Vasoactive intestinal peptide: a possible transmitter of nonadrenergic relaxation of guinea pig airways

Vasoactive intestinal peptide, a smooth-muscle relaxant neuropeptide with neurotransmitter properties, was relaxed during electrical field stimulation of guinea pig trachea. The amount released correlated with the degree of relaxation, and the release was blocked by tetrodotoxin. Prior incubation of the trachea with antiserum to vasoactive intestinal peptide reduced the relaxation. Thus vasoactive intestinal peptide may mediate the nonadrenergic relaxation of tracheal smooth muscle.     

Vasoactive intestinal polypeptide-like substance: the potential transmitter for cerebral vasodilation

In vitro pharmacological studies demonstrated that exogenously applied vasoactive intestinal polypeptide (VIP) relaxes the smooth muscle cells of cat cerebral arteries, whereas substance P constricts them. Ultrastructural-immunocytochemical techniques show that a VIP-like substance is present in the large granular vesicles of nonsympathetic nerve axons and terminals in the cerebral arterial walls. These results provide strong evidence in favor of the hypothesis that a VIP-like substance is the transmitter for vasodilation in cerebral blood vessels.     

Purification and sequence analysis of bioactive atrial peptides (atriopeptins)

Mammalian cardiac atria have several biologically active peptides that exert profound effects on sodium excretion, urine volume, and smooth muscle tone. In the present study two such peptides of low molecular weight were purified and separated from each other on the basis of differences in charge, hydrophobicity, and biological profile. The first peptide, designated atriopeptin I, exhibits natriuretic and diuretic activity and selectivity relaxes intestinal smooth muscle but not vascular smooth muscle strips. The second peptide, atriopeptin II, is a potent natriuretic and diuretic that relaxes both intestinal and vascular strips. Sequence analysis of atriopeptin I indicates that it is composed of 21 amino acids, of which serine and glycine residues predominate. The amino terminal sequence of atriopeptin II up to residue 21 is the same as that of atriopeptin I, with the addition of the Phe-Arg extension at the carboxyl terminus. Both peptides appear to be derived from a common high molecular weight precursor (designated atriopeptigen); their biological selectivity and potency may be determined by the site of carboxyl terminal cleavage.     

忍冬藤提取物对兔离体肠平滑肌的舒张作用及其机制

【目的】胃肠平滑肌过度收缩可引起腹痛腹泻等临床常见的疾病。目前,临床上对治疗胃肠平滑肌过度收缩的药物主要以西药为主,如钙离子通道阻断药硝苯地平和抗胆碱药阿托品等,硝苯地平长期使用可引起负性肌力和负性传导的现象,而阿托品由于其不良反应较大,在临床应用中受到一定的限制。因此,开发具有有效防治胃肠平滑肌痉挛、低毒、低残留的天然中草药意义重大。试验以兔离体小肠平滑肌为研究对象,利用丰富的忍冬藤资源,研究忍冬藤提取物对兔离体小肠平滑肌收缩的影响,并探讨其作用机制。【方法】采用兔离体小肠平滑肌试验,应用BL-420E生物机能实验系统,观察忍冬藤提取物对正常状态下兔离体小肠平滑肌自发性收缩的影响;进而使用工具药乙酰胆碱、组胺和氯化钡致兔小肠痉挛性收缩后,观察忍冬藤提取物对其痉挛性收缩的影响;为研究忍冬藤提取物抑制兔离体小肠平滑肌收缩的作用机制,应用IP_3受体阻断剂肝素(HP)、肌浆网ryanodine受体阻断剂钌红(RR)和一氧化氮合酶抑制剂左旋硝基精氨酸甲酯(L-NAME),探明忍冬藤提取物对兔离体小肠平滑肌作用的机制。【结果】忍冬藤提取物可浓度依赖性抑制兔离体小肠平滑肌自发性收缩,药物浓度在7.5 g·L~(-1)时可显著抑制兔离体小肠平滑肌收缩的频率(P0.05),药物浓度在5g·L~(-1)时可极显著抑制兔离体小肠平滑肌收缩的振幅(P0.05);工具药乙酰胆碱、组胺和氯化钡可显著诱导兔小肠平滑肌收缩的振幅,忍冬藤提取物可显著抑制由乙酰胆碱、组胺和氯化钡诱导的兔离体小肠平滑肌收缩的频率(P0.05),可极显著抑制兔离体小肠平滑肌收缩的振幅(P0.01)。IP_3受体阻断剂肝素能增强忍冬藤提取物舒张兔离体小肠平滑肌收缩的作用(P0.01),而肌浆网ryanodine受体阻断剂钌红对忍冬藤提取物舒张兔小肠平滑肌的作用无明显影响(P0.05)。左旋硝基精氨酸甲酯能够部分阻断忍冬藤提取物舒张兔离体小肠平滑肌收缩的作用(P0.01)。【结论】忍冬藤提取物可显著抑制兔离体小肠平滑肌收缩的频率和振幅,其机制可能与增加一氧化氮浓度,抑制IP_3受体介导的内钙释放有关,但对肌浆网ryanodine受体途径引起的内钙释放无关。     

Hyperpolarizing vasodilators activate ATP-sensitive K+ channels in arterial smooth muscle

Vasodilators are used clinically for the treatment of hypertension and heart failure. The effects of some vasodilators seem to be mediated by membrane hyperpolarization. The molecular basis of this hyperpolarization has been investigated by examining the properties of single K+ channels in arterial smooth muscle cells. The presence of adenosine triphosphate (ATP)-sensitive K+ channels in these cells was demonstrated at the single channel level. These channels were opened by the hyperpolarizing vasodilator cromakalim and inhibited by the ATP-sensitive K+ channel blocker glibenclamide. Furthermore, in arterial rings the vasorelaxing actions of the drugs diazoxide, cromakalim, and pinacidil and the hyperpolarizing actions of vasoactive intestinal polypeptide and acetylcholine were blocked by inhibitors of the ATP-sensitive K+ channels, suggesting that all these agents may act through a common pathway in smooth muscle by opening ATP-sensitive K+ channels.     

血根碱对兔离体肠平滑肌运动的舒张作用

【目的】探讨血根碱对兔离体肠平滑肌的舒张作用及机制。【方法】采用离体肠肌试验,应用BL-420E生物机能实验系统,比较血根碱对正常肠肌及工具药乙酰胆碱、酚妥拉明、氯化钡作用下兔离体肠平滑肌活动的影响,记录肠肌的收缩频率和振幅,并计算抑制率。【结果】血根碱可浓度依赖性的抑制兔小肠平滑肌自发性收缩的频率和振幅。0.4 mg•mL-1的血根碱对由乙酰胆碱、氯化钡引起的离体肠肌的兴奋性收缩有明显的拮抗作用,而对酚妥拉明阻断肾上腺素能受体后,仍能显著降低离体肠平滑肌收缩的振幅。【结论】血根碱对小肠平滑肌的舒张作用可能与乙酰胆碱竞争,阻断M受体、与酚妥拉明竞争,兴奋α受体及直接抑制肠肌兴奋性有关。     

鸡肠道组织中血管活性肠肽的分布特点

为探讨鸡肠道组织中肽能神经支配的途径及其功能,运用免疫组织化学超敏SP法,对不同生长阶段鸡肠道中血管活性肠肽(Vasoactive intestinal peptide,VIP)的分布特点进行了研究。结果显示,肠壁中VIP的表达范围较为广泛,涉及黏膜上皮和固有层、肌层和外膜,尤以固有层和肌层最为典型;随着日龄增加,黏膜上皮间VIP阳性细胞数量逐渐增多;从肠道不同部位的分布来看,十二指肠中VIP的表达强于同时期其他部位,空肠中的表达次之,回肠和盲肠的表达相对较弱。黏膜固有层和肌层一直分布有染色较深的VIP阳性神经纤维,呈串珠状、细线状或膨体状。提示鸡肠道是产生VIP的又一个重要部位,肠道中的VIP可参与鸡免疫器官的功能调节,并作为一种信息分子介导神经内分泌系统和黏膜免疫系统之间的相互作用。     

Regulation of myosin phosphatase by a specific interaction with cGMP- dependent protein kinase Ialpha

Contraction and relaxation of smooth muscle are regulated by myosin light-chain kinase and myosin phosphatase through phosphorylation and dephosphorylation of myosin light chains. Cyclic guanosine monophosphate (cGMP)-dependent protein kinase Ialpha (cGKIalpha) mediates physiologic relaxation of vascular smooth muscle in response to nitric oxide and cGMP. It is shown here that cGKIalpha is targeted to the smooth muscle cell contractile apparatus by a leucine zipper interaction with the myosin-binding subunit (MBS) of myosin phosphatase. Uncoupling of the cGKIalpha-MBS interaction prevents cGMP-dependent dephosphorylation of myosin light chain, demonstrating that this interaction is essential to the regulation of vascular smooth muscle cell tone.     

蛙心体外循环系统及刺激豚鼠回肠检测外啡肽生物学活性的相关性研究

采用离体蛙心灌流和离体回肠灌流的方法将小麦面筋蛋白胃蛋白酶酶解液分别加入蛙心体外循环系统和豚鼠回肠体外循环系统中,通过BL-420生物机能实验系统测定蛙心心肌和肠道平滑肌收缩力变化,并随即加入特异性阿片肽阻断剂——纳洛酮,以检测小麦面筋蛋白胃蛋白酶酶解液的生物学活性,并将两种方法所得的实验结果经处理后进行相关性比较研究。结果表明,小麦面筋蛋白胃蛋白酶酶解液能显著引起蛙心心肌和肠道平滑肌收缩力加强,并可被纳洛酮逆转此现象,说明小麦面筋蛋白胃蛋白酶酶解液含有外啡肽,对两种方法具有显著的相关性,表明用蛙心灌流法测定外啡肽活性与经典的豚鼠回肠法测定结果是一致的,但蛙心灌流法更易推广。     

淫羊藿对家兔离体小肠平滑肌生理特性的影响

[目的]观察淫羊藿苷对家兔离体小肠平滑肌收缩活动的影响。[方法]取家兔离体小肠（十二指肠）肠段,将其置于恒温平滑肌槽中,连接张力传感器,信号输入BL-420E生物机能实验系统,加入不同浓度的淫羊藿苷溶液,分别记录小肠平滑肌的收缩活动。结果不同浓度淫羊藿苷（10-4、10-3、10-2mol/L）对小肠平滑肌自发收缩活动有抑制作用,其收缩幅度变化值与用药前比较差异显著。[结论]淫羊藿苷对小肠平滑肌活动有抑制性影响。     

鸡胆汁对动物小肠平滑肌及胆汁分泌的影响

采用肠管运动实验的在体法和离体法证明鸡胆汁对家兔在体和离本肠管平滑肌的收缩强度均有极显著的抑制作用，其抑制率分别为３９．９１％和６２．４９％，但对两者的收缩频率则均无显著影响。另外，本文还观察了鸡胆汁对大鼠胆汁分泌量的影响，结果表明，鸡胆汁能显著地提高大白鼠的胆汁分泌量。     

一枝蒿对兔离体小肠平滑肌运动试验的研究

用两种自制的一枝蒿制剂型对家兔离体小肠平滑肌运动影响的试验表明：一枝蒿有明显加强小肠平滑肌运动的作用。为临床治疗消化道及其有关的一类疾病提供了理论依据。     

Brain peptides as neurotransmitters

Numerous peptides appear to be neurotransmitter candidates in the brain. Some, such as the opioid peptide enkephalins, neurotensin, and substance P, were first isolaterd from the brain. Peptides, such as cholecystokinin and vasoactive intestinal polypeptide, were known as intestinal hormones and later recognized as brain constituents. Certain hypothalamic-releasing hormones, pituitary peptides, and blood-derived peptides like angiotensin II and bradykinin, may also be central neurotransmitters. The diversity of localization of these peptides throughout the brain implies a multiplicity of potential roles.     

软枣猕猴桃对家兔小肠平滑肌的影响

[目的]观察药用植物软枣猕猴桃滤液对家兔小肠离体平滑肌运动功能的影响。[方法]制作家兔离体肠段标本,记录处理前后肠段的平滑肌收缩强度和静息张力,换算成张力和频率进行比较。[结果]较低浓度（5~15 mg/ml）的软枣猕猴桃滤液可明显兴奋小肠平滑肌的自发收缩活动,并显著减弱氯化乙酰胆碱对小肠平滑肌活动的增强效应;而在高浓度时（30~50 mg/ml）则增加平滑肌的静息张力。[结论]软枣猕猴桃滤液对胃肠运动具有较为复杂的调整作用。     

血管活性肠肽在动情周期大鼠子宫中的分布

采用免疫组化SP法,观察血管活性肠肽(VIP)免疫反应阳性物质在SD大鼠动情周期子宫中的分布情况和变化规律。结果表明,在内膜层中,VIP免疫阳性产物定位于子宫内膜上皮细胞、腺上皮细胞、基质细胞和血管内皮细胞中。在肌层中,VIP免疫阳性产物主要位于VIP样阳性神经纤维中。VIP免疫阳性产物相对表达量的t检验表明:子宫内膜VIP在动情后期表达量较发情前期极显著减少(P0.01);与动情前期相比,子宫肌层VIP在动情期的表达量显著减少(P0.05),在动情后期的表达量极显著减少(P0.01)。但是在动情间期VIP的表达量较动情后期又极显著回升(P0.01)。VIP在动情周期大鼠子宫中表达分布存在一定规律性,可能与其免疫调节和腺体分泌等功能有关。     

皖西白鹅腔上囊VIP和NPY阳性神经元分布的研究

应用免疫组织化学SABC染色法,对皖西白鹅腔上囊的血管活性肠肽(VIP)和神经肽Y(NPY)定位进行了研究。结果发现免疫阳性神经元在粘膜、粘膜下层,囊小结的皮质、髓质以及血管有表达,提示禽类的腔上囊内有肽能神经分布,并有可能参与禽的免疫器官的功能调节和控制淋巴细胞的迁移。     

高山兀鹫的食管组织学观察

应用大体解剖技术、H.E染色法,观察了高山兀鹫食管组织学结构并与家禽和哺乳动物的食管比较。结果表明:高山兀鹫的食管上段皱襞很少,而下段则形成很多皱襞;食管黏膜上皮为复层扁平上皮,角质化明显;黏膜肌层由分散的平滑肌束构成;食管上段黏膜下层内食管腺丰富,而下段食管腺很少;食管肌层分为两层:纵肌和环肌,食管下段比上段的肌层发达;食管外膜是一层薄的纤维层,内含血管、神经。     

巫山神茶水提物对昆明小鼠小肠蠕动的影响

通过建立动物模型,以及观察活性炭在小肠中的状态和血清中内皮素、乙酰胆碱酯酶和血管活性肠肽水平,就巫山神茶水提物对昆明小鼠小肠蠕动的影响进行了评价.结果表明,血清中内皮素、血清乙酰胆碱酯酶和血管活性肠肽水平,以及活性炭肠道推进率随着巫山神茶水提物浓度的增加而增加,而活性炭小肠推进距离和首粒含活性炭黑便排出时间则随巫山神茶水提物浓度的增加而降低.由此认为,巫山神茶在一定程度上可促进小鼠小肠的蠕动.     

刺糖对小鼠肠推进和离体小肠平滑肌运动的影响

通过观察刺糖对小鼠离体小肠和在体小肠平滑肌运动的影响,以中华墨汁的推进距离与小肠总长的比值计算小肠推进率;采用离体肠管平滑肌收缩实验,以小鼠小肠平滑肌的收缩幅度、收缩频率及运动指数为指标,观察在正常台氏液中刺糖对小鼠离体肠管的影响,同时观察胃肠通和阿托品对不同浓度刺糖的作用。结果表明,刺糖可增强小鼠小肠运动功能（P〈0.01）,但与胃肠通相比作用缓和（P〈0.01）。35%,70%刺糖溶液均可促进正常离体肠管的收缩功能（P〈0.01,P〈0.01）,能拮抗阿托品引起的舒张作用（P〈0.01,P〈0.01）和胃肠通引起的收缩运动（P〈0.01,P〈0.01）。体内外实验结果表明,刺糖对小鼠小肠运动在体内外均具有调节作用。     

Innervation of periosteum and bone by sympathetic vasoactive intestinal peptide-containing nerve fibers

Neural control of bone metabolism and growth has been suggested, although the identity of participating neurons and neurotransmitters effecting this control has not been established. Immunohistochemical studies demonstrated a system of vasoactive intestinal peptide (VIP)-immunoreactive nerve fibers that innervate periosteum and bone in several mammalian species. Thoracic sympathetic chain ganglionectomy resulted in an ipsilateral loss of VIP-immunoreactive fibers in the periosteum of ribs, whereas dorsal root ganglionectomy had no effect. Injection of fast blue into rib periosteum labeled a population of VIP-immunoreactive sympathetic postganglionic neurons. Thus, postganglionic sympathetic neurons may provide an important means by which VIP regulates bone mineralization.