Vigilance and EEG power in rats: effects of potent inhibitors of the neuronal nitric oxide synthase

We examined the effects of potent neuronal nitric oxide synthase inhibitors, 3-bromo-7-nitro indazole (3-Br-7-NI) and S-methyl-L-thiocitrulline (S-Me-TC) on general behaviour, vigilance stages and electro-encephalographic (EEG) power spectra in rats. In addition, we studied the effect of 7-nitro indazole (7-NI) on EEG power spectra in rats during dark and light periods. 3-Br-7-NI induced ptosis and decrease of slow wave sleep and rapid eye movement sleep in the rat. 7-NI and 3-Br-7-NI reduced the EEG power density in all frequency bands in the rat, suggesting a depression of central neuronal activity. This effect of 7-NI was more prominent during the day than during the night, indicating a circadian variation in the nitric oxide synthase (NOS) response to NOS inhibitor. EEG power was the most reduced in the 7-9Hz range of the rhythmic slow activity (theta rhythm), which is in accordance with decreased locomotion observed following administration of NOS inhibitors. Although S-Me-TC is the most potent NOS inhibitor in vitro experiments, it had less effect on vigilance and EEG power in the rat than other NOS inhibitors used in this study, probably due to its short lasting and blood pressure raising effect. The present results indicate that nitric oxide exerts an excitatory and circadian dependent effect in the central neuronal structures involved in the regulation of vigilance. Received: 16 September 1996 / Accepted: 4 April 1997     

NOS抑制剂L－NAME的镇痛、致痛和致瘫作用

鞘内注射（ｉｔ）ＮＯＳ抑制剂Ｌ－ＮＡＭＥ０．１２５～４μｍｏｌ可剂量依赖性抑制大鼠足底注射Ｆｏｒｍａｌｉｎ引起的癌症反应，并有７／３１大鼠出现迟发性一过性双后肢瘫痪。ｉｔＬＮＡＭＥ５μｍｏｌ对正常大鼠无明显影响，但１０μｍｏｌ和２０μｍｏｌ均引起明显的痛敏及截瘫．ｉｔ另一ＮＯＳ抑制剂氨基胍０．２～１．０μｍｏｌ也显著抑制Ｆｏｒｍａｌｉｎ痛定反应，１．２５～７．０μｍｏｌ则引起正常大鼠剂量依赖性痛敏行为，但对后肢运动功能无影响。结果表明脊髓水平ＮＯ在痛觉传递与调制中起重要作用，过度抑制ＮＯ的产生可引起痛觉敏化和瘫痪。     

NOS抑制剂L－NAME的镇痛、致痛和致瘫作用

鞘内注射（ｉｔ）ＮＯＳ抑制剂Ｌ－ＮＡＭＥ０．１２５～４μｍｏｌ可剂量依赖性抑制大鼠足底注射Ｆｏｒｍａｌｉｎ引起的癌症反应，并有７／３１大鼠出现迟发性一过性双后肢瘫痪。ｉｔＬＮＡＭＥ５μｍｏｌ对正常大鼠无明显影响，但１０μｍｏｌ和２０μｍｏｌ均引起明显的痛敏及截瘫．ｉｔ另一ＮＯＳ抑制剂氨基胍０．２～１．０μｍｏｌ也显著抑制Ｆｏｒｍａｌｉｎ痛定反应，１．２５～７．０μｍｏｌ则引起正常大鼠剂量依赖性痛敏行为，但对后肢运动功能无影响。结果表明脊髓水平ＮＯ在痛觉传递与调制中起重要作用，过度抑制ＮＯ的产生可引起痛觉敏化和瘫痪。     

大鼠脑出血周边组织NO含量和NOS活性变化及对细胞凋亡的影响

目的：研究大鼠脑出血周边组织一氧化氮(NO)含量和一氧化氮合酶(NOS)活性变化及与细胞凋亡的关系。方法：①Wistar大鼠104只,随机分为对照组、脑出血组、脑出血 氮硝基左旋精氨酸(NNLA)组,后两组各分为(4h、6h、12h、1d、3d、7d)6个时间点。②测定出血周边组织NO含量、NOS活性及神经细胞凋亡。结果：①大鼠脑出血周边组织NO、诱导型一氧化氮合酶(iNOS),4h开始升高,3di NOS、NO达峰值。②大鼠脑出血周边组织6h出现凋亡,细胞3d凋亡细胞达峰值,与iNOS峰值对应,7d时仍存在较多凋亡细胞。③NNLA干预后NO含量、iNOS活性及凋亡细胞数量与脑出血组对应时间点比较显著下降,差异显著。结论：大鼠脑出血周边组织神经细胞存在长时间凋亡,NO、iNOS可以促进其凋亡,NOS抑制剂减少大鼠脑出血周边组织神经细胞凋亡。     

硝基精氨酸—赖氨酸三肽合成及其对一氧化氮合酶的抑制作用

液相合成法合成了由左旋精氨酸、左旋赖氨酸组成的硝基精氨酸-赖氨酸三肽HCl．Arg(NO     

Pharmacokinetics and Pharmacodynamics of 7-Nitroindazole,a Selective Nitric Oxide Synthase Inhibitor,in the Rat Hippocampus

Purpose. This study was conducted to assess the pharmacokinetics and pharmacodynamics of 7-nitroindazole (7-NI), a selective inhibitor of neuronal nitric oxide synthase (NOS). Methods. Male Sprague-Dawley rats were equipped with peritoneal/venous cannulae and a microdialysis probe in the hippocampal cortex. Rats received 7-NI in peanut oil (25 mg/kg) ip every 2 h for 14 h or peanut oil alone. Blood samples were obtained at timed intervals for serum 7-NI; brain tissue microdialysate for determination of extracellular 7-NI and NO was obtained every 20 min. A pharmacokinetic-pharmacodynamic model was constructed to evaluate the effects of 7-NI on NOS activity. Results. Consistent with previous reports, NOS activity in controls evidenced circadian variation. These cyclic changes in NO production were incorporated into the model of 7-NI effects on NOS. 7-NI produced a rapid (within 2 h) decrease in hippocampal NO. Under the conditions of this experiment, 7-NI produced an 50% decrease in hippocampal NO, which was sustained during 7-NI administration. The decrease in NOS activity by 7-NI was concentration-dependent with an apparent IC₅₀ of 17 g/ml. Conclusions. Multiple ip injections of 7-NI result in a predictable, sustained decrease in NO production in the hippocampus. The pharmacokinetic-pharmacodynamic model developed allows design of dosing regimens that can produce designated changes in brain NO content, facilitating use of 7-NI to probe the pharmacological implications of NO in the central nervous system.     

Different effects of dexamethasone and the nitric oxide synthase inhibitor L-NAME on caerulein-induced rat acute pancreatitis, depending on the severity

Effects of dexamethasone and N^G-nitro-L-arginine methyl ester (L-NAME), the nitric oxide (NO) synthase inhibitor, on caerulein-induced acute pancreatitis were examined in rats. Acute pancreatitis was induced by caerulein (20 μg/kg, s.c.) given repeatedly 2 or 4 times every hour, and serum amylase levels, pancreas weight and myeloperoxidase (MPO) activity were measured 6 h after the first injection of caerulein. Dexamethasone (3 mg/kg) and L-NAME (30 mg/kg) were administered p.o. 30 min before the first injection of caerulein. Caerulein caused moderate or severe pancreatitis, depending on the times of injections, resulting in different degrees of increase in serum amylase levels and pancreas weight, and the marked elevation of MPO activity was observed only after injections of caerulein given 4 times per hour. Both dexamethasone and L-NAME suppressed the severity of pancreatits, yet the effect of L-NAME as compared with dexamethasone was more potent against mild pancreatitis but less potent against severe pancreatitis. These results suggest that caerulein-induced acute pancreatitis shows different responsiveness to L-NAME and dexamethasone, depending on the severity; the former is more effective against pancreatitis with less inflammation, while the latter is more effective against pancreatitis with severe inflammation. It is assumed that endogenous NO may be involved in oedema formation as the early event in the development of acute pancreatitis.     

Effects of nitric oxide synthase inhibitors on the discriminative stimulus effects of cocaine in rats

RATIONALE: Nitric oxide synthase (NOS) inhibitors may modulate the discriminative stimulus effects of cocaine because they alter dopamine (DA) release. OBJECTIVES: The effects of the NOS inhibitors NG-nitro-L-arginine methyl ester (L-NAME) and 7-nitro-indazole (7-NI) were examined in experiments designed to better understand the mechanisms that may underlie the interactions between NOS inhibitors and cocaine. METHODS: Rats were trained to discriminate 10 mg/kg cocaine from saline, and then substitution and pretreatment tests with L-NAME and 7-NI were conducted. To determine if the combined effects of NOS inhibitors and cocaine might be related to DA mechanisms and/or to N-methyl-D-aspartate (NMDA) receptor mechanisms, substitution tests with other indirect DA agonists and NMDA antagonists were carried out in the presence and absence of L-NAME. In addition, the roles of the D1 and D2 families of DA receptors in mediating the cocaine-altering effects of L-NAME and 7-NI were examined in antagonism tests using SCH 23390 and haloperidol, respectively. RESULTS: The results demonstrated that neither NOS inhibitor alone substituted for the 10 mg/kg cocaine training dose, but when given as a pretreatment, 100 mg/kg L-NAME as well as 10 mg/kg 7-NI enhanced the discriminative stimulus and rate-decreasing effects of cocaine. L-NAME pretreatment also enhanced the potency of (+)-amphetamine and GBR 12909, but not MK-801, phencyclidine, or NPC 17742, for producing discriminative stimulus and rate-decreasing effects in substitution tests. Further testing showed that the cocaine-enhancing effects of L-NAME and 7-NI were attenuated by doses of haloperidol and SCH 23390 that minimally altered the effects of cocaine alone. CONCLUSIONS: These findings suggest that L-NAME and 7-NI may increase the potency of cocaine and other indirect DA agonists through a central mechanism whereby DA neurotransmission is directly enhanced by NOS inhibition.     

孟鲁司特钠的心肌保护作用及对一氧化氮合酶的影响

目的观察白三烯受体拮抗剂孟鲁司特钠对大鼠心肌坏死的保护作用及一氧化氮合酶（NOS）的影响。方法大鼠sc异丙肾上腺素（2 mg·kg^-1）造成心肌坏死模型，ig不同剂量孟鲁司特钠，测定血清乳酸脱氢酶（LDH）、肌酸磷酸激酶（CK）、丙二醛（MDA）及心肌一氧化氮（NO）含量和坏死心肌面积，免疫组化检测心肌NOS 3种同功酶的表达。结果大鼠预先给予孟鲁司特钠10或30 mg·kg^-1可降低血清LDH，CK，MDA含量，缩小心肌坏死面积。孟鲁司特钠30 mg·kg^-1还能激活内皮型NOS（eNOS）表达，抑制诱导型NOS（iNOS）表达，促进心肌NO释放。结论孟鲁司特钠通过拮抗白三烯的致炎作用及激活eNOS、抑制iNOS表达，对大鼠异丙肾上腺素心肌坏死具有保护作用，在心肌缺血治疗中有潜在应用前景。     

Synergistic depression of NMDA receptor-mediated transmission by ketamine, ketoprofen and L-NAME combinations in neonatal rat spinal cords in vitro

BACKGROUND AND PURPOSE: Spinal N-methyl-D-aspartate (NMDA) receptor/cyclooxygenase (COX) and nitric oxide synthase (NOS) pathways play a major role in nociceptive processing, and influencing them simultaneously may induce synergistic analgesia. This study determined the spinal antinociceptive interactions between ketamine (NMDA receptor channel blocker), ketoprofen (COX inhibitor) and L-NAME (NOS inhibitor) combinations. EXPERIMENTAL APPROACH: Using an in vitro neonatal rat spinal cord preparation, two A-fibre-mediated reflexes, the monosynaptic reflex (MSR) and the low-intensity excitatory postsynaptic potential (epsp), and one C-fibre-mediated reflex, the high-intensity epsp, were evoked electrically. The effect of drugs and drug combinations on these reflexes was assessed and the type of interaction determined by isobolographic analysis. KEY RESULTS: Infusion of ketamine alone decreased all three reflexes. That of ketoprofen decreased both the low and the high-intensity epsp only. Infusion of L-NAME alone produced no significant effects. Co-infusion of fixed ratios of IC(40) fractions of both (ketamine+ketoprofen) and (ketamine+L-NAME) were synergistic for depressing the low and the high-intensity epsps. The interaction was sub-additive for both combinations on the MSR. The only significant effect for the (ketoprofen+L-NAME) combination was synergism on the high-intensity epsp. CONCLUSIONS AND IMPLICATIONS: All three combinations synergistically depressed nociceptive spinal transmission, and both ketamine and ketoprofen and ketamine and L-NAME combinations did so with potentially decreased motor side effects. If such combination profiles also occur in vivo, the present findings raise the possibility of ultimate therapeutic exploitation of increased analgesia with fewer side effects.     

唑尼沙胺对癫痫大鼠血清及脑组织 NO 含量及 NOS 活性的影响

摘要： 目的 探讨新型抗癫痫药物唑尼沙胺对癫痫大鼠血清及脑组织 NO 含量及一氧化氮合酶 （NOS） 活性的影响。方法 50 只健康雄性 SD 大鼠中随机抽取 8 只为正常对照组, 剩余 42 只全部腹腔注射戊四氮制成癫痫模型, 从中随机抽取 24 只, 以完全随机分组法分为癫痫模型组、 唑尼沙胺组及苯巴比妥组, 监测各组大鼠经药物干预后血清及脑组织 NO、 丙二醛（MDA）含量及 NOS、 超氧化物歧化酶（SOD）的活性变化。结果 35 只（83%）大鼠模型制备成功; 戊四氮致痫大鼠的脑电图中均可见阵发性癫痫波; 与正常对照组比较, 癫痫模型组和唑尼沙胺组大鼠的血清和脑组织的 NO、 MDA 含量及 NOS 活性明显升高, SOD 活性下降; 苯巴比妥组脑组织 NO、 MDA 含量升高, SOD 活性下降, 血清 MDA 含量升高。与癫痫模型组比较, 唑尼沙胺组和苯巴比妥组大鼠血清和脑组织 NO、 MDA 含量及 NOS 活性明显降低, SOD 活性升高, 差异有统计学意义 （P＜0.05）。结论 唑尼沙胺通过降低脑组织 NO 含量而发挥其抗癫痫作用。     

Pharmacokinetics and protein binding of the selective neuronal nitric oxide synthase inhibitor 7-nitroindazole

Utilization of nitric oxide (NO) synthase (NOS) inhibitors to probe the role of NO in various central nervous system processes requires use of an inhibitor selective for neuronal NOS, and is facilitated by knowledge of the pharmacokinetics of the inhibitor. The present project was undertaken to elucidate the disposition of the selective neuronal NOS inhibitor 7-nitroindazole (7-NI). A simple, specific HPLC assay was developed with requisite sensitivity to quantitate 7-NI in serum after administration of pharmacologically relevant doses. Further experiments were performed to assess the effects of administered dose on 7-NI disposition. 7-NI displayed marked nonlinearity, consistent with saturable elimination, when administered by ip injection in peanut oil. The nonlinearity was related to total dose, but not to the concentration of 7-NI in the vehicle. Binding of 7-NI in rat serum was concentration-independent and does not contribute to the nonlinearity. Various formulations for iv administration of this water-insoluble compound were evaluated; the optimal vehicle, from the standpoint of 7-NI solubility, appeared to inhibit the clearance of 7-NI from the systemic circulation. Considering the nonlinear disposition of 7-NI, knowledge of the pharmacokinetics of this inhibitor is requisite to designing administration protocols to achieve the desired magnitude and duration of NOS inhibition.     

Biology,Chemistry and Therapeutic Applications of Nitric Oxide: First International Conference

The First International Conference on the Biology, Chemistry and Therapeutic Applications of Nitric Oxide represented a milestone in the history of nitric oxide (NO) research. This meeting combined the two major conferences on NO, the Biology of Nitric Oxide and the Biochemistry and Molecular Biology of Nitric Oxide. The conference was held at the Hyatt Regency Hotel in San Francisco under the auspices of the Nitric Oxide Society. This meeting successfully brought together scientists from all disciplines currently working in the field. There were three sessions on each day of the meeting, one session for each of the three areas (biology, chemistry and therapy). Each session consisted of two plenary lectures of 20 min duration followed by a series of short 10 min papers, with a total of 70 oral presentations. The meeting also included approximately 400 excellent poster presentations and a hot topics session. All the presentations and posters were of a very high standard and the conference chairs, J Parkinson and G Rubanyi and their co-chairs and scientific advisory board are to be congratulated on such an excellent programme. This review cannot begin to attempt to cover all the contributions, but only to convey the major themes and overall enthusiasm of the meeting. The interested reader is referred to the complete abstracts of the meeting which are published in Nitric Oxide, the journal of the Nitric Oxide Society [1].     

NO 、NOS、SOD及氧自由基在分泌性中耳炎中耳积液和血清中的表达及意义

目的：探讨一氧化氮(nitric oxide，NO)、一氧化氮合酶(nitric oxide synthase，NOS)、超氧化物歧化酶(superoxide dismutase，SOD)及氧自由基在分泌性中耳炎(secretory otitis media，SOM)发病机制中的作用。方法：对实验性SOM和SOM患者中耳积液和血清中NO、NOS、SOD及氧自由基进行检测，并比较单纯应用抗生素与NO合成抑制荆 抗氧化荆 抗生素治疗SOM后血清中各指标的变化情况。结果：实验性SOM和SOM患者血清中NO、NOS、SOD、MDA含量均明显高于正常对照组。鼓室积液中NO、NOS、SOD、MDA含量均明显高于血清中含量。NO合成抑制荆 抗氧化荆 抗生素治疗SOM后血清NO、NOS、SOD、MDA含量明显低于单纯应用抗生素组，差别有统计学意义。结论：NO、NOS、SOD及氧自由基在分泌性中耳炎发病和转归中起重要作用，N-硝基-L-精氨酸甲酯(L-NAME)、维生素C、维生素E及SOD对SOM的治疗有效。     

荆花胃康胶丸对溃疡大鼠胃黏膜NO,NOS和ET含量的影响

目的:观察荆花胃康胶丸对溃疡大鼠胃黏膜内皮素(ET)、一氧化氮(NO)、一氧化氮合酶(NOS)含量的影响。方法:采用Okabe氏法造成大鼠胃溃疡模型,随机将模型动物分为蒸馏水对照组、荆花胃康胶丸30,20, 10 mg·kg~(-1)·d~(-1)组、硫糖铝10 mg·kg~(-1)·d~(-1)及法莫替丁5 mg·kg~(-1)·d~(-1)组,每组8只。各组均灌胃给药,qd,连续10 d。末次给药后次日,测定各组溃疡面积,并测定溃疡周围组织NO,NOS及ET含量。结果:与对照组相比,荆花胃康胶丸30,20,10 mg·kg~(-1)·d~(-1)组的溃疡面积显著降低,溃疡周围组织NO及NOS的含量明显增高,ET的含量明显降低(P＜0．01),且呈现剂量依赖性;荆花胃康胶丸30 mg·kg~(-1)·d~(-1)组的保护作用优于硫糖铝及法莫替丁组(P＜0．05)。结论:荆花胃康胶丸可能通过增加胃溃疡组织NO及NOS的含量及降低ET的含量来发挥胃黏膜修复作用。     

7-Nitroindazole, but not NG-nitro-L-arginine, enhances the anticonvulsant activity of pregabalin in the mouse maximal electroshock-induced seizure model

The objective of this study was to determine the effects of 7-nitroindazole (7NI--a preferential neuronal nitric oxide synthase (NOS) inhibitor) and NG-nitro-L-arginine (NNA--a non-selective NOS inhibitor) on the anticonvulsant action of pregabalin (PGB--a third-generation antiepileptic drug) in the maximal electroshock (MES)-induced seizure model in mice. Electroconvulsions were produced in mice by means of an alternating current (50 Hz, 500 V, 25 mA, ear-clip electrodes, 0.2 s stimulus duration, tonic hindlimb extension taken as the endpoint). The anticonvulsant action of PGB in the MES test was expressed as median effective doses (ED50 values) of the drug, protecting 50% of animals tested against MES-induced seizures. The acute adverse-effect potentials of PGB in combination with 7NI and NNA were evaluated in the chimney test (motor coordination), step-through passive avoidance task (long-term memory) and grip-strength test (skeletal muscular strength) in mice. 7NI (50 mg/kg, ip) significantly enhanced the anticonvulsant action of PGB by reducing the ED50 value of PGB from 145.0 mg/kg to 74.4 mg/kg (p<0.01). Similarly, 7NI at the lower dose of 25 mg/kg also potentiated the anticonvulsant action of PGB by lowering the ED50 value of PGB from 145.0 mg/kg to 117.9 mg/kg, although the results did not attain statistical significance. In contrast, NNA (40 mg/kg, ip) had no impact on the anticonvulsant effects of PGB. Moreover, none of the examined combinations of PGB with 7NI and NNA affected motor coordination, long-term memory and skeletal muscular strength in mice. Based on this preclinical study, one can conclude that 7NI significantly enhanced and NNA had no effect on the anticonvulsant activity of PGB against MES-induced seizures in mice.     

高压氧对脑梗死后血清一氧化氮和一氧化氮合酶含量的影响

目的 研究高压氧对脑梗死后血清一氧化氮、一氧化氮合酶含量的影响。方法 将脑梗死患者分为高压氧治疗组和非高压氧治疗组,观察不同病期血清一氧化氮、一氧化氮合酶含量的变化,并与正常对照组进行比较。结果 高压氧治疗组一氧化氮含量较非高压氧治疗组上升快,在治疗后15天恢复正常,但在一疗程高压氧治疗结束后,却又有所下降;一氧化氮合酶含量在治疗后均有上升,未能恢复到正常水平,两组之间无差异。结论 高压氧通过提高NO的含量,减轻缺血区脑组织的损伤,改善脑血循环;高压氧对NOS有一定影响,但作用不大;应适当延长高压氧疗程,尽可能缓解因NOS含量下降所造成的NO释放量不足。     

Suppression of nitric oxide synthesis by L-NAME reverses the beneficial effects of pioglitazone on scopolamine-induced memory impairment in mice

Pioglitazone, an agonist of peroxisome proliferator-activated receptor gamma (PPARγ), which is widely used in treatment of type 2 diabetes, has shown some therapeutic effect in Alzheimer's disease. In this study, effects of acute pioglitazone on acquisition, consolidation and retrieval of memory, and also the involvement of nitric oxide (NO) in the effects of pioglitazone on spatial recognition memory has been investigated in a two-trial recognition Y-maze test and passive avoidance in mice. Memory impairment was induced by scopolamine (1 mg/kg, i.p.). Pioglitazone (10 and 20 mg/kg, p.o.) was administrated prior to either acquisition, consolidation or retention trials, while L-NAME (N-nitro-l-arginine methyl ester), a non-specific NO synthase inhibitor, was administered (10 mg/kg, i.p.) 30 min before each trial. Results: 1) pioglitazone improved the acquisition of recognition spatial memory-impaired by scopolamine; L-NAME dramatically reversed improving effects of pioglitazone on memory acquisition; 2) pioglitazone did not change the consolidation of spatial memory, impaired by scopolamine; 3) pioglitazone improved the retrieval of spatial memory and L-NAME did not alter the beneficial effect of pioglitazone; 4) pioglitazone did not affect scopolamine-induced cognitive impairments in the passive avoidance test.The present study demonstrates the beneficial effect of acute pioglitazone administration on acquisition and retrieval of scopolamine-induced cognitive deficits. This effect was reversed only in acquisition phase by nitric oxide synthase inhibitor, L-NAME, therefore, it could be concluded that NO might be involved in the pioglitazone beneficial effect of spatial memory acquisition.     

五味子对去卵巢小鼠的记忆保持和海马NOS神经元表达的影响

目的：研究五味子（Fructus Schisandrae Chinensis）改善记忆与类雌激素作用的关系，并探讨相关的作用机制。方法：采用一次性被动回避反应行为学方法研究五味子对去卵巢小鼠记忆能力的影响；NADPH—d酶组化染色观察五味子对小鼠海马亚区一氧化氮合酶（NOS）阳性神经元形态及数日的影响。结果：去卵巢可明显降低小鼠的记忆能力，同时降低海马各区NOS阳性神经元数目。五味子醇提物具有改善去卵巢小鼠记忆保持的能力，显著增加海马各区NOS阳性神经元数目；五味子脂提物却明显抑制去卵巢小鼠的记忆保持，相应降低海马各区NOS阳性神经元的数目。结论：五味子改善记忆保持与类雌激素作用有关，其类雌激素作用的主要成分存在于乙醇提取物中，但五味子脂提物存在拮抗类雌激素的作用。影响海马各区NOS阳性神经元的合成及分布可能是五味子醇提物的类雌激素作用机制之一。     

四逆汤对失血性休克家兔一氧化氮（NO）和一氧化氮合酶（NOS）的影响

目的：探讨中药四逆汤对失血性休克家兔一氧化氮的影响。方法：采用动物分组对照实验，测量不同状态下动物血浆一氧化氮和一氧化氮合酶(NOS)的变化。结果：与休克前比较，休克组的家兔血浆一氧化氮水平各时段均明显提高(P＜0．01)，而治疗组仅在治疗后30min家兔一氧化氮及NOS水平明显提高(P＜0．01)，其他时段与休克前比较，未见显著差异(P＜0．01)，且休克后lh、4h、8h休克组一氧化氮水平显著高于治疗组(P＜0．01)。经药物治疗的失血性休克家兔血浆一氧化氮水平明显降低。