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.

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.

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.

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.

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.

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

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.

OBJECTIVEThis 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).

METHODSSix 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.

RESULTSNPY-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).

CONCLUSIONNPY-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.

Animals ; Male ; Nerve Fibers ; metabolism ; pathology ; Neuropeptide Y ; analysis ; physiology ; Rats ; Rats, Sprague-Dawley ; Signal Processing, Computer-Assisted ; Temporomandibular Joint ; innervation

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.

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.