The thalamocortical (TC) circuit is closely associated with pain processing. The hyperpolarization-activated cyclic nucleotide-gated (HCN) 2 channel is predominantly expressed in the ventral posterolateral thalamus (VPL) that has been shown to mediate neuropathic pain. However, the role of VPL HCN2 in modulating TC circuit activity is largely unknown. Here, by using optogenetics, neuronal tracing, electrophysiological recordings, and virus knockdown strategies, we showed that the activation of VPL TC neurons potentiates excitatory synaptic transmission to the hindlimb region of the primary somatosensory cortex (S1HL) as well as mechanical hypersensitivity following spared nerve injury (SNI)-induced neuropathic pain in mice. Either pharmacological blockade or virus knockdown of HCN2 (shRNA-Hcn2) in the VPL was sufficient to alleviate SNI-induced hyperalgesia. Moreover, shRNA-Hcn2 decreased the excitability of TC neurons and synaptic transmission of the VPL-S1HL circuit. Together, our studies provide a novel mechanism by which HCN2 enhances the excitability of the TC circuit to facilitate neuropathic pain.
Animals ; Mice ; Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels/genetics* ; Neuralgia ; RNA, Small Interfering ; Thalamus/metabolism* ; Up-Regulation

Mice ; Animals ; Alzheimer Disease/complications* ; Entorhinal Cortex/metabolism* ; Brain-Derived Neurotrophic Factor/metabolism* ; Memory Disorders/etiology* ; Thalamus/metabolism* ; Disease Models, Animal

Crossed aphasia (CA) is defined as language impairment following right-hemispheric brain lesion in right-handed person. Exact mechanism responsible for CA is ambiguous, and recently several brain lesions have been proposed to be associated with aphasia using lesion mapping method. Corpus callosum has dual bloody supply which makes it less vulnerable to infarction. Speech difficulties such as stuttering after corpus callosum infarction have been reported in the past, but aphasia is rare, which makes CA more unique. We report an extraordinary case of CA after right corpus callosum infarction. A 74-year-old female patient with a previous history of right thalamus infarction with no neurologic sequela has developed language disturbance without apraxia 1 month ago and a diffusion-weighted magnetic resonance imaging showed newly developed infarction at right corpus callosum. The aphasia quotient of the Korean version of the Western Aphasia Battery was 2.5, implying severe global aphasia. Positron emission tomography-computed tomography showed decreased metabolism in right corpus callosum and left frontal and temporal cortex, suggesting that interhemispheric diaschisis may be responsible for the CA. This is an extraordinary case report of an isolated manifestation of CA secondary to right corpus callosum infarction.
Aged ; Aphasia ; Apraxias ; Brain ; Brain Infarction ; Corpus Callosum ; Electrons ; Female ; Humans ; Infarction ; Magnetic Resonance Imaging ; Metabolism ; Methods ; Stuttering ; Temporal Lobe ; Thalamus

OBJECTIVETo investigate the expressions of gamma aminobutyric acid transporter 1 (GAT-1) and glutamate decarboxylase 65 (GAD65) mRNA in different brain regions at brain propofol uptake equilibrium in dogs.

METHODSEighteen 12- to 18-month-old healthy hybrid dogs were randomized equally into control group (group C), low dose group (group L), and high dose group (group H). In groups L and H, anesthesia was administered by intravenous injection of 5.5 and 7.0 mg/kg propofol followed by propofol infusion at a constant rate of 55 and 70 mg·kg(-1)·h(-1) for 50 min, respectively. Blood samples were taken from the internal carotid artery and jugular vein to measure plasma propofol concentrations, and the brain tissues of the hypothalamus, sub thalamus, dorsal thalamus, hippocampus, pons, parietal lobe and frontal lobe were examined for GAT-1 and GAD65 mRNA expressions using quantitative real-time PCR.

RESULTSIn groups L and H, propofol infusion at a constant rate for 50 min resulted in comparable plasma propofol concentrations between the internal carotid artery and jugular vein (P>0.05), but the concentrations differed significantly between the two groups (P<0.01). GAT-1 mRNA levels in the hypothalamus and hippocampus were significantly higher in groups L and H than in group C (P<0.05 and P<0.01), but comparable between the former two groups. The variations of GAT-1 mRNA levels between the hypothalamus and hippocampus were similar in both group L [(61.26∓7.17)% and (79.34∓39.95)%, P>0.05] and group H [(74.64∓19.63)% and (97.12∓32.31)%, P>0.05]. GAT-1 mRNA levels in other brain regions showed no significant difference among the 3 groups. GAD65 mRNA levels were similar between group L and group H, but both significantly higher than that in group C (P<0.01). GAD65 mRNA in other brain regions had no significant difference among the 3 groups.

CONCLUSIONGAT-1 mRNA in the hypothalamus and hippocampus and GAD65 mRNA in the dorsal thalamus are upregulated when propofol uptake reaches an equilibrium in the brain of dogs.

Animals ; Brain ; drug effects ; metabolism ; Dogs ; GABA Plasma Membrane Transport Proteins ; genetics ; metabolism ; Glutamate Decarboxylase ; genetics ; metabolism ; Hippocampus ; drug effects ; metabolism ; Hypothalamus ; drug effects ; metabolism ; Propofol ; pharmacology ; RNA, Messenger ; genetics ; Thalamus ; drug effects ; metabolism

OBJECTIVETo explore the effect of simulated navigation stimulation on the anesthetic sensitivity of sevoflurane in rats, so as to provide basis for rational using sevoflurane during navigation.

METHODSSD rats were stimulated by Crampton model and the conditioned taste aversion (CTA) was regarded as criterion of motion sickness. (1) 60 rats were randomly divided into control (n = 15) and rotation group (n = 45). The changes of behavior and autonomic activity, sevoflurane concentration achieved sleep and anesthesia states, and the revitalization time were observed in two group rats. (2) 32 rats were randomly divided into control (I), rotation (II), anesthesia (III) and rotation plus anesthesia (IV) group (n = 8). The acetylcholine (Ach), norepinephrine (NE), r-aminobutyric acid (GABA), glutamic acid (Glu) of brain cortex, thalamus and hippocampus were determined respectively in the four group rats.

RESULTSIn control group, the sevoflurane concentration achieved sleep and anesthesia states were 1.74% +/- 0.05% and 3.54% +/- 0.05% respectively, but, those concentrations were 1.51% +/- 0.06% and 3.14% +/- 0.08% in rotation group. There were lower significantly in rotation group than those in control group (P < 0.01). It was a major characteristic that all of the neurotransmitters were reduced significantly in II group, this was even more in brain cortex and thalamus (P < 0.01). In II group, Ach was upward in brain cortex, NE and GABA were reduced in hippocampus obviously. The change tendency of neurotransmitters in IV group was more close to II group, that was, the effect of rotation stimulation was more obvious.

CONCLUSIONThe anesthetic sensitivity of sevoflurane could be obvious increased in rats simulated navigation stimulation.

Anesthetics ; pharmacology ; Animals ; Cerebral Cortex ; drug effects ; metabolism ; Gravity, Altered ; Hippocampus ; drug effects ; metabolism ; Male ; Methyl Ethers ; pharmacology ; Neurotransmitter Agents ; analysis ; Norepinephrine ; analysis ; Physical Conditioning, Animal ; Rats ; Rats, Sprague-Dawley ; Rotation ; Thalamus ; drug effects ; metabolism ; gamma-Aminobutyric Acid ; analysis

OBJECTIVE: To examine the changes of metabolites in the bilateral thalamus of patients with secondarily generalized tonic-clonic seizure (SGTCS) and to explore the mechanism of SGTCS. METHODS: Thirty patients with SGTCS (epilepsy group) and 30 matched healthy controls (control group) were examined by 1H-magnetic resonance spectroscopy (1H-MRS). The levels of N-acetyl aspartate (NAA), choline-containing compounds (Cho), creatine phosphocreatine (Cr-PCr), and myo-inositol (mI) of the bilateral thalamus were measured in both the epilepsy group and the control group. The ratios of NAA/Cr-PCr, NAA/(Cr-PCr+Cho), Cho/Cr-PCr and mI/Cr-PCr were compared and analyzed in the 2 groups. RESULTS: The ratios of NAA/Cr-PCr, and NAA/(Cr-PCr+Cho)(1.7074 ± 0.2214; 0.9333 ± 0.2173) in the left thalamus in the epilepsy group were significantly lower than those in the control group(1.8834 ±0.2093; 1.1243 ±0.2447)(P<0.05). The ratios of NAA/Cr-PCr, and NAA/(Cr- PCr+Cho) (1.7472 ±0.2439; 0.9165 ±0.2462) in the right thalamus in the epilepsy group were also significantly lower than those in the control group(1.8925 ± 0.2004; 1.0941 ± 0.2372)(P<0.05). There were no significant differences in the ratios of NAA/Cr-PCr, NAA/(Cr-PCr+Cho), Cho/Cr- PCr, and mI/Cr-PCr between the bilateral thalamis in the epilepsy group (P>0.05). CONCLUSION There is neuronal dysfunction in the bilateral thalamus in the epilepsy group. Abnormal changes of the bilateral thalamus are involved in the mechanism of SGTCS.
Adolescent ; Adult ; Aspartic Acid ; analogs & derivatives ; analysis ; Brain Chemistry ; Case-Control Studies ; Choline ; analysis ; Energy Metabolism ; physiology ; Epilepsy, Generalized ; metabolism ; physiopathology ; Epilepsy, Tonic-Clonic ; metabolism ; physiopathology ; Female ; Humans ; Magnetic Resonance Spectroscopy ; methods ; Male ; Middle Aged ; Thalamus ; metabolism ; physiopathology ; Young Adult

The aim of this study was to evaluate the effect of early motor balance and coordination training on functional recovery and brain plasticity in an ischemic rat stroke model, compared with simple locomotor exercise. Adult male Sprague-Dawley rats with cortical infarcts were trained under one of four conditions: nontrained control, treadmill training, motor training on the Rota-rod, or both Rota-rod and treadmill training. All types of training were performed from post-operation day 1 to 14. Neurological and behavioral performance was evaluated by Menzies' scale, the prehensile test, and the limb placement test, at post-operation day 1, 7, and 14. Both Rota-rod and treadmill training increased the expression of synaptophysin in subcortical regions of the ischemic hemisphere including the hippocampus, dentate gyrus, and thalamus, but did not affect levels of brain-derived neurotrophic factor or tyrosin kinase receptor B. The Rota-rod training also improved Menzies' scale and limb placement test scores, whereas the simple treadmill training did neither. The control group showed significant change only in Menzies' scale score. This study suggests that early motor balance and coordination training may induce plastic changes in subcortical regions of the ischemic hemisphere after stroke accompanied with the recovery of sensorimotor performance.
Animals ; Brain Ischemia/metabolism/physiopathology ; Brain-Derived Neurotrophic Factor/metabolism ; Dentate Gyrus/metabolism ; Disease Models, Animal ; Hippocampus/metabolism ; Immunohistochemistry ; Male ; Motor Activity ; Neuronal Plasticity/physiology ; Physical Conditioning, Animal ; Physical Therapy Modalities ; Rats ; Rats, Sprague-Dawley ; Receptor, trkB/metabolism ; Stroke/*metabolism/physiopathology ; Synaptophysin/*metabolism ; Thalamus/metabolism ; Time Factors

OBJECTIVETo investigate the presence of abnormal metabolism in the thalamus and hypothalamus in patients with first-episode depression.

METHODSThirty drug-naive patients with first-episode depression and 30 age-matched controls were scanned with proton magnetic resonance spectroscopy ((1)H-MRS) for Naa, Cho, Cr and mI.

RESULTSCompared with the control group, the patients showed significantly reduced mI and mI/Cr of the hypothalamus, reduced mI/Cr of the left thalamus, and lowered Cho, ml, and ml/Cr of the right thalamus (P<0.05).

CONCLUSIONPatients with first-episode depression may have myo-inositol and phosphoric acid metabolism disorder in the thalamus and hypothalamus with malfunction of cellular osmotic pressure adjustment mechanism. Abnormal mI/Cr in the thalamus and hypothalamus may represent an important biochemical change in advanced patients with depression.

Adolescent ; Adult ; Case-Control Studies ; Choline ; metabolism ; Creatine ; metabolism ; Depression ; diagnosis ; Female ; Humans ; Hypothalamus ; metabolism ; Inositol ; metabolism ; Magnetic Resonance Spectroscopy ; methods ; Male ; Middle Aged ; Protons ; Thalamus ; metabolism ; Young Adult

OBJECTIVETo investigate the cerebral uptake and regional distribution of propofol when plasma propofol concentration reaches equilibrium in the internal carotid artery and internal jugular vein in dogs.

METHODSEight male hybrid dogs aged 12-18 months weighing 10-12 kg were anesthetized with propofol at a single bolus (7 mg/kg) in 15 s followed by propofol infusion at a constant rate of 70 mg.kg(-1).h(-1) via the great saphenous vein of the right posterior limb. Blood samples were taken from the internal carotid artery and internal jugular vein at 30 min (T30) after propofol infusion for measurement of plasma propofol concentrations by high-pressure liquid chromatography (HPLC). The thalamus, epithalamus, metathalamus, hypothalamus, subthalamus, frontal lobe, parietal lobe, temporal lobe, hippocampus, cingulate gyrus, cerebellum, midbrain, pons, medulla oblongata and cervical cord were then dissected to determine propofol concentrations in these tissues by HPLC.

RESULTSThe propofol concentrations in the internal carotid artery and internal jugular vein blood plasma were comparable at T30 (6.16-/+1.02 vs 6.17-/+1.00 microg/ml, P>0.05). The propofol concentration was 6.11-/+1.07 microg/g in the epithalamus, 6.14-/+0.98 microg/g in the metathalamus, 6.12-/+1.02 microg/g in the hypothalamus, 6.15-/+1.00 microg/g in the subthalamus, 6.20-/+1.03 microg/g in the frontal lobe, 6.18-/+1.02 microg/g in the parietal lobe, 6.13-/+1.00 microg/g in the temporal lobe, 6.07-/+0.99 microg/g in the hippocampus, 6.14-/+1.06 microg/g in the cingulate gyrus, 6.15-/+1.00 microg/g in the cerebellum, 6.13-/+1.05 microg/g in the midbrain, 6.18-/+1.01 microg/g in the pons, 6.15-/+0.93 microg/g in the medulla oblongata, and 6.13-/+1.00 microg/g in the cervical cord, showing no significant differences in the distributions (P>0.05). Propofol concentration in the thalamus (8.68-/+0.88 microg/g) was significantly higher than those in the other brain tissues (P<0.05).

CONCLUSIONSAt the constant intravenous propofol injection rate of 70 mg.kg(-1).h(-1), plasma propofol concentration reaches equilibrium 30 min after the injection in the internal carotid artery and internal jugular vein with even distribution in the cerebral tissues in dogs, but the thalamus contains high propofol concentration.

Absorption ; Anesthetics, Intravenous ; blood ; pharmacokinetics ; Animals ; Brain ; metabolism ; Carotid Artery, Internal ; metabolism ; Dogs ; Jugular Veins ; metabolism ; Male ; Propofol ; blood ; pharmacokinetics ; Thalamus ; metabolism

OBJECTIVE: To examine the differential expression of protein of thalamus in rats with diffuse axonal injury. METHODS: Twenty-five rats were randomly divided into a normal group (n=10) and a trauma group (n=15). Total proteins of brain trauma tissue and normal brain tissue were extracted separately, and then proteins were separated by two dimensional gel electrophoresis and stained with Coomassie brilliant blue. The differentially expressed protein spots were identified with biospectrometry. Images were analyzed by PDQuest 7.0. RESULTS: The distribution of protein spots in the trauma group was similar to that of the normal group, the matching rate was 95%, and the repeatability was good. Proteins were mainly displayed at pI 3-8, with relative molecular mass 14.4-75.0 kD. Compared with the normal group, 16 spots of proteins increased and 18 spots of proteins decreased in the trauma group. CONCLUSION There is some difference in protein expression between the normal group and the trauma group. Brain trauma may lead to changes of proteins in the thalamus.
Animals ; Diffuse Axonal Injury ; metabolism ; Electrophoresis, Gel, Two-Dimensional ; Male ; Proteome ; analysis ; Proteomics ; methods ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Thalamus ; metabolism