家兔脑内P物质介导侧脑室注射乙酰胆碱的心血管效应

大量工作表明 ,乙酰胆碱 (ａｃｅｔｙｌｃｈｏｌｉｎｅ ,ＡＣｈ)广泛分布于中枢心血管控制核团 ,参与正常血压的调节 ,且与原发性高血压的发生、发展有关。但是 ,关于脑内ＡＣｈ在整体水平对心脏收缩功能的直接影响 ,国内外尚未见报道。Ｐ物质 (ｓｕｂｓｔａｎｃｅＰ ,ＳＰ)是一种神经肽 ,广泛存在于中枢神经系统 ,作为一种神经递质或调质参与心血管活动的调节 ,中枢应用ＳＰ可产生与ＡＣｈ相一致的升压效应。有资料表明 ,ＡＣｈ与ＳＰ在大鼠桥脑共存于同一个神经元。那么 ,ＡＣｈ和ＳＰ在中枢心血管活动调节中的相互关系如何呢 ?目前。国内…     

去甲痛上腺素在大鼠缰核引起的心血管效应及其机制

Cardiovascular effect of norepinephrine (NE) in the habenular nucleus (Hb) and the underlying mechanism were investigated in urethane-anesthetized rats. NE microinjection into Hb produced a dose-dependent increase in mean arterial blood pressure and heart rate, an effect that could be attenuated by the pretreatment in Hb with alpha-receptor blocker phentolamine, but not by the pretreatment with beta-receptor blocker propranolol or physiological saline. Microinjection of kainic acid into Hb gave rise to a marked increase in mean arterial blood pressure and heart rate, but microinjection of lidocaine did not elicit significant cardiovascular effect. The above results suggest that NE in Hb plays an important role in cardiovascular control as a result of Hb excitation through activation of alpha-receptor.     

家兔侧脑室注射P物质和毒扁豆碱对心血管控制的影响及其相互关系

采用电磁血流量计测量家兔主动脉血流量(心输出量)的方法,观察47只麻醉家兔侧脑室注射(icv.)SP和毒扁豆碱对心输出量、血压和心率的影响及其相互关系。结果如下:(1)icv.SP(20μg)或毒扁豆碱(60μg),均产生明显的心输出量和血压增高,不改变心率。(2)SP的效应不能被icv.阿托品(150μg)所阻断。(3)毒扁豆碱的效应可被预先icv.SP拮抗剂(25μg)阻断。结果提示,脑内SP参与了胆碱能机制对血压的调节,ACh通过脑内SP起作用。     

糖皮质激素在孤束核内对去甲肾上腺素/神经肽Y引起的心血管效应的影响及其机制

本研究观察了糖皮质激素自身在孤束核（ＮＴＳ）内的心血管效应,以及它在ＮＴＳ内对ＮＡＮＰＹ诱导的心血管活动变化的影响及机制。结果发现,大剂量地塞米松（Ｄｅｘ）在大鼠ＮＴＳ内能很快导致血压下降,血清中ＮＯ浓度升高。小剂量Ｄｅｘ在ＮＴＳ内能很快抑制ＮＡＮＰＹ在ＮＴＳ内诱导的心血管效应,并维持较长时间。表明Ｄｅｘ对ＮＡＮＰＹ在ＮＴＳ诱导的心血管效应的抑制作用可能有基因和非基因两种途径参与。进一步分析它的非基因机制发现这种快速抑制作用与胞内糖皮质激素受体无关,而是通过兴奋ＧＡＢＡＡ受体,降低减压反射;或者降低α２受体的敏感性,抑制ＮＯ的形成;或者直接作用于细胞膜上的离子通道以影响它们对ＮＡＮＰＹ的反应;从而抑制ＮＡＮＰＹ在ＮＴＳ内诱导的降压和心率减慢的效应     

侧脑室注射去甲肾上腺素及其拮抗剂对清醒家兔脑电活动的影响

经慢性埋藏导管给清醒家兔侧脑室分别注射去甲肾腺素及其拮抗剂——妥拉苏林、心得安后,记录皮层脑电图的改变。结果:注入去甲肾上腺素后,β波明显增多,δ、θ波不仅频率减少,波幅也显著降低,表现出皮层去同步化的激醒作用。相反注入妥拉苏林则出现δ、θ波明显增多,波幅增高的同步化现象;而注入心得安后对脑电波无明显的规律性的变化。当静脉注射氯丙嗪脑电波出现大慢波后,再由侧脑室注入去甲肾上腺素,则不再出现皮层的去同步化作用。提示去甲肾上腺素经中枢内的α受体对皮层有激醒作用,去甲肾上腺素可能是作用于脑干而引起皮层脑电变化的。     

β-内啡肽和强啡肽参与可乐宁和去甲肾上腺素的中枢降压效应

大鼠侧脑室注射(icv)可乐宁和去甲肾上腺素(NE)引起血压降低和心率减慢。此效应可被α受体阻断剂酚妥拉明对抗。icvβ-内啡肽抗体、强啡肽抗体或大剂量阿片受体阻断剂纳洛酮也可防止可乐宁和 NE 降压效应的出现;而甲啡肽抗体、亮啡肽抗体或小剂量纳洛酮均无拮抗作用。以上结果表明,内源性β-内啡肽和强啡肽参与可乐宁和 NE 脑室注射所引起的降压效应。     

去甲肾上腺素转运体的研究进展

随着分子克隆技术的发展和应用,已经可以克隆出人的去甲肾上腺素转运体(Norepinephrine transporter,NET)基因转染进哺乳动物细胞内进行体外研究。去甲肾上腺素转运体在神经传递中有着非常重要的作用,许多神经以及精神系统方面的疾病,心血管疾病等都与去甲肾上腺素转运体的功能缺失或紊乱有关。本文主要介绍了去甲肾上腺素转运体的基本概念和近年来国外对去甲肾上腺素转运体的研究概况,综述了与该转运体相关的药物的研究进展以及由于去甲肾上腺素转运体的功能紊乱或丧失而导致的疾病的临床研究。最近几年对于NET基因表达调控以及各种临床疾病的研究对这些疾病的治疗方法的探索有着非常重要的意义。     

家兔第四脑室注射P物质对肺动脉压和颈动脉压的影响

本工作将P物质(SP)注入麻醉家兔第四脑室,观察其对肺动脉压和颈动脉压的影响。结果观察到:(1)脑室注射SP后,肺动脉压升高或降低,颈动脉压上升,心率减慢。(2)切断肺动脉压下降组家兔的两侧颈部迷走神经,再ivt.SP,则引起肺动脉压的升高,降心率反应则明显减弱。(3)预先用酚妥拉明或α_1受体阻断剂哌唑嗪均可阻断SP引起的肺动脉和颈动脉升压反应。(4)α_2受体阻断剂育亨宾或纳洛酮均可增强这二个升压反应。(5)心得安对这二个升压反应无明显影响。(6)SP的心血管效应可被SP受体拮抗剂[D-pro~2.D-Trp~(7.9)]-SP阻断。 实验结果表明:脑中SP升高可通过SP受体引起肺动脉压和颈动脉压上升,心率减慢;在SP引起的加压反应的中枢环节中有肾上腺素能α_1受体活动参与;中枢肾上腺素能α_2受体系统和内啡肽系统对传递SP中枢加压作用的路径有抑制性的调制作用。看来,SP与儿茶酚胺及阿片样物质一起参与脑干对血压的调节。     

猫海马注射去甲肾上腺素对血浆皮质浓度的影响

In the present experiment, the effect of injection of NE into the different areas of hippocampus on the plasma cortisol level and the kind of NE receptor involved were studied in 83 cats anesthetized with Nembutal. The plasma cortisol level was increased following injection of NE into the ventral hippocampus (VHIP), however, there was no significant change when injection was made into dorsal hippocampus. The NE-VHIP effect can be blocked by injection of phentolamine, yohimbine or prazosin but not by propranolol. Thus, these results show that, in the regulation of the plasma cortisol level, the alpha-receptor system of VHIP is more specifically involved.     

Glutamate-stimulated ATP release from spinal cord astrocytes is potentiated by substance P

ATP has recently emerged as a key molecule mediating pathological pain. The aim of this study was to examine whether spinal cord astrocytes could be a source of ATP in response to the nociceptive neurotransmitters glutamate and substance P. Glutamate stimulated ATP release from these astrocytes and this release was greatly potentiated by substance P, even though substance P alone did not elicit ATP release. Substance P also potentiated glutamate-induced inward currents, but did not cause such currents alone. When glutamate was applied alone it acted exclusively through alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionate receptors to stimulate Ca(2+) influx-dependent ATP release. However, when substance P was co-applied with glutamate, ATP release could be elicited by activation of NMDA and metabotropic glutamate receptors. Activation of neurokinin receptor subtypes, protein kinase C and phospholipases A(2), C and D were needed for substance P to bring about its effects. These results suggest that astrocytes may be a major source of ATP in the spinal cord on activation of nerve fibres that release substance P and glutamate.     

外周P物质受体介导伤害性刺激所致脊髓背角c-fos基因的表达

用免疫组化染色方法,观察了Ｐ物质受体在外周对伤害性刺激信息的介导作用。于福尔马林注入双侧后肢足底前１０ｍｉｎ,将不同浓度的ＳＰ受体特异性拮抗剂Ｌ６６８,１６９注入一侧足底,另一侧注入生理盐水。结果：１０＾－４ｍｏｌ／Ｌ的Ｌ６６８,１６９明显抑制了该侧脊髓背角浅层ｃ－ｆｏｓ基因的表达而对深层影响不大;     

脑内P物质在谷氨酸兴奋腹内侧核引起的升压反应中之作用

目的：分析谷氨酸兴奋下兵脑腹内侧核（NVM）引起升压反应的机制。方法：大鼠脑内或静脉注射不同药物,记录血压和心率的变化。结果：①L－谷氨酸（Glu)兴奋NVM、P物质（SP）注入背内侧核（NDM）室旁核（NPV）或延髓头端腹外侧区（RVL）均引起升压反应;②NVM升压反应可被双侧NDM、NPV或PVL内预先注射[D-Pro^2,D-Phe^7,D-Trp^9]-P物质（SP拮抗剂）衰减,但RVL内注射阿托品无此效应;③酚妥拉明（i.v.）也能使NVM升压反应减小,而心得安或甲基阿托品（i.v.）对该升压反应无影响。结论：兴奋NVM可通过NDM（SP受体）,作用于NPV（SP受体）升压区和RVL（SP受体）－交感缩血管神经系统产生升压反应。心交感和心迷走神经不参与该反应。     

Functional and immunological responses of Jurkat lymphocytes transfected with the substance P receptor

1. We have transfected the rat substance P receptor (SPR) cDNA into the leukemic T-lymphocyte cell line Jurkat (J-wt) in order to study the effects of substance P (SP) on lymphocyte signaling mechanisms and the resultant neuropeptide-induced immunological changes. 2. The SPR cDNA was transfected into J-wt by the method of electroporation. Clones expressing SPRs were selected using a functional assay that measured SP-induced mobilization of intracellular Ca2+ ([Ca2+]i) in a fluorescence activated cell sorter (FACS) and by their expression of specific 125I-SP binding. 3. One clone, J-SPR, was identified and shown by Northern blot and 125I-SP saturation binding techniques to express the 2.2-kb SPR message and approximately 50,000 SPRs/cell with a Kd of 0.3 nM, respectively. Stimulation of J-SPR by SP resulted in the rapid mobilization of [Ca2+]i. This response was dose dependent in the range 10(-11)-10(-6) M SP and was maximal at 10(-7) M SP, with an EC50 of 0.3-0.5 nM SP. We further demonstrated that the SPR is rapidly desensitized following SP stimulation and by activation of the cell's T-cell receptor (TCR). Whole-cell patch-clamp experiments on J-SPR show that SP stimulation induces a Cl- current by a Ca2+ mediated process dependent on Ca2+/calmodulin-dependent protein kinase (CaMK). 4. Stimulation of J-SPR by SP results in changes in the cell surface expression of a number of molecules that play important roles in cell adhesion and activation: the expression of LFA-1 is decreased, and CD2 and IL-2 receptors are increased by 30 min, 6 hr, and 24 hr, respectively, following stimulation, as assessed by antibody staining in a FACS. 5. The expression of functional SPRs in Jurkat lymphocytes will not permit a detailed examination of how the activation of SPRs result in altered immune responses and further elucidate the role this neuropeptide receptor plays in inflammation.     

Effect of mitogen-activated protein kinases on chemokine synthesis induced by substance P in mouse pancreatic acinar cells

Substance P, acting via its neurokinin 1 receptor (NK1 R), plays an important role in mediating a variety of inflammatory processes. Its interaction with chemokines is known to play a crucial role in the pathogenesis of acute pancreatitis. In pancreatic acinar cells, substance P stimulates the release of NFκB-driven chemokines. However, the signal transduction pathways by which substance P-NK1 R interaction induces chemokine production are still unclear. To that end, we went on to examine the participation of mitogen-activated protein kinases (MAPKs) in substance P-induced synthesis of pro-inflammatory chemokines, monocyte chemoanractant protein-1 (MCP-I), macrophage inflammatory protein-lα (MIP-lα) and macrophage inflammatory protein-2 (MIP-2), in pancreatic acini. In this study, we observed a time-dependent activation of ERK1/2, c-Jun N-terminal kinase (JNK), NFκB and activator protein-1 (AP-1) when pancreatic acini were stimulated with substance P. Moreover, substance P-induced ERK 1/2, JNK, NFκB and AP-1 activation as well as chemokine synthesis were blocked by pre-treatment with either extracellular signal-regulated protein kinase kinase 1 (MEK1) inhibitor or JNK inhibitor. In addition, substance P-induced activation of ERK 112, JNK, NFκB and AP-1-driven chemokine production were attenuated by CP96345, a selective NK1 R antagonist, in pancreatic acinar cells. Taken together, these results suggest that substance P-NK1 R induced chemokine production depends on the activation of MAPKs-mediated NFκB and AP-1 signalling pathways in mouse pancreatic acini.     

Effects of intracerebroventricular administration of neurotensin,substance P and calcitonin on gastrointestinal motility in normal and vagotomized rats

The effects of intracerebroventricular (ICV) vs. intravenous (IV) injection of neurotensin, substance P and calcitonin on intestinal myoelectrical activity were examined in fed rats. ICV administered neurotensin and calcitonin restored the ‘fasted’ pattern of intestinal activity, i.e. the migrating myoelectric complex (MMC) at a dose as low as 12 and 0.2 pmol, respectively, whereas substance P only reduced significantly ($\text{P < 0.01}$) the duration of the postprandial pattern when injected ICV (48 pmol).Administered systemically at doses 100 times higher than the smallest active doses by the ICV route, calcitonin induced a fasted pattern, while neurotensin and substance P did not modify the fed pattern.The effects of ICV administration of neurotensin and calcitonin were abolished after vagotomy but the shortening effect of substance P on the duration of the postprandial pattern was still present.It is concluded that these three neuropeptides act centrally to control the pattern of intestinal motility in fed rats by shortening the ‘fed’ pattern for substance P and by restoring the MMC pattern for calcitonin and neurotensin, this last effect being mediated by the vagus.     

Acute reduction of brain substance P induced by nicotine

Ten minutes after a single injection of 0.8 mg/kg nicotine SC (free base) the level of substance P-like immunoreactivity (SPLI) was reduced by 61–73% in rat caudate-putamen, nucleus accumbens, and olfactory tubercle, with smaller and not significant reductions in the frontal cortex, substantia nigra, and ventral tegmental area. The nicotinic receptor antagonist mecamylamine (1.0 mg/kg IP) prevented the reductions in SPLI. The rapidity and the degree of the changes in SPLI after nicotine exceed those previously reported for other agents and implicate substance P neurotransmission as a major component of nicotinic action.Preliminary data were presented at the 17th annual meeting of the American Society for Neurochemistry, Montreal, 1986 (1).     

Intrathecal substance P augments morphine-induced antinociception: Possible relevance in the production of substance P N-terminal fragments

The present study sought to examine the mechanism of substance P to modulate the antinociceptive action of intrathecal (i.t.) morphine in paw-licking/biting response evoked by subcutaneous injection of capsaicin into the plantar surface of the hindpaw in mice. The i.t. injection of morphine inhibited capsaicin-induced licking/biting response in a dose-dependent manner. Substance P (25 and 50 pmol) injected i.t. alone did not alter capsaicin-induced nociception, whereas substance P at a higher dose of 100 pmol significantly reduced the capsaicin response. Western blots showed the constitutive expression of endopeptidase-24.11 in the dorsal and ventral parts of lumbar spinal cord of mice. The N-terminal fragment of substance P (1–7), which is known as a major product of substance P by endopeptidase-24.11, was more effective than substance P on capsaicin-induced nociception. Combination treatment with substance P (50 pmol) and morphine at a subthreshold dose enhanced the antinociceptive effect of morphine. The enhanced effect of the combination of substance P with morphine was reduced significantly by co-administration of phosphoramidon, an inhibitor of endopeptidase-24.11. Administration of d-isomer of substance P (1–7), [d-Pro², d-Phe⁷]substance P (1–7), an inhibitor of [³H] substance P (1–7) binding, or antisera against substance P (1–7) reversed the enhanced antinociceptive effect by co-administration of substance P and morphine. Taken together these data suggest that morphine-induced antinociception may be enhanced through substance P (1–7) formed by the enzymatic degradation of i.t. injected substance P in the spinal cord.     

Inflammatory responses induced by substance P in rat paw.

Substance P (SP) injection in the plantar region of rat hind paw caused a dose related inflammation, which reached a peak within 10 min of injection and declined after 60 min. Low doses (0.25-0.063 mg/kg) of SP-antagonists like (D-Pro2, D-Trp7,9)-SP and (D-Pro2, D-Phe7, D-Trp9)-SP pretreatment significantly inhibited the SP induced paw oedema, while higher doses (0.5-1 mg/kg) showed agonistic effects. Pretreatment with diphenhydramine alone or along with low doses of SP-antagonists was highly significant in blocking this inflammation, the latter combination being more effective than the former. Pretreatment with acute capsaicin produced a synergestic effect on SP induced paw oedema, while pretreatment with chronic capsaicin significantly inhibited this SP induced paw oedema. The results indicate involvement of histamine and possible therapeutic importance of capsaicin in SP mediated inflammatory type of responses.     

Fever and acute-phase response induced in rabbits by intravenous and intracerebroventricular injection of interleukin-6

We investigated the effect of human recombinant interleukin-6 (IL-6) on body temperature and acute-phase response, including changes in plasma levels of iron, zinc, copper, and fibrinogen and in circulating leukocyte count. The intravenous (IV) injection of IL-6 (2 micrograms/kg) produced a monophasic fever. The intracerebroventricular (ICV) injection of IL-6 produced a dose-dependent fever that developed gradually and remained elevated throughout the 5-h recording period. The IV injection of IL-6 decreased the plasma concentration of iron and zinc and increased the circulating leukocyte count. The ICV injection of IL-6 resulted in similar trace metal and leukocyte changes, and increased plasma levels of fibrinogen. These results show that IL-6 can cause fever when injected IV or ICV and induces some acute-phase responses through its action on peripheral target organs and in the central nervous system.