一氧化氮合成酶阳性神经元在大鼠下丘脑的分布及其衰老性变化

实验用青年（２－３个月），中年（１５－１８个月）和老年（２６－３０个月）三组Ｓｐｒａｇｕｅ－Ｄａｗｌｅｙ大鼠，采用ＮＡＤＰＨ－Ｄ酶组织化学技术及计算机图像分析，研究了一氧化氮合成酶（ＮＯＳ）阳性神经元在大鼠下丘脑的分布及其衰老性变化，结果发现，ＮＯＳ阳性神经元分布于室旁核，视上核，下丘脑外侧区，穹窿周核及乳头体核；在正中隆起我侧带发现一些小阳性神经元，第三脑室室管膜上皮层内也含有阳性神经元，我们是     

γ—氨基丁酸B受体参与猴实验性失神癫痫发作

本研究观察了γ－氨基丁酸能Ｂ受体激动剂氯苯氨丁酸和新型γ－氨基丁酸能Ｂ受体阻断剂ＣＧＰ４６３８１对猕猴由γ－羟基丁酸诱发的实验性失神癫痫发作状态的影响。静脉注射γ－羟基丁酸（２００和４００ｍｇ／ｋｇ）诱发剂量依赖性类失神癫痫发作样行为和脑电变化，其特点是双侧同步的“棘一慢波”，放电频率为１．２８～２．０８Ｈｚ（１．６０±０．１０Ｈｚ）。氯苯氨丁酸使”棘一慢波”放电时间增加，而ＣＧＰ４６３８１则使“棘一慢波”放电时间明显缩短，两者均为剂量依赖性的。静脉单独注射氯苯氨了酸也可引出类失神癫痫发作样行为和脑电变化，“棘一慢波”频率为１．２５～２．３３Ｈｚ（１．７６±０．１２Ｈｚ）。结果提示脑内Ｂ型γ－氨基丁酸能递质活动的增强很可能是失神性癫痫发作的主要原因。同时，γ－氨基丁酸能Ｂ受体阻断剂有希望成为新型抗癫痫药物。     

脑型和诱导型一氧化氮合成酶mRNA在大鼠体内表达的差异

本研究用逆转录/聚合酶链式反应（RT/PCR）技术检测脑型和诱导型一氧化氮合成酶（NOS）mRNA在Sprague—Dawley大鼠大脑皮质、垂体、小脑、心脏、肺脏、肝脏、脾脏、小肠、肾脏和肾上腺的表达。结果发现，脑型NOSmRNA表达于小脑、心脏和肾上腺组织；而诱导型NOSmRNA表达于中枢神经系统以外的所有受检组织。本文初步探讨了各组织NOSMRNA表达阳性的生理意义。     

EFFECTS OF VALSARTAN ON STRESS-INDUCED CHANGES OF SERUM VASCULAR ENDOTHELIAL GROWTH FACTOR AND NITRIC OXIDE IN MICE

This study investigated the effects of renin-angiotensin system (RAS) blockade on stress-induced changes of serum vascular endothelial growth factor (VEGF) and nitric oxide (NO) in mice. Chronic stress increased the serum NO levels significantly compared to control group (p = .0172). Valsartan, an angiotensin II receptor antagonist, alone, did not make significant difference versus control group. In chronic stress + valsartan group, serum NO levels decreased nonsignificantly compared to chronic stress group. There was a nonsignificant increase in serum VEGF levels after chronic stress. Valsartan alone or with chronic stress did not significantly affect the serum VEGF levels. In conclusion, there was no correlation between NO and VEGF changes during the stress response. In this respect, there may be other mechanisms to explain the stress-induced NO increase.     

L-NAME减少三叉神经脊束核尾侧段和上颈髓后角c-fos和nNOS的表达

目的:进一步研究NO在偏头痛发病机制中的作用,探讨三叉神经血管反射的中枢机制。方法:应用电刺激猫上矢状窦区硬脑膜动物模型,冰冻组织连续切片后行免疫组化染色,分别观察了NOS抑制剂Nω-nitro-L-argi-nine methylester(L-NAME,100mg/kg)对下延髓、上颈髓c-fos蛋白和神经元型NOS(nNOS)表达的影响。结果:c-fos和nNOS阳性神经元主要位于延髓三叉神经脊束核尾侧段和C1后角的浅层(Ⅰ、Ⅱ层),其深层、孤束缝核和中央核、中央导水管两侧可见数个直径较大、轴突较长的nNOS阳性神经元;而nNOS阳性神经纤维遍布后角及中央导水管两侧,并似向前角和后角浅层方向投射,其中后角浅层着色明显比其它部位深。电刺激后可见较长的纤维呈串珠样改变。刺激组动物的c-fos及nNOS阳性神经元数均比假手术对照组明显增加(P<0.01),L-NAME组比刺激组明显减少(P<0.01),而刺激组动物的c-fos及nNOS阳性神经元数与生理盐水组相比均无显著差异(P>0.05)。结论:刺激猫上矢状窦区硬脑膜可激活三叉神经脑干中枢神经元,L-NAME可能通过抑制NO的生成阻断此部位神经元的激活,从而终止偏头痛发作。     

The influence of L-NG-nitroarginine methyl ester, an inhibitor of nitric oxide synthase, upon the anticonvulsive activity of conventional antiepileptic drugs against maximal electroshock in mice

Summary. N^G-Nitro-L-arginine methyl ester (L-NAME, an unspecific nitric oxide synthase inhibitor), applied at 1 and 40 mg/kg, did not influence the electroconvulsive threshold, but impaired the anticonvulsant activity of valproate (at 40 mg/kg) and phenobarbital (at 1 and 40 mg/kg). No effect was observed in the case of carbamazepine and diphenylhydantoin. The effect of L-NAME upon the protective activity of phenobarbital was not reversed by L-arginine (500 mg/kg), a source of endogenous nitric oxide. Moreover, this nitric oxide synthase inhibitor did not alter the plasma levels of antiepileptic drugs studied, so a pharmacokinetic interaction is not probable. L-NAME per se (40 mg/kg) caused a moderate motor impairment but did not affect long-term memory. The combined treatment of L-NAME and antiepileptic drugs (providing a 50% protection against maximal electroshock) resulted in motor disturbances. On the other hand, mice performed the memory task better upon combined treatment of antiepileptic drugs with L-NAME compared to antiepileptic drugs alone. A 4-day administration of L-NAME, similarly to acute injections, decreased the protective action of phenobarbital but not that of diphenylhydantoin. The results indicate that L-NAME is able to reduce the protective activity of some conventional antiepileptics and this effect may be not associated with impaired synthesis of nitric oxide. Accepted November 19, 1997 / Received July 15, 1997     

NITRIC OXIDE SYNTHASE INHIBITION SUPPRESSES WET DOG SHAKES AND AUGMENTS CONVULSIONS IN RATS

Electrical stimulation of limbic structures, pharmacological interventions, and getting wet induces wet dog shakes (WDS) in rats. WDS are often associated with the occurrence of seizures. In this study, we evaluated the effects of reduced NO production on physiologically (wetting)- or pharmacologically (kainic acid; KA)-induced WDS and KA-triggered seizures. Following wetting, naive and saline-treated rats displayed more WDS than rats treated with NO synthase (NOS) inhibitor, N^ω-nitro-L-arginine (L-NA). In another experiment, WDS and seizures were monitored after KA treatment alone or in combination with L-NA. Again, NOS inhibition reduced the number of KA-triggered WDS but augmented the number and severity of seizures. Our results suggest that not only do physiologically- and kainate-induced WDS share a common mechanism that includes NO, but that there is also an antagonism between WDS and convulsions.     

NITROUS OXIDE ACUTELY SUPPRESSES ETHANOL CONSUMPTION IN HAD AND P RATS

Nitrous oxide (N₂O) has been reported to reduce post-withdrawal craving in alcoholic humans, aiding in their continued abstinence. This article assessed the ability of N₂O to suppress alcohol drinking in genetically selected high alcohol-drinking (HAD) and alcohol-preferring (P) rats. Although water was available ad libitum, they were accustomed to a limited access (1 h/day) choice between 10% ethanol (EtOH) and water. When drinking stabilized, the rats were exposed for 30, 60, or 120 min to a mixture of N₂O and pure oxygen, timed to end 1 h before the limited access. N₂O suppressed EtOH consumption at 1, but not 25 h after exposure in both HAD and P rats. This result is consistent with the efficacy of N₂O for acute reduction of EtOH drinking, and supports further research into the use of N₂O as an adjunct to treatment.     

ROLE OF NITRIC OXIDE ON AGE-DEPENDENT ALTERATIONS: INVESTIGATION OF ELECTROPHYSIOLOGIC AND BIOCHEMICAL PARAMETERS

In this experiment 40 young (3 months) and 40 middle-age (12 months) Wistar rats were used as subjects. These animals were assigned to eight groups as: young control (YC), middle-age control (MC), young + L-arginine (YA), middle-age + L-arginine (MA), young + L-NAME (YN), middle-age + L-NAME (MN), young + vitamin E (YE), and middle-age + vitamin E (ME). While physiological solution was administered to control groups, 160 mg/kg/day L-arginine, 10 mg/kg/day L-NAME, and 25 mg/kg/day vitamin E were injected into the experimental groups. After eight weeks of treatment, visual-evoked potentials (VEPs) were recorded, and thiobarbituric acid reactive substances (TBARS) and nitrite levels were determined in all experimental groups. It was observed that brain TBARS and nitrite levels increased significantly with age. There were also significant increments in the brain TBARS levels of YN and MN groups with respect to their controls. Although brain TBARS levels in YA, MA, YE, and ME groups were found to be increased compared with their corresponding controls, they didn t reach statistically significant levels. Brain nitrite level was found to be significantly decreased in the MN group, but increased in the MA group compared with the MC group. However, vitamin E caused a significant decrement in brain nitrite levels of YE and ME groups with respect to their control groups. P1 in the YN group and P1, P2, and N2 components in the MN group were delayed with respect to their corresponding controls, yet there were no significant changes between other groups. Data obtained from amplitudes showed that P2N2 and N2P3 amplitudes were decreased significantly in MN and ME groups with respect to the MC group. However, there were no important changes in amplitudes of other groups.     

EFFECTS OF FLUVOXAMINE ON LEVELS OF DOPAMINE,SEROTONIN, AND THEIR METABOLITES IN THE HIPPOCAMPUS ELICITED BY ISOLATION HOUSING AND NOVELTY STRESS IN ADULT RATS

The authors investigated the effects of fluvoxamine on neurochemical changes in the hippocampus elicited by isolation housing and novelty stress. Male F344 rats (11 w) were housed one per cage for four weeks. On each day of the last week (7 days) they were s.c. injected with fluvoxamine (20 mg/kg), and then subjected to novelty stress. Isolation housing significantly increased dihydroxyphenyl-acetic acid (DOPAC) and 5-hydroxyindoleacetic acid (5-HIAA) levels, whereas fluvoxamine significantly decreased them. Isolation housing significantly increased the DOPAC/DA ratio. Fluvoxamine significantly decreased the DA level, and partially restored the DOPAC and 5-HIAA levels increased by isolation housing.     

Is nitric oxide involved as a mediator of cerebrovascular changes in the early phase of experimental pneumococcal meningitis?

Abstract

Nitric oxide (NO) is a mediator of haemodynamic changes and cytotoxicity in in vivo models of inflammation such as endotoxaemic shock. The purpose of this study was to investigate whether NO may be involved in the increase of cerebral blood flow (CBF), intracranial pressure (ICP) and brain water content, known to occur in the early phase of pneumococcal meningitis. Rats injected intracisternally with live pneumococci were either untreated or received 5 mg kg^–1 i.v. N^G-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthase. Pretreatment with L-NAME prevented the increase in CBF, ICP and brain water content, as seen in untreated animals. CBF tended to return towards baseline when rats were treated with L-NAME 2 h after pneumococcal injection. Whereas none of the untreated and L-NAME-pretreated animals died during the 6 h observation period 3 out of 9 rats treated with L-NAME and 7 out of 9 rats with simultaneous i.v. injection of L-NAME and L-arginine died. Our results provide preliminary evidence that NO may be involved as a mediator of CBF changes and oedema formation in the early phase of pneumococcal meningitis in the rat. NO inhibition, however, may have detrimental effects of still unidentified cause, as indicated by the increased mortality in treated animals. Further studies with analysis of the causes of mortality, structurally different NO synthase inhibitors and direct evaluation of NO synthase induction are needed to further support this hypothesis. [Neurol Res 1994; 16: 108-112]     

PSYCHOTROPIC ANALGESIC NITROUS OXIDE FOR ACUTE COCAINE WITHDRAWAL IN MAN

This article reports the first single-blind study using psychotropic analgesic nitrous oxide (PAN) for treating acute withdrawal states following cocaine abuse. Thirty-one of the 33 cases responded by a reduction of symptom scores of 50% or more, which clinical experience has shown to be synonymous with observed recovery. Five subjects were placebo responders without further improvement following PAN. Eleven subjects were not improved by placebo but responded positively to PAN. Fifteen responded to both the O₂ with a further improvement following PAN. Aggregate scores of symptoms such as craving, anxiety, and dysphoria were greatly decreased by O₂. These improvements were even greater following PAN as compared to post O₂ scores. Two patients failed to respond to any treatment condition. Thus 93.9% of the subjects were improved by the use of PAN and/or O₂ alone.     

Nitric oxide and gamma-aminobutyric acid as regulators of neurogenesis in the brain of adult mammals: Models of seizure activity

New neurons are known to be generated in the brain of adult mammals throughout their entire life in the area of the lateral ventricles and the subgranular zone of the dentate gyrus. The regulatory mechanisms of neurogenesis are complex and poorly understood. Numerous studies performed during the last decade have shown that the intensity of generation of new cells in the germinative regions of the brain is significantly influenced by various environmental factors. Pronounced changes in neurogenesis were also found in the models of various pathologies of the central nervous system (such as neurodegeneration, brain ischemia, and epilepsy). This review is focused on the regulation of neurogenesis in the brain of adult mammals in the course of experimental epilepsy. The involvement of nitric oxide and gamma-aminobutyric acid in the regulation of the proliferation and differentiation of brain cells during seizure activity is discussed.     

SEX AND HANDEDNESS DIFFERENCES IN EYE-HAND VISUAL REACTION TIMES IN HANDBALL PLAYERS

Sex and handedness differences in the eye-dominant hand, the right eye-right hand and the left eye-left hand visual reaction times were studied in 270 right-handed and 56 left­-handed young handball players. Reaction­ time was assessed by a software package. All visual reaction times were longer in women than in men. In the eye-dominant hand and the left eye-­left hand visual reaction times, the left-handers had a superiority over the right handers, but there was no difference between the right eye-right hand visual reaction times of the right- and left-handers. In right-handers, all visual reaction times were longer in women than in men, but there was no sex difference in left-handers. The results suggest that left-handed players have probably an intrinsic neurological advantage.     

神经生长因子对严重烫伤大鼠纹状体及海马NOS阳性神经元的影响

应用ＮＡＤＰＨ－ｄ 酶组织化学方法,观察了大鼠烫伤后脑内ＮＯＳ阳性神经元数目和阳性反应面积的变化及ＮＧＦ对其影响。结果显示：大鼠体表烫伤后３ 天,纹状体ＮＯＳ阳性神经元数目明显增加,染色呈强阳性,阳性反应面积增加。海马的ＮＯＳ阳性神经元数变化不明显,仅见阳性反应面积增加,ＮＧＦ可降低纹状体的ＮＯＳ阳性神经元数目、阳性反应面积,ＮＯＳ阳性神经元着色较淡;海马的ＮＯＳ阳性反应面积减少,ＮＧＦ的作用与Ｌ－ＮＡＭＥ抑制ＮＯＳ的作用相似。这些结果提示,ＮＧＦ可能通过降低ＮＯＳ活性,从而减轻烫伤引起的神经元损伤。     

Influence of endothelial nitric oxide synthase gene polymorphisms (-786T>C, 4a4b, 894G>T) in Korean patients with coronary artery disease

INTRODUCTION: Endothelium-derived nitric oxide (NO) is synthesized from l-arginine by endothelial nitric oxide synthase (eNOS) encoded by the eNOS3 gene on chromosome 7. The effects of the eNOS polymorphisms with the risk of coronary artery disease are conflicting. In this study, we investigated the association of the eNOS genotypes with coronary artery disease in Koreans. MATERIALS AND METHODS: A case-control study was performed to evaluate the association between the eNOS -786T>C, 4a4b, or 894G>T polymorphism and coronary artery disease. 147 consecutive patients with coronary artery disease and 222 healthy controls were recruited. The genotypes of eNOS -786T>C and 894G>T polymorphisms were determined by the polymerase chain reaction-restriction fragment length polymorphism analysis. The genotypes of a 27 bp insertion/deletion in intron 4 (eNOS 4a4b) were determined by the banding pattern on gel electrophoresis. RESULTS: The eNOS -786T>C (odds ratio [OR]; 1.61, 95% confidence interval [CI]; 0.97-2.69), 894G>T (OR; 1.12, 95% CI; 0.65-1.92) and 4a4b (OR; 1.44, 95% CI; 0.87-2.39) polymorphisms were not an independent predisposition factor to coronary artery disease. However, a subgroup analysis adjusted with various cardiovascular risk factors confirmed positive association of the -786T>C polymorphism in CAD patients with hypertension and a smoking history and also a significant association of the intron 4 genotypes with a smoking history, but no significance has been found in the eNOS polymorphisms of 894G>T upon any risk adjustment. In this study we also found that the distribution of heterozygotes (-786TC, 894GT, and 4a4b) and variant homozygotes for the -786C, 894T, and intron 4a alleles of eNOS in Koreans were significantly lower than in Caucasian populations. CONCLUSIONS: The present study demonstrates that polymorphisms of the eNOS -786T>C and 4a4b are associated with coronary artery disease with adjustments for cardiovascular risk factors in the Koreans.     

Brief Communication SEX DIFFERENCES AND RIGHT-LEFT ASYMMETRIES IN RAT HIPPOCAMPAL COMPONENTS

Previous reports have indicated morphologic hippocampal asymmetry in thickness in male and female rats. In the present study, the possible sex differences and right-left asymmetries in rat hippocampal components were investigated. Pyramidal cells in four hippocampal sectors on thionin-stained sections were counted and the thickness of the hippo campal components was measured on microslide-projected images. The present study showed significant sexual dimorphism in two hippocampi as well as asymmetry in male. These findings agree with those found in humans.     

SEX DIFFERENCES IN HUMAN LYMPHOCYTE Na,K-ATPase AS STUDIED BY LABELED OUABAIN BINDING

Lymphocytes Na,K-ATPase is a plasma membrane enzyme that is up-regulated under lymphocytes activation. It is also studied as a model of brain cells Na,K-ATPase. Data about sex-related specificities of the enzyme are not available.The binding of tritium-labelled ouabain to lymphocyte plasma membrane Na,K-ATPase was studied in healthy volunteers of both sexes. The binding interactions were expressed in terms of K_D and B_Max. The first parameter is related to the affinity of ouabain for the enzyme whereas the second one is related to its density on the cell membrane. Distinct sex-related differences were found. Whereas in males there is a significant direct correlation between the parameters K_D and B_Max, in females this is not present. However, in females there is a significantly lower K_D in the 25–37 age range. The latter result probably reflects the expression of subunit variants giving a greater affinity for ouabain. This circumstance may be relevant both to lymphocytes’ ability to be activated and to brain function, if one admits that lymphocyte Na,K-ATPase faithfully represents the brain-borne one.     

SEX AND HANDEDNESS DIFFERENCES IN HEARING DURATIONS OF THE RIGHT AND LEFT EARS IN HEALTHY YOUNG ADULTS

The aim of this work was to study the sex and handedness differences in hearing durations of the right and left ears in healthy young adults. The hearing durations were assessed using a modified Rinne test. The hearing durations of both the right and left ears were longer in males than females. In right-handers, the hearing duration of the right ear was longer than that of the left ear; in left-handers, the hearing duration of the left ear was longer than that of the right ear. These results suggest a male superiority in auditory perceptual acuity; a left-ear advantage in left-handers may result in the superiority of non-right-handers in musical tasks.     

EVALUATION OF BRAINSTEM AUDITORY POTENTIAL IN BRUCELLOSIS PATIENTS WITH AND WITHOUT NEUROLOGICAL INVOLVEMENT

This study investigated the changes in brainstem auditory evoked potentials (BAEPs) in acute phase of brucellosis. Twenty-two patients with brucellosis without neurologic involvement and seven patients with neurobrucellosis were included. BAEPs were evaluated before treatment. No patient had a symptom of hearing loss. Patients who had neurologic involvement did not show any abnormalities in their BAEPs recording. This study suggests that patients with brucellosis who are in the acute phase of the disease with or without neurological involvement may have normal BAEPs. BAEPs do not seem to be a sensitive method for central nervous system involvement of brucella patients in the acute phase of the disease.