生长抑素在齐口裂腹鱼消化道和脑中的定位

采用链霉亲合素一生物素过氧化物酶复合物免疫组化法研究生长抑素（Somatostatin，Som）在齐口裂腹鱼（Schizothorax prenanti）脑和消化道中的定位。在消化道中，口咽腔和食道为阴性反应；肠道有Som强阳性细胞，其中前肠密度最高，后肠最低。这些Som阳性细胞多分布于粘膜上皮，形态多样。肠道巨噬细胞呈Som强阳性反应。Som广泛分布于各脑区的神经元或神经纤维中，呈弱或强阳性反应，其中下丘脑下叶乳头体内Som阳性细胞密度最高，背嗅核、侧嗅核、原始纹体、视前核、内嗅沟旁、缰核下区、前丘脑核、前圆核、下丘脑中叶、下丘脑下叶、中脑室侧次之；小脑分子层和延脑VI、V核较少。端极和脑上腺有阳性神经纤维。这说明Som在肠道中的分布与该鱼食性、消化道结构和功能密切相关；Som在下丘脑中的分布特点为鱼类GH调控提供了形态学证据；Som在脑中广泛分布，提示可能作为一种神经递质或调质，发挥更为广泛的生理功能。

The distributive patterns of somatostatin in the digestive tract and brain of Schizothorax prenanti

In order to provide the morphological evidence for further researches in the regulation of digestive and neuroen-docrine activities, the distributive patterns of somatostatin (Som) in the digestive tract and brain of Schizothorax prenanti were studied. Strept avidin-biotin-peroxidase complex (SABC) immunocytochemical method associated with image analysis was used to observe Sore positive reactions in the different parts of Schizothorax prenanti's digestive tract and brain. There was no Som-positive reaction in the oropharyneal cavity and esophagus. Sore-positive cells with strong inten-sity were detected in the intestine, being the highest in the foregut(anterior segment: 58.20±10.97 number/mm2; poste-rior segment : 57.34±8.12 number/mm2) , medium in the midgut (46.17±12.99 number/mm2), and lower in the hind gut (anterior segment : 21.36±7.25 number/mm2; posterior segment : 13.64±4.24 number/mm2). Som-positive cells in the intestine were often distributed in the mucosal epithelium, presenting various kinds of forms such as ovoid, globu-lar, triangle, elongated or spindle-shaped aspects. The macrophages located in the intestine showed strong Som-positive reaction. Sore-positive reaction with weak or strong intensity was widely located in the neurons and nerve fibers of the brain. Reaching 1496.80±233.42 number/mm2, most of Som-positive cells were greatly distributed in the corpus mam-millare of inferior lobe in the hypothalamus. The number densities of Som-positive cells were medium in the dorsal olfactory (795.67±67.12 number/mm2) and lateral olfactory nuclei (740.52±87.38 number/mm2) , the primordial striatum (278.34±12.14 number/mm2), preoptic nucleus (283.60±89.13 number/mm2) , latero-rhinal fissure (299.36±78.61 number/mm2) , nucleus habenulae (346.63±83.12 number/mm2) , nucleus anterior thalami (173.31±23.54number/mm2) , nucleus prerotundus (199.57±32.80 number/mm2) , medium lobe of hypothalamus (101.31±21.45 number/mm2), Diverticulum of hypothalamus inferiors lobes (217.43±39.23 number/mm2) , the bilateral parts of the mesencephalon chamber (346.63±105.76 number/mm2) , lower in the molecular layer of cerebella valvula (91.48±11.14 number/mm2), the nuclei Ⅵ and Ⅴ of myelencephalon (nucleus Ⅵ: 47.27±15.76 number/mm2;nucleus Ⅴ: 78.78±13.79 number/mm3). In addition, Som-positive nerve fibers were observed in the lamina terminali and epiphy-sis. Our study has further confirmed that Som is a kind of brain-gut peptide. The distributive patterns of the Som-posi-tive cells in the digestive tract of Schizothorax prenanti are greatly related to its feeding habits, intestinal functions and structures as well, indicating that Som may play an important role in the modulation of the secretive and suppressive activi-ties of intestine. The distributive characteristics of Som-positive cells in the hypothalamus of Schizothorax prenanti provide the morphorlogieal evidence for the regulation of GH in the fish. Som is widely distributed in the different parts of the brain, suggesting that Som not only plays a role in the regulation of the physiological activities in the hypothalamus-hy-pophysial axis, but also has wide functions as a nervous transmitter, or regulator by affecting different target cells.