去甲肾上腺素在大鼠缰核引起的心血管效应及其机制

在乌拉坦麻醉的大鼠,研究了去甲肾上腺素(NE)在缰核(Hb)引起的心血管效应及其机制。Hb内微量注射NE使平均动脉压和心率呈剂量依赖性增加。用α受体阻断剂酚妥拉明预处理Hb,可明显减弱NE在Hb引起的心血管效应,但β受体阻断剂心得安或生理盐水不引起任何影响。Hb内微量注射海人酸使平均动脉压和心率明显增加,但Hb内微量注射利多卡因则不能引起明显的心血管效应。上述结果表明,Hb内NE在调节心血管活动中起重要作用,而这种效应可能是通过激活α受体使Hb兴奋的结果。     

NO—样松驰因子在大鼠止血带休克中的作用

为探讨NO-样松驰因子(NO-LRF)在休克中的效应及其病理生理意义,本工作在大鼠止血带休克(ToS)模型上发现离体灌流的主动脉环对去甲肾上腺素的反应性降低,组织cGMP含量增加。用NO前体L-精氨酸(L-Arg)或NO合成阻断剂L-NNA,可溶性乌苷酸环化酶抑制剂亚甲蓝灌流,分别增强或减轻ToS动物主动脉的上述变化,而且这些药物的作用不受血管内皮是否存在的影响。实验结果提示非内皮细胞源的NO-LRF是引起ToS动物血管低反应性的因素之一。体内实验表明 L-Arg治疗缓解,而L-NNA恶化ToS病程,提示NO-LRF可能参与机体的适应保护机制。     

豚鼠肠系膜下神经节细胞电活动与结肠运动的关系

在豚鼠肠系膜下神经节(IMG)及其支配的结肠段联合标本上,对IMG细胞内电位与肠段纵肌或环肌舒缩活动进行了同步记录。实验结果表明:(1)肠段预置张力为零时,约50％IMG细胞有自发的快兴奋性突触后电位(EPSP)活动,切断结肠神经或以筒箭毒(50μmol/L)灌流IMG后消失;(2)筒箭毒或低钙高镁溶液阻断神经节传递时,环肌节律性收缩幅度增大,节律变慢,但对纵肌节律性收缩无明显影响,(3)串刺激节前神经,在IMG细胞引起一串快EPSP或动作电位并常跟随迟慢的EPSP,同时,纵肌在0.1-0.2s潜伏期后出现迅速的、时程基本与动作电位串一致的舒张波,后者在筒箭毒灌流IMG后消失,而环肌运动可见舒张、舒张波延长或收缩波增大。结果提示:IMG不仅中继经典的胆碱能传出功能,还参与以胆碱能传递为中介的肠-肠反射,该反射活动的传出效应主要在于抑制环肌收缩。     

人子宫内膜纤蛋白溶酶元激活因子及其抑制因子的分布与调控

人子宫内膜中存在组织型(tPA)及尿激酶型(uPA)两类纤蛋白溶酶元激活因子,其含量在增殖期高于分泌期。本文应用免疫组织化学定位证实uPA及tPA两类抗原存在于子宫内膜的腺体细胞和间质细胞中。应用SDS-PAGE分高蛋白质,继而应用纤蛋白-琼脂糖铺盖技术测得离体培养下间质细胞仅释放tPA,腺体细胞仅释放uPA,但两种细胞均分泌PA的抑制因子(PAI)。培液中加入孕酮,明显抑制PA和刺激PAI生成。雌二醇作用与孕酮相反。某些肽类激素hCG、PRL、GnRH及cAMP作用基本与雌二醇相同。但福司克林(FK)则刺激间质、腺体两种细胞产生tPA及少量uPA,抑制PAI生成。本工作表明人子宫内膜中存在PA及PAI作用相反的酶,受激素调控,其生理意义尚待进一步探讨。     

下丘脑室旁核加压素能神经元参与电针刺激对实验性内脏痛的抑制

本实验采用内脏痛的实验模型,探讨室旁核中的加压素在针刺抑制内脏痛中的作用。实验结果如下:(1)大鼠在在射酒石酸锑钾(0.1％,10ml/kg,i.p.)后,出现可定量的扭体反应,能作为观察内脏痛的客观指标。(2)电针对内脏痛有抑制效应,即具有镇痛作用。(3)电刺激室旁核,能加强电针对内脏痛的抑制效应,损毁室旁核,则此抑制效应基本消失。(4)脑室注射加压素抗血清(14μl)或加压素拮抗剂[d(CH_2)_5Tyr(Me)-AVP,500ng/5μl]都能明显减弱电针的抑制效应。(5)腹腔注射加压素拮抗剂(10μg/kg),不能翻转电针的抑制效应。上述实验结果表明,下丘脑室旁核的加压素能神经元参与了电针刺激对实验性内脏痛的抑制。     

四氯化碳中毒对大鼠离体再生肝细胞钾离子外漏的影响

本工作用三种剂量四氯化碳(CCl_4,10,15和20mmol/L)损伤正常大鼠离体肝细胞,分别在5,10,15和20min测定细胞内K~+和GPT漏出量。实验观察到细胞内K~+和GPT漏出量与CCl_4染毒的剂量和时间有明显关系,而且K~+漏出量较GPT更能灵敏地反映细胞的损伤程度;用中等剂量CCl_4(15mmol/L)损伤离体再生肝细胞20min后,细胞内K~+漏出的变化百分数明显低于正常肝细胞。这些结果表明,大鼠离体再生肝细胞具有较强的抗CCl_4损伤作用,其机制可能与再生肝细胞膜稳定性较强有关。     

一个拖延了半个多世纪的研究课题的总结汇报

本文是汤佩松教授为北京植物生理学会1992年年会准备的发言稿,并以庆祝中国植物生理学会成立30周年。后“北京年会”因故未开,本刊应汤老要求按原样发表于此(并附英文摘要),以飨读者。     

Evolution of the expression of the Gld gene in the reproductive tract of Drosophila.

During the preadult development of Drosophila melanogaster, the GLD (glucose dehydrogenase) gene (Gld) is expressed in a variety of tissues, including the immature reproductive tract. At the adult stage the expression of Gld becomes largely restricted to the reproductive tract of males and females. We examined the expression of GLD in the adult reproductive tract of 50 species in the genus Drosophila, as well as in those of a few representative species from four other closely related genera. GLD exhibits considerable organ-specific diversity in the reproductive tract of males and females. Among these species, five male GLD phenotypes and six female GLD phenotypes were found. In contrast, the preadult expression of GLD in representative species from each distinct adult pattern type was determined and found to be highly conserved in both the immature reproductive tract and non-reproductive organs. Moreover, the set of reproductive organs that express GLD during preadult development is equivalent to the sum of the five male and six female adult GLD phenotypes. To initially define the contribution of cis- versus trans-acting factors responsible for differences in adult GLD expression between two of these species--D. melanogaster and D. pseudoobscura--we transferred the D. pseudoobscura Gld to the genome of D. melanogaster and investigated its expression. GLD expression patterns of these transformants displayed characteristics that are unique to both species, suggesting the presence of both cis- and trans-acting differences between these two species.     

Characterization of fall armyworm mitochondrial DNA (Lepidoptera: Noctuidae)

Mitochondrial DNA from the fall armyworm, Spodoptera frugiperda (J.E. Smith), was cloned and characterized using restriction enzyme mapping. Genome size is approximately 16.3 kilobase (Kb), consistent with that of most animals. Three fragments, 8.1 Kb, 6.2 Kb, and 2.0 Kb, were produced by digestion with restriction enzyme Xbal and cloned into a pUC19 vector. Twenty-nine restriction enzymes were used to generate a detailed physical restriction enzyme map of the three cloned fragments. These data represent the first detailed characterization of a lepidopteran mitochondrial genome. © 1992 Wiley-Liss, Inc.     

Gastric effects of thyrotropin-releasing hormone microinjected into the dorsal vagal nucleus in cats

We investigated the gastric acid secretory and motility responses to microinjection of thyrotropin-releasing hormone (TRH) into the dorsal motor nucleus of the vagus (DMV) in anesthetized cats. Gastric acid output was collected every 15 min through a gastric cannula after saline flush and titrated to pH 7.0. Antral and corpus contractions were continuously recorded by extraluminal force transducers. TRH dissolved in 200 nl of saline and microinjected unilaterally into the DMV induced a dose-dependent (50-200 ng) increase in gastric acid secretion. The acid secretory response began in the first 15 min collection and lasted 45 min. TRH frequently increased the force of contractions of the antrum and corpus within one minute of microinjection. The minimal effective dose for eliciting increased motility was lower than for inducing acid secretion. These results demonstrate that TRH acts in the DMV of cats to stimulate gastric acid secretion and contractions.