γ—氨基丁酸（GABA）对离体大鼠卵巢颗粒细胞孕酮分泌的影响

本文观察了ＧＡＢＡ对大鼠分散颗粒细胞生孕酮的影响。结果表明：当ＧＡＢＡ浓度为１０＾－＾６ｍｏｌ／Ｌ时明显促进颗粒细胞基础孕酮分泌（Ｐ＜０．０５）。但更高浓度（１０＾－＾５ｍｏｌ／Ｌ）时则表现抑制ＨＣＧ刺激孕酮生成的效应（Ｐ＜０．０２）。提示颗粒细胞的激素分泌功能可能受到ＧＡＢＡ的调控。     

B型γ—氨基丁酸受体研究进展

ＧＡＢＡＢ受体是近年来新发现的ＧＡＢＡ受体亚型。它的活化在突触后膜增加Ｋ＾＋电导,引起长时程晚抑制性突触后电位;在突触前膜则抑制Ｃａ＾２＋电导,使兴奋性或抑制性递质的释放减少,该受体活动对机体的镇痛、肌肉痉挛、癫痫的发作等生理和病理生理过程都有重要的影响。     

抗胃酸分泌物对胃内菌群的影响

收集４０例内镜确诊为胃十二指汤溃疡病人,随机分成两组,分别予泰胃美、奥美拉唑口服;干服药后分别行胃检查,并抽吸胃液行需氧菌、厌氧菌及真菌培养。结果示：胃液细菌量及硝酸盐还原菌量与胃液ＰＨ值呈正相关。     

促胰液素和生长抑素经血管灌流大鼠离体胃抑制胃酸分泌

本工作利用血管灌流离体大鼠胃研究促胰液素和生长抑素对泌酸的影响及其与内源性前列腺素E(PGE)和前列环素(PGI_2)释放的关系。结果表明:(1)促胰液素和生长抑素都能有效地抑制五肽胃泌素(G_5)促进胃酸分泌的作用,消炎病可翻转这种抑制作用。(2)促胰液素能显著促进PGE和PGI_2代谢产物6-酮-前列腺素F_(1α)(6-Keto-PGF_(1α))释放;生长抑素只能促进FGE释放。消炎痛分别阻断促胰液素对PGE和6-keto-PGF_(1α)释放及生长抑素对PGE释放的促进作用。上述结果提示:(1)促胰液素的抑酸效应由促进PGI_2和PGE释放介导;(2)生长抑素的抑酸效应通过促进PGE释放介导。     

杀虫剂分子靶标:γ-氨基丁酸A型受体(二)

4与GABAA受体变异有关的神经不敏感性抗性机理多氯环烷烃类杀虫剂的长期使用,选择了大量的抗性害虫种群。已报道的504种抗性害虫中,该类杀虫剂的抗性种群占57．7％,共291种[24]。神经不敏感性是该类杀虫剂最重要的抗性机制之一,神经敏感性降低单个抗性机制即可使黑尾果蝇对狄氏剂产生4270倍的高抗性[19]神经不敏感性抗性机制的分子机理研究主要集中在两个方面：GABAA受体数目的变异和受体的质变。Matsumra（1987）等[25]报道抗环戊二烯类的蜚蠊品系受体密度显著减少,与二氢苦毒宁的亲和力仅为敏感品系的1/10Tauaha（1987）[26]的…     

γ-氨基丁酸B型受体(GABABR)研究最新进展

有两种类型的GABA受体,一种是离子通道型的受体,GABA_AR和GABA_CR,这两者都是氯离子通道;另外一种是代谢型的受体——GABA_BR。GABA_BR的大部分生理功能都与它通过G蛋白对电压敏感型钙通道(主要是N,P/Q,L-型)和内向补偿性钾通道(Kir)的调节有关。在突触前膜,     

脑室注射组胺H1受体激动剂对大鼠胃酸分泌的作用机制

本文对中枢注射ＰＥＡ抑制胃酸分泌的作用机制进行分析。雄性Ｗｉｓｔａｒ大鼠,重２００－３００ｇ,用３７（生理盐水通过恒流泵进行连续胃灌流。第三脑室给药,观察其对五促胃液素（１６０μｇ／ｋｇ,ｓ．ｃ．）诱导的胃酸分泌的影响。结果如下：（１）预先注射纳洛酮２．５μｇ可阻断１０μｇＰＥＡ的中枢抑酸效应;（２）双侧膈下迷走神经切除可翻转ＰＥＡ（５－２０μｇ）的抑酸效应,且有量效关系;双侧肾上腺摘除对ＰＥＡ中     

白介素-1β对壁细胞酸分泌等胃功能的主要作用及机制

白介素（IL）－1β是已知具有胃细胞保护性,抗溃疡,抗分泌和延迟胃排空的最强力因子,它通过刺激胃内前列腺素合成而产生作用。IL－1β通过多种通路抑制培养壁细胞的酸分泌,该抑制发生于后受体水平。IL－1β对分泌酸的壁细胞,和分泌组胺的ECL细胞二者具有阻滞作用。壁细胞表达IL－1受体。IL－1β抑制卡马可和胃泌素刺激的壁细胞酸分泌作用,对组胺刺激也有一定作用。HP感染导致浸润的胃粘膜炎症细胞释放包括IL－1β的细胞因子。IL－1β可通过其对ECL细胞分泌组胺活性的抑制,相应地介导酸分泌的抑制。     

铃蟾肽(Bombesin)对离体灌流大鼠胃的胃泌素、生长抑素、胰升糖素及胃酸释放的影响

本研究用离体大鼠胃灌流技术来观察铃蟾肽对胃-肠激素及胃酸分泌的影响。2×10~(?)mol/L铃蟾肽以0.3ml/min速度作动脉内输注,可刺激胃酸的分泌,自2.50±0.05×10~(-1)增至5.50±1.50×10~(-1)mEq/min,但与外源性五肽胃泌素无协同作用。铃蟾肽引起两次性的门脉中胃泌索及生长抑素的释放,但抑制胰升糖素释放。这三种激素的基础释放率分别为:胃泌素62±8pg,生长抑素5.9±1.1ng,胰升糖素0.40±0.03ng/min;2×10~(-8)mol/L铃蟾肽以0.3ml/min作动脉内输注,胃泌素及生长抑素的峰值分别为1,000±20pg及12.2±2.0ng/min,胰升糖素的最低值为0.17±0.05ng/min,三种激素的反应均与铃蟾肽的浓度成正比。在胃腔流出液中也可测到上述三种激素,但量要少得多。     

神经介质C对促胃液素分泌的影响

采用带血管灌流的离体大鼠胃模型,就铃蟾肽类肽能神经介质Ｃ（ＮＭＣ）对促胃液素分泌的影响及其与胆碱能神经的关系,以及铃蟾肽受体拮抗剂（ＢＮ－Ａｎｔ）Ｄ－Ｐｈｅ~６－ＢＮ（６－１３）ＯＭｅ对ＮＭＣ诱导的促胃液素分泌的影响等问题进行探讨。实验结果表明,ＮＭＣ可明显刺激大鼠胃分泌促胃液素（从基础的５５０±１２６ｐｇ／１０ｍｉｎ增加到刺激时的１０６０±１８０ｐｇ／１０ｍｉｎ）,与对照组或自身基础状态比较,差异非常显著（Ｐ＜０．０１）;此效应（净增量）被Ｄ－Ｐｈｅ~６－ＢＮ（６－１３）ＯＭｅ完全消除或被阿托品抵消约６０％（Ｐ＜０．０１）。本实验结果证实,铃蟾肽类肽能神经递质ＮＭＣ是促胃液素分泌的强刺激剂;新近问世的ＢＮ－ＡｎｔＤ－Ｐｈｅ~６－ＢＮ（６－１３）ＯＭｅ具有高效拮抗ＮＭＣ刺激促胃液素分泌的作用;同时揭示,ＮＭＣ的作用机制不仅直接对胃Ｇ细胞、而且还可能通过影响胆碱能神经而发挥效应。     

IN VITRO PROTEIN SYNTHESIS ON FREE POLYRIBOSOMES ISOLATED FROM THE DEVELOPING MOUSE BRAIN

Abstract— Free polyribosomes were isolated at three ages (newborn, 2 weeks and 8 weeks) from the developing mouse brain. All three preparations were found to be highly polyribosomal in nature and were essentially identical with respect to their chemical composition and sedimentation properties. An estimate of the sedimentation coefficients of the first seven members of these polysome preparations yielded S °_20,w values of 76, 114, 146, 174, 196, 217 and 236. All three preparations were found to be very active when employed in in vitro protein synthesizing systems. An age-dependent response to the concentration of K⁺ was observed in the activities of the in vitro protein synthesizing systems. Optical K⁺ concentrations for the 0, 2 and 8 week old systems were 30, 50 and 65 mm, respectively. No such age dependence was observed when NH⁺₄ was used as the sole monovalent cation, with all systems exhibiting maximal activity at 50mm-NH⁺₄. The highest in uitro activities were consistently observed (at all three ages) when NNH⁺₄ was employed as the sole monovalent cation. Under optimal conditions, the newborn in vitro protein synthesizing system was observed to be approx 40% as active as either the 2 week or the 8 week systems which were equivalent in activity. The reduced activity of the newborn system appeared to be a function of both the polyribosomal and pH 5 enzyme preparations.     

乙醇对着床前小鼠胚胎体外发育的影响

用含不同浓度乙醇的Whitten氏培养液对小鼠2细胞、4细胞、8细胞和桑椹期胚胎分别进行体外培养,研究了乙醇对小鼠不同发育时期胚胎体外发育的影响。首先利用含0、0．1％、0．5％、1．0％、1．5％、2．0％、3．0％、5．0％和10．0％乙醇的Whitten氏培养液对2细胞胚胎进行培养,发现小鼠2细胞胚胎对培养液中乙醇浓度的耐受极限在1．5％左右。然后又用含1％和3％乙醇的Whitten氏培养液分别对小鼠2细胞、4细胞、8细胞和桑椹期胚胎进行培养。结果发现：含1％乙醇的培养液对于8细胞胚胎和桑椹胚的囊胚形成有促进作用,而在2细胞和4细胞胚胎中则影响不明显。3％乙醇则对各期胚胎均有不同程度的抑制作用,但随着胚胎发育其对乙醇的耐受力逐渐增强。     

THE IN VITRO SECRETION OF GROWTH REGULATORS BY ISOLATED CALLUS TISSUES

Tissues from a wide variety of plants were surface sterilized, isolated, and grown on different media. These isolated tissues were bioassayed for growth regulatory activity. The secretions from four of the 20 callus tissues inhibited the growth of Bacillus subtilis. An aseptic method for measuring the growth of Lemna was developed and used to detect inhibitory materials in medium which had supported the growth of five isolated callus tissues. In the seed (Lycopersicon esculentum) germination test five callus tissues had an inhibitory influence while two callus tissues showed a stimulatory effect. The study also included expressed juices and extracts of callus tissues which secreted regulatory materials. The expressed juice of five callus tissues contained materials which inhibited the growth of Lemna. Two expressed juices inhibited the growth of Bacillus subtilis. The water extract of two callus tissues inhibited the growth of Lemna. Fifty percent of the plants which have been reported to produce growth regulatory materials in nature also produced callus tissue which was capable of regulating growth of assay organisms.     

模拟微重力环境对昆明小鼠早期胚胎体外发育的影响

90年代初,美国航空航天局(NASA)设计研制出一种转壁式生物反应器(Rotating Wall Vessel Bioreactor,RWVB)。采用RWVB进行基地试验时,意外地发现离体细胞在RWVB中呈现高密度聚集,并形成较大的组织样结构。RWVB的核心结构是由两个同心圆柱体构成的旋转培养装置。将细胞与培养液置入内、外圆柱体之间,整个装置绕水平纵轴旋转,使培养物长时间保持悬浮状态。由于在旋转过程中     

CARDIAC MUSCLE CELL DIFFERENTIATION IN VITRO FROM A CHARACTERISTIC CELL LINE ISOLATED FROM MOUSE TERATOCARCINOMA

A characteristic in vitro cell line, SEBIII, was isolated from the mouse teratocarcinoma OTT6050. The SEBIII line, which maintains the structure of the embryoid body, grows rapidly in suspension culture. The chromosome number is near diploid. SEBIII cells, which were transferred to the peritoneal cavity of 129/Sv strain mice and left for one week, differentiated into several tissues in the subsequent in vitro culture. Of the tissues differentiated, the most dominant was the spontaneously pulsating muscle cells. Electron microscopic observations of these muscle cells revealed the presence of myofilaments with Z bands and intercalated disks. The nature of the factor(s) which induce the differentiation of SEBIII EB into cardiac muscle cells is discussed.     

五肽胃泌素和胆囊收缩素对血管灌流大鼠离体胃运动的影响

用血管灌流大鼠离体胃制备,研究五肽胃泌素(G5)和八肽胆囊收缩素(CCK8)对胃窦收缩运动的影响。结果表明:(1)血管灌流G5和CCK8都能显著兴奋胃窦收缩运动,并有量效关系;(2)抗胃泌素血清(1:100)可完全取消G5对胃窦收缩运动的兴奋作用;(3)CCK受体阻断剂双丁酰环磷鸟苷和抗CCK8血清(1:100)都能完全取消CCK8对胃窦收缩运动的兴奋作用;(4)M受体阻断剂阿托品能完全阻断G5对胃窦收缩运动的兴奋作用,部分阻断CCK8对胃窦收缩运动的兴奋作用。上述结果提示:(1)G5可特异性兴奋血管灌流大鼠胃窦收缩运动,该作用通过壁内胆碱能神经系统介导;(2)CCK8对血管灌流大鼠胃窦收缩运动亦有特异性兴奋作用,该作用只是部分与壁内胆碱能神经系统有关。