LPS-induced proNGF synthesis and release in the N9 and BV2 microglial cells: a new pathway underling microglial toxicity in neuroinflammation.

Purpose: While aberrant activation of microglial cells was evidently involved in neuroinflammation and neurotoxicity in the neurodegenerative diseases such as Alzheimer's and Parkinson's disease, objective of study was to address if activated microglias deliver their effect by releasing pro-neurotrophins.

Materials And Methods: By in vitro culture of N9 and BV2 cell lines and lipopolysaccharide (LPS) stimulation model, generation and release of proNGF, proBDNF and MMP-9 was studied in the activated microglial cells by immunocytochemistry, western blotting and bioassay methods.

Results: Activation of microglial cells was observed with obvious increasing iba1-immunoreactivity following LPS stimulation in cell culture.

The proform of glia cell line-derived neurotrophic factor: a potentially biologically active protein.

Growing evidences have revealed that the proforms of several neurotrophins including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT3), by binding to p75 neurotrophin receptor and sortilin, could induce neuronal apoptosis and are implicated in the pathogenesis of various neurodegenerative diseases. The glial cell line-derived neurotrophic factor (GDNF), one of the most potent useful neurotrophic factors for the treatment of Parkinson's disease (PD), is firstly synthesized as the proform (proGDNF) like other neurotrophin NGF, BDNF, and NT3. However, little is known about proGDNF expression and secretion under physiological as well as pathological states in vivo or in vitro.

Glutamate release through connexin 43 by cultured astrocytes in a stimulated hypertonicity model.

We investigated the role of connexin 43 (Cx43) hemichannels in the release of glutamate by astrocytes after hypertonic stimulus. Mechanical, osmotic and oxidative stress, and changes in the extracellular or intracellular Ca(2+) levels induce connexin hemichannels located in the plasma membrane to open and release small ions and molecules with signaling potential such as glutamate, ATP, etc. In our past studies, we primarily found that acute hypertonic stimulus induced the release of glutamate.

Acute hyperosmotic stimulus-induced Fos expression in neurons depends on activation of astrocytes in the supraoptic nucleus of rats.

Acute hyperosmolarity induced a time-dependent expression of Fos protein in both neurons and astrocytes of the rat supraoptic nucleus, with peak Fos expression occurring at 45 min in astrocytes and at 90 min in neurons after hypertonic stimulation in vivo. To determine whether the two cell types were activated separately or in an integrated manner, animals were pretreated with fluorocitrate, a glial metabolic blocker or carbenoxolone, a gap junction blocker followed by an acute hypertonic stimulation similar to that of the controls. Antibodies against glial fibrillary acidic protein, connexin 43, vasopressin, and oxytocin were used in serial sections to identify the cellular elements of the supraoptic nucleus.

A NMDA receptor antagonist, MK-801 impairs consolidating extinction of auditory conditioned fear responses in a Pavlovian model.

Background: In auditory fear conditioning, repeated presentation of the tone in the absence of shock leads to extinction of the acquired fear responses. The glutamate N-methyl-D-aspartate receptor (NMDAR) is thought to be involved in the extinction of the conditioned fear responses, but its detailed role in initiating and consolidating or maintaining the fear extinction memory is unclear. Here we investigated this issue by using a NMDAR antagonist, MK-801.

Involvement of medullary dorsal horn glial cell activation in mediation of masseter mechanical allodynia induced by experimental tooth movement.

Objective: To investigate the involvement of microglial and astrocytic activation in the medullary dorsal horn (MDH) during the mediation of masseter area allodynia induced by experimental tooth movement (ETM).

Design: Five groups of adult Sprague-Dawley rats (n=60) were divided into control (CON), minocycline (MIN), ETM, and 10mg/kg or 30mg/kg MIN plus ETM (METM) groups. The upper-first-molar was moved mesially for rats in ETM and METM groups.

Hypertonic stimulation induces synthesis and release of glutamate in cultured rat hypothalamic astrocytes and C6 cells.

Objective: To investigate whether hypertonic saline (HS) can induce the synthesis and release of glutamate in cultured hypothalamic astrocytes or C6 cell line.

Methods: Astrocytes were isolated, cultured, purified and identified from the hypothalamus of newborn rat (1 day). The astrocytes were randomly divided into five groups: isotonic (IS) and HS groups, astrocytes were incubated by IS and HS (320 mosM NaCl) medium, respectively, for 1, 3, 5, 10 or 15 min; carbenoxolone (CBX)+IS and CBX+HS groups, astrocytes were pre-treated with CBX (100 mmol/L) for 1 h at 37 degrees C in a 5% CO(2) / 95% atmosphere, then removed to IS and HS medium, respectively, for 1, 3, 5, 10 or 15 min; Ca(2+)+HS group, astrocytes were pre-incubated with Ca Ca(2+) (1,000 micromol/L) for 1 h at 37 degrees C in a 5% CO(2) / 95% atmosphere, followed by a wash with isotonic FBS/DMEM, and then removed to hypertonic saline for 1, 3, 5, 10 or 15 min.

[Changes in plasticity of rat hypothalamic neurons and astrocytes in humid and hot environment].

Objective: To study the changes in the plasticity of the neurons and astrocytes in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus of rats exposed to a humid and hot environment.

Methods: The rats were subjected to stimulation with a humid and hot environment for 120 min in a climate chamber (dry bulb temperature of 40.0-/+0.

Electro-acupuncture of Tsusanli and Shangchuhsu regulates gastric activity possibly through mediation of the vagus-solotary complex.

Background/aims: Acupuncture has been reportedly used to treat gastrointestinal diseases, however, its precise mechanism remains unknown.

Methodology: In our study, the effects and mechanism of electro-acupuncture (EA) at Tsusanli (ST 36), Shangchuhsu (ST 37) on regulation of gastric activity were observed.

Results: EA at Tsusanli showed that gastric electric change was the most obvious, with significantly higher frequency and wave amplitude compared with that of the Shangchuhsu group and other groups.

[Effect of carbenoxolone on expression of Fos, NMDAR2 and GFAP in the hippocampus of pentylenetetrazo-kindled epileptic rats].

Objective: Gap junctions, the clusters of intercellular channels, play an important role in synchronizing electrical activity. This study investigated the effect of gap junction blocker carbenoxolone (CBX) on epileptic activity in pentylenetetrazo (PTZ)-kindled rats.

Methods: Thirty adult male SD rats were randomly divided into three groups: control, PTZ-kindled and CBX-treated groups (n=10 each).

[Influence of intrathecal injection of fluorocitrate on the protective effect of electroacupuncture on gastric mucosa in high humid heat stress rats].

Objective: To study if the spinal glial cells involve in the protective effect of acupuncture on gastric mucosa in high humid heat stress rats.

Methods: Thirty-six male SD rats were randomized into 6 groups: control, stress model, electroacupuncture (EA), Fluorocitrate(FCA, intrathecal injection of FCA. 1 microL, 60 min before humid heat stress), EA+ normal saline (NS, intrathecal injection of NS) and EA+ FCA groups.

Electro-acupuncture of Foot YangMing regulates gastric activity possibly through mediation of the dorsal vagal complex.

Acupuncture at some specific acupoints of Foot Yangming can regulate gastric activity. However, its precise mechanism remains unknown. In our study, the effects and mechanism of electro-acupuncture (EA) at Tsusanli (ST 36), Shangchuhsu (ST 37) on the regulation of gastric activity were observed.

Topiramate reduced sweat secretion and aquaporin-5 expression in sweat glands of mice.

Decreased sweat secretion is a primary side effect of topiramate in pediatric patients, but the mechanism underlying this effect remains unclear. This study aimed to better understand how topiramate decreases sweat secretion by examining its effect on the expression of carbonic anhydrase (CA) II and aquaporin-5 (AQP5), total CA activity, as well as on tissue morphology of sweat glands in mice. Both developing and mature mice were treated with a low (20 mg/kg/day) and high dose (80 mg/kg/day) of topiramate for 4 weeks.

Blocking the glial function suppresses subcutaneous formalin-induced nociceptive behavior in the rat.

This study examined whether glial cells in the trigeminal nucleus caudalis (Sp5C) were necessary for orofacial nociception and nociceptive processing induced by subcutaneously (s.c.) injection of 5% formalin into left mystacial vibrissae.

Aberrant activation of CDK5 is involved in the pathogenesis of OPIDN.

Exposure to triorthocresyl phosphate (TOCP) may result in a late neurological complication, i.e. organophosphate-induced delayed neuropathy (OPIDN).

The lumbar spinal cord glial cells actively modulate subcutaneous formalin induced hyperalgesia in the rat.

We investigated the response and relationship of glial cells and neurons in lumbar spinal cord to hyperalgesia induced by the unilateral subcutaneous formalin injection into the hindpaw of rats. It was demonstrated that Fos/NeuN immunoreactive (-IR) neurons, glial fibrillary acidic protein (GFAP)-IR astrocytes and OX42-IR microglia were distributed in dorsal horn of lumbar spinal cord, predominantly in the superficial layer. In the time-course studies, GFAP-IR astrocytes were firstly detected, OX42-IR microglia were sequentially observed, Fos/NeuN-IR neurons were found slightly late.

Activity-induced rapid synaptic maturation mediated by presynaptic cdc42 signaling.

Maturation of presynaptic transmitter secretion machinery is a critical step in synaptogenesis. Here we report that a brief train of presynaptic action potentials rapidly converts early nonfunctional contacts between cultured hippocampal neurons into functional synapses by enhancing presynaptic glutamate release. The enhanced release was confirmed by a marked increase in the number of depolarization-induced FM4-64 puncta in the presynaptic axon.

[Effects of N-methyl-D-aspartate receptor in visceral, hypersensitivity in rats with colonic inflammation].

Objective: To investigate the effects of N-methyl-D-aspartate receptor (NMDAR) in the spinal dorsal horn in visceral hypersensitivity in rats with colonic inflammation.

Methods: Seventy adult male Sprague-Dawley (SD) rats were randomly divided into the experimental group and the control group. Colonic inflammation was induced in the experimental rats by intraluminal administration of trinitrobenzenesulfonic acid (TNBS).

GFAP and Fos immunoreactivity in lumbo-sacral spinal cord and medulla oblongata after chronic colonic inflammation in rats.

Aim: To investigate the response of astrocytes and neurons in rat lumbo-sacral spinal cord and medulla oblongata induced by chronic colonic inflammation, and the relationship between them.

Methods: Thirty-three male Sprague-Dawley rats were randomly divided into two groups: experimental group (n = 17), colonic inflammation was induced by intra-luminal administration of trinitrobenzenesulfonic acid (TNBS); control group (n = 16), saline was administered intra-luminally. After 3, 7, 14, and 28 d of administration, the lumbo-sacral spinal cord and medulla oblongata were removed and processed for anti-glial fibrillary acidic protein (GFAP), Fos and GFAP/Fos immunohistochemistry.

[Three-dimensional structural reconstruction of the neurons and astrocytes in rat hippocampal CA3 area].

Objective: To observe the distribution of the pyramidal neurons and the surrounding astrocytes in rat hippocampal CA3 area and reconstruct their three-dimension structure.

Methods: Whole-cell patch-clamp recording of the brain slices, intracellular staining with Lucifer yellow, glial fibrillary acidic protein (GFAP) immunofluorescence, and confocal laser scanning microscopy were utilized in this study.

Results: According to the firing patterns, the hippocampal pyramidal neurons were classified into phasic or non-phasic firing neurons.

[Spinal cord neuronal apoptosis induced by triorthocresyl phosphate poisoning in hens].

Objective: To investigate the role of neuronal apoptosis in organophosphorus poisoning-induced delayed neuropathy (OPIDN) and its dynamic pathological changes.

Methods: To establish OPIDN animal model, triorthocresyl phosphate (TOCP)was given to hens with a single dose (1 000 mg/kg, im). Changes of neuropathology, number of neurons and apoptotic cells in the third lumbar spinal cord were observed by HE, Nissl and TUNEL methods 3, 5, 7, 10, 14, 18 days after injection.

Ultrastructure of junction areas between neurons and astrocytes in rat supraoptic nuclei.

Aim: To determine the ultrastructure of junction areas between neurons and astrocytes of supraoptic nuclei in rats orally administered 30 g/L NaCl solution for 5 days.

Methods: The anti-connexin (CX) 43 and anti-CX32 double immunoelectromicroscopic labeled method, and anti-Fos or anti-glial fibrillary acidic protein (GFAP) immunohistochemistry were used to detect changes in the junctional area between neurons and astrocytes in supraoptic nuclei of 5 rats after 30 g/L NaCL solution was given for 5days.

Results: A heterotypic connexin32/connexin43 gap junction (HGJ) between neurons and astrocytes (AS) in rat supraoptic nuclei was observed, which was characterized by the thickening and dark staining of cytomembranes with a narrow cleft between them.

Dentate granule cell neurogenesis after seizures induced by pentylenetrazol in rats.

Epileptic seizures originating from the limbic system have been shown to stimulate the proliferation rate of granule cell precursors in the adult brain, but it is not clear if other type(s) of seizures have the similar effects. This study examined the effects of pentylenetrazol (PTZ)-induced generalized clonic seizures on dentate granule cell neurogenesis in adult rats. Using systemic bromodeoxyuridine (BrdU) to label dividing cells, we studied the proliferation rate of neural precursor cells in the dentate gyrus at various time points after PTZ-induced seizures.

Expression of heat shock protein after +Gz exposure and its protective effects on +Gz-induced brain injury.

Objective. To investigate the rule of intensity and duration of HSP70 expression in rat brain and its relationship with brain injury after repeated +Gz exposures. Method.