The nuclei of origin of brain stem enkephalin and substance P projections to the rodent nucleus raphe magnus

The sites of origin of brain stem enkephalin and substance P projections to the rodent nucleus raphe magnus were studied utilizing the combined horseradish peroxidase retrograde transport-peroxidase-antiperoxidase immunohistochemical technique. Several brain stem areas were found to contain both enkephalin- and substance P-like immunoreactive double labeled neurons following injection of horseradish peroxidase into the raphe magnus. Nuclei providing both enkephalin and substance P inputs to the raphe magnus include the nucleus reticularis paragigantocellularis, the nucleus cuneiformis, the nucleus solitarius and the trigeminal subdivision of the lateral reticular nucleus. Enkephalin projections to the raphe magnus were also found to originate from the dorsal parabrachial nucleus, the nucleus reticularis gigantocellularis pars α and from an area which corresponds to the A5 group of Dahlström &; Fuxe. Additional neurons containing substance P-like immunoreactivity and horseradish peroxidase reaction product were identified in the superior central raphe nucleus and the nucleus pontis oralis. The midbrain periaqueductal gray contributes very few enkephalin and substance P fibers to the raphe magnus.The nucleus raphe magnus is a key structure in the intrinsic analgesia system and it has also been implicated in other diverse and non-nonciceptive functions. The present study identifies several brain stem sites which provide enkephalin and substance P input to this raphe nucleus. Several of these nuclei have been implicated in central analgesic mechanisms or in non-nociceptive autonomic functions. The present investigation raises the possibility that these brain stem regions may modulate neuronal activity in the raphe magnus via enkephalin or substance P projections and thus influence the involvement of the raphe magnus in both opiate related mechanisms of pain control and non-nociceptive functions.     

Neuregulin-1对血管生成的影响

Neuregulin-1(NRG1)简称神经调节因子1,属于NRG家族的一员,广泛存在于人体各组织之中。NRG是一个由4种基因编码的多肽家族,其包含4种异构体NRG1、2、3和4。NRG的功能性受体由erb B酪氨酸激酶受体所组成。Erb B蛋白属于跨膜酪氨酸激酶的表皮生长因子受体(EGFR)家族成员。NRG通过与特异性Erb B受体结合,并活化后者而发挥其相应的生物学效应。本文总结归纳NRG1对血管方面的影响和作用。     

设施设备心脏组织特异性表达Neuregulin-2转基因小鼠的建立及心脏功能分析

目的神经调节蛋白2(neuregulin-2,NRG2)可促进神经系统发育,基因缺失表现早期生长延迟,NRG2在心脏中也有表达,但其在心脏发育尤其是病理刺激时对心脏结构及功能的影响尚未见报道。本文目的是建立心脏组织特异性表达NRG2转基因小鼠,分析其在正常及压力负荷刺激时对心脏结构及功能的影响。方法将人NRG2基因插入到心脏特异性启动子α-MHC下游,构建转基因表达载体,显微注射法建立NRG2转基因小鼠,PCR鉴定转基因小鼠基因型,western blot鉴定NRG2蛋白在心脏中的表达并筛选高表达的转基因品系,主动脉缩窄术(transverse aortic constriction,TAC)制备压力负荷诱导的心肌肥厚小鼠模型。利用超声影像分析和病理学观察小鼠心脏结构和功能改变。结果建立了心脏组织特异性高表达NRG2转基因小鼠品系。与同窝阴性转基因小鼠相比,转基因小鼠左心室舒张末期后壁厚度(LVPWD)明显增加,3月龄时可达15.6%(P0.05),经压力负荷刺激后,NRG2转基因手术小鼠心室壁增厚程度显著下降,心室腔增大,同时心肌排列紊乱程度和纤维化程度明显比NTG手术小鼠严重。结论在压力负荷下,转基因表达NRG2缩短了肥厚过程,同时加速了心衰进程。     

Neuregulin 1 and age of onset in the major psychoses

Genetic vulnerability to psychiatric illness extends across major psychiatric illness. Neuregulin 1 (NRG1) is a large gene on chromosome 8p, that has been identified as a susceptibility factor in bipolar disorder and schizophrenia. In particular, a core at risk haplotype has received considerable attention for a putative role in the pathophysiology of the major psychoses (schizophrenia and bipolar disorder). This core haplotype can be represented by three markers 478B14-848, 420M9-1395, and SNP8NRG221533. We genotyped 312 families with bipolar probands, and 120 families with schizophrenia probands. Association of the core haplotype was tested for with age-at-onset and with three phenotypes: major psychosis, schizophrenia, and bipolar disorder. Neither age of onset (P = 0.893) nor the major psychosis phenotype (P = 0.374) was associated with the core haplotype in the overall sample. Ours was the first study to investigate the NRG1 core haplotype with age of onset of major psychoses, and despite our preliminary negative findings, this area deserves further investigation.     

Genetic variation in the schizophrenia‐risk gene neuregulin 1 correlates with brain activation and impaired speech production in a verbal fluency task in healthy individuals

Impaired performance in verbal fluency tasks is an often replicated finding in schizophrenia. In functional neuroimaging studies, this dysfunction has been linked to signal changes in prefrontal and temporal areas. Since schizophrenia has a high heritability, it is of interest whether susceptibility genes for the disorder, such as NRG1, modulate verbal fluency performance and its neural correlates. Four hundred twenty‐nine healthy individuals performed a semantic and a lexical verbal fluency task. A subsample of 85 subjects performed an overt semantic verbal fluency task while brain activation was measured with functional magnetic resonance imaging (MRI). NRG1 (SNP8NRG221533; rs35753505) status was determined and correlated with verbal fluency performance and brain activation. For the behavioral measure, there was a linear effect of NRG1 status on semantic but not on lexical verbal fluency. Performance decreased with number of risk‐alleles. In the fMRI experiment, decreased activation in the left inferior frontal and the right middle temporal gyri as well as the anterior cingulate gyrus was correlated with the number of risk‐alleles in the semantic verbal fluency task. NRG1 genotype does influence language production on a semantic level in conjunction with the underlying neural systems. These findings are in line with results of studies in schizophrenia and may explain some of the cognitive and brain activation variation found in the disorder. More generally, NRG1 might be one of several genes that influence semantic language capacities. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.     

Neuregulin 1 genotype and schizophrenia

The neuregulin 1 (NRG1) gene has been the subject of considerable excitement within the psychiatric genetics literature since it was originally identified as a potential susceptibility locus for schizophrenia. Here we provide an update of our first meta-analysis of this association. Case-control and family-based genetic association studies of the NRG1 gene in healthy control groups and clinically diagnosed schizophrenia patients were included. We repeated the search strategy in our earlier meta-analysis for studies published between December 31, 2005, and September 30, 2007, and updated the results of our original meta-analysis accordingly. Superficially, the results of our updated meta-analysis are consistent with those in our previous report, although it is notable that the strength of evidence as based on our haplotype analysis has weakened over this period. The evidence for association of the SNP8NRG221533 polymorphism continued to be nonsignificant. We discuss a number of problems in the interpretation of a disparate and inconsistent gene-disease association literature, including the difficulties associated with determining what constitutes replication across studies which vary in their methods, marker sets employed, phenotype definition, and other study characteristics.     

NRG1在肝细胞肝癌中杂合性丢失和蛋白表达的研究

目的：分析在肝细胞性肝癌中NRG1基因的两个多态性位点D8S278和D8S499杂合性丢失（loss ofheterozygosity,LOH）情况及其与NRG1蛋白表达水平之间的关系,探讨NRG1在肝细胞肝癌发生发展中的作用。方法：酚氯仿抽提经石蜡包埋的肝癌和癌旁正常组织DNA,进行PCR扩增,扩增出来的产物进行变性聚丙烯酰胺凝胶电泳并分析两位点杂合性丢失情况;用免疫组织化学方法检测肝癌组织和癌旁正常组织中NRG1的表达情况。结果：D8S278和D8S499的LOH率分别为32.43%（24/74）、37.86%（26/69）,总频率为48.65%（36/74）;NRG1在肝癌组织中的阳性表达率为67.57%（50/74）,显著低于在正常组织中的表达水平（97.30%,72/74）（P〈0.05）,这种降低与NRG1基因多态性位点的LOH有关;NRG1表达下调与肿瘤大小、Edmondson分级相关,而与年龄、性别、HBsAg、AFP、肝硬化和肝内外转移无明显相关。结论：NRG1基因可能是肝细胞肝癌的一个候选抑癌基因,在肝癌发生发展中起一定的作用;可为临床诊断、治疗及预后评估提供理论依据。     

Support for the involvement of the ERBB4 gene in schizophrenia: A genetic association analysis

Cellular, animal and human studies support the involvement of aberrant NRG–ErbB signaling in the pathogenesis of schizophrenia. The aim of the present study was to examine whether genetic variation in the human ERBB4 gene is associated with susceptibility to schizophrenia. Two hundred and twenty-seven unrelated chronic inpatients with schizophrenia were enrolled in the study, and the genetic variation in the polymorphisms of the ERBB4 gene in the patients was compared with that of the control group, which consisted of 223 subjects free of psychiatric illness. The results showed that one coding-synonymous polymorphism (rs3748962, Val1065Val) was in genotypic (p = 0.0027) and allelic (p = 0.0007) association with schizophrenia. In comparison with subjects of the rs3748962-TT type, those of the rs3748962-CT and rs3748962-CC types were at 1.74- and 2.64-fold greater risk of schizophrenia (CT vs. TT: OR = 1.71 (95% CI = 1.15–2.53), p = 0.0014; CC vs. TT: OR = 2.64 (95% CI = 1.37–5.23), p = 0.0047), which supports the hypothesis of an additive model of transmission (p = 0.0006). Furthermore, the frequency of haplotype ATC of rs3791709–rs2289086–rs3748962 was found to be significantly higher in the patients with schizophrenia than in the controls (case vs. control = 36.0% vs. 24.4%, permutation p-value = 0.0002). The findings support the involvement of the ERBB4 gene in schizophrenia in Han Chinese.     

DDT myoclonus: Sites and mechanism of action

Intragastric injection of the insecticide DDT produces a stimulus-sensitive myoclonus in mice and rats. Unilateral stereotaxic infusions of DDT into rat medullary reticular formation also induced generalized myoclonus, identical to that produced by systemic administration. Similar myoclonus, but of lesser intensity, occurred when DDT was injected into cerebellar nuclei, red nucleus, and the inferior olive. Multiple other regions of the brain were resistant to the myoclonic action of locally infused DDT. Direct infusions into the medullary reticular formation of allethrin, which has a similar action on neuronal membranes as DDT, or the glycine receptor antagonist, strychnine, also elicited myoclonus.