Co-existence of calcium-binding proteins and γ-aminobutyric acid or glycine in neurons of the rat medullary dorsal horn

Background We investigated the co-expression of calbindin-D28k (CB), calretinin (CR) and parvalbumin (PV, a combination of the three is referred to as CaBPs ) with γ-aminobutyric acid (GABA) or glycine in neurons of the rat medullary dorsal horn (MDH). Methods Immunofluorescence histochemical double-staining for CaBPs and GABA or glycine was performed on the sections from rat MDH. Results CB-, CR-, PV-, GABA- and glycine-like immunoreactive (LI) neurons were differentially observed in all layers of the MDH, but particularly in lamina Ⅱ. Neurons that exhibited immunoreactivity for both CaBPs and GABA or glycine were also observed mainly in lamina Ⅱ. A fewof them were found in laminae Ⅰ and Ⅲ. The percentages of neurons which co-expressed CB/GABA or CB/glycine out of the total numbers of CB- and GABA-LI neurons or CB- and glycine-LI neurons were 5.3% and 12.1% or 4.1% and 10.0%, respectively. The ratios of CR/GABA or CR/glycine coexisting neurons out of the total numbers of CR- and GABA-LI neurons or CR- and glycine-LI neurons were 5.8% and 7.6% or 4.4% and 7.1%, respectively. The rates of PV/GABA or PV/glycine colocalized neurons out of the total numbers of PV- and GABA-LI neurons or PV- and glycine-LI neurons were 11.1% and 5.1% or 9.9% and 5.1%, respectively. Conclusion The results indicate that some neurons in the MDH contain both CaBPs and GABA or glycine.     

Retinal pigment epithelial cells: biological property and application in Parkinson’s disease

Parkinson＇s disease is a neurodegenerative disorder mainly caused by degeneration of the dopaminergic neurons in the substantia nigral pars compacta （SNpc）. The typical motor symptoms of this disease are tremor, akinesia, and rigidity, which are mostly caused by dysfunction of the nigro-striatal pathway. Dopaminergic neurons in the SNpc project long axons to caudate nucleus and the putamen, and secrete dopamine.     

Neuronal firing in the globus pallidus internus and the ventrolateral thalamus related to parkinsonian motor symptoms

Background It has been proposed that parkinsonian motor signs result from hyperactivity in the output nucleus of the basal ganglia, which suppress the motor thalamus and cortical areas. This study aimed to explore the neuronal activity in the globus pallidus internus （GPi） and the ventrolateral thalamic nuclear group （ventral oral posterior/ventral intermediate, Vop/Vim） in patients with Parkinson＇s disease （PD）. Methods Twenty patients with PD who underwent neurosurgery were studied. Microelectrode recording was performed in the GPi （n=10） and the Vop/Vim （n=10） intraoperatively. Electromyography （EMG） contralateral to the surgery was simultaneously performed. Single unit analysis was carried out. The interspike intervals （ISI） and coefficient of variation （CV） of ISI were calculated. Histograms of ISI were constructed. A unified Parkinson＇s disease rating scale （UPDRS） was used to assess the clinical outcome of surgery. Results Three hundred and sixty-three neurons were obtained from 20 trajectories. Of 175 GPi neurons, there were 15.4% with tremor frequency, 69.2% with tonic firing, and 15.4% with irregular discharge. Of 188 thalamic neurons, there were 46.8% with tremor frequency, 22.9% with tonic firing, and 30.3% with irregular discharge. The numbers of three patterns of neuron in GPi and Vop/Vim were significantly different （P 〈0.001）. ISI analysis revealed that mean firing rate of the three patterns of GPi neurons was （80.9±63.9） Hz （n=78）, which was higher than similar neurons with 62.9 Hz in a normal primate. For the Vop/Vim group, ISI revealed that mean firing rate of the three patterns of neurons （n=95） was （23.2±17.1） Hz which was lower than similar neurons with 30 Hz in the motor thalamus of normal primates. UPDRS indicated that the clinical outcome of pallidotomy was （64.3±29.5）%, （83.4±19.1）% and （63.4±36.3）%, and clinical outcome of thalamotomy was （92.2±12.9）%, （68.0±25.2）% and （44.3±7.2）% for tremor, rigidity and bradykinesia, respectively. A significant difference of tremor and rigidity was found between GPi and VopNim （P 〈0.05）. Conclusions Different changes in neuronal firing rate and the pattern in GPi and Vop/Vim are likely responsible for parkinsonian motor signs. The results support the view that abnormal neuronal activity in GPi and Vop/Vim are involved in the pathophysiology of parkinsonism.     

Electrophysiological evidence of P2X2 receptor expression in the neurons of intracardiac and paratracheal ganglia

Objective： To investigate the expression of P2X receptors on rat intracardiac and paratracheal ganglion neurons. Methods： For preparation of intracardiac neurons, hearts were excised, the atria were separated and the medial region containing intracardiac ganglia was isolated and cut into pieces. For preparation of paratracheal neurons, the tracheas were removed and the superficial membranous layer containing paratracheal ganglia was rapidly isolated. Intracardiac and paratracheal ganglion neurons were dissociated after digestion by collagenase and trypsin. Whole-cell patch clamp recording was used to identify the pharmacological properties of P2X receptors in cultured neurons. Results：Neurons from these two ganglia responded to ATP with a rapidly activating, sustained inward current, αβ-meATP failed to evoke any re- sponses in paratracheal ganglion neurons while a few of intracardiac ganglion neurons responded to αβ- meATP with a tiny sustained inward current. ADP and UTP had no effect on intracardiac neurons. Lowering pH potentiated ATP responses in neurons from these two ganglia whereas increasing pH inhibited ATP responses. Co-application of Zn^2＋ potentiated ATP responses in intracardiac and paratracheal ganglion neurons. Conclusion： The receptor subtypes involved in intracardiac and paratracheal ganglia appear to be homomeric P2X2, while heteromeric P2X2/3 could not be completely excluded from intracardiac neurons.     

Embryonic Limb Buds Derived Neurotrophins on the Survival of Neurons and the Growth of Axons in Culture in Vitro

Bioactive proteins from SD rat limb buds were extracted and purified.Fractions of 22 ku, 34 ku and 95 ku were proved to have neurotrophic activity to neurons, and the combined activity of these three fractions was the highest. So they were combinedly added into the culture medium of sensor neurons in dorsal root ganglia and motor neurons of anterior spinal cord from 2-week-old embryonic rats, and PBS was added as control. Phase-contrast microscopic and electron microscopic observations, and true cholinesterase measurements were performed to evaluate the survival and changes in growth, function, and ultrastructure of these cultured neurons. In the experimental group, it was found that the AchE activity was higher (P<0.01), ultrastructural changes in mitochondria,Gorgi's complex and other cell organs were milder than those in the control group. The results showed limb buds derived neurotrophins played an important role in maitaining the survival of the neurons and promoting the growth of axons. It was conc     

Quantitative autoradiographic study on receptor regulation in the basal ganglia in rat model of levodopa-induced motor complications

In order to study neurotransmitter receptor regulation in the basal ganglia involved in the functional changes underlying levodopa-induced motor complications, quantitative autoradiography was used to observe receptor bindings of dopamine D1 and D2, N-methyl-D-aspartate （NMDA）, amino-3-hydroxy-5-methylisoxazole propionic acid （AMPA） and amino butyric acid （GABA） in the basal ganglia of rats that had unilateral nigrostriatal lesions and had been chronically treated with levodopa until motor complications developed. The rats were randomly assigned to three groups： normal, denervated and treatment-complicated groups. The results showed that response duration to levodopa became progressively shorter and abnormal involuntary movement （AIM） score was progressively increased during the course of levodopa treatment. Chronic treatment augmented D1 receptors more than denervation, and reduced D2 receptors that were also increased by dopamine denervation. Striatal NMDA receptors were substantially up-regulated in the treatment-complicated group. Levodopa treatment did not change receptors of nigral AMPA, pallidal GABA, and subthalamic GABA, which remained the same as that in denervation group. However, chronic treatment reversed the increase of nigral GABA receptors caused by the lesion. It was concluded that a shortening of response duration and AIM mimicked levodopa-induced motor complications of Parkinson＇s patients. These data suggested that up-regulation of dopamine D1 and NMDA receptors in the striatum leads to an imbalance of stimulation through the striatal output pathways, which is associated with levodopa-induced motor complications.     

Experimental Study on Inhibition of Neuronal Toxical Effect of Levodopa by Ginkgo Biloba Extract on Parkinson Disease in Rats

Summary:In order to observe neuronal toxical effect of Levodopa and investigate if using Levodopatogether with Ginkgo Bilobar Extract(EGb)would be an workable method to treat Parkinson dis-ease,rat models of Parkinson disease(PD)were made by injecting 6-OHDHDA stereotaxically to rightside of the mesencephic ventral tegmental area(VTA)and substantia nigra pars compacta(SNc).Rotational behavioral observation,TUNEL,immunocytochemistry,Nissl's body staining were per-formed to measure the difference between group treated by Levodopa(50 mg/kg every day for 3days,5 days,7 days,L-dopa group)and group treated by Levodopa combined with EGb(100 mg/kg every day,E-D group).The results showed that in the L-dopa group,the numbers of apoptosisof substantial nigra,rings of rotational behavior were more than those in the E-D group(P<0.05).The numbers of Nissl’s cells in L-dopa group were fewer than in E-D group(P<0.05).The resultssuggested that Levodopa had neur toxic effect and EGb may decrease the toxicity of levodopa     

Effect of HIV-1 Tat on Secretion of TNF-α and IL-1β by U87 Cells in AIDS Patients with or without AIDS Dementia Complex

Objective To explore the role of HIV-1 tat gene variations in AIDS dementia complex(ADC) pathogenesis.Methods HIV-1 tat genes derived from peripheral spleen and central basal ganglia of an AIDS patient with ADC and an AIDS patient without ADC were cloned for sequence analysis. HIV-1 tat gene sequence alignment was performed by using CLUSTAL W and the phylogentic analysis was conducted by using Neighbor-joining with MEGA4 software. All tat genes were used to construct recombinant retroviral expressing vector MSCV-IRES-GFP/tat. The MSCV-IRES-GFP/tat was cotransfected into 293T cells with pCMV-VSV-G and pUMVC vectors to assemble the recombinant retrovirus. After infection of gliomas U87 cells with equal amount of the recombinant retrovirus, TNF-α, and IL-1β concentrations in the supernatant of U87 cells were determined with ELISA. Results HIV-1 tat genes derived from peripheral spleen and central basal ganglia of the AIDS patient with ADC and the other one without ADC exhibited genetic variations. Tat variations and amino acid mutation sites existed mainly at Tat protein core functional area(38-47aa). All Tat proteins could induce U87 cells to produce TNF-α and IL-1β, but the level of IL-1β production was different among Tat proteins derived from the ADC patient's spleen, basal ganglia, and the non-ADC patient's spleen. The level of Tat proteins derived from the ADC patient's spleen, basal ganglia, and the non-ADC patient's spleen were obviously higher than that from the non-ADC patient's basal ganglia. Conclusion Tat protein core functional area(38-47aa) may serve as the key area of enhancing the secretion of IL-1β. This may be related with the neurotoxicity of HIV-1 Tat.     

Expression changes of parvalbumin and microtubule-associated protein 2 induced by chronic constriction injury in rat dorsal root ganglia

Background  Parvalbumin (PV), as a mobile endogenous calcium buffer, plays an important role in affecting temporospatial characteristics of calcium transients and in modulating calcium homeostasis. PV is expressed in neurons in the dorsal root ganglion (DRG) and spinal dorsal horn and may be involved in synaptic transmission through regulating cytoplasm calcium concentrations. But the exact role of PV in peripheral sensory neurons remains unknown. Microtubule-associated protein 2 (MAP-2), belonging to structural microtubule-associated protein family, is especially vulnerable to acute central nervous system (CNS) injury, and there will be rapid loss of MAP-2 at the injury site. The present study investigated the changes of PV expressing neurons and the MAP-2 neurons in the DRG after an operation for chronic constriction injury to the unilateral sciatic nerve (CCI-SN), in order to demonstrate the possible roles of PV and MAP-2 in transmission and modulation of peripheral nociceptive information.

Methods  Seventy-two adult male Sprague-Dawley (SD) rats, weighing 180–220 g, were randomly divided into two groups (36 rats in each group), the sham operation group and chronic constriction injury (CCI) group. Six rats in each group were randomly selected to receive mechanical and thermal sensitivity tests at one day before operation and 1, 3, 5, 7, and 14 days after surgery. After pain behavioral test, ipsilateral lumbar fifth DRGs were removed and double immunofluorescence staining was performed to assess the expression changes of PV and of MAP2 expressing neurons in the L5 DRG before or after surgery.

Results  The animals with CCI-SN showed obvious mechanical allodynia and thermal hyperalgesia (P <0.05). Both the thermal and mechanical hyperalgesia decreased to their lowest degree at 7 days after surgery compared to the baseline before surgery (P <0.01). In normal rats before surgery, a large number of neurons were MAP-2 single labeled cells, and just a small number of PV-expressed neurons were found. PV-positive neurons, PV-positive nerve fibers and PV-negative neurons, formed a direct or close contact for cross-talk. We used immunocytochemical staining to quantify the time course of changes to PV and MAP-2 expressing neurons in tissue, and found that the number of PV expressing neurons began to slightly decrease at 3 days after surgery, and had a significant reduction at CCI day 5, day 7 (P <0.05). But MAP-2 neurons significantly decreased on just the 3rd day after CCI (P <0.05). No changes in PV and MAP-2 expression were almost found in sham operated rats. The number of PV positive neurons, was positively correlated with the hyperalgesia threshold.

Conclusions  A sharp decline in MAP-2 neurons may be the early response to surgical injury, and PV positive neurons were much more effective at affecting the changes of pain behaviors, indicating that the down-regulation of PV protein could participate in, at least in part, the modulation of nociceptive transmission.

     

Quantitative detection of amplification of proto-oncogenes in breast cancer.

In the present study, dot-blot hybridization, serial dilution analysis and densitomctric scanning were used to detect amplification of proto- oncogenes including c-erbB2, c-myc, int-2 and c-Ha-ras in 104 paraffin-embedded breast cancers. Expression of c-erbB2 was also examined by immunohistochemistry. Amplification of c-erbB2. c-myc and int-2 genes was found in 34.7%, 17.8% and 11.9% of breast cancers respectively. However amplification of c-Ha-ras was not detected in all cases. In 11.9% of cases co-amplification of two or more oncogenes was observed. Positive immunostain-ing of c-erbB2 was seen in 23.8% of the cases and it was significantly associated, but not always corresponding to the amplification of the gene. There was no difference between primary and metastatic breast cancer in the alterations of proto-oncogenes examined in this study, which suggested that the amplification and overexpression of these proto-oncogenes occured prior to and maintained in the process of metastasis of breast cancer. S     

Neuronal firing in the ventrolateral thalamus of patients with Parkinson’s disease differs from that with essential tremor

Background Although thalamotomy could dramatically improve both parkinsonian resting tremor and essential tremor （ET）, the mechanisms are obviously different. This study aimed to investigate the neuronal activities in the ventrolateral thalamus of Parkinson＇s disease （PD） and ET. Methods Thirty-six patients （PD： 20, ET： 16） were studied. Microelectrode recordings in the ventral oral posterior （Vop）and the ventral intermediate nucleus （Vim） of thalamus was performed on these patients who underwent thalamotomy.Electromyography （EMG） was recorded simultaneously on the contralateral limbs to surgery. Single unit analysis and the interspike intervals （ISIs） were measured for each neuronal type. ISI histogram and auto-correlograms were constructed to estimate the pattern of neuronal firing. Mann-Whitney test and Kruskal-Wallis （K-W） test were used to compare the mean spontaneous firing rate （MSFR） of neurons of PD and ET patients. Results Three hundred and twenty-three neurons were obtained from 20 PD trajectories, including 151 （46.7%） tremor related neuronal activity, 74 neurons （22.9%） with tonic firing, and 98 （30.4%） neurons with irregular discharge. One hundred and eighty-seven neurons were identified from 16 ET trajectories including 46 （24.6%） tremor-related neuronal activity, 77 （41.2%） neurons with tonic firing, and 64 neurons （34.2%） with irregular discharge. The analysis of MSFR of neurons with tonic firing was 26.7 （3.4-68.3） Hz （n=74） and that of neurons with irregular discharge （n=98） was 13.9 （3.0-58.1） Hz in PD; whereas MSFR of neurons with tonic firing （n=77） was 48.8 （19.0-135.5） Hz and that of neurons with irregular discharge （n=64） was 26.3 （8.7-84.7） Hz in ET. There were significant differences in the MSFR of two types of neuron for PD and ET （K-W test, both P〈0.05）. Significant differences in the MSFR of neuron were also obtained from Vop and Vim of PD and ET （16.3 Hz vs. 34.8 Hz, 28.0 Hz vs. 49.9 Hz） （K-W test, both P 〈0.05）, respectively. Conclusion In consistent with recent findings, the decreased MSFR of neurons observed in the Vop is likely to be involved in PD whereas the increased MSFR of neurons seen in the Vim may be a cause of ET.     

Effect of deep brain stimulation on substantia nigra neurons in a rat model of Parkinson’s disease

Background  Parkinson’s disease (PD) is a common neurodegenerative disease, which occurs mainly in the elderly. Recent studies have demonstrated that apoptosis plays an important role in the occurrence and development of PD. Subthalamic nucleus deep brain stimulation (STN-DBS) has been recognized as an effective treatment for PD. Recent clinical observations have shown that STN-DBS was able to delay early PD progression, and experiments in animal models have also demonstrated a protective effect of STN-DBS on neurons. However, the correlation between the neuron-protective effect of STN-DBS and the progression of substantia nigra pars compacta (SNc) neuronal apoptosis is still unknown. The aim of this study was to investigate the protective effect and potential mechanism of STN-DBS on SNc neurons in PD rats.

Methods  After the establishment of a PD rat model by unilateral/2-point injection of 6-hydroxydopamine in the medial forebrain bundle of the brain, DBS by implanting electrodes in the STN was administered. Behavioral changes were observed, and morphological changes of SNc neurons were analyzed by Nissl staining and DNA in situ end-labeling. Through extracellular recording of single neuron discharges and microelectrophoresis, the causes of and changes in SNc excitability during STN-DBS were analyzed, and the protective effect and potential mechanism of action of STN-DBS on SNc neurons in PD rats was investigated.

Results  SNc neuron apoptosis was significantly decreased (P <0.05) in the stimulation group, compared with the sham stimulation PD group. Spontaneous discharges of SNc neurons were observed in normal rats and PD model rats, and the mean frequency of spontaneous discharges of SNc neurons in normal rats ((40.65±11.08) Hz) was higher than that of residual SNc neurons in PD rats ((36.71±9.23) Hz). Electrical stimulation of the STN in rats was associated with elevated excitation in unilateral SNc neurons. However, administering the gamma-aminobutyric acid receptor blocker, bicuculline significantly reduced SNc neuron excitation, but the change in SNc neuron excitation was not present when MK801, a glutamate receptor blocker, was administered.

Conclusions  High-frequency stimulation of the STN has a protective effect on SNc neurons in PD rats. The possible molecular mechanism may be related to changes in the distribution and metabolism of neurotransmitters in the SNc region.

     

Expressions of Substance P in Trigeminal Ganglia in Rats with Occlusal Reconstruction

Objective To study the expressions of substance P （SP） in trigeminal ganglia （TG） in rats with occlusal reconstruction. Methods 30 Wistar male rats were randomly divided into 3 experimental groups and 3 control groups, 5 rats in each group. The molar of right maxillary and mandibular of rats in experimental groups were ground to the gingival level without occlusal contact. The occlusal contact was recovered by stopping grounding molar of the rats. The section of trigeminal ganglia underwent the immunohistological study to evaluate the expressions of SP by using SABC method. Light microscope and microscoic photo analytic software were employed to detect the percentage of SP positive neurons in frozen section of TG in 30 rats. SPSS10.0 statistical software was used for statistical analysis. Results There was no significantly difference in the percentage of SP positive neurons between the early occlusal reconstruction experiment group and control group （P〉0.05）. There was significantly difference in the percentage of SP positive neurons between the later occlusal reconstruction experiment group and control group （P〈0.01, P〈0.05）. Conclusion The expressions of SP in TG can recover normal in the early occlusal reconstruction and that not in the later occlusal reconstruction. SP might participate in the histopathologic mechanism of temporomandibular disorders.     

PATHOLOGICAL INVESTIGATION OF TESTES AND EPIDIDYMAL FUNCTION FROM INFERTILE MEN WITH VARICOCELE

A systematic reproductive pathological study of testes biopsies taken from 60 infertile men with varicocele was performed using light and electron microscopy, detection of immune complex deposition and epididymal function assays were conducted in certain cases as well. Three main pathological alterations were noticed in testes, i.e. exfoliation of germ cells, interstitial oedema, and pathological changes occured in the contralateral testis, among which the interstitial oedema might be the most characteristic lesion. Electronmicroscopically, distinct changes were revealed not only in the adluminal but also in the basal compartment of seminiferous tubules, so that spermatogenesis impairments under varicocele involves disorders in spermatogonia proliferation, spermatocyte meiosis and spermiogenesis. Immune complex deposition were found in some cases. L-carnitine and α-glucosidase assays demonstrated the presence of epididymal dysfunction. Based on these observations preliminary mode of etiologic mechanism for infertility with varicocele was proposed.     

Downregulation of metabotropic glutamate receptors mGluR5 and glutamate transporter EAAC1 in the myenteric plexus of the diabetic rat ileum

Objective: To study the morphologic abnormalities of the myenteric plexus in diabetic rats and to explore the mechanism of their effect on gastrointestinal motility. Methods: Forty rats were randomly divided into a diabetic group and a control group, Gastric emptying and small intestine transit rates were measured and histologic and molecular changes in glutamatergic nerves in the ileal myenteric plexus were observed, mGluR5 receptor and EAAC1 transporter changes in the diabetic rats were studied using fluorescence immunohistochemistry and RT-PCR. Results:Eighteen weeks after the establishment of the diabetic rats model, gastric emptying and small intestine transit rates were found to be significantly delayed in the diabetic group when compared with the control group. The density of glutamatergic ganglia and neurons in the ileal myenterie plexus were significantly decreased in the diabetic group when compared with control group(P < 0.05) and the mGluR5 receptors and EAAC1 transporters were downregulated in the diabetic rats(P < 0.05). Conclusion: Decreased glutamatergic enteric ganglia and neurons and decreased mGluR5 receptors and EAAC1 transporters in the intestinal myenteric plexus is one of the mechanisms of diabetic gastroenteropathy in rats.     

EFFECTS OF PHYCOCYANIN ON EXPRESSION OF CytC mRNA AND CASPASE-3 mRNA AFTER FOCAL CEREBRAL ISCHEMIA／REPERFUSION IN RATS

Objective To study the effects of phycocyanin on the expression of Cytochrome C (CytC) genes and Caspase-3 genes after focal cerebral ischemia/reperfusion in rats. Methods A rat middle cerebral artery occlusion (MCAO)/reperfusion model was produced using the intraluminal filament method. The rats were divided into three groups: sham operation group, model control group and phycocyanin group. After MCAO, the neurobehavioral testing of all rats was made. The infarction area was evaluated with the method of 2,3,7-triphenylt-etrazolium chloride (TTC) staining. The expression of CytC mRNA and Caspase-3 mRNA were determined by in situ hybridization. Results In the sham operation group and the model control group, there was only a few CytCpositive cells were seen in the normal cerebral tissue. In the model control group, the upregulation of CytC mRNA began 6h after ischemia, reached a maximum at 12h (cortex)-24h (striatum) , then subsided gradually, but still in high level. In the phycocyanin group, CytC-positive cells were also mainly in cortex and striatum, but the number of the cells was significantly lower than the number of the model control group. The time-phase pattern of CytC mRNA in the phycocyanin group was similar to the pattern of the model control group. In the sham operation group and the model control group, there was only a few Caspase-3-positive cells were seen in the normal cerebral tissue. In the model control group, the upregulation of Caspase-3 mRNA began 6h after ischemia, reached a maximum at 24h and subsided at 48h, but still in high level. In the phycocyanin group, Caspase-3-positive cells were also mainly in the penumbral area, but the number of the cells were significantly lower than the number of the model control group. The time-phase pattern of Caspase-3 mRNA in the phycocyanin group was similar to the pattern of the model control group. Conclusion The over-expression of CytC mRNA and Caspase-3 mRNA might play a key role in ischemic cerebral injury after MCAO. Phycocyanin could inhibit the over-expression of CytC mRNA and Caspase-3 mRNA in the cerebral cortex, and might play an important role in the protection of ischemic neurons.     

Influences of NR2B-containing NMDA receptors knockdown on neural activity in hippocampal newborn neurons

Adult-born neurons undergo a transient period of plasticity during their integration into the neural circuit.This transient plasticity may involve NMDA receptors containing NR2B,the major subunit expressed at early developmental stages.The main objective of the present study was to investigate the effects of NR2B gene knockdown on the functional integration of the adult-born granule cells generated from the subgranule zone (SGZ) in the hippocampus.The small interfering RNA (siRNA) was used to knock down the NR2B gene in the adult-born hippocampal neurons.In the functional integration test,the mice were exposed to a novel environment (open field arena),and the expression of c-fos was immunohistochemically detected in the hippocampus.After exposure to the novel environment,siRNA-NR2B mice were significantly different from control mice in either the number of squares or the number of rears they crossed,showing decreased horizontal and vertical activity (P<0.05).Moreover,the c-fos expression was increased in both control and siRNA-NR2B mice after open field test.But,it was significantly lower in siRNA-NR2B neurons than in control neurons.It was concluded that the neural activity of newborn neurons is regulated by their own NR2B-containing NMDA glutamate receptors during a short,critical period after neuronal birth.     

Laterodorsal tegmentum and pedunculopontine tegmental nucleus circuits regulate renal functions: Neuroanatomical evidence in mice models

Neurons in the laterodorsal tegmentum (LDTg) and pedunculopontine tegmental nucleus (PPTg) play important roles in central autonomic circuits of the kidney. In this study, we used a com-bination of retrograde tracers pseudorabies virus (PRV)-614 and fluorescence immunohistochemistry to characterize the neuroanatomic substrate of PPTg and LDTg innervating the kidney in the mouse. PRV-614-infected neurons were retrogradely labeled in the rostral and middle parts of LDTg, and the middle and caudal parts of PPTg after tracer injection in the kidney. PRV-614/TPH double-labeled neurons were mainly localized in the rostral of LDTg, whereas PRV-614/TH neurons were scattered within the three parts of LDTg. PRV-614/TPH and PRV-614/TH neurons were located predomi-nantly in the caudal of PPTg (cPPTg). These data provided direct neuroanatomical foundation for the identification of serotonergic and catecholaminergic projections from the mid-brain tegmentum to the kidney.     

Differential expression of alpha-adrenoceptor subtypes in rat dorsal root ganglion after chronic constriction injury

Summary： mRNAs of alpha-adrenoceptor （α-AR） subtypes are found in neurons in dorsal root ganglion （DRG） and change after peripheral nerve injury. In this study, the distribution of α-AR subtype proteins was studied in L5 DRG of normal rats and rats with chronic constriction injury of sciatic nerve （CCI）. Using immunofluorescence technique, it was found that α1A-, α1B-, and α2A-AR proteins were expressed in large, medium, and small size neurons in normal DRG, and significantly increased in all size neurons 14 days after CCI. α1D- and α2C-AR was also expressed in all size neurons in normal DRG. However, α1D-AR was significantly increased and α2C-AR was decreased in small size neurons 14 days post CCI. α2B-AR neurons were not detectable in normal and CCI DRG. Co-expression of α1A- and α2A-AR in the same neuron was observed in normal DRG and increased post CCI. Collectively, these results indicated that there is distinct distribution of α-AR subtypes in DRG neurons, and the distribution and levels of expression of α-AR subtypes change differently after CCI. The up-regulation of α-AR subtypes in DRG neurons may play an important role in the process of generating and transmitting neuropathic pain.     

Role of MR imaging in the diagnosis of intracranial germinoma

Objective: To investigate the role of MRI in the diagnosis of intracranial germinoma. Methods: MRI features of 19 cases of intracranial germinoma confirmed by operations and pathological findings were analyzed retrospectively. Results: Germinomas were found in the seUar region in 10 patients (including 5 males and 5 females), in the pineal region in 6 and in the thalamus and basal ganglia in 3, the 9 patients in the latter 2 groups all being males. The characteristic MRI findings of intracranial germinomas were as follows : ( 1 ) Lesions were isointense or slightly hypointense on TlWI while isointense or slightly hyperintense on T2WI. The germinomas in the seUar region and pineal region showed no edema, but lesions in the thalamus basal ganglia showed mild to moderate edema and space-occupying effects. (2) Homogeneous or inhomogeneous Gd-DTPA enhancement were seen in most of the tumors. Conclusion:Muhiaxial imaging and Gd-DTPA enhancement in MRI are helpful in the diagnosis and differentiation of intracranial germinomas on the basis of the patients gender, the location of the tumor and its imaging characteristics.