The neurotrophin-tyrosine receptor kinase B (TrkB) signaling pathway plays an important role in regulating the balance of excitation and inhibition in the primary visual cortex (V1). Previous studies have revealed its mechanism of regulating the level of cortical excitability by increasing the efficiency of excitatory transmission, but it has not been elucidated how TrkB receptors regulate the balance of excitation and inhibition through the inhibitory system, which in turn affects visual cortex function. Therefore, the objective of this study was to investigate how the TrkB signaling pathway specifically regulates the most important inhibitory neuron-PV neurons affects the visual cortex function of mice. The expression of TrkB receptor on PV neurons in the V1 region was specifically reduced by the virus, the functional changes of inhibitory and excitatory neurons in the primary visual cortex were recorded by multi-channel electrophysiological in vivo. The orientation discrimination ability of mice was tested by behavioral experiments, and altered orientation discrimination ability of mice was tested by behavioral experiments. The results showed that reduced expression of TrkB receptors on PV inhibitory neurons in primary visual cortex significantly increased the response intensity of excitatory neurons, reduced the orientation discrimination ability of inhibitory and excitatory neurons, and increased the signal-to-noise ratio, but the orientation discrimination ability at the individual level in mice showed a decrease. These results suggest that the TrkB signaling pathway does not modulate the function of PV neurons solely by increasing excitatory transmission targeting PV neurons, and its effect on neuronal signal-to-noise ratio is not due to enhancement of the inhibitory system.
Mice ; Animals ; Receptor, trkB/metabolism* ; Neurons/metabolism* ; Signal Transduction

OBJECTIVE: To investigate the inhibitory effect of ANA-12 that blocks brain-derived neurotrophic factor (BDNF)/ tropomyosin receptor kinase B (TrkB) signaling on inflammatory pain in rats and explore the underlying mechanism. METHODS: Forty-two adult SD rats were randomized into BDNF-induced acute pain group (n=24) and CFA-induced chronic pain group. The former group were randomly divided into 4 subgroups, including a control group, ANA-12 treatment group, BDNF treatment group, and BDNF+ANA-12 treatment group; the latter group were subgrouped into control group, CFA treatment group (CFA) and CFA + ANA-12 treatment group. The effects of ANA-12 treatment on pain behaviors of the rats with BDNF-induced acute pain and CFA-induced chronic inflammatory pain were observed. Western blotting was used to examine TrkB signaling and expressions of microglia marker protein Iba1 and TNF-α in the spinal cord of the rats. RESULTS: BDNF injection into the subarachnoid space significantly increased the number of spontaneous paw withdrawal of the rats (P < 0.05), which was obviously reduced by ANA-12 treatment (P < 0.05). The rats with intraplantar injection of CFA, showed significantly increased ipsilateral mechanical stimulation sensitivity (P < 0.05), and ANA-12 treatment obviously increased the ipsilateral foot withdrawal threshold (P < 0.05). Treatment with either BDNF or CFA significantly increased the phosphorylation level of TrkB (Y705) in the spinal cord of the rats (P < 0.05), which was significantly lowered by ANA-12 treatment (P < 0.05). Treatment with BDNF and CFA both significantly up-regulated the expressions of Iba1 and TNF-α in the spinal cord (P < 0.05), but ANA-12 significantly reduced their expression levels (P < 0.05). CONCLUSION ANA-12 can reduce spinal cord inflammation and relieve acute and chronic pain in rats by targeted blocking of BDNF/TrkB signaling.
Animals ; Brain-Derived Neurotrophic Factor/metabolism* ; Chronic Pain/drug therapy* ; Inflammation ; Rats ; Rats, Sprague-Dawley ; Receptor, trkB/metabolism*

OBJECTIVE: To explore the effect of electrical stimulation at auricular points (EAS) combined with sound masking on the expression of cAMP-response element binding protein (CREB), brain-derived neurotrophic factor (BDNF) and tyrosine receptor kinase B (TrkB) in the auditory cortex of tinnitus rats. METHODS: A total of 27 adult male SD rats were randomly divided into a control group, a model group and an EAS group. The rats in the model group and the EAS group were intervened with intraperitoneal injection of sodium salicylate to induce tinnitus model, while the rats in the control group were intervened with injection of 0.9% NaCl solution. After the model was successfully established, the rats in the EAS group were treated with electrical stimulation at "Shenmen" (TF) and "Yidan" (CO), combined with sound masking; the treatment was given once a day for 15 days. The gap prepulse inhibition of acoustic startle (GPIAS) and prepulse inhibition (PPI) testing were performed using the acoustic startle reflex starter package for rats. The expression of BDNF, TrkB, CREB and p-CREB in the auditory cortex of each group were measured with Western Blot analysis. RESULTS: ① Compared with the control group, the GPIAS values in 12 kHz, 16 kHz, 20 kHz and 28 kHz were significantly decreased in the model group (all <0.05); compared with the model group, GPIAS values in 12 kHz, 16 kHz, 20 kHz and 28 kHz were significantly increased in the EAS group (all <0.05). ② Compared with the control group, the expression of BDNF and p-CREB in the model group was significantly increased (<0.01), and the expression of TrkB in the model group was significantly increased (<0.05); the differences of expression of BDNF, TrkB, CREB and p-CREB between the model group and the EAS group had no statistics significance (all >0.05). CONCLUSION EAS could improve the GPIAS values of high-frequency background sound in tinnitus rats, which may be related with the upregulation of the BDNF/TrkB/CREB signaling pathway in the auditory cortex, leading to the reversion of the maladaptive plasticity.
Acupuncture Points ; Animals ; Auditory Cortex ; Brain-Derived Neurotrophic Factor ; metabolism ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Electric Stimulation ; Male ; Rats ; Rats, Sprague-Dawley ; Receptor, trkB ; metabolism ; Tinnitus ; metabolism ; therapy

BackgroundGlehnia littoralis has been used for traditional Asian medicine, which has diverse therapeutic activities. However, studies regarding neurogenic effects of G. littoralis have not yet been considered. Therefore, in this study, we examined effects of G. littoralis extract on cell proliferation, neuroblast differentiation, and the maturation of newborn neurons in the hippocampus of adult mice.

MethodsA total of 39 male ICR mice (12 weeks old) were randomly assigned to vehicle-treated and 100 and 200 mg/kg G. littoralis extract-treated groups (n = 13 in each group). Vehicle and G. littoralis extract were orally administrated for 28 days. To examine neurogenic effects of G. littoralis extract, we performed immunohistochemistry for 5-bromo-2-deoxyuridine (BrdU, an indicator for cell proliferation) and doublecortin (DCX, an immature neuronal marker) and double immunofluorescence staining for BrdU and neuronal nuclear antigen (NeuN, a mature neuronal marker). In addition, we examined expressional changes of brain-derived neurotrophic factor (BDNF) and its major receptor tropomyosin-related kinase B (TrkB) using Western blotting analysis.

ResultsTreatment with 200 mg/kg, not 100 mg/kg, significantly increased number of BrdU-immunoreactive () and DCX cells (48.0 ± 3.1 and 72.0 ± 3.8 cells/section, respectively) in the subgranular zone (SGZ) of the dentate gyrus (DG) and BrdU/NeuN cells (17.0 ± 1.5 cells/section) in the granule cell layer as well as in the SGZ. In addition, protein levels of BDNF and TrkB (about 232% and 244% of the vehicle-treated group, respectively) were significantly increased in the DG of the mice treated with 200 mg/kg of G. littoralis extract.

ConclusionG. littoralis extract promots cell proliferation, neuroblast differentiation, and neuronal maturation in the hippocampal DG, and neurogenic effects might be closely related to increases of BDNF and TrkB proteins by G. littoralis extract treatment.

Animals ; Apiaceae ; chemistry ; Blotting, Western ; Brain-Derived Neurotrophic Factor ; metabolism ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Dentate Gyrus ; cytology ; drug effects ; Hippocampus ; cytology ; drug effects ; Immunohistochemistry ; Male ; Mice ; Microtubule-Associated Proteins ; metabolism ; Neurogenesis ; drug effects ; Neuropeptides ; metabolism ; Plant Extracts ; pharmacology ; Receptor, trkB ; metabolism

OBJECTIVETo observe the effects of acute immobilization stress on the mRNA expression of tyrosine kinase B (TrkB) in rats' hippocampus.

METHODSEighteen SD rats were randomly divided into three groups, i.e., the normal control group, the model group, and the medication group, 6 in each group. The acute immobilization stress model was prepared in the model group using acute immobilization for 2 h. Ginsenoside Rb1 (40 mg/kg) was peritoneally injected to rats in the medication group 30 min before modeling, with the same procedure as those for rats in the model group. No treatment was performed to rats in the normal control group. The plasma adrenocorticotropic hormone (ACTH) and corticosterone (CORT) contents were detected using ELISA. The mRNA expression of TrkB in the rats' hippocampus was detected using real-time fluorescence quantitative RT-PCR.

RESULTSBefore modeling there was no statistical difference of plasma CORT or ACTH concentrations among three groups (P >0.05). The plasma CORT and ACTH concentrations increased in the model group and the medication group more significantly after modeling than before modeling, showing statistical difference (P <0.05). Besides, they were obviously higher in the model group than in the normal control group (P <0.05). They were obviously higher in the medication group than in the model control group (P <0.05). Compared with the normal control group, the mRNA expression of TrkB significantly decreased in the model group (87.73 +/- 7.62 vs 50.65 +/- 5.19, P < 0.05), showing statistical difference. The mRNA expression of TrkB was significantly higher in the medication group (78.91 +/- 18.07) than in the model group, showing statistical difference (P <0.05).

CONCLUSIONPretreatment by ginsenoside Rb1 could increase the plasma CORT and ACTH concentrations, maintain the mRNA expression of TrkB, thus relieving injury induced by acute immobilization stress.

Adrenocorticotropic Hormone ; blood ; Animals ; Corticosterone ; blood ; Ginsenosides ; pharmacology ; Hippocampus ; metabolism ; Male ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley ; Receptor, trkB ; genetics ; metabolism ; Stress, Psychological ; metabolism

OBJECTIVETo observe the effects of Shuyu Ningxin Recipe (SNR) on the praxiology and the expressions of hippocampal brain-derived neurotrophic factor (BDNF) and its receptor tyrosine kinase B (TrkB) of model rats with chronic stress-induced depression, thus exploring its anti-depression mechanisms.

METHODSSixty adult SD rats were randomly divided into 6 groups, i.e., the normal control group, the model group, the fluoxetine group, the high dose SNR group, the medium dose SNR group, and the low dose SNR group, 10 in each group. All rats were subjected to establish chronic stress-induced depression model for 21 consecutive days. Except those in the normal control group, rats in the rest groups received gastrogavage from the 22nd day. Mice in the model group were administered with normal saline by gastrogavage. SNR at 25.0, 7.5, and 2.5 g/kg was respectively administered to rats in the high dose SNR group, the medium dose SNR group, and the low dose SNR group by gastrogavage. Fluoxetine suspension (12 mg/kg) was given to rats in the fluoxetine group by gastro-gavage. All medication lasted for 3 successive weeks. The weight, open-field test, and the immobility time in forced swimming test were determined before modeling, 3 weeks (after successful modeling), and 6 weeks (by the end of medication). The expressions of hippocampal BDNF and TrkB were measured after the brain tissues were drawn by the end of the experiment.

RESULTSCompared with the normal control group, the body weight grew slowly, the behavior index decreased, the immobility time in forced swimming test was prolonged, and the expressions of BDNF and TrkB were weaken in the model group (P <0.05, P <0.01).The body weight increased, the behavior was improved, the immobility time in forced swimming test was shortened, and the expressions of BDNF and TrkB were enhanced in the high dose SNR group and the fluoxetine group by the and of medication, showing statistical difference when compared with the model group (P <0.05, P <0.01).

CONCLUSIONSNR could exert anti-depression by improving the expression levels of hippocampal BDNF and TrkB.

Animals ; Behavior, Animal ; Brain-Derived Neurotrophic Factor ; metabolism ; Depression ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Hippocampus ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Receptor, trkB ; metabolism ; Stress, Psychological ; metabolism

The purpose of the present study was to investigate the effects of icariin (ICA) on the content of beta-amyloid (Abeta) and the expression of neurotrophic factors in the brain of mitochondrial deficiency model rats. SD rats were infused subcutaneously with sodium azide, which is an inhibitor of mitochondrial respiratory chain complex IV, via a minipump (0. 5 mg . kg-1 h-1) for 28 days to establish the mitochondrial deficiency animal model. The activity of mitochondrial respiratory chain complex IV (i. e. cytochrome C oxidase, COX) in hippocampus was measured by biochemical methods. ELISA method was used to detect the content of Abeta in the brain. The expression of neurotrophic factors was detected by Western blot and immunohistochemistry methods. Image analysis was performed by Image-pro software. The results showed that chronic infusion of sodium azide by minipump induced a significant decrease in the activity of mitochondrial cytochrome C oxidase, an obvious increase in the content of Abeta, and a marked decline in the expression of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and its receptor TrkB in the brain of rats. Intragastrical administration of ICA (12 or 36 mg . kg-l) significantly ameliorated all these abnormalities in the model rats. In conclusion, ICA can increase mitochondrial activity, inhibit Abeta production, and enhance the expression of neurotrophic factors in the brain of model rats induced by sodium azide. The results suggested that ICA may have beneficial prospect for the treatment of Alzheimer's disease.
Amyloid ; metabolism ; Animals ; Brain ; drug effects ; metabolism ; Brain-Derived Neurotrophic Factor ; metabolism ; Disease Models, Animal ; Enzyme-Linked Immunosorbent Assay ; Flavonoids ; pharmacology ; therapeutic use ; Mitochondria ; drug effects ; metabolism ; pathology ; Mitochondrial Diseases ; drug therapy ; metabolism ; Nerve Growth Factor ; metabolism ; Nerve Growth Factors ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor, trkB ; metabolism

OBJECTIVETo study the effect o f Bushen Huoxue Decoction (BHD) on neurobiochemical markers in the hippocampus of female rats with repeated immobilization stress.

METHODSSixty female rats were randomly divided into the normal group, the model group, the positive control group (treated with Liuwei Dihuang Pill at the dose of 3.3 g crude drug/kg), and the high, middle, and low BHD treated groups (at the dose of 8, 4, 2 g crude drug/kg), ten in each group. Chronic psychological stress was induced using repeated immobilization stress in rats. Medication was conducted by gastrogavage while modeling once a day for twenty successive days. The hippocampal neurohumoral levels were detected with high-performance liquid chromatography. The expression levels of BDNF and its receptor in the hippocampus were detected by Westem blot. Effect of BHD on neurobiochemical markers in the hippocampus of rats with repeated immobilization stress was observed.

RESULTSThe levels of Glu, GABA, and BDNF in the hippocampus of the normal group were 1280.0 +/- 258.3 ng/mg, 588.3 +/- 115.1 ng/mg, and 13.26 +/- 2.57 gray value, respectively. But the hippocampal neurohumoral levels and the expression of BDNF in the model group obviously decreased when compared with the normal group, being 1016.9 +/- 215.9 ng/mg, 485.1 +/- 71.0 ng/mg, and 7.23 +/- 0.61 gray value, respectively. The levels of Glu (ng/mg) in hippocampus of the three BHD treated groups were 1459.1 +/- 413.5, 1894.7 +/- 542.8, and 1373.3 +/- 345.7, respectively. GABA levels (ng/mg) inthe hippocampus were 631.6 +/- 161.4, 899.1 +/- 262.1, and 656.4 +/- 140.8, respectively. BDNF levels (gray value) were 16.57 +/- 1.52, 29.85 +/- 1.37, and 24.44 +/- 3.81, respectively, significantly higher than that of the model group (P<0.05, P<0.01). The level of Glu in the positive control group (1216.5 +/- 193.8 ng/mg) was significantly higher than that of model group (P<0.05).

CONCLUSIONBHD showed significant accommodation on the hippocampal neurohumoral levels and the expression of BDNF in the female rats with repeated immobilization stress.

Animals ; Brain-Derived Neurotrophic Factor ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Female ; Glutamic Acid ; metabolism ; Hippocampus ; drug effects ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor, trkB ; metabolism ; Restraint, Physical ; Stress, Psychological ; metabolism ; gamma-Aminobutyric Acid ; metabolism

OBJECTIVETo study the effects of TrkB-BDNF signal pathway on the synthesis and secretion of vascular endothelial growth factor (VEGF) in human neuroblastoma cells (NB).

METHODSTrkB protein expression in SY5Y cells before and after all-trans-retinoicacid (ATRA) treatment was detected by Western blot. P-TrkB protein expression in SY5Y cells before and after the treatment of ATRA along with BDNF was also detected by Western blot. VEGF concentrations in the SY5Y cell culture supernatants were measured using ELISA after the treatment with ATRA, BDNF, tyrosine kinase inhibitor K252a and PI3k inhibitor LY294002.

RESULTSTrkB protein was undetectable in SY5Y cells before ATRA treatment. After the treatment of 1, 10 and 100 nM/L ATRA for five days, TrkB protein was expressed in SY5Y cells and the TrkB protein level increased with the increasing ATRA concentration. P-TrkB protein was not expressed in SY5Y cells treated only with 10 nM/L ATRA, but it was detectable after the treatment of ATRA along with BDNF. VEGF concentrations in the group treated with ATRA+BDNF were significantly higher than those in the untreated control and the ATRA alone treatment groups (P<0.01). VEGF concentrations in the K252a pretreated ATRA+BDNF group were significantly lower than those in the group treated with ATRA+BDNF (P<0.05). VEGF concentrations in the LY294002 treatment group (ATRA+LY294002+BDNF group) were also significantly lower than those in the group treated with ATRA+BDNF (P<0.01).

CONCLUSIONSActivation of TrkB-BDNF signal pathway may increase the synthesis and secretion of VEGF in human NB cells. The synthesis and secretion of VEGF can be inhibited by blocking TrkB-BDNF signal pathway with K252a or blocking the TrkB-BDNF downstream signal pathway PI3K/Akt with LY294002.

Brain-Derived Neurotrophic Factor ; physiology ; Cell Line, Tumor ; Enzyme-Linked Immunosorbent Assay ; Humans ; Neuroblastoma ; metabolism ; pathology ; Phosphatidylinositol 3-Kinases ; physiology ; Proto-Oncogene Proteins c-akt ; physiology ; Receptor, trkB ; physiology ; Signal Transduction ; physiology ; Tretinoin ; pharmacology ; Vascular Endothelial Growth Factor A ; analysis ; biosynthesis

OBJECTIVETo investigate the effects of Chaihu Shugan Powder (CHSGP) on the behavior and the expressions of brain-derived neurotrophic factor (BDNF) and its receptor tyrosine kinase receptors B (TrkB) in the hippocampus, amygdala, and the frontal lobe of depression model rats.

METHODSSixty adult Sprague-Dawley rats were randomly divided into 6 groups, i. e., the normal control group (NC), the model control group (MC), the CHSGP group, the disassembly 1 group (CI), the disassembly 2 group (CII), and the Fluoxetine control group (FC), 10 in each group. Except those in the NC, the rest rats were singly housed and exposed on an unpredicted sequence of mild stressor. From the fifteenth day, all rats were administered with equal volume of normal saline (to the NC group and the MC group) and of corresponding medicinal liquid (5.9 g/kg to the CHSGP group, 3.3 g/kg to the CI group, 2.6 g/kg to the CII group, and 1.8 mg/kg to the FC group) by gastrogavage for 2 successive weeks. The rats' body weight, sucrose consumption volume in the sucrose preference test, and times of grooming in the open field test were detected on the 0, 7th, 14th, 21st, 28th day, respectively. The mRNA expressions of BDNF and TrkB in the hippocampus, amygdala, and the frontal lobe were detected by immunohistochemical assay and Real-time fluorescent quantitation PCR.

RESULTSCompared with the NC group, the rats' body weight was put up slowly in the MC group. The scores in the open field test decreased. The times of grooming and sucrose consumption volume were both reduced. The time of staying in central square was postponed. The mRNA expressions of BDNF and TrkB in the hippocampus, amygdala, and the frontal lobe decreased with statistical significance (P<0.05, P<0.01). Compared with the MC group, the behavior indices of rats in the CHSGP, CI, CII, and FC groups were significantly improved. The mRNA expressions of BDNF and TrkB in the hippocampus, amygdala, and the frontal lobe were obviously enhanced with statistical significance (P<0.05, P<0.01).

CONCLUSIONSCHSGP could obviously improve the depressive state of the model rats. Its mechanism might be correlated with increasing the mRNA expressions of BDNF and TrkB in the hippocampus, amygdala, and the frontal lobe.

Amygdala ; metabolism ; Animals ; Behavior, Animal ; drug effects ; Brain-Derived Neurotrophic Factor ; metabolism ; Depression ; drug therapy ; metabolism ; Frontal Lobe ; metabolism ; Hippocampus ; metabolism ; Male ; Plant Extracts ; pharmacology ; therapeutic use ; Rats ; Rats, Sprague-Dawley ; Receptor, trkB ; metabolism