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。     

失血性休克大鼠下丘脑室旁核一氧化氮合酶阳性细胞的变化

目的通过观察失血性休克大鼠下丘脑室旁核（PVN）的一氧化氮合酶（NOS）阳性细胞的表达变化来探讨其在大鼠失血性休克发生发展中可能的作用。方法雄性SD大鼠24只，随机分成对照组（假手术组）、休克时组、休克45min组和休克90min组。对照组经股动脉插管后灌注固定，其他各组经股动脉插管放血复制失血性休克模型，分别在休克时、休克45min和休克90min灌注固定。取大鼠脑干和垂体进行冰冻切片，行NADPH—d组化染色，对PVN大细胞部的NOS阳性细胞的形态、数量进行观察。结果PVN大细胞部NOS阳性细胞在失血性休克后呈明显增多，浓染，其中休克45min组与对照组比较差异有统计学意义（P〈0．05）。结论大鼠PVN的NOS阳性细胞可能通过多种途径参与了失血性休克的发生发展。     

交感神经系统内一氧化氮合酶对血管平滑肌增殖的影响

目的探讨交感神经系统中的一氧化氮合酶(NOS)对血管平滑肌增殖的影响及调控。方法用三氯化铁(FeCl3)损伤颈总动脉建立大鼠平滑肌增殖模型,实验分为假手术组、术后存活1d组、5d组,在5d组中加设注射抑制剂N-硝基-L精氨酸(LNNA)组,每组6只大鼠,采用还原型尼克酰胺腺嘌呤二核苷酸黄递酶(NADPH-d)组织化学染色和荧光金(FG)逆向追踪双标,观察颈交感神经节和脊髓中间外侧核神经细胞一氧化氮合酶的变化;苏木素-伊红(HE)染色观察血管平滑肌增殖变化。结果血管损伤后1d、5d组的颈交感神经节中有较多NADPH-d染色阳性细胞表达,尤其5d组更明显;手术侧的T1～T3脊髓侧角NADPH-d阳性细胞数也增多,而抑制剂组的NADPH-d阳性细胞数明显减少;HE染色可见血管损伤后有平滑肌增殖,而抑制剂组增殖更明显。结论损伤颈总动脉后颈交感神经节和T1～T3脊髓侧角内的NOS活性增强,可能参与血管平滑肌细胞(VSMC)增殖的调控。     

BDNF,NT-3对体外培养的胚鼠脊髓AChE和NADPH-d阳性神经元生长发育的影响

利用AChE和NADPH-d酶组织化学染色法研究了脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)和神经营养因子-3(neurotrophin-3,NT-3)对离体培养的胚胎大鼠脊髓胆碱能神经元和一氧化氮能神经元生长发育的影响.结果显示:BDNF处理组和NT-3处理组AChE阳性神经元数和NADPH-d阳性神经元数均显著高于对照组(P＜0.05).BDNF组AChE阳性神经元和NADPH-d阳性神经元胞体平均直径、每细胞突起数和最长突起长度均显著高于对照组(P＜0.05).NT-3组NADPH-d阳性神经元的生长发育与对照组无明显差异,仅AChE阳性神经元的每细胞突起数和最长突起长度显著高于对照组(P＜0.05),对胞体发育无影响.结果提示:BDNF,NT-3促进脊髓神经元的存活和生长发育,二者的作用具有选择性和特异性.     

Activity-dependent heterogeneous populations of nitric oxide synthase neurons in the rat dorsal raphe nucleus

The brainstem dorsal raphe nucleus (DRN) contains an abundant distribution of nitric oxide (NO) synthase (NOS)-containing neuronal profiles in two distinct populations: faint- and intense-immunoreactive cells in midline (ventromedial and dorsomedial) and lateral wing subregions, respectively. This study tested the hypothesis that different functional dynamics underlie the topography of NOS-containing cells in the DRN rostrocaudal and mediolateral neuraxis by using a capsaicin challenge paradigm (50 mg/kg, subcutaneous). Compared with vehicle, capsaicin significantly and preferentially increased nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d, an index of constitutive NOS) reactivity in the rostral midline and caudal lateral wing subregions. Furthermore, capsaicin activated more Fos-positive cells than vehicle within all subregions of the DRN but with a caudal versus rostral predominance in activation pattern. In addition, a high proportion of capsaicin-induced Fos cells in the midline but almost none in lateral wing stained for NADPH-d. These observations suggest the existence of two functionally distinct populations of NOS neurons in the DRN. Furthermore, capsaicin increased galanin immunoreactivity with predominant staining in cell soma and fiber processes in midline and lateral wing subregions of the nucleus, respectively. The total capsaicin-induced galanin immunoreactivity was higher in rostral versus caudal DRN, and a high proportion of galanin-positive cells in the midline also contained NADPH-d and neuronal NOS, thus suggesting a potential NO-galanin interaction in these neurons. The differential pattern of Fos/NADPH-d colocalization across the nucleus suggests that midline and lateral wing NOS neurons of the DRN express their neuromodulatory actions on discrete efferent targets via different intracellular mechanisms.     

高碘对小鼠额皮质及海马组织NOS阳性神经元的影响

目的 观察高碘对小鼠额皮质及海马NOS阳性神经元的影响。方法 昆明种小鼠（雌雄各半12只）分为适碘与高碘组，分别喂以碘浓度为50μg／L，5000μg／L的蒸馏水6个月，作Morris水迷宫行为学测试后以还原型尼克酰胺腺嘌呤二核苷酸脱氢酶（NADPH—d）组化法显示小鼠额皮质及海马组织NOS阳性神经元。结果与适碘组相比，高碘组小鼠脑额皮质、海马NOS阳性神经元密度显著降低，且染色变浅；行为学测试中小鼠逃避潜伏期显著延长。结论 额皮质及海马NOS阳性神经元减少可能是高碘时中枢神经系统功能损伤的病理基础。     

Correlation of Enteric NADPH-d Positive Cell Counts with the Duration of Incubation Period in NADPH-d Histochemistry

Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) staining can be used in the enteric nervous system to determine nitrergic neuronal counts, critical in motility disorders such as intestinal neuronal dysplasia and hypoganglionosis. The reported incubation periods of specimens with NADPH-d staining solution has varied from 2 to 24 h. The aim of this study is to investigate the impact of the incubation period on the overall NADPH-d positive cell counts in porcine rectal submucosal plexus. The submucosal plexus of rectal specimens from 12-week-old pigs (n = 5) were studied. Conventional frozen sections were used to identify nitrergic neurons while whole-mount preparations were used to quantify the effect of prolonged duration of incubation on positively identified ganglion cells with NADPH-d histochemistry. The same submucosal ganglia on the conventional sections, and a minimum of 12 ganglia per whole-mount preparation specimen were photographed sequentially at 2, 6, and 24 h and used to count the number of nitrergic cells per ganglion. The same staining solution was used throughout the experiment. Results were analysed using a one-way ANOVA test. Prolonged incubation with the staining solution revealed new NADPH-d positive cells in the ganglia on the conventional sections. The total number of neurons counted in the 12 adjacent ganglia in the whole-mount specimens was 180 ± 55, the mean neuronal cell per ganglion was 15 ± 8 after 2 h of incubation. This increased to 357 ± 17, and to 29 ± 12 after 6 h (p < 0.05). A further increase was observed of 515 ± 19 and 43 ± 17 after 24 h (p < 0.05). When the photomicrographs were retrospectively analysed, not even the outline of the neuronal cells that stained with prolonged incubation was evident at the earlier time points. NADPH-d positive cell counts increase in proportion to the duration of incubation in NADPH-d histochemistry. Comparative studies attempting to quantify nitrergic cell counts in dysmotility disorders must take into account the variability in NADPH-d positive cell count associated with prolonged incubation in NADPH-d histochemistry.     

c-fos Expression and NADPH-d reactivity in spinal neurons after fatiguing stimulation of hindlimb muscles in the rat

The distribution of Fos-immunoreactive (Fos-ir) and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d)-reactive neurons in the rat lumbar spinal cord was examined following muscle fatigue caused by intermittent high-rate (100 s⁻¹) electrical stimulation of the triceps surae muscle or the ventral root L5 (VRL5) for 30 min. Following both types of stimulation, the fatigue-related c-fos gene expression was more extensive in the L2–L5 segments on the stimulated side, and the majority of Fos-ir neurons were concentrated in the dorsal horn. After direct muscle stimulation, the highest number of Fos-ir neurons were detected in two regions: layer 5, and superficial layers (1 and 2_o), although many labeled cells were also found in layers 3, 4, 6, and 7. In response to VRL5 stimulation, the maximal density of Fos-ir neurons was detected in the middle and lateral parts of layers 1 and 2_o, the zone of termination of high-threshold muscle afferents_. Statistically significant prevalence of Fos-ir cell number was also found in layers 5 and 7 on the stimulated side. A few Fos-ir neurons were detected in the ventral horn (layer 8 and area 10) on both sides. The lamellar distribution of NADPH-d-reactive neurons was similar over all experimental groups of animals. In the L3–L6 segments, such reactive cells were arranged in two distinct regions: dorsal horn (layers 2_i, 3, and 5) and area 10; in the L1 and L2 segments, an additional cluster of NADPH-d positive cells was found in the intermediolateral cell column (IML). Double-labeled cells were not detected. We suggest that c-fos expression in response to muscle fatigue reveals activity of functionally different types of spinal neurons which could operate together with NOS-containing cells in pre-motoneuronal networks to modulate the motoneuron output.     

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.