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Objective To investigate the response of astrocytes and neurons in the medullary visceral zone (MVZ) to neuropathic pain induced by the spared nerve injury (SNI, the tibial nerve and the common peroneal nerve were sectioned, while the sural nerve was intacted). Methods The SNI operation and sham operation (only incised the skin of thigh, but the tibial nerve and the common peroneal nerve did not cut) were performed in adult male Sprague-Dawley rats. The paw withdrawal mechanical threshold (PWMT) was measured at 10,20,30 days after operation. By using single or double immunofluorescent staining method,we investigated and measured that the mean fluorescent intensity (MFI) of anti-glial fibrillary acidic protein (GFAP, a marker of astrocytes) signal in the astrocytes, the mean member of Fos/ GFAP double labeled astrocytes and Fos / tyrosine hydorxylase (TH) double labeled neurons in MVZ after operation. Results As compared with control or sham groups, SNI induced that the PWMT became significant sensitivity and peaked at 20 days after SNI. The activated astrocytes revealed an activated morphology, the MFI of anti-GFAP signal markedly strengthened, the mean number of Fos/GFAP double labeled astrocytes and Fos/TH double labeled neurons in the nucleus of the tract solitarius (NTS) and the ventral lateral medulla (VLM) increased significantly and peaked at 20 days after SNI. Conclusion The neurons and astrocytes in MVZ were sensitively activated by SNI.
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Objective To investigate the effects of electro-acupuncture on gastric emptying and Fos expression in the neuron of vagal-solitary complex (VSC) of rat bulbus after lipopolysaccharide (LPS) intraperitoneal injection (i.p.). Methods 40 male SD rats were randomly assigned to 4 groups: control group, LPS i.p. group, LPS i.p. plus electro-acupuncture at Tsusanli point group and LPS i.p. plus electro-acupuncture at non-meridian-non-acupoint group, 10 rats for each group. Immunohistochemical techniques were used to detect the Fos expression in VSC. The animal's gastric emptying was measured by phenol red method. Results The rats with gastric emptying decreased greatly to (20.7±4.5)% 2.5 hours after LPS injection, and Fos-positive neurons were significantly found in VSC (83.2±6.6) compared with control group. However, in the group of LPS i.p. plus electro-acupuncture at Tsusanli point, the gastric emptying was up-regulated to (44.1±6.2)%, and the expression of Fos -positive neurons were down-regulated to (37.9±3.8) compared with LPS i.p. group. No significant difference was found between the group of LPS i.p. plus electro-acupuncture at non-meridian-non-acupoint and the group of LPS i.p. Conclusion LPS i.p. can retard the gastric motility in rats, electro-acupuncture at Tsusanli point may well regulate the function in LPS model rats. This function may be connected with its protective effects on Fos immunoreactive neurons activity in VSC of rat bulbus.
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BACKGROUND: Lipopolysaccharide(LPS), as a polyclonal immune exciter, can simulate immune excitation status, which is useful in the observation of whether the catecholaminergic neurons in paraventricular nucleus of hypothalamus(PVN) projected from medullary visceral zone(MVZ) react towards LPS stimulation that is to provide a theoretical gist for the researches on the protection of brain function.OBJECTIVE: To observe whether PVN catecholaminergic neurons projected from MVZ react towards LPS stimulation for the exploration of the impacts of MVZ-PVN catecholaminergic access in "immune-to-brain communication".DESIGN: A randomized controlled study using experimental animals as subjects.SETTING: An Institute of Neurosurgery and Neurology of one Military University of Chinese PLA.MATERIALS: The study was conducted in the Department of Neurosurgery of Zhujiang Hospital affiliated to Southern Medical University and the Institute of Neurology of the Fourth Military Medical University of Chinese PLA from January to December in 2002. Ten healthy adult SD rats in cleanness grade were obtained from the experimental animal center of the Fourth Military Medical University of Chinese PLA.METHODS: WGA-HRP was injected into PVN of one side of the rat, and the immune exciter LPS was injected into the abdominal cavity after 48 hours of survival to induce immune response. Samples were stained by triple labels of WGA-HRP method and double immunohistochemical staining of anti-Fos and anti-TH antibodies.MAIN OUTCOME MEASURES: To observe the distributions and expressions of WGA-HRP labeled cells, Fos protein, and catecholaminergic neuron(labeled by TH) in MVZ.RESULTS: Seven immune-reactive(IR) positive neurons were found in MVZ, i. e., HRP, Fos or TH single labeled cells, Fos/HRP, Fos/TH or HRP/TH double labeled cells, and Fos/HRP/TH triple labeled cells. Fos/HRP double labeled neurons and Fos/HRP/TH triple labeled neurons accounted for 12. 5% and 39.6% of HRP labeled cells respectively.CONCLUSION: MVZ reacts to LPS immune stimulation, which could upload the immune message to PVN through Catecholaminergic neurons.MVZ might be a relay station in "immune-to-brain communication", which exerts immune modulatory impact through "MVZ→PVN" access.
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BACKGROUND: It is considered traditionally that epilepsy is a kind of complicated nervous conduct disorder caused by abnormally excited neuron in different area in brain. While the research on the function of astrocyte in epileptic attack is very rare.OBJECTIVE: To study the reaction of neuron and astrocyte in medullary visceral zone after epilepsy induced by pentetrazole in rats.DESIGN: A randomized controlled experimental research.SETTING and MATERIALS: The experiment was done in the Neurosurgery Laboratory of Zhujiang Hospital Affiliated to Southern Medical University and Neuroscience Institute of Fourth Military Medical University of Chinese PLA. Fourteen healthy adult SD rats, weighing 180 - 220 g, clean grade, were provided by the Experimental Animal Center of Fourth Military Medical University of Chinese PLA.INTERVENTIONS: Distribution of neuron and astrocyte in MVZ 1 hour after epileptic attack was shown by laserconfocal microscopic technique combined with triplication immunofluorescence histochemistry of anti-Fos protein, anti-tyrosine hydroxylase(TH) and anti-glial fibrillary acidic protein(GFAP).MAIN OUTCOME MEASURES: Observation of distribution of positive cells of Fos, GFAP and TH in MVZ and relationship between GFAP positive astrocyte and neuron.RESULTS: Fos positive neurons and GFAP positive astrocytes in MVZ increased significantly. Triplication immunofluorescence histochemistry showed reaction neuron(Fos positive) closely related with reaction astrocyte(GFAP positive) . Three kinds of N-ASC compounds with different labels were found, which were TH +/Fos +/GFAP + three labeled compound, TH + /GFAP +/Fos- and Fos+/GFAP +/TH- two labeled compound.CONCLUSION: Neuron and astrocyte in MVZ reacted strongly when epilepsy attacks. N-ASC as a functional unit may regulate onset of epilepsy.
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BACKGROUND: Astrocytes play active roles in neuronal activity through reciprocal communication with neurons.OBJECTIVE: To observe the distribution of pyramidal cells and astrocytes in rat hippocampal CA3 area and to reconstruct their three-dimensional relationship.DESIGN: A randomized controlled experiment based on rats.SETTING: Neurosurgery department in a university and neuroscience institute in a military medial university of Chinese PLA.MATERIALS: The experiment was conducted in the Neurosurgery Department of Zhujiang Hospital of Southern Medical University and the Neuroscience Institute of Fourth Military Medial University of Chinese PLA from October 2001 to June 2003. Thirty-day-old male SD rats were provided by the Experimental Animal Center of Fourth Military Medial University of Chinese PLA.METHODS: The techniques used in this study were brain slice patch-clamping whole-cell recording, lucifer yellow (LY) staining, immunofluorescence and laser scanning confocal microscopy(LSCM).MAIN OUTCOME MEASURES: The discharge features of neurons and the spatial distribution of astrocytes.RESULTS: The hippocampal neurons were classified into 2 types according to their discharge patterns: phasic and non-phasic neurons. The observation under both LSCM and three-dimensional reconstruction revealed that a large number of astrocytes aggregated around LY-dyed pyramidal cells and there were tight contacts between them. The contacts between astrocytes and the two types of neurons differed in that they were found both on dendrites and cell body of non-phasic neurons but on dendrites of phasic neurons.CONCLUSION: The spatial distributions of astrocytes around different types of hippocampal pyramids may be different.
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Objective To investigate the effects of tegaserod on visceral sensitivity and explore the regulating mechanism.Methods Forty-two male Spragre-Dawley rats,which were induced colonic inflammation by intraluminal administration of trinitrobenzenesulfonic acid(TNBS),were randomly divided into eight groups.In the three colorectal distention(CRD) treated groups(n=6),abdominal contractions were recorded after 3,7 and 14 days of intra-gastric administration of tegaserod 2mg/kg d.In the three CRD control groups(n=4),abdominal contractions were recorded after 3,7 and 14 days of intra-gastric injection of saline 2.0mL/d.In immunohistochemistry(IH) treated group(n=6) and IH control group(n=6),samples of colon were removed and processed for SP and CGRP immunohistochemistry after 7 days of intra-gastric administration of tegaserod and saline,respectively.Results Abdominal contractions induced by colonic distention decreased significantly at 1.2mL and 1.6mL distention volume after 3 days of tegaserod administration(P
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Aim To investigate the changes of plasticity and distribution in the lungs of asthmatic guinea pigs.Methods Guinea pigs were divided into asthma group and control group.Immunohistochemistry was used in this study to observe the changes of ERK1/2 and Elk phosphoryiation in the lungs of guinea pigs.Results There were significant changes in distribution of EPK1/2 and Elk in the lungs of asthma group.The positive cells were detected on the walls of respiratory bronchioles and alveolar ducts,especially on the smooth muscle layer and basement membrane.In addition,the numbers of positive cell were clearly increased in asthma group(P< 0.01). Conclusion There is close relationship between the EPK1/2 and Elk phosphoryiation and attack of asthma.It may be a reason for persistence and progress of asthma.
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Objective To investigate the expression of GFAP in rat hypothalamus after acute heat stress. Methods The rats were caged in a experimental incubator for 60 minutes,the temperature within the incubator was adjusted to 24℃,34℃,38.5℃ or 42℃,the humidity was 60%.Single anti-GFAP immunohistochemical(ABC) method and anti-Fos and GFAP double immunohistochemical method were used to observe the expression of GFAP in hypothalamus in different ambient temperatures after heat stress. Results The GFAP-positive cells were rare in hypothalamus at 24℃,however it was increased in many nuclei(anterior hypothalamic area,paraventricular nucleus,arcuate nucleus,suprachiasmatic nucleus and supraoptic nucleus)at 34℃ and peaked when ambient temperature was 38.5℃,and then decreased.However,Fos/GFAP-IR double labelled astrocytes were observed at 42℃.Conclusion Astrocytes participate in the pathophysiological process of heat stress.
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Objective To explore the role of plastic astrocytes in focal cerebral infarct. Methods Immunohistochemical and double immunofluorescence techniques were used in the study. Results The astrcytes positive for glial fibrillary acidic protein(GFAP) occurred in the periinfarct area appeared hypertrophy and proliferation,specially on their processes and formed a network,and the processes oriented toward the infarct center from the periinfarction.The expression of excitatory amino acid transporter 1( EAAT1) increased in the penumbra area of cerebral infarct and manifested spot and fibre.The confocal laser scanning microscopic analysis showed the double staining for EAAT1 and GFAP.Conclusion The plastic astrocytes might participate in the pathological process of cerebral infarct recovery by enhancing the expression of EAAT1.;
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Objective To investigate the responses of neurons and astrocytes within rat′s spinal trigeminal nucleus(Sp5C) following nocuous pain stimulation induced by subcutaneous formalin injection into the unilateral upper lip. Methods By means of anti\|phospholipase(PLC),anti\|Fos protein and anti\|glial fibrillary acidic protein(GFAP) immunohistochemical method,the distribution of reactive neurons and astrocytes in the Sp5C was observed at different time after formalin injection. Results No immunohistochemical staining was found in normal rat Sp5C.After formalin injection,PLC like immunoreaction(\|LI),Fos\|LI and GFAP\|LI were found in astrocytes while PLC\|LI and Fos\|LI in neurons.The labeled astrocytes and neurons showed similar distribution and close relationship.PLC\|LI and Fos\|LI were found earlier than that in neurons.Conclusion\ The results suggested that the astrocytes in the Sp5C might participate in pain modulation in CNS and actively regulate neuron′s function.
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Objective To observe the instant reactions and relationship of astrocytes(AS) and neurons in rat spinal cord after the unilateral tibia and fibula bone fracture. Methods With single or double immunohistochemical staining method,the expression of Fos-like immunoreaction(-LI), glial fibrillary acidic protein(GFAP-LI), and protein kinase C(PKC-LI) were observed. Results Here we showed 1
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Objective To observe the instant reactions and relationship of astrocytes(ASs) and neurons(Ns) in rat forebrain after the unilateral tibia and fibula bone fracture. Methods With immunohistochemical triple staining method,the expression of Fos-protein,glial fibrillary acidic protein(GFAP) and tyrosine hydroxydase(TH) were observed. Results Here we showed 1.After the nociception of the treatment,GFAP-like immunoreactive (-LI) ASs exhibited clear character of nuclei distribution in the lateralmedial habenular nucleus(LHb),paraventricular nucleus of the hypothalamus(Pa),supraoptic nucleus(SON),suprachiasmatic nucleus(SCh),bed nucleus of of stria terminalis(BST),central amygdaloid nucleus(Ce) medial amygdaloid nucleus(Me) and cortex;2.The distribution of Fos-LI Ns and GFAP-LI ASs in above nuclei were similar,there were close relationship between Fos-LI Ns and GFAP-LI ASs.3.There were many double-labelled Fos/TH-LI Ns that were surrounded by the GFAP-LI ASs,and formed the neuron-astrocyte complex(N-ASC).Conclusion The ASs as well as Ns of the above nuclei or regions may be involved in instant response and adjustment of the lower extremity bone fracture nociception simultanneously.
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Objective Monocular deprivation(MD) and binocular deprivation(BD) were used to examine the experience\|dependent structural plasticity of astrocytes in the central visual brain regions of young rats. Methods Pups eyelids were monocularly or binocularly sutured on postnatal day 7(P7) and maintained until 80?d,while an unoperated light experienced group was used for comparisions(L).Immunohistochemical ABC method was employed to investigate the immunoreactive changes of astrocytic bodies and processes for glial fibrillary acidic protein(GFAP) in the central visual brain regions. Results The results showed that the amount of astrocytic bodies and processes in the brain was decreased both in MD and BD groups compared to L group.The amount of GFAP\|positive immunoreactivity in the optic chiasma,optic tract,and contralateral central visual brain regions (including suprachiasmatic nucleus,lateral geniculate nucleus,occipital visual cortex,optic nerve layer of the superior colliculus and pretectal area) was significantly decreased in MD group.GFAP\|positive structures presented complementary distribution in bilateral visual cortex.For bilateral brain regions mentioned above,the amount of GFAP\|positive structures basically disappeared in BD group.There was,however,an increase in the olfactory cortex of GFAP immunoreactive in MD and BD groups. Conclusion\ The data suggested that the structure of astrocytes might be influenced by visual experience during development.
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<p><b>OBJECTIVE</b>This investigation aimed at explore the total distribution of neuropeptide Y-like immunoreactive (NPY-LI) fibers and their changes post-trauma in rat temporomandibular joints (TMJs).</p><p><b>METHODS</b>Six groups of rats were killed individually before trauma, 1, 3, 7, 14 and 28 days after trauma. TMJs were extracted totally, and the avidin-biotin-peroxidase complex method and image analysis were employed to detect NPY-LI fibers in frozen sections of TMJs.</p><p><b>RESULTS</b>NPY-LI fibers were distributed extensively in TMJs, except the central disc band and bone, and they were mainly located around blood vessels, especially arteries. The densities of fibers in the six groups were 160.4 +/- 27.5, 95.8 +/- 16.4, 88.6 +/- 14.5, 114.3 +/- 17.0, 135.0 +/- 20.7, 158.6 +/- 19.5 (unit:mm2).</p><p><b>CONCLUSION</b>NPY-LI nerve fibers are distributed extensively in the periphery of blood vessels of TMJs and densities changed dynamically when TMJs were impacted. NPY may play an important role in pathologic change of TMJ by regulating local blood circulation.</p>
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Animals , Male , Rats , Nerve Fibers , Metabolism , Pathology , Neuropeptide Y , Physiology , Rats, Sprague-Dawley , Signal Processing, Computer-Assisted , Temporomandibular JointABSTRACT
Objective To elucidate the existence of reciprocal pathways between medullary visceral zone (MVZ) and hypothalamic paraventricular nucleus (PVN) or supraoptic nucleus(SON) following hyperosmotic stimulation. Methods Hyperosmosis was produced in rats by drinking 3% sodium chloride solution. The distributions and expressions of HRP retrogradely labeled neurons, Fos, tyrosine hydroxylase (TH) or vasopressin (VP) positive neuron and glial fibrillary acidic protein (GFAP) positive astrocytes(AST) in MVZ, SON and PVN were observed by quadruplicate labeling methods of WGA HRP retrograde tracing combined with anti Fos, TH (or VP) and GFAP immunohistochemical technique. Results Fos positive neurons within the MVZ, PVN and SON were increased markedly. There was also a marlced increase in GFAP positive structures in the brain, and their distribution pattern was fundamentally similar or analogous to Fos positive neurons in the above mentioned areas. The augmented GFAP structures manifested as hypertrophic cell bodies, with thicker and longer processes. Quadruplicate immunohistochemical staining showed that neurons were surrounded by many AST to form neuron astrocytic complex (N ASC). Conclusion The neurons and AST, as a functional unif in the form of N ASC, might actively participate in modulating osmotic pressure. There was reciprocal osmoregulation pathways between the MVZ and SON or PVN in the brain
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Objective To observe the influences of electroacupuncture(EA) on the morphological changes in neurons and glia cells in sacral dorsal commissural nucleus(SDCN) of rats with ulcerative colitis(UC),and study the mechanism of acupuncture in modulating central nervous system in UC.Methods Forty-eight male SD rats were randomly assigned to four groups: control group,UC model group,EA Tsusanli group(UC plus EA at Tsusanli acupoint) and EA non-acupoint group(UC plus EA non-acupoint group).According to the acupuncture duration,EA Tsusanli group was divided into three subgroups: 1-day,3-day and 5-day subgroup(8 rats for each subgroup).UC model of rats was reproduced by instillation of a solution containing ethanol and 2,4,6,-trinitrobenzenesulfonic acid(TNBS) into the distal colon.When the treatment was ended,all the rats were sacrificed and SDCN slides were prepared.The expressions of Fos,glial fibrillary acidic protein(GFAP) and OX42 immunoreactivity in SDCN were assessed and calculated by using single or double immunohistochemical methods.Results In the three experimental groups,the Fos-positive neurons,GFAP-positive astrocytes and OX42-positive microglia were mainly expressed in SDCN.In UC model group and EA non-acupoint group,the expressions of Fos,GFAP and OX42 immunoreactivity were stronger than those in EA Tsusanli group(P
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Objective:To observe the quantitative and morphological changes of astrocytes in nucleus of solitary tract(NTS) after vagus nerve stimulation(VNS).Methods:Light and electron microscopy immunohistochemisty were used to examine the relationship between astrocytes and neurons by observing the expression of glial fibrillary acidic protein(GFAP),which is the specific protein for astrocytes. Results:Immunoreactivities of GFAP were significantly enhanced after VNS in NTS of rats. Meanwhile,the hypertrophy cell bodies and dark long processes could be seen under high power field. For electron microscopy,immunopositive GFAP astrocytes connected closely with the dendrites or axons of the neurons. The number of synapse increased remarkably after VNS compared with that of the control. Conclusion:Our data indicate that not only the neurons but also the astrocytes in the NTSs play a very important role in the process of the antiepileptic mechanism during VNS.
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Objective To investigate the related brain areas and nucleus involved in the inhibition of vagus nerve stimulation (VNS) on epilepsy. Methods Using the kainic acid kindling epilepsy rats model,we observed the distribution of Fos positive neurons in the brain after VNS treatment combined with immunohistochemical method. Results VNS induced a significant increase in Fos immunoreactivity in the bilateral nucleus of solitary tract,the locus coeruleus,parabrachial nucleus,periaqueductal gray of midbrain,lateral habenular nucleus,paraventricular thalamic nucleus,rhomoid thalamic nucleus,paraventricular hypothalamic nucleus.Dense Fos immunoreactive staining was also seen in the central nucleus of amygdala,bed nucleus of stria terminalis,lateral septal nucleus and prepirifiorm cortex.Pretreatment with electric stimulation on cervical vagual nerve stem, c fos expressing of hippocampus formation,cingulate gyrus and frontal,parietal,temporal lobus significantly diminished after KA injection. Conclusion This finding may suggest that VNS activates various brain structure that could be involved in the regulation of seizures.
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The cholinergic neurons and fibers of the hypothalamus could not be revealedsuccessfully in the past,therefore,there has been general agreement that the hypotha-lamus is very poorly innervated by cholinergic system.In this study,choline acetyl-trans ferase (ChAT)-like immunoreactive positive neurons and fibers of the hypo-thalamus were revealed successfully by using avidin-biotin immunocytochemical me-thod.This study demonstrated for the first time that the cat hypothalamus is richlyinnervated by cholinergic system.We found cholinergic neurons of varying numbersin the following areas:dorsomedial hypothalamic nucleus,paraventricular nucleus,dorsal hypothalamic area,the area of the tuber cinereum surrounding ventromedialhypothalamic nucleus,lateral hypothalamic area,anterior hypothalamic area,anteriorhypothalamic nucleus,parvocellular hypothalamic nucleus,tuber-mammillary nucl-eus,posterior hypothalamic area,anterior mammillary nucleus and supramammillarynucleus.There were a lot of ChAT-like positive fibers in the lateral hypothalamicarea,mammillary area,dorsal hypothalamic area,paraventricular nucleus,parvocel-lular hypothalamic nucleus,the area of the tuber cinereum.Three kinds of neuronperikarya related to cholinergic system were identified in the hypothalamus of thecat:1.cholinergic perikarya;2.noncholinergic-cholinoceptive perikarya;3.choli-nergic-cholinoceptive perikarya.There were also immunoreactive positive fiberswhich were non-varicose and varicose.Two kinds of varicose-fibers,one withstrong immunoreactivity and the other with weak immunoreactivity were distingui-shed.
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Immunoelectron microscopic technique was used in the present study to observe the serotonin (5-HT)-, substance P (SP)-, and leucine-enkephalin (L-Enk)-like immunoreactive ultrastructures in the nucleus raphe magnus (NRM) of the rat. 5HT-like immunoreactive (5-HT-LI) axonal terminals were found to form axosomatic, axo-dendritic, and axo-axonic synapses with non-5-HT-LI neuronal cell bodies, 5-HT-LI and non-5-HT-LI dendrites, and non-5-HT-LI axonal terminals respectively. Non-5-HT-LI axonal terminals formed axo-somatic and axo-dendritic synapses with 5-HT-LI neuronal cell bodies and dendrites. SP-LI (or L-Enk-LI) axonal terminals formed axo-somatic, axo-dendritic synapses with SP-LI (or L-Enk-LI) and non-SP-LI (or non-L-Enk-LI) neuronal cell bodies and dendrites, respectively. L-Enk-LI axonal terminals constituting axo-axonic synapses with L-Enk-LI axonal boutons were observed less frequently. The most common synaptic type made by 3 kinds immunoreactive profiles mentioned above was axo-dendritic synapses made by non-immunoreactive axonal terminals with immunoreactive dendrites. The majority of the immunoreactive axonal boutons were mainly filled by clear spherical vesicles, but sometimes were mixed with small number of flat and granular vesicles. The immunoreactive products were irregular electron-dense substances, and were located on both inner and outer surfaces of the vesicles, or on the surface of the membranous cell organelles in the cytoplasm, etc.