Neuronal NADPH-d/NOS expression in the nodose ganglion of severe hypoxic rats with or without mild hypoxic preconditioning

This study aimed to test the hypothesis that mild hypoxic preconditioning (MHPC)-induced NOS expression would attenuate the neuropathological changes in the nodose ganglion (NG) of severe hypoxic exposure (SHE) rats. Thus, the young adult rats were caged in the altitude chamber for 4 weeks prior to SHE for 4 h to gain hypoxic preconditioning. The altitude chamber was used to set the height at the level from 5500 m (0.50 atm; pO2=79 Torr) to 10,000 m (0.27 atm; pO2=43 Torr) for MHPC and SHE, respectively. The experimental animals were allowed to survive for 0, 7, 14, 30 and 60 successive days, respectively. Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry and neuronal nitric oxide synthase (nNOS) immunohistochemistry were used to detect NADPH-d/nNOS reactivity in the NG at various time points following hypoxic exposure. The present results showed that about 38% of the neurons in the NG displayed NADPH-d/nNOS positive [NADPH-d/nNOS(+)] in normoxic rats. In SHE rats, a peak in the percentage (71%) and staining intensity (230%) of NADPH-d/nNOS(+) nodose neurons at 0 day, which then gradually decreased at 7-60 days. About 25% of the nodose neurons died 60 days after SHE. However, in MHPC rats subjected to SHE, NADPH-d/nNOS(+) neurons peaked in the percentage (51%) and staining intensity (171%) at 0 day, which then decreased at 7-60 days. In addition, neuronal survival was markedly increased by MHPC. These results suggested that MHPC might have a neuroprotective effect that reduces the susceptibility of the nodose neurons to NOS mediated neuropathy subsequent to SHE.     

The immunohistochemical localization of neuronal nitric oxide synthase in the basal forebrain of the dog

The present work describes for the first time the anatomical distribution of neuronal nitric oxide synthase (nNOS) immunoreactivity and NADPH-d activity in the basal forebrain of the dog. As in other species, small, intensely nNOS-immunoreactive cells were seen within the olfactory tubercle, caudate nucleus, putamen, nucleus accumbens and amygdala. In addition, a population of mixed large and small nNOS positive cells was found in the medial septum, diagonal band and nucleus basalis overlapping the distribution of the magnocellular cholinergic system of the basal forebrain. Our results show that the distribution of NOS containing neurons in these nuclei in the dog is more extensive and uniform than that reported in rodents and primates. When double labeling of nNOS and NADPH-d was performed in the same tissue section most neurons were double labeled. However, a considerable number of large perikarya in the diagonal band and nucleus basalis appeared to be single labeled for nNOS. Thought a certain degree of interference between the two procedures could not be completely excluded, these findings suggest that NADPH-d histochemistry, which is frequently used to show the presence of NOS, underestimates the potential of basal forebrains neurons to produce nitric oxide. In addition, a few neurons mainly localized among the fibers of the internal capsule, appeared to be labeled only for NADPH-d. These neurons could be expressing a different isoform of NOS, not recognized by our anti-nNOS antibody, as has been reported in healthy humans and AD patients.     

急性缺氧小鼠海马CAl区NOS活力和nNOS蛋白表达的时程变化

目的:观察急性缺氧小鼠海马CAl区一氧化氮合酶(NOS)和神经元型一氧化氮合酶(nNOS) 阳性神经元的时程变化,探讨NO在脑缺氧中的作用并为抗脑缺氧提供依据。方法:复制小鼠急性缺氧模型,采用NADPH-d组织化学和nNOS免疫组织化学方法,研究急性缺氧后不同时程点小鼠海马CAl区NADPH-d 和nNOS阳性神经元数量的变化。结果:与正常对照组相比较,急性缺氧后0.5h组小鼠海马CAl区NADPH-d 和nNOS阳性神经元的数量无明显变化,差异无显著性(P>0.05),3h、6h和12h组逐渐增多并于12h升高达到最高峰,差异有显著性(P<0.05),而于24h后开始降低,48h恢复正常。结论:急性缺氧后早期海马CAl区NOS和nNOS水平明显增多,NO在缺氧所致早期脑损伤中起重要作用。     

Nitrergic and peptidergic innervation in the developing rat heart

The phenotypic expression and anatomic distribution of nitrergic and peptidergic innervation in the developing rat heart was localized by reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemistry and immunohistochemistry using antibodies against neuronal isoform of nitric oxide synthase (nNOS), neuropeptide Y (NPY) and calcitonin-gene-related peptide (CGRP). NPY-immunoreactive nerve fibers showed the earliest expression by 16 days of gestation, with preferential innervation of the nodal and perinodal areas, followed by the innervation of the valves and ventricles by postnatal day 7. NPY immunoreactivity was also localized to a large proportion of the intrinsic cardiac ganglia from 16 days of gestation onwards with a progressive increase in the number of neuronal cell bodies per ganglia with age. CGRP-positive nerve fibers appeared by 19 days of gestation and were less dense during the gestational and early postnatal periods, and showed a quantitative increase in density by 7 days, followed by a decrease by 3 weeks postnatal. None of the intrinsic ganglia were stained positive for CGRP, indicating the extrinsic sensory origin of these stained fibers. Nitrergic innervation paralleled the sensory innervation, with the cardiac ganglia and nerve fibers showing a positive labeling from 19 days of gestation onwards. NADPH-d and nNOS were partially co-localized. Double-label immunohistochemistry showed that a considerable proportion of sensory CGRP-immunopositive fibers were also immunoreactive for NOS. The results of the present study show that neuropeptides and nitric oxide are expressed by the late gestational period and that autonomic efferent innervation precedes sensory and nitrergic innervation in the developing heart. Accepted: 4 January 2000     

海人酸、使君子酸致Huntington病鼠纹状体NOS阳性细胞的变化

为了研究海人酸和使君子酸对大鼠纹状体 NOS阳性细胞的影响 ,用神经毒海人酸、使君子酸破坏大鼠左侧尾壳核 ,将夜间活动超过 6 0 0次、主动回避试验阳性率在 35 %以下的大鼠作为成功的 Huntington舞蹈病模型。注射后 2个月 ,将动物脑切片进行 Nissl、NADPH-d组化和 GF AP免疫组化反应。结果表明 ,海人酸和使君子酸均可使纹状体 n NOS阳性神经元丢失、出现i NOS阳性胶质细胞和侧脑室扩大 ,两者无显著差异。在损伤中心区 n NOS阳性神经元减少甚至消失 ,但这种变化自中心向周围呈渐变趋势 ;i NOS阳性胶质细胞呈两种不同形态 :一类胞体略大而突起粗短 ,一类胞体小而突起相对较长。对侧纹状体及伤侧纹状体非损毁部均未见 NOS阳性胶质细胞 ;NADPH-d组化和 GFAP免疫组化双重反应表明一些 i NOS胶质细胞为 GFAP阳性胶质细胞。本研究提示 ,海人酸和使君子酸均可使纹状体 n NOS神经元减少消失 ,损毁区出现的 NOS阳性胶质细胞为诱导型神经胶质细胞 (i NOS)。海人酸和使君子酸所引起的 Huntington病模型鼠形态学及行为变化均无明显差异     

神经元性一氧化氮合酶活性在app/ps1双转基因AD模型小鼠皮质和海马的分布

本实验用 4～ 5月龄和 15～ 16月龄的 app/ ps1dtg小鼠各 5只 ,同龄野生型小鼠每个年龄组各 5只 ,用β-NADPH组织化学染色显示神经元一氧化氮合酶活性 ,刚果红组织学染色显示神经炎性斑 ,无偏性体视学计量皮质和海马神经炎斑的总体积 ,研究神经元一氧化氮合酶活性在 app/ ps1双转基因 (app/ ps1dtg) AD模型小鼠大脑皮质和海马的异常分布 ,探讨其在该模型小鼠及 AD患者脑内病理改变中的作用。结果显示 ,n NOS阳性神经元在各组小鼠皮质和海马内的分布没有区别 ,4～ 5月龄 app/ps1dtg小鼠皮质和海马可见神经炎斑 (NP)和营养不良性 NOS阳性神经突 (DTN) ;15～ 16月龄 app/ ps1dtg小鼠皮质和海马内NP的体积分别是 4～ 5月龄 app/ ps1dtg小鼠皮质 NP的 5倍 (P<0 .0 0 5 )和 8倍 (P<0 .0 0 1) ;15～ 16月龄 app/ ps1dtg小鼠皮质内 DTN的体积明显增大 (P<0 .0 1) ;且伴有 NOS阳性神经元形态的改变及海马 CA1 区 NOS阳性神经元数量的减少 (P<0 .0 5 ) ,DTN的形成与 NP呈正相关关系 (r=0 .85 ,P<0 .0 5 )。本实验结果表明 ,app/ ps1dtg小鼠能够模拟 AD患者脑内 NOS阳性神经元的病理改变 ,DTN的形成可能与 Aβ的毒性作用有关 ,DTN产生的 NO可能参与 app/ ps1dtg小鼠和 AD的神经病理过程。     

Ultrastructural localisation of NADPH-d/nNOS expression in the superior cervical ganglion of the hamster

This study examined NADPH-d and nNOS expression in the SCG of hamsters. By light microscopy, numerous NADPH-d/NOS positive processes were widely distributed in the ganglion. Ultrastructurally, the NADPH-d reaction product was associated with the membranous organelles of neuronal soma, dendrites, myelinated fibres, small granular cells, and axon profiles bearing agranular vesicles. The NOS immunoreaction product, on the other hand, was localised in the cytoplasm of principal neurons and dendrites. Some of the NADPH-d/NOS labelled processes formed junctional contacts including synapses or zonulae adherentia. Compared with the neurons, the nonneuronal cells in the ganglion, namely, macrophages, satellite cells and endothelial cells were labelled by NADPH-d but devoid of nNOS immunoreaction product. The results suggest that the NADPH-d/NOS positive fibres in the SCG originate not only from the projecting fibres of the lateral horns of thoracic spinal cord, but also from the principal neurons and small granular cells; some may represent visceral afferent fibres. Electron microscopic morphometry has shown that about 67% of the principal neurons contain NADPH-d reaction product, and that the majority were small to medium sized neurons based on cross-sectional areas in image analysis. On the basis of the present morphological study, it is concluded NO is produced by some local neurons and possibly some nonneuronal cells in the SCG as well as some fibres of extrinsic origin. In this connection, NO may serve either as a neurotransmitter or neuromodulator.     

Soluble guanylate cyclase and neuronal nitric oxide synthase colocalize in rat nucleus tractus solitarii

Nitric oxide has been implicated in transmission of cardiovascular signals in the nucleus tractus solitarii (NTS). Pharmacological studies suggest that activation of neurons by nitric oxide in the NTS may involve soluble guanylate cyclase (sGC). However, anatomical data supporting this suggestion have not been available. In this study, we tested the hypothesis that neurons and fibers containing neuronal nitric oxide synthase (nNOS) lie in close proximity to those containing sGC and the two enzymes colocalize in some neurons and fibers in the NTS. We perfused six rats and obtained brain stem sections for double immunofluorescent staining utilizing antibodies selective for sGC and for nNOS combined with confocal microscopy. The distribution and staining intensity of nNOS-immunoreactivity (IR) was similar to our earlier reports. IR of sGC was present in cell bodies, proximal dendrites and fibers of many brain stem regions. Strong sGC-IR was noted in the hypoglossal, dorsal motor nucleus of vagus and gracilis nuclei. The NTS exhibited moderate sGC-IR. Superimposed images showed that many NTS neurons contained both nNOS-IR and sGC-IR. The percentage of sGC-IR positive cells that were also nNOS-IR positive differed among NTS subnuclei. Similarly, the percentage of nNOS-IR positive cells that were also sGC positive differed among NTS subnuclei. Fibers stained for both nNOS-IR and sGC-IR were also present in NTS subnuclei. In addition, we identified fibers that were stained for nNOS-IR or sGC-IR alone and often found such singly labeled fibers apposed to each other. These data support our hypothesis and provide anatomical support for the suggestion that nitroxidergic activation of the NTS involves sGC.     

Expression of NADPH-diaphorase and nitric oxide synthase in lumbosacral motoneurons after knee joint immobilisation in the guinea pig

The expression of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) and nitric oxide synthase (NOS) in spinal ventral horn neurons was studied in the guinea pig after right knee joint immobilisation (RKJI). At 1 wk after RKJI, neurons in the ipsilateral ventral horn from L4 to S1 segments showed a moderate reactivity for NADPH-d staining. At 2 wk, NADPH-d labelled neurons were also observed in the contralateral ventral horn. Ipsilateral NOS immunoreactive cells were not detectable until wk 2. The intensity of NADPH-d and NOS labelled neurons in the bilateral ventral horns was sustained, peaking at the 4th wk after RKJI. In guinea pigs subjected to 4 wk of RKJI and subsequently released from the immobilisation for 2 and 4 wk, NADPH-d and NOS reactivity in ventral horn neurons diminished. The expression of NADPH-d positive neurons differed from that of NOS labelled neurons in terms of time interval, cell number and staining intensity, the latter being later, fewer and weaker. It is suggested that the induction and upregulation of NADPH-d and NOS are attributable to reduced activity of muscles acting on the knee joint after RKJI; the changes are reversible. It is speculated that increased levels of NO production are involved in protective mechanisms against possible neuronal degeneration as a consequence of target dysfunction.     

Obstructive jaundice activates nitroxidergic neurons of the vago-vagal neural circuit that regulates the hepatobiliary system in rabbits

In this study, we investigated the expression of neuronal nitric oxide synthase (nNOS) and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d), two specific enzymes for nitric oxide (NO) synthesis, in the development of liver fibrosis induced by chronic bile duct ligation (BDL) in the rabbit. We specifically studied the liver-innervated nitroxidergic neurons that originate in the nodose ganglion (NG), nucleus of the solitary tract (NTS) and dorsal motor vagal nucleus (DMV). Our data showed that BDL resulted in overexpression of NADPH-d/nNOS in the NG, NTS and DMV neurons. Using densitometric analysis, we found a significant increase in NADPH-d expression as a result of BDL in the NG, NTS and DMV (72.6, 79.4 and 57.4% increase, respectively). These findings were corroborated by serum biochemistry and hepatic histopathological examination, which were influenced by NADPH-d/nNOS-generated NO in the liver following BDL. Upregulation of NADPH-d/nNOS expression may have important implications, including (1) facilitation of extrahepatic biliary parasympathetic tone that promotes gallbladder emptying of excess stagnant bile; (2) relaxation of smooth muscles of bile canaliculi thus participating in the pathogenesis of cholestasis; (3) dilation of hepatic sinusoids to counter BDL-induced intrahepatic portal hypertension in which endothelia may be damaged, and (4) alterations in hepatic metabolism, such as glycogenesis, bile formation and secretion, and bilirubin clearance.     

NOS在大鼠杏仁皮质核传入神经元内的分布

目的研究一氧化氮合酶(NOS)在杏仁皮质核传入投射神经元中的分布。方法采用霍乱毒素B亚单位(CTb)逆行追踪和还原型尼克酰胺腺嘌呤二核苷酸脱氢酶(NADPH-d)组织化学双重染色相结合的方法。结果双标神经元(NADPH/CTb)主要分布在孤束核(Sol)、蓝斑(LC)、臂旁内侧核(MPB)、中缝背核(DR)、中央灰质外侧部(CGL)、中央灰质背侧部(CGD)、丘脑室旁核(PV)、下丘脑室旁核(Pa)、下丘脑室周核(Pe)、下丘脑腹内侧(VMH)核以及杏仁内侧核(ME)等神经核团。结论NOS在大鼠杏仁皮质核传入投射神经元中主要分布于上述核团,并且提示NO参与杏仁皮质核的功能调节。     

一氧化氮合酶在大鼠杏仁基外侧核传入神经元内的分布

目的：研究一氧化氮合酶(NOS)在大鼠杏仁基外侧核(BLA)传入投射神经元中的分布。方法：采用霍乱毒素B亚单位(CTb)逆行追踪和还原型尼克酰胺腺嘌呤二核苷酸脱氢酶(NADPH—d)组织化学双重染色相结合的方法。结果：双标神经元(NADPH-d／CTb)主要分布在孤束核、蓝斑、臂旁内侧核、中缝背核、中央灰质背侧部、丘脑室旁核、下丘脑室旁核、下丘脑室周核、下丘脑腹内侧核以及杏仁内侧核等神经核团。结论：NOS在大鼠BLA传人投射神经元中主要分布于上述核团,并且提示NO参与BLA的功能调节。     

SOMAN诱发惊厥后c-fos在大鼠杏仁核簇─氧化氮神经元中的表达

运用FOS免疫组化结合NADPH－d组化双重标记技术，研究了soman诱发惊厥大鼠杏仁核内c－fos高表达神经元与NADPH－d阳性神经元之间的关系。结果显示：在soman诱发惊厥后的1．5h至48h，杏仁核簇内c－fos呈现持续过度表达、FOS免疫阳性神经元的分布具有显著的亚核定位特征。NADPH－d活性在惊厥后明显增强。有10％的FOS阳性神经元同时也呈现NADPH－d阳性。而几乎所有的NADPH－d阳性神经元均呈FOS染色阳性。鉴于FOS表达的诱导和NADPH－d的激活具有共同的上游事件，即NMDA介导的钙内流，可以认为FOS引发的目的基因表达及NO的神经毒作用可能存在于杏仁核的神经元损伤机制中。     

大鼠胃伤害性刺激后胃壁一氧化氮合酶的变化

目的：探索胃在受到外源性酸、碱伤害性刺激后，胃壁内一氧化氮合酶（NOS）阳性神经元的数量和染色强度的变化。方法：分别用0．6％乙酸和0．2％NaOH造成大鼠胃伤害性刺激，按不同时程，以还原型尼克酰胺腺嘌呤二核苷酸脱氢酶（NADPH－d)组化法对胃壁NOS阳性神经元的数量和染色强度的变化进行了观察。结果：胃壁皮区的粘膜下层中都没有观察到NADPH－d阳性神经元，胃壁腺区（特别是泌酸区）粘膜下层中都观察到阳性神经元。两实验组泌酸区此层内的阳性神经元数约是对照组的1．4倍，P＜0．05，灌酸组此层内强染色阳性神经元与弱染色阳性神经元的比例由对照组的1：1．5变为1：2．5；灌碱组泌酸区此层内的阳性神经元数强弱比约为1．5：1。结论：胃的外源性酸、碱刺激影响胃粘膜下层中氮能神经元的表达。     

大鼠端脑内一氧化氮合酶阳性神经元的发育

目的研究大鼠胚胎时期及生后早期一氧化氮合酶（NOS）阳性神经元在端脑的分布,探讨一氧化氮（NO）在脑发育过程中的作用。方法应用还原型尼克酰胺腺嘌呤二核苷酸磷酸脱氢酶（NADPH-d）组织化学方法观察孕14d起至生后14d大鼠端脑内NOS阳性神经元的形态和分布。结果孕14d没有观察到阳性神经元。孕15d纹状体腹外侧已有NOS阳性表达。孕17d在大脑皮质、梨状皮质观察到NOS阳性神经元,但胞体小,树突短,且分支少。随着年龄的增长神经元的胞体数目增多、染色增强或维持一定的水平。到孕20d,NOS阳性神经元分布广泛,梨状皮质、纹状体腹外侧及终纹床核均有大量NOS阳性神经元,其胞体明显增大,树突分支复杂化,长度增加。在生后,除上述脑区的阳性神经元进一步发育分化,大脑皮质和纹状体的NOS阳性纤维相互编织成疏密不等的纤维网外,在胼胝体、海马也观察到NOS阳性神经元。到生后14d,NOS阳性神经元的分布模式总体上已与成年大鼠相似。结论NOS阳性神经元在端脑独特的表达模式提示NO在脑发育和成熟过程中扮演重要角色。     

大鼠中缝背核一氧化氮合酶神经元投射纤维在大脑皮质微血管的分布

目的：研究通过损毁脑干中缝背核(DR)，探讨中缝背核NOS阳性神经元是否投射分布于大脑皮质微血管。方法：将16只SD雄性成年大鼠分为实验组与对照组。对实验组大鼠中缝背核微量注射喹啉酸，饲养1w，灌注固定，然后将大脑及脑干作冠状冰冻切片，NADPH—d组化染色。结果：实验组大鼠的中缝背核被有效损毁，其NOS阳性神经元的数量减少了59．1％(P＜0．001)。额、顶叶皮质NOS阳性纤维终末减少了32．1％(P＜0．05)，其中附着于皮质微血管的NOS阳性纤维终未了减少了37．8％(P＜0．01)。而枕额叶皮质NOS阳性纤维终末也减少了32．8％(P＜0．05)，其中附着于皮质微血管的阳性纤维终末减少了39．4％(P＜0．01)。结论：位于中缝背核的NOS阳性神经元投射分布于大脑皮质微血管，可能参与大脑皮质血流量的调节。     

Upregulation of NMDA receptor and neuronal NADPH-d/NOS expression in the nodose ganglion of acute hypoxic rats

Nitric oxide may serve as a neuronal messenger in the regulation of cardiorespiratory function via the N-methyl-D-aspartate (NMDA) receptor-mediated neuronal nitric oxide synthase (nNOS) activation. Since hypoxic stress would drastically influence the cardiorespiratory function, the present study aimed to examine if the expression of nNOS and NMDA receptor subunit 1 (NMDAR1) in the nodose ganglion (NG) would alter under different extents of hypoxia treatment. The nicotinamine adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry, nNOS and NMDAR1 immunofluorescence were used to examine nNOS and NMDAR1 expression in the NG following exposing of adult rats in the altitude chamber (0.27 atm, PO(2)=43 torr) for 2 and 4 h. The present results showed that NADPH-d, nNOS and NMDAR1 reactivities were co-localized in the NG under normoxic and hypoxic environment. Quantitative evaluation revealed that about 43% of neurons in the NG showed positive response for NADPH-d/nNOS and NMDAR1 reactivities. However, in animals subjected to hypoxia, both the percentage and the staining intensity of NADPH-d/nNOS and NMDAR1 labeled neurons were drastically increased. The percentage of NADPH-d/nNOS and NMDAR1-immunoreactive neurons in the NG was raised to 68% as well as 77%, respectively, following 2 and 4 h of hypoxic exposure. The magnitude of up-regulation was positively correlated with the duration of hypoxic periods. No significant cell loss was observed under this experimental paradigm. These findings suggest that different extents of hypoxia might induce the higher expression of nNOS and NMDAR1 in the NG, which could contribute to the neuronal integration as responding to the different physiological demands under hypoxic stress.     

Localization of nitrergic neuronal and non-neuronal cells in the ultimobranchial glands of the chicken

The ultimobranchial glands of 20 chickens, aged 2–3 months, were investigated for their nicotinamide adenine dinucleotide hydrogen phosphate-diaphorase (NADPH-d) reactivity and the distribution of nitric oxide synthase (NOS), using NADPH-d histochemistry and NOS immunocytochemistry respectively. Formazan, the blue reaction product of NADPH-d, was localised in the neuronal cell bodies and nerve fibres. Most of the cell bodies were found in the parenchyma. Some of them occurred in the wall of the ultimobranchial cysts, and a few in the immediate vicinity of the blood vessels. Labelled nerve fibres mostly travelled with blood vessels, while few of them appeared in the cystic lining. In addition to neuronal profiles, some C cells, cystic lining, and vascular endothelium were also labelled. NOS staining was found in neuron-like cells and fibres that were confirmed as neurons in adjacent sections stained with antibodies against neuron-specific enolase. It was also detected in cystic lining and in some C cells, but not in vascular endothelium. The distribution patterns of NADPH-d and NOS suggest that NO may play a role in the regulation of the secretory activity of and the blood flow through the ultimobranchial glands.     

金纳多对血管性痴呆小鼠海马结构NOS表达的影响

目的观察银杏叶提取物(EGB)金纳多对血管性痴呆(VD)小鼠海马结构神经元型一氧化氮合酶(nNOS)表达的影响,探讨银杏叶提取物对血管性痴呆的治疗作用。方法复制VD小鼠模型,利用Y-迷宫检测VD模型小鼠学习记忆能力及不同剂量EGB治疗组的改善作用,实时定量PCR方法检测不同剂量EGB对VD小鼠海马结构中NOSmRNA转录水平的影响,组织化学和免疫组化方法研究其对NOS和nNOS蛋白表达的影响。结果行为学结果显示VD模型组和各治疗组小鼠均比对照组小鼠Y-迷宫学习记忆训练次数明显增多(<0.05),高低两个剂量EGB治疗组迷宫学会次数与模型组相比明显减少(<0.05),有剂量依赖性。实时定量PCR结果显示在背侧海马VD模型组nNOS mRNA转录水平显著提高,而高低EGB治疗组的nNOS mRNA转录水平显著降低(<0.05)。组织化学和免疫组化结果显示在海马结构CA1区VD模型组比对照组NOS和nNOS阳性神经元的数量明显增多(<0.05),高低两个EGB治疗组与VD模型组相比阳性神经元数量明显减少(<0.05)。结论银杏叶提取物对VD小鼠神经元有保护作用,可能与减少海马结构NOS的表达相关。