Abstract: Gastrointestinal hormones play important roles in regulating the digestive processes of small mammals,and
change with age. Substance P (SP)and somatostatin (SS)immunoreactive (IR)cells have opposite functions:the former promotes motility of the small intestine,and the latter acts as an inhibitor. To clarify age-dependent variation in distribution, as well as interactive features of SS and SP-IR cells along the gut in the Mongolian gerbils (Meriones unguiculatus), localization and comparison of both endocrine cells in the five portions (duodenum,small intestine,caecum,colon and rectum)of the gut in young,adult,and old gerbils were studied in winter using avidin-biotin-peroxidase complex immunohistochemical method. Both endocrine cells showed similar morphological features at different ages,being round,oval, shuttle,cone,or irregular in shape. The distribution of SS-IR cells tended to be narrower with increased age. SS-IR cells were found mainly in the duodenum and small intestine for all ages,and no immunoreactivity was found in the colon and the rectum in old gerbils. In the caecum,old gerbils showed higher densities of SS-IR cells than did young and adult gerbils, but no significant differences were found in any other portion of the gut. SP-IR cells displayed the highest densities in the colon,caecum,and rectum for young,adult and old gerbils,respectively,and no immunoreactivity was found in the colon and the rectum for adult gerbils. Different from SS-IR cells,SP-IR cells displayed significant differences for the each portion of gut for different ages. In conclusion,SS and SP-IR cells showed different distributions and age-dependent developmental features along the gut of Mongolian gerbils,which may be related to food quality and the opposing physiological functions of the two endocrine cells.

Key words: Age, Gut, Mongolian gerbil (Meriones unguiculatus), Somatostatin (SS), Substance P (SP)

摘要： 胃肠激素对调节小哺乳动物的消化功能具有重要作用。本文应用卵白素- 生物素- 过氧化物酶复合物(Avidin-biotin-peroxidase complex,ABC)免疫组织化学法,对冬季幼年、成年和老年长爪沙鼠肠道生长抑素(Somtostatin,SS)和P 物质(Substance P,SP)细胞进行了定位和比较。结果显示:不同年龄组两种内分泌细胞的形态学特征相似,呈圆形、椭圆形、梭形、锥形或不规则形。SS 细胞随年龄增加而分布范围缩小,主要分布于小肠和十二指肠,老年鼠的结肠和直肠无分布;盲肠段老年鼠高于幼年鼠和成年鼠,其余各段均无年龄差异。幼年鼠、成年鼠和老年鼠SP 细胞分别以结肠、盲肠和直肠密度为最高,成年鼠结肠和直肠无分布;肠道各段的密度均有年龄差异。这些结果表明,长爪沙鼠肠道SS 和SP 细胞的分布模式和发育特点有年龄差异,这可能与其生存环境的食物质量和两种内分泌细胞相互拮抗的消化生理功能有关。

关键词: 肠道, 生长抑素, P 物质, 年龄, 长爪沙鼠