脑室注射脑啡肽和纳洛酮对北京鸭胃酸分泌的影响

本实验观察了第三脑室注射甲硫氨酸脑啡肽和阿片受体阻断剂纳洛酮对北京鸭胃酸分泌的影响,结果表明：（１）将５μｌ脑啡肽（０．０７５ｇ／Ｌ）注入脑室后,北京鸭胃酸分泌明显抑制,且注药后２０ｍｉｎ抑制作用最为显著,（２）预先注射阿片受体阻断剂纳洛酮后,再注射同样剂量的脑啡肽,抑制胃酸分泌的现象消失,结果提示,脑室注射脑啡肽对胃酸分泌有抑制作用,此作用是通过作用于阿片受体而实现的。     

Corticotropin-releasing factor receptors in rat forebrain: autoradiographic identification

Corticotropin-releasing factor (CRF) receptors were identified in rat forebrain by autoradiography with an iodine-125-labeled analog of ovine CRF substituted with norleucine and tyrosine at amino acid residues 21 and 32, respectively. High-affinity receptors for CRF were found in discrete areas of rat forebrain, including laminae I and IV of the neocortex, the external layer of the medium eminence, the lateral nucleus of the amygdala, and the striatum. These results are consistent with earlier findings on the immunohistochemical distribution of CRF and suggest that endogenous CRF has a physiological role in regulating activity of the central nervous system.     

Synthetic competitive antagonists of corticotropin-releasing factor: effect on ACTH secretion in the rat

Polypeptide analogs of the known members of the corticotropin-releasing factor (CRF) family were synthesized and tested in vitro and in vivo for enhanced potency or competitive antagonism. Predictive methods and physicochemical measurements had suggested an internal secondary alpha-helical conformation spanning about 25 residues for at least three members of the CRF family. Maximization of alpha-helix-forming potential by amino acid substitutions from the native known sequences (rat/human and ovine CRF, sauvagine, and carp and sucker urotensin 1) led to the synthesis of an analog that was found to be more than twice as potent as either of the parent peptides in vitro. In contrast, certain amino-terminally shortened fragments, such as alpha-helical CRF or ovine CRF residues 8 to 41, 9 to 41, and 10 to 41, were found to be competitive inhibitors in vitro. Selected antagonists were examined and also found to be active in vivo.     

Electrophysiology of the elasmobranch stomach

A consequence of the recent study of the mechanism of gastric secretion has been the presumption, implicit (1) if not explicit (2), that the distinctive gastric transmucosal potential has a fundamental role in the formation of hydrochloric acid. The following report indicates that the isolated surviving elasmobranch gastric mucosa does secrete acid but, unlike that of other vertebrates, does so without developing a significant epithelial potential difference. The gastric transmembrane potential is neither necessary for hydrogen ion secretion nor is its generation a fundamental feature of the mechanism that leads to the formation of hydrochloric acid.     

Interleukin-1 stimulates the secretion of hypothalamic corticotropin-releasing factor

There is now evidence that the immune system, during times of infectious challenge, can stimulate the secretion of glucocorticoids, the adrenal steroids that mediate important aspects of the response to stress. Specifically, secretion of interleukin-1 (IL-1), a monocyte lymphokine secreted after infection, appears at least in part responsible for this effect. Glucocorticoids are secreted in response to a neuroendocrine cascade involving, first, the brain, then the pituitary, and finally the adrenal gland. In this report, human IL-1 is shown to activate the adrenocortical axis at the level of the brain, stimulating the release of the controlling hormone corticotropin-releasing factor (CRF) from the hypothalamus. Infusion of IL-1 induced a significant secretion of CRF into the circulation exiting the hypothalamus, whereas immunoneutralization of CRF blocked the stimulatory effect of IL-1 on glucocorticoid secretion. IL-1 appeared to have no acute direct stimulatory effects on the pituitary or adrenal components of this system. Furthermore, IL-1 did not cause a nonspecific release of other hypothalamic hormones. Thus, the lymphokine acts in a specific manner to activate the adrenocortical axis at the level of the brain; this effect appears to be unrelated to the known pyrogenic effects of IL-1 within the hypothalamus.     

复合酸化剂对断奶仔猪生长性能、营养物质表观消化率及相关理化指标的影响

为探讨酸化剂对早期断奶仔猪生长影响,选择平均体重相近(7.5±0.15)kg断奶仔猪90头,随机分为3个处理,每个处理6个重复,每个重复5头。试验1、2组日粮分别在对照组基础上添加0.2%、0.4%酸化剂。结果表明:与对照组比较,试验1、2组仔猪日增重分别提高0.75%、11.39%(P<0.05),料肉比降低了4.27%(P<0.05)和3.40%。添加酸化剂提高了胃蛋白酶、十二指肠内容物中脂肪酶、淀粉酶活性,显著降低胃内容物pH值,对肠道pH影响不显著。表明在早期断奶仔猪饲粮中添加复合酸化剂可刺激胃酸和胃蛋白酶分泌,提高十二指肠消化酶活性,从而提高仔猪营养物质消化率和生长性能。     

Effects of Supplemental Histamine on Gastric Acid Secretion, Digestive Enzyme Activities, Intestinal Microfloral of Early Weaned Piglets

Two experiments were conducted to study the effect of supplemental histamine in the diet ofearly-weaned piglets. In experiment A, 24 cross bred piglets with an average body weight of 6.10±0.40 kg,weaned at the age of 28 days, were divided into four groups, fed with basal diet of low dietary copper without(control) or with supplemental histamine at 60, 120, 180 μg kg-1 BW. During the two weeks and the thirdweek after weaning, ADG(average daily gain) of piglets were increased by 15.8% (P＜0.05), 9.5% (P＜0.10) by addition of 60 μg kg-1BW histamine, but decreased by addition of 180 μg kg-1BW histamine, whichalso increased the amount of E. coli in colon and the scour incidence. The secretion of gastric acid and pepsinwere improved by both dose of supplemental histamine (60, 180 pg kg-1BW) and gastric digesta pH were de-creased by both. Addition of 60 μg kg-1 BW histamine improved the activities of trypsin, amylase in duodelumdigesta. In experiment B, 12 cross bred piglets with an average body weight of 6.85±0.35 kg, weaned at theage of 28 days, were divided into two groups, fed with basal diet of high dietary copper without (control) orwith supplemental 60 μg kg-1 BW histamine. During the two weeks and the third week after weaning, ADG ofpiglets were increased by 9.8% (P＜0.05), 7.0% (P＜0.10). The secretion of gastric acid, activities oftrypsin and amylase in duodelum digesta, were also improved by addition of 60 μg kg-1 BW histamine. The re-sults showed that addition of histamine (60 μg kg-1 BW) in early weaned piglets could increase the secretion ofgastric acid and pepsin, reduce gastric digesta pH and scour incidence, improve activities of trypsin, amylasein duodelum digesta, and the growing performance of early weaned piglets.     

Ontogeny of gastric acid secretion in the rat: evidence for multiple response systems

Gastric acid secretion has been thought to depend on histamine stimulation of the parietal cell. However, in the 2-week-old rat neither exogenous histamine nor the H-2 receptor agonist impromidine stimulates acid secretion, whereas pentagastrin and the cholinergic agent bethanechol are potent stimuli. At this age, the effect of pentagastrin in acid secretion is not blocked by the H-2 receptor antagonist cimetidine, nor is it potentiated by impromidine. These data suggest that, in the rat pup, the acid secretory response to pentagastrin and cholinergic agents occurs before the histamine-mediated system is functional and operates independently of the actions of histamine.     

Changes in the cell membranes of the bullfrog gastric mucosa with Acid secretion

The effective area, resistance, and configuration of the apical and basolateral cell membranes of the bullfrog gastric mucosa were studied as a function of acid secretion rate, by alternating-current impedance methods. The drop in transepithelial resistance with acid secretion is attributed to the great increase in apical membrane area (hence conductance) associated with tubulovesicles. There is no evidence of a change in basolateral membrane resistance or of apical membrane premeability per unit area.     

不同类型酸化剂对早期断奶仔猪胃酸分泌、免疫功能和抗氧化机能的影响

选择体重平均、(28±2)日龄断奶约克夏仔猪30头,随机分为5组,每组3个重复,研究饲料中添加酸化剂对早期断奶仔猪胃酸分泌、免疫功能和抗氧化机能的影响。对照组日粮为玉米-膨化大豆-豆粕型基础日粮,试验组日粮分别以0.02%黄霉素、1.5%柠檬酸、0.3%磷酸、1%复合酸等量替代基础日粮中的玉米。结果表明,添加酸化剂对早期断奶仔猪的胃酸分泌能力及免疫功能均无显著影响(P>0.05)。添加柠檬酸可显著提高断奶仔猪血清超氧化物歧化酶(SOD)的活性和总抗氧化能力(T-AOC)(P<0.05)。断奶两周内添加酸化剂效果优于断奶两周后。     

Expression of a cloned rat brain potassium channel in Xenopus oocytes

Potassium channels are ubiquitous membrane proteins with essential roles in nervous tissue, but little is known about the relation between their function and their molecular structure. A complementary DNA library was made from rat hippocampus, and a complementary DNA clone (RBK-1) was isolated. The predicted sequence of the 495-amino acid protein is homologous to potassium channel proteins encoded by the Shaker locus of Drosophila and differs by only three amino acids from the expected product of a mouse clone MBK-1. Messenger RNA transcribed from RBK-1 in vitro directed the expression of potassium channels when it was injected into Xenopus oocytes. The potassium current through the expressed channels resembles both the transient (or A) and the delayed rectifier currents reported in mammalian neurons and is sensitive to both 4-aminopyridine and tetraethylammonium.     

Corticotropin-releasing factor-producing neurons in the rat activated by interleukin-1

Intraperitoneal administration of human recombinant interleukin-1 (IL-1) to rats can increase blood levels of corticosterone and adrenocorticotropic hormone (ACTH). The route by which IL-1 affects pituitary-adrenal activity is unknown. That the IL-1-induced pituitary-adrenal activation involves an increased secretion of corticotropin-releasing factor (CRF) is indicated by three lines of evidence. First, immunoneutralization of CRF markedly attenuated the IL-1-induced increase of ACTH blood levels. Second, after blockade of fast axonal transport in hypothalamic neurons by colchicine, IL-1 administration decreased the CRF immunostaining in the median eminence, indicating an enhanced release of CRF in response to IL-1. Third, IL-1 did not stimulate ACTH release from primary cultures of anterior pituitary cells. These data further support the notion of the existence of an immunoregulatory feedback circuit between the immune system and the brain.     

Immunoreactive dynorphin-(1-8) and corticotropin- releasing factor in subpopulation of hypothalamic neurons

Immunoreactive corticotropin-releasing factor (CRF) and dynorphin-(I-8) were visualized in rat hypothalamus by immunohistofluorescence with specific antibodies. In brains from colchicine-treated, adrenalectomized rats, neuronal perikarya with immunoreactive CRF were observed in the paraventricular nucleus of the hypothalamus. The CRF occurred together with the dynorphin-(1-8). However, the CRF immunoreactivity occurred only in a subpopulation of the dynorphin-(1-8) immunoreactive cells. These findings suggest that there may be a functional interrelationship of CRF with dynorphin-related opioid peptides and provide further evidence that neurons may contain more than one bioactive substance.     

银莱汤对胃肠积热合并肺炎大鼠胃肠动力的作用及机制研究

目的 制作胃肠积热合并肺炎模型,观察银莱汤对胃肠积热合并肺炎大鼠胃排空及小肠推进率的影响,通过检测血清中胃饥饿素（Ghrelin）、NO含量变化,初步探讨银莱汤调节胃肠动力的具体机制。方法 将实验大鼠分为正常组、胃肠积热组、胃肠积热合并肺炎组和银莱汤治疗组共4组,每组10只。其中胃肠积热组、胃肠积热合并肺炎组和银莱汤治疗组给予高热量饲料喂养,并结合52%牛奶溶液灌胃的方法制作食积动物模型,且后2组采用0.5 mg/mL LPS吸入雾化处理,并予以生理盐水或银莱汤灌胃相应的干预。采集大鼠宏观表征,行胃排空和小肠推进实验,并用Elisa法测定各组大鼠血清中Ghrelin、NO含量。结果 与正常组相比,胃肠积热组大鼠的活动度较差,摄食量减少,体质量显著降低（P<0.05）;与胃肠积热合并肺炎组相比,银莱汤治疗组大鼠胃排空和小肠推进率明显增加（P<0.05）;与胃肠积热合并肺炎组相比,银莱汤治疗组大鼠血清的Ghrelin有所升高,且NO含量明显降低（P<0.05）。结论 胃肠积热和肺炎因素会影响胃肠道内相关激素的分泌,从而导致其胃排空和小肠推进率的异常,而银莱汤能够通过升高血清中Ghrelin含量,并能抑制NO的激素水平,来达到促进胃肠动力作用。     

Inhibition of adrenocorticotropic hormone secretion in the rat by immunoneutralization of corticotropin-releasing factor

Intravenous administration of rabbit antiserum to ovine corticotropin-releasing factor (CRF) markedly reduced the CRF-induced rise of plasma adrenocorticotropic hormone (ACTH) in intact nonstressed adult male rats while blocking more than 75 percent of the ACTH release observed in rats exposed to ether stress. Furthermore, antiserum to CRF significantly lowered ACTH levels in adrenalectomized animals. These results suggest that endogenous CRF plays a physiological role in regulating ACTH secretion.     

香猪采食前后胃液分泌与血浆胃泌素浓度的变化

在装置长久性隔离小胃和临时性颈静脉插管的香猪试验发现,动物在早晨饲喂前小胃胃液分泌量极少,甚至没有。饲喂后小胃胃液分泌量骤然升高,约３ｈ达到高峰。进食前胃液酸度很低,甚至可达ｐＨ６６。进食后胃液酸度显著升高,ｐＨ在１９左右。游离酸含量比结合酸高３倍,同时胃蛋白酶活性明显增强,可维持５～６ｈ。血浆胃泌素水平正常变动范围在１６７±７８５ｐｇ／ｍｌ,并受进食的影响,进食后１,３ｈ均出现高峰。     

果树断根铁素营养研究

 果树断根对铁的吸收是被动吸收 ,铁被吸收、运输的形态均为二价态 ,断根吸收的铁绝大部分被运往叶片。整根吸收的铁大部分淀积在根内。铁胁迫致苹果黄叶时进行根系输铁液能在较短时间内提高叶片叶绿素和铁的含量从而达到复绿的效果 ,在 Fe- citric acid、Fe- EDTA和 Fe- N3种铁肥中 ,Fe- N是适宜根系输液的铁肥品种 ,主干强力高压注射铁肥复绿较慢 ,叶面喷布效果不显著     

2味中药复方对大鼠胃黏膜损伤保护作用及血液指标的影响

[目的]观察2味中药复方(LWZY)抗大鼠胃黏膜损伤作用及对血液指标的影响。[方法]采用无水乙醇致大鼠胃黏膜损伤模型、阿司匹林致大鼠胃黏膜损伤模型、盐酸致大鼠胃黏膜损伤模型,预防性灌胃给药,以胃黏膜的损伤指数、凝血酶原时间(PT)、纤维蛋白原(FIB)、活化部分凝血活酶时间(APTT)、凝血酶时间(TT)为指标,评价2味中药复方药剂对各动物模型的抗胃黏膜损伤作用及对血液指标的影响。[结果]西米替丁及LWZY各给药组对阿司匹林大鼠胃黏膜损伤模型、盐酸大鼠胃黏膜损伤模型、无水乙醇大鼠胃黏膜损伤模型均有明显的保护作用,各给药组胃黏膜损伤指数均较模型组明显降低(P0.05;P0.01);无水乙醇模型中的血液值;LWZY组较模型组比较PT、FIB、APTT、TT值有明显降低(P0.05;P0.01),有统计学意义;盐酸模型中的血液值,模型组PT、FIB、APTT、TT值较正常组比较略有升高,LWZY组较模型组比较PT、FIB值有明显降低,但无统计学意义,而APTT、TT值有明显降低(P0.05;P0.01),有统计学意义;阿司匹林模型中的血液指标中模型组PT、FIB、APTT、TT值较正常组比较明显升高,LWZY组较模型组比较PT、FIB、APTT、TT值有明显降低(P0.05;P0.01),有统计学意义。[结论]LWZY对无水乙醇、阿司匹林、盐酸致大鼠胃黏膜损伤有明显的保护作用,并且有一定的体内促凝血作用,作用机制可能和凝血因子以及调节激素水平有关。     

Stress-induced inhibition of reproductive functions: role of endogenous corticotropin-releasing factor

In the adult castrated male rat, exposure to inescapable, intermittent electroshocks inhibited the pulsatile pattern of luteinizing hormone release and markedly lowered its plasma concentrations. The central administration of the corticotropin-releasing factor (CRF) antagonist alpha-helical ovine CRF residues 9 to 41 reversed the inhibitory action of stress. Neither its peripheral injection, nor the intraventricular injection of the inactive CRF analog des-Glu to Arg ovine CRF was effective. These results suggest that endogenous CRF may mediate some deleterious effects of noxious stimuli on reproduction.     

Activation of apical chloride channels in the gastric oxyntic cell

Oxyntic cells that retain distinct morphological polarity between apical and basolateral membranes were isolated from the gastric mucosa of the amphibian Necturus. Patch-clamp techniques were applied to these cells to identify apical membrane ion channels associated with hydrochloric acid secretion. A single class of voltage-dependent, inwardly rectifying chloride channels was observed in the apical membranes of both resting and stimulated (acid-secreting) oxyntic cells. Stimulation of the cells with dibutyryladenosine 3',5'-monophosphate and isobutylmethylxanthine increased channel open probability and simultaneously increased apical membrane surface area. This chloride channel is probably responsible for electrogenic chloride secretion by the gastric mucosa and may also participate in the fluid- and enzyme-secretory functions of the oxyntic cell, analogous to the chloride channels found in the apical membranes of other exocrine cells.