垂体后叶素对家兔尿分泌的影响

垂体后叶素引起抗利尿作用表现为三个时期。文献中对无尿期的形成看法各异。本文实验证明无尿期是在注药后输尿管下部二分之一处生理状态改变所致。以苯酚随机处理输尿管,提示垂体后叶素作用时可能有神经反射途径。最后的少尿期才是垂体后叶素的抗利尿作用。 垂体后叶素具有加压和抗利尿作用。在垂体后叶素抗利尿作用中。顺序出现无尿期、多尿期和少尿期三个阶段,并认为无尿期的出现是由于输尿管的痉挛引起的。但也有报告无尿期无尿除可能是输尿管痉挛外,还可能有其它原因。虽然这一内容被广泛在普通生理学实验课中采用,但其机制未见报导,各院校做法不尽相同,解释也有差异。本实验在于进一步探讨初期无尿的原因。     

冠脉康胶囊对心肌缺血缺氧动物模型的影响

摘要: 目的复制心肌缺血缺氧动物模型,观察冠脉康胶囊抗心肌缺血缺氧作用。方法采用大鼠舌下静脉注射 垂体后叶素诱发急性心肌缺血模型,观察各组注射垂体后叶素后不同时间段内心电图T 波高度变化; 应用密闭容 器造常压缺氧环境,观察冠脉康胶囊对小鼠耐缺氧能力。结果冠脉康胶囊能对抗垂体后叶素引起的T 波变化; 能延长常压缺氧条件下的小鼠存活时间。结论冠脉康胶囊具有抗心肌缺血作用,并具有耐常压缺氧能力。     

槭酮对抗大鼠急性心肌缺血和血栓形成的研究

目的 观察槭酮(槭叶草总黄酮)对垂体后叶素引起大鼠心电图S-T段变化的影响以及观察槭酮对血小板血栓形成的影响.方法 灌胃给药法.结果 中剂量和大剂量组具有一定对抗垂体后叶素引起的S-T段变化的作用,槭酮大剂量组具有较好的抗血小板血栓作用.结论 槭酮对大鼠缺血性心肌具有保护作用并可对抗血小板血栓的形成,具有一定抗血小板聚集作用.     

桂枝茯苓丸对垂体后叶素致大鼠急性心肌缺血的保护作用

目的:观察桂枝茯苓丸对垂体后叶素致大鼠心肌缺血的保护作用,为拓宽其临床应用提供科学依据.方法:腹腔注射垂体后叶素(25U/kg)建立大鼠心肌缺血模型,观察桂枝茯苓丸对心肌缺血大鼠血流动力学参数及心肌组织的影响.结果:桂枝茯苓丸能对抗垂体后叶素致心肌缺血大鼠血流动力学指标的异常,降低LVEDP、-LVdp/dtmax,升高+LVdp/dtmax,改善心脏舒缩功能;对心肌组织病理学检测表明药物能明显改善缺血心肌组织的病理损伤.结论:桂枝茯苓丸对垂体后叶素所致心肌缺血具有一定的保护作用.     

银杏叶制剂对大鼠心肌缺血的保护作用

目的:观察银杏叶片对大鼠急性缺血心肌的保护作用.方法:将大鼠随机分为正常对照组、银杏叶片组、消心痛组.灌胃5d后均静脉注射垂体后叶素造成心肌缺血损伤模型,观察三组大鼠心电图ST段偏移及心律失常的发生情况.结果:银杏叶片能明显缓解垂体后叶素所引起的心电图ST段变化(P<0.05),并能使大鼠心律失常的发生率显著下降(P<0.05).结论:银杏叶片对垂体后叶素所致急性缺血心肌具有保护作用.     

一口钟液保护实验性心肌缺血及耐缺氧作用的研究

目的探讨一口钟液对实验性心肌缺血的保护作用.方法采用小鼠常压耐缺氧试验和垂体后叶素诱发大鼠急性心肌缺血性试验.结果一口钟液能明显提高小鼠耐缺氧能力,能预防垂体后叶素诱发大鼠急性心肌缺血性心电图的变化.结论一口钟液对实验性心肌缺血有明显的保护作用.     

正常分娩产后出血中垂体后叶素不同用法的临床疗效比较

探讨正常分娩过程中垂体后叶素不同用法的效果。将100例符合纳入条件的正常分娩产妇随机分为两组,每组50例,胎盘娩出后,常规20U缩宫素加入5%葡萄糖液500m L中快速滴注,A组产妇予以垂体后叶素6U加入5%葡萄糖250mL液体中滴注,先快后慢(快速时20~40滴),宫缩好转后,可6滴/min,酌情根据需要选择滴注时长;B组产妇予以垂体后叶素6U经腹壁宫体注射。比较两组临床效果。结果 :两组产妇在产时出血量、产后24h出血量及其他宫缩抑制剂应用率上差异无统计学意义(P0.05);用药后两组的收缩压、舒张压、心率比较差异无统计学意义(P0.05),但A组收缩压及舒张压上升率、心率上升率较B组明显(P0.05))。正常分娩中,单纯宫体直接注射垂体后叶素即能达到良好的促宫缩、减少出血的目的;静脉滴注垂体后叶素,心血管反应明显,在低血容量或心功能不全、高血压等血流动力异常的产妇中应慎用,以免诱发心衰等不良反应。     

注射用复方荭草冻干粉针剂(FFHC)对垂体后叶素诱导大鼠急性心肌缺血的保护作用

目的观察注射用复方荭草冻干粉针剂(FFHC)对脑垂体后叶素诱导大鼠急性心肌缺血的保护作用.方法大鼠舌下静脉注射脑垂体后叶素诱导急性心肌缺血模型.以心电图J点位移、PR间期、Q-T间期以及其变化率为检测指标.结果 FFHC高、中剂量能明显对抗垂体后叶素引起的心电图T波、P-R间期和Q-T间期的变化.结论 FFHC对垂急性心肌缺血具有一定的保护作用.     

注射用复方荭草冻干粉针剂(FFHC)对垂体后叶素诱导大鼠急性心肌缺血的保护作用

目的观察注射用复方荭草冻干粉针剂(FFHC)对脑垂体后叶素诱导大鼠急性心肌缺血的保护作用.方法大鼠舌下静脉注射脑垂体后叶素诱导急性心肌缺血模型.以心电图J点位移、PR间期、Q-T间期以及其变化率为检测指标.结果 FFHC高、中剂量能明显对抗垂体后叶素引起的心电图T波、P-R间期和Q-T间期的变化.结论 FFHC对垂急性心肌缺血具有一定的保护作用.     

思他宁联合小剂量垂体后叶素治疗急性上消化道大出血的疗效观察

目的 总结思他宁联合小剂量垂体后叶素治疗急性上消化道大出血的临床疗效.方法 回顾性分析120例急性上消化道大出血病例的诊治资料,依据用药方式不同分为三组:垂体后叶素治疗组40例(A组)、思他宁联合小剂量垂体后叶素治疗组42例(B组)及思他宁治疗组38例(C组),观察各组止血有效率及药物毒副反应发生率.结果 三组病例的止血治疗总有效率分别为60.0%、95.5%和81.5%,药物毒副反应总发生率分别为30.0%、9.5%和10.5%.结论 思他宁联合小剂量垂体后叶素治疗急性上消化道大出血止血迅速、效果显著,既能提升临床疗效,还能较好地减少药物毒副作用,值得在临床中推广应用.     

Cloning and characterization of a vasopressin V2 receptor and possible link to nephrogenic diabetes insipidus.

The antidiuretic effect of arginine vasopressin (AVP) is mediated by renal-type (V2) receptors linked to adenylyl cyclase. We report here the cloning of the rat kidney V2 AVP receptor complementary DNA that encodes a 370-amino-acid protein with a transmembrane topography characteristic of G protein-coupled receptors, and with similarity to the V1a (hepatic) AVP receptor in its seven membrane-spanning domains. Expression of the cloned cDNA in mammalian cells showed specific ligand binding and activity characteristic of the native V2 AVP receptor. The receptor messenger RNA is detected only in the kidney. The human V2 receptor gene has been localized to the long arm of the X chromosome close to the locus for nephrogenic diabetes insipidus, an X-linked recessive disorder characterized by renal resistance to the antidiuretic action of AVP.     

Central target for the behavioural effects of vasopressin neuropeptides

The neurohypophysial hormone vasopressin exerts antidiuretic, vasopressor and behavioural effects (for example, facilitation of memory processes). Vasopressin may alter animal behaviour via direct effect on brain processes. Recently, however, it has been suggested that vasopressin acts mainly at peripheral receptor systems and influences behavioural mechanisms by altering visceral afferent signals. We now present data showing that (1) central administration of [Arg8]vasopressin (AVP) and more potently [pGlu, Cyt]AVP(4-8), the desglycinamide derivative of a peptide generated from AVP by brain synaptic membranes, produce the behavioural effect (promotion of passive avoidance behaviour) without the pressor effect; (2) central administration of a vasopressor antagonist blocks the behavioural but not the pressor effect of systemically administered AVP; and (3) [pGlu, Cyt]AVP(4-8) induces the behavioural effect in the absence of the pressor effect. The results indicate that AVP and related peptides affect passive avoidance behaviour by a direct central action and that the structural requirement for activation of central vasopressin receptors differs from that of the peripheral cardiovascular receptors, although both can be blocked by the same vasopressor antagonist.     

Carboxy terminus of vasopressin required for activity but not binding

Vasopressin antagonists are valuable pharmacological tools for investigating physiological and behavioural functions of the nonapeptide arginine-vasopressin (AVP). The removal of glycinamide from the carboxy terminus of AVP drastically reduces its characteristic vasopressor and antidiuretic activities. In contrast to this we show here that removal of the carboxy-terminal glycinamide or the glycine at position 9 from several vasopressin antagonists makes little difference to their ability to block vasopressor and antidiuretic responses to AVP. These data demonstrate the critical structural requirements of the carboxy-terminal position for receptor activation, in contrast to the lack of such requirements for receptor binding. They also provide an avenue to a wide variety of antagonists substituted at the carboxy terminus (for example radiolabelled derivatives and affinity ligands) and suggest clues for the development of more potent and/or selective antagonists.     

No requirements of cyclic conformation of antagonists in binding to vasopressin receptors

Early reports that acyclic analogues of oxytocin and vasopressin (AVP) have drastically reduced agonistic activities established as dogma that an intact hexapeptide ring structure is essential for the pharmacological activities of analogues of neurohypophysial hormones. Thus, virtually all the many hundreds of agonistic and antagonistic analogues of the neurohypophysial peptides that have been reported contain an intact ring. Here we report that an intact ring is not essential for binding of antagonistic AVP analogues to vasopressor (V1) or antidiuretic (V2) AVP receptors. In fact, one acyclic AVP analogue seems to be about as potent as any previously reported cyclic V2 antagonist. This finding suggests new possibilities for the design of AVP analogues as pharmacological probes and for therapeutic use. Similar modifications might be useful in the design of analogues of other cyclic peptides, such as calcitonin, somatostatin and the atrial natriuretic factors.     

Osmotic stress mimics effects of vasopressin on learned behaviour

It has been suggested that arginine vasopressin (AVP) is involved in the retention of learned responses, in addition to its classical physiological functions of water retention and modulation of blood pressure. AVP administered subcutaneously (s.c.), intraventricularly or intracerebrally can prolong extinction of active avoidance behaviour and can enhance retention in inhibitory (passive) avoidance. These effects have been interpreted as a direct action of AVP on the central nervous system to facilitate memory consolidation. AVP also has facilitatory effects on cognitive function in humans, and marked deficits in AVP function have been associated with certain types of psychopathology. Alternative hypotheses for the behavioural actions of AVP have involved motivational constructs such as arousal, and our recent work has focused on the role of arousal resulting from the activation of peripheral visceral signals in the behavioural effects of peripherally administered AVP. The development of a specific antagonist for AVP, 1-deaminopenicillamine-2-O-methyl tyrosine arginine vasopressin (dPTyr(Me)AVP), which can reverse the behavioural effects of exogenously administered AVP, has provided a powerful tool for examining the role of AVP in the behavioural responses produced by physiological challenges known to release vasopressin. However, the relationship between the behavioural effects of exogenously administered AVP and the behavioural function of endogenously released AVP has not been evaluated. We report here that a potent peripheral osmotic stimulus, the intraperitoneal (i.p.) injection of hypertonic saline, at doses known to release AVP both centrally and peripherally, will produce behavioural effects similar to those of exogenously administered AVP. Furthermore, the prolongation of active avoidance induced by this osmotic stimulus is reversed by pretreatment with dPTyr(Me)AVP, suggesting that endogenously released AVP may also produce behavioural effects.     

Vasopressin alters female sexual behaviour by acting on the brain independently of alterations in blood pressure

Subcutaneous (s.c.) administration of Arg-vasopressin (AVP) prolongs retention of a learned behaviour and elevates arterial blood pressure. Intracerebroventricular (i.c.v.) injection of a thousandfold lower dose of AVP than needed with s.c. injection produces the same behavioural effect, suggesting that AVP acts on the brain to control behaviour. However, as i.c.v. injection of AVP also elevates arterial blood pressure, it was suggested that AVP, and perhaps other peptides as well, influences behaviour indirectly by eliciting a peripheral response, for example blood pressure changes, rather than by acting directly on the brain. The suprachiasmatic nuclei (SCN) of the hypothalamus, a source of vasopressin production, inhibit sexual receptivity in oestradiol-17 beta-treated ovariectomized rats during the light phase of the daily lighting cycle, leading to speculation that vasopressin might inhibit sexual behaviour. Here we report that i.c.v. injections of AVP (1, 4 or 10 ng) inhibit sexual behaviour in receptive rats. This behavioural response is prevented by i.c.v. injection of an antiserum to AVP 30 min before AVP injection. Subcutaneous injection of a high dose of AVP (1 microgram) has no behavioural effect but elevates arterial blood pressure within 30 min of administration. Intracerebroventricular injection of a behaviourally effective dose of AVP (1 ng) has no effect on blood pressure. The results provide direct evidence that AVP can alter behaviour by an action on the brain and independently of its effect on blood pressure.     

酚妥拉明治疗肺结核大咯血的临床观察

目的:观察酚妥拉明治疗肺结核大咯血的临床疗效。方法:120例肺结核大咯血随机分为2组,治疗组采用酚妥拉明静滴,对照组采用垂体后叶素静滴。结果:治疗组总有效率88.4％,对照组总有效率76.7％。结论:酚妥拉明与垂体后叶素均为治疗肺结核大咯血有效药物,但酚妥拉明副作用少,应用范围更广,更应受到临床重视。     

支持联合查询的高效可搜索对称加密方案

采用基于Diffie-Hellman类型操作的安全两方计算实现的OXT方案是目前支持联合查询的最优可搜索对称加密方案,但Diffie-Hellman类型操作计算开销大,将成为该方案的计算性能瓶颈.为了提高计算性能,提出一个支持联合查询的高效可搜索对称加密方案(EXT方案).该方案采用客户端单独计算关键字与文档之间的关系,并交给服务器检验该关系的方法来实现联合查询,从而避免了Diffie-Hellman类型操作.并从正确性、安全性以及性能方面对EXT方案进行分析.分析结果表明:与OXT方案相比较,EXT方案将系统初始化的计算量、查询时客户端的计算量、查询时服务器的计算量、存储开销分别降低了95.05%、97.67%、98.48%、55.05%.