电刺激三叉神经节对蝶腭神经节内一氧化碳合酶和血管活性肠肽阳性神经元的影响

目的：观察实验性偏头痛大鼠副交感神经蝶腭神经节内一氧化氮合酶（NOS）和血管活性肠肽（VIP）阳性神经元的变化。方法：12只雄性SD大鼠随机分为实验组和对照组（均n=6）。实验组为电刺激三叉神经节建立的偏头痛大鼠模型。对照组仅作手术而不刺激三叉神经节。用组织化学的方法观察蝶腭神经节内NOS阳性神经元的变化,用免疫荧光法观察蝶腭神经节内V1P阳性神经元的变化。结果：实验组和对照组大鼠的蝶腭神经节内均有NOS和VIP阳性神经元,但实验组NOS和VIP阳性神经元均较对照组显著增加（P〈0．01）。结论：电刺激三叉神经节可以通过三叉-副交感神经反射系统,显著升高蝶腭神经节中NOS和VIP神经元的数目。偏头痛发病过程中脑膜及颅内大血管的剧烈扩张很可能与蝶腭神经节中NOS和VIP神经元增加有关。     

Anticonvulsant Activity of New and Potent Inhibitors of Nitric Oxide Synthase

The effects of new and potent NOS inhibitors, S-methyl-

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-thiocitrulline (S-Me-TC), 3-bromo 7-nitro indazole (3-Br-7-NI), and 1-(2-trifluoromethylphenyl)imidazole (TRIM), were examined on the pilocarpine-induced seizures in mice. 3-Br-7-NI and TRIM decreased the frequency of status epilepticus and mortality, while TRIM, in addition, significantly reduced the incidence of seizures. The latencies to onsets of seizures, status epilepticus, and mortality were significantly prolonged by all three NOS inhibitors, while duration of seizures was reduced by 3-Br-7-NI and TRIM. These data suggest an excitatory effect of NO in the neuronal structure involved in the pilocarpine-induced seizures.     

Retinal Ganglion Cell Depletion Alters the Phenotypic Expression of GABA and GAD in the Rat Retina

We have looked at the phenotypic expression of γ-aminobutyric acid (GABA) and the two isoforms of its synthetic enzyme [glutamic acid decarboxylase (GAD)-65 and -671 in adult rat retinas that had the superior colliculus, pretectum and optic tract lesioned unilaterally at birth. It has been shown previously that this type of manipulation induces retrograde degeneration of retinal ganglion cells presumably without affecting other intraretinal neurons. We present evidence that GABAergic amacrine cells are affected by such manipulation. The number of cells immunoreactive for GABA, GAD-65 and GAD-67 decreased in the inner nuclear layer. In the retinal ganglion cell layer, however, the number of GABA- and GAD-65–labelled cells increased, while the number of GAD-67–labelled cells did not change. Biochemical assay showed that overall GAD activity was not altered in retinas of lesioned animals. Our results support the notion that, while neonatal lesion reorganizes the expression of GABA and GAD in the retina, enzyme activity is maintained within normal levels.     

Effect of Nitric Oxide Synthase Inhibition on Fos Expression in the Hypothalamus of Female Rats Following Central Oxytocin and Systemic Urethane Administration

Three experiments were carried out to investigate the pattern of neuronal activation induced by central oxytocin administration and its modulation by nitric oxide (NO). First, we compared the induction of Fos-like immunoreactivity (lir) in the supraoptic (SON) and paraventricular (PVN) nuclei and medial preoptic area (MPOA) after central oxytocin administration between nonlactating and lactating rats. Next, we investigated whether NO modulated Fos induction following central oxytocin administration using a nitric oxide synthase (NOS) inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME). Finally, to determine whether the effects of NOS inhibition on Fos induction would generalize to stimuli other than oxytocin, we compared Fos-lir in the SON and PVN of lactating and nonlactating rats following L-NAME and urethane administration. In the first two experiments, oxytocin (50 ng in 2 microl) or vehicle was administered into the third ventricle. L-NAME (50 mg/kg) was given by an intraperitoneal (i.p.) injection 30 min before oxytocin administration (experiment 2) or an i.p. injection of urethane (1.4 g/kg) (experiment 3). In all experiments, lactating rats were tested on day 12 or 13 postpartum and nonlactating females at least 11 days after surgery or the start of the experiment. Central oxytocin infusion induced Fos expression in the SON and PVN in lactating and nonlactating rats and in the MPOA and bed nucleus of the stria terminalis in lactating rats. Overall, lactating rats that received L-NAME and oxytocin had a greater number of cells showing Fos-lir in both the SON and PVN. Conversely, L-NAME administration reduced Fos-lir in the SON and PVN in oxytocin-stimulated nonlactating rats. In urethane-treated rats, L-NAME administration did not change Fos-lir in lactating rats but reduced Fos-lir in nonlactating rats. These data suggest that the role of NO in modulating the activity of neurones in discrete nuclei in the hypothalamus varies across reproductive state and with the stimulus presented.     

Effect of Collicular Proteoglycan on the Survival of Adult Rat Retinal Ganglion Cells Following Axotomy

Consistent with numerous previous studies, we have found that in adult rats 29% of cells retrogradely prelabelled by injections into retino-recipient nuclei are lost 1 week after intraorbital section of the optic nerve. This figure increases to 76% 2 weeks after axotomy. Intraocular injections of 150 ng of 480 k d a chondroitin sulphate proteoglycan purified from the superior colliculi of neonatal rats were performed every third day after axotomy. This procedure resulted in the loss of only 3 and 28% of the axotomized retinal ganglion cells 7 and 14 days respectively after optic nerve section. Intraocular injections of chondroitin sulphate type C, one of the sugar types present on the collicular proteoglycan, also resulted in a significant saving of axotomized ganglion cells (with the loss of only 48% 14 days after optic nerve lesion). These findings suggest that the collicular proteoglycan, and to a lesser extent its sugar moieties, substantially slows down the degeneration of adult retinal ganglion cells following axotomy.     

脑缺氧缺血新生大鼠诱生型一氧化氮合酶基因的表达及其与脑细胞凋亡的关系

目的　探讨新生大鼠缺氧缺血后脑内诱生型一氧化氮合酶 (i NOS)基因表达的变化及其与脑缺氧缺血所致细胞凋亡的关系。方法　建立新生大鼠缺氧缺血性脑损伤动物模型 ,应用快速竞争性逆转录 PCR技术及原位末端标记法观察脑缺氧缺血后不同时间点缺氧缺血侧大脑组织中 i NOS m RNA的表达及神经细胞凋亡的情况。结果　新生大鼠缺氧缺血后 ,缺氧缺血侧大脑 i NOS m RNA表达自 6h开始明显增强 ,其相对表达量为(0 .41± 0 .1 3 ) ;2 4h达高峰 ,相对表达量为 (2 .0 2± 0 .2 4) ,7d时回至基线水平。缺氧缺血侧脑组织中凋亡细胞数目亦自缺氧缺血后 6h开始明显增多 ,平均为 (2 1 .3± 3 .5 ) /1 0个高倍视野 (1 0 hpf) ;2 4h达高峰 ,约 (63 .7±3 .2 ) /1 0 hpf,与对照组 [平均为 (7.3± 2 .3 ) /1 0 hpf]比较差异有显著性 (P <0 .0 1 )。i NOS m RNA的表达高峰与缺氧缺血后脑细胞凋亡的高峰时相相吻合。结论　缺氧缺血可使新生大鼠脑 i NOS m RNA的表达增强和凋亡细胞增加 ,i NOS过表达在缺氧缺血后脑细胞凋亡的调控过程中起一定作用。     

Relationship of Neuronal Nitric Oxide Synthase Immunoreactivity to GnRH Neurons in the Ovariectomized and Intact Female Rat

The present study has used a rat neuronal nitric oxide synthase (nNOS) antibody to examine the relationship of nNOS immunoreactivity to GnRH neurons in the ovariectomized and intact diestrous and proestrous rat. A striking band of nNOS-immunoreactive cells was identified in the rostral preoptic area which began in the median preoptic nucleus and organum vasculosum of the lamina terminalis and formed an inverted Y-type distribution above the rostral third ventricle at the level of the anteroventral periventricular nucleus. Another band of nNOS-immunoreactivity was found extending through the internal zone of the median eminence into the arcuate nucleus. Although nNOS immunoreactivity was not detected within GnRH neuronal cell bodies in any of the experimental groups, GnRH perikarya located in the rostral preoptic area, but not elsewhere, were found to be surrounded by nNOS-containing cells. In the median eminence, nNOS and GnRH immunoreactivities were distributed separately in the internal and external zones, respectively.
These results provide evidence that, regardless of their pattern of activity, GnRH neurons in the female rat do not express nNOS. Instead, a close anatomical relationship between nNOS-immunoreactive cells and GnRH perikarya and fibers has been identified within specific sub-regions of the rostral preoptic area and in the median eminence. Such findings are compatible with a role for NO at both sites in regulating the release of GnRH throughout the estrous cycle.     

Implication of Nitric Oxide in NGF-Induced Cell Differentiation: Differences Between Neuronal and Beta Cells

Both pancreatic beta cells (insulin-secreting cells) and neuronal cells express functional receptors for nerve growth factor. However, while the effect of nerve growth factor on neuronal differentiation is well known, its role on pancreatic beta cells is not established. It has been demonstrated that in PC12 cells, a well characterized NGF-responsive cell line, NGF increases the production of nitric oxide by inducing the expression of nitric oxide synthase. Nitric oxide is subsequently responsible for growth arrest, a step necessary for neuronal differentiation, visualized by the extension of neuronal-like processes. In the present study, we studied the effect of nerve growth factor on nitric oxide synthesis in INS-1 cells, an insulin-producing cell line which possesses the machinery necessary to respond to nerve growth factor. It was demonstrated that the expression of none of the three isoforms of nitric oxide was induced by nerve growth factor in INS-1 cells, strongly suggesting that nerve growth factor does not induce an increase in nitric oxide production in this cell line. Finally, we demonstrated that whereas growth arrest occurred in INS-1 cells cultured in the presence of a donor of nitric oxide (SNP), the simultaneous addition of SNP and nerve growth factor is not sufficient to induce the extension of neuronal-like processes in INS-1 cells. These dissimilarities strongly suggest that NGF plays a different role in neuronal and pancreatic beta cells.     

Expression of Immunoreactivity to Neurokinin-1 Receptor by Subsets of Cranial Parasympathetic Neurons: Correlation with Neuropeptides, Nitric Oxide Synthase, and Pathways

We examined the patterns of coexistence of immunoreactivity to the neurokinin-1 (NK(1)) tachykinin receptor, nitric oxide synthase, and neuropeptides in the sphenopalatine and otic ganglia of guinea pigs using a combination of multiple-labeling immunohistochemistry and pathway tracing in vitro. Most neurons had immunoreactivity to vasoactive intestinal peptide (85-96%) and neuropeptide Y (60%). Subpopulations of vasoactive intestinal peptide-immunoreactive neurons also had immunoreactivity to nitric oxide synthase (37-48%) or enkephalin (25-35%), but these formed mutually exclusive populations. Almost all neurons expressing NK(1) receptor immunoreactivity contained immunoreactivity to enkephalin, vasoactive intestinal peptide, and neuropeptide Y, but not nitric oxide synthase. Using a combination of retrograde axonal tracing and axonal crushing, we found that most neurons with immunoreactivity to nitric oxide synthase projected along the nasopalatine and ethmoidal nerves to the nasal mucosa. In contrast, most neurons with immunoreactivity to enkephalin followed the zygomatic nerve to the facial skin and lacrimal gland. Based on their peptide content, we conclude that the neurons with immunoreactivity to enkephalin and NK(1) receptor projected selectively to the skin. In both the sphenopalatine and the otic ganglia, about half of the neurons with NK(1) receptor immunoreactivity were surrounded by varicose nerve fibers with substance P immunoreactivity. Many of these fibers are likely to have originated in the trigeminal ganglion. Taken together, these observations establish a strong anatomical basis for a range of interactions between trigeminal and cranial parasympathetic pathways that may underlie pathophysiological conditions such as trigeminal neuralgia.     

Induction of Adhesion/Differentiation of Human Neuroblastoma Cells by Tumour Necrosis Factor-α Requires the Expression of an Inducible Nitric Oxide Synthase

Neuroblastoma cell lines (SK-N-SH and SK-N-MC) were induced to differentiate, as detected by the expression of neurofilament proteins of 68 and 200 kDa, and to express adhesion molecules (intercellular adhesion molecule-1 and vascular cell adhesion molecule) after stimulation with tumour necrosis factor-α (TNF-α). This induction was accompanied by the arrest of cell growth. The induction of neuroblastoma adhesion by TNF-α could be inhibited by the nitric oxide synthase inhibitors, L-N-monomethyl arginine (L-NMMA) and _L-N⁶-(1–imidoethyl)-lysine (highly specific for the inducible enzyme), but not by the inactive enantiomer D-NMMA. These results indicate that TNF-α induces the adhesion of neuroblastoma cells via nitric oxide. This was confirmed by the finding that the adhesion/differentiation of SK-N-SH and SK-N-MC cells can be directly induced by the addition of nitric oxide donors, sodium nitroprusside and S-nitroso- N -acetyl-penicillamine, into the culture medium. The isoform of the nitric oxide synthase induced in human neuroblastoma cells by TNF-α treatment was identified enzymatically as isoform II by Western blotting and by the polymerase chain reaction. Thus TNF-α induces the in vitro adhesion/differentiation of human neuroblastoma cells through nitric oxide synthesized by a calcium-independent inducible form of nitric oxide synthase, clearly indicating that isoform II of nitric oxide synthase can be expressed in human neuronal cell types.     

Benign Multiple Sclerosis is Associated with Reduced Thinning of the Retinal Nerve Fiber and Ganglion Cell Layers in Non-Optic-Neuritis Eyes

Background and Purpose

It is exceedingly difficult to differentiate benign multiple sclerosis (BMS) from relapsing-remitting multiple sclerosis (RRMS) based on clinical characteristics, neuroimaging, and cerebrospinal fluid tests. Optical coherence tomography (OCT) allows quantification of retinal structures, such as the retinal nerve fiber layer (RNFL) thickness, at the optic disc and the ganglion cell layer (GCL) at the macula, on a micrometer scale. It can also be used to trace minor alterations and the progression of neurodegeneration, help predict BMS, and influence the choice of therapy. To utilize OCT to detect the extent of changes of the optic disk and macular microstructure in patients with BMS and RRMS compared to healthy controls (HCs), with special focus on changes related to the presence/absence of optic neuritis (ON).

Methods

Spectral-domain OCT was applied to examine eyes from 36 patients with multiple sclerosis (MS), comprising 11 with BMS and 25 with RRMS, and 34 HCs.

Results

The RNFL and GCL were significantly thinner in eyes previously affected by ON, irrespective of the type of MS (i.e., BMS or RRMS), than in HCs. Significant thinning of the GCL was also observed in non-ON RRMS (and not non-ON BMS) compared to HCs. Correspondingly, a significant association between disease duration and thinning rates of the RNFL and GCL was observed only in non-ON RRMS (-0.54±0.24 and -0.43±0.21 µm/year, mean±SE; p<0.05 for both), and not in non-ON BMS (-0.11±0.27 and -0.24±0.24 µm/year).

Conclusions

The RNFL and GCL were thinner in both ON- and non-ON MS, but the change was more pronounced in ON MS, irrespective of the MS subtype studied herein. GCL thinning and the thinning rate of both the GCL and RNFL were less pronounced in non-ON BMS than in non-ON RRMS. These findings may help to predict the course of BMS.     

Quantitative Immunohistochemical Analysis of Nitric Oxide Synthases and Apoptosis Regulator Proteins in the Fetal Rat Brain Following Maternal Uterine Artery Ligation

The purpose of this study was to determine the relation between nitric oxide synthases (calcium-independent iNOS and calcium-dependent eNOS) and apoptosis regulator proteins (anti-apoptotic Bcl-2, pro-apoptotic p53) of fetal rat brain in experimental intrauterine growth retardation (IUGR) model via quantitative immunohistochemistry. Cortical zone of parietal cerebral cortex and ventricular zone of third ventricle were studied following bilateral uterine artery ligation on gestational day 18. Significant increase in iNOS immunoreactivity was determined in parietal cerebral cortex and ventricular zones as eNOS immunoreactivity increased in ventricular zone of IUGR group. Bcl-2 expression was significantly decreased in ventricular zone; whereas cortical zone of IUGR group expressed p53 immunoreactivity.     

Comparative Distribution of Nitric Oxide Synthase (NOS) in Pancreas of the Dog and Rat: Immunocytochemistry of Neuronal Type NOS and Histochemistry of NADPH-Diaphorase

We investigated the localization of nitric oxide synthase in the pancreas of the dog in comparison to the rat by the methods of immunocytohemistry using antineuronal type nitric oxide synthase serum and histochemistry using NADPH-diaphorase activity. In both species, the most intense staining was observed in neuronal cell bodies and fibers in the pancreas and nitric oxide synthase immunoreactivity was completely colocalized with NADPH-diaphorase activity. However, there were differences of the distribution between the two species. In the dog pancreas, immuno- and NADPH-diaphorase-positive nerve fibers were numerous around pancreatic ducts and moderate around the arteries and the acini but few in the islets. In contrast, in the rat pancreas, immuno- and diaphorase-positive fibers were fewer around the pancreatic ducts and acini and more abundant in the islets. The expression ratio of NADPH-diaphorase in intrapancreatic ganglion cell bodies that were scattered in the interlobular connective tissue was low to moderate (28.1% in the right lobe, 49.5% in the left lobe) in the dog, while the ratio in rat pancreas was very high in both lobes of the pancreas (about 86%). Except for neuronal staining, weak NADPH-diaphorase-positive reactions were detected in the vascular endothelial cells of the pancreas in both species. In rat islet cells, weak neuronal type nitric oxide synthase immunoreactivity was observed; however, in dog islet cells, no immunoreactivity was detected. These results suggest that nitric oxide in the pancreas is derived from vascular endothelium and neuronal tissue in both species and that the neuronal nitrergic regulation of the exocrine and endocrine pancreas is different between the species.