocrine cells was estimated in six normal controls and six dogs who had received 1500 cGy in six equal fractions of 250 cGy. Choline acetyltransferase, acetylcholinesterase, vasoactive intestinal peptide (VIP), substance P, peptide YY (PYY), and motilin were measured in tissue specimens divided into mucosalsubmucosal (MS) and muscularis externa (ME) layers. Tissue samples were obtained from the duodenum, jejunum, ileum, and proximal and distal colon. In addition, serum levels of motilin and PYY were determined before and during the administration of 1500 cGy in four separate dogs instrumented to record upper gut contractile activity. Intrinsic cholinergic activity as estimated by choline acetyltransferase activity was unchanged, while acetylcholinesterase activity increased in the MS layers of distal small bowel and colon. VIP was increased in the MS layers of jejunum and proximal colon as well as in the ME layers the jejunum and ileum. By contrast, substance P increased in the jejunal and proximal colonic MS layers and in the ME layers of the jejunum and ileum. Duodenal and jejunal motilin levels markedly decreased after radiation exposure, while serum motilin levels continued to cycle at a decreased peak level with migrating motor complexes. Colonic PYY remained unchanged but serum PYY levels decreased after irradiation. Increased neuronal synthesis and inhibition of neurotransmitter release are potential explanations for elevated tissue concentrations of VIP, substance P, and acetylcholinesterase. There appeared to be differences in the sensitivity of gut endocrine cells to irradiation. Changes in gut regulatory peptides and cholinergic enzyme activity occur with fractionated doses of abdominal irradiation, while the same schedule of irradiation produces striking changes in the canine small intestinal and colonic motor activity. It is therefore likely that alterations of contractile events may be produced by changes in gut neuroendocrine products.