Expression changes of c-Fos and D1R/p-ERK1/2 signal pathways in nucleus accumbens of rats after ketamine abuse

Ketamine is a commonly used dissociative anesthetic in clinical applications. However, the abuse potential has posted limits to its use and the mechanism remains to be studied. We aimed to investigate the changes of dopamine D1 receptors (D1R), phosphorylation of extracellular-regulated protein kinase 1/2 (p-ERK1/2), and c-Fos expression in the nucleus accumbens (NAc) of ketamine abuse rats. Ketamine induced severe anxiety in rats, as shown by an open field test. Nissl staining demonstrated clearly different morphologies between neurons of ketamine abuse rats and normal rats. The molecular expression changes were examined using immunohistochemistry assay and western blotting. D1R, p-ERK1/2, and c-Fos were significantly highly-expressed in NAc during ketamine exposure and were decreased by D1R antagonist SCH23390 and MAPK kinases inhibitor U0126. Taken together, the results suggest that ketamine abuse may induce the overexpression of c-Fos in NAc by up-regulating the expression of D1R and p-ERK1/2.

[Effects of electroacupuncture on myelin-related protein in corpus callosum of rats with focal cerebral ischemia]

OBJECTIVE

To observe the effect of electroacupuncture(EA)on the expression of myelin basic protein (MBP), axon growth inhibitor Nogo-A and Nogo receptor (NgR) in corpus callosum of rats with focal cerebral ischemia, so as to explore the mechanism of EA underlying improving ischemic white matter injury.

METHODS

Fourty male SD rats were randomly divided into normal, sham operation, model and EA groups, with 10 rats in each group. The focal cerebral ischemia rat model was established by occlusion of the middle cerebral artery (MCAO). EA was applied to "Baihui"(GV20) and "Zusanli"(ST36) on the left side for 30 min, once daily for 14 days. Neurological function score and the adhensive removal test were used to evaluate neurological deficit severity; Hematoxylin-esion staining was used to observe the pathological changes in myelin of corpus callosum and luxol fast blue（LFB） staining was used to observe the myelin of corpus callosum. Immunohistochemical staining and Western blot were used to detect the expressions of MBP、Nogo-A and NgR in the ischemic corpus callosum.

RESULTS

After MCAO, the neurological function score was significantly increased (P<0.05), the time required for contact with tape and tape removal was longer (P<0.001), the intensity of LFB staining and the expression of MBP decreased, while the veside area and the expression of Nogo-A and its receptor NgR increased (P<0.01, P<0.05) in the model group relevant to the normal and sham operation groups. The fiber arrangement of the corpus callosum on the ischemic side was disordered and a large amount of myelin sheath was lost in the model group. Following the treatment, the neurological deficit score of EA group was gradually decreased and significantly decreased on the 3^rd, 7^th and 14^th day (P<0.05), and the time to remove the adhesive tape was shortened at the 7^th and 14^th day (P<0.001). The shape of the corpus callosum in the EA group was close to normal, and the myelin structure was relatively complete. The intensity of LFB staining and the expression of MBP was increased (P<0.05, P<0.01) while the expression of Nogo-A and its receptor NgR were decreased in the EA group relevant to the model group (P<0.01).

CONCLUSION

EA can play a protective role in myelin of the corpus callosum after cerebral ischemia, which may be related to down-regulating the expressions of Nogo-A and NgR.

Effects of Electroacupuncture on Expression of D1 Receptor (D1R), Phosphorylation of Extracellular-Regulated Protein Kinase 1/2 (p-ERK1/2), and c-Fos in the Insular Cortex of Ketamine-Addicted Rats

BACKGROUND The aim of this study was to investigate the effects of electroacupuncture (EA) on expression of the D1 receptor (D1R), phosphorylation of extracellular-regulated protein kinase 1/2 (p-ERK1/2) and c-Fos in the insular cortex (IC) of ketamine-addicted rats. MATERIAL AND METHODS Sprague-Dawley rats were randomly divided into 7 groups: the normal group, the normal saline (NS) group, the ketamine (Ket) group, the U0126+Ket group, the SCH23390+Ket group, the Ket+acupoints EA (EA1) group, and the Ket+ non-acupoints EA (EA2) group. We used immunohistochemistry to detect the expression of D1R, p-ERK1/2, and c-Fos. We also used Nissl staining techniques to study the morphology of IC neurons. RESULTS Our study demonstrated that the ketamine group had sparsely distributed neurons, large intracellular vacuoles, nuclei shift, and unclear nucleolus. The number of Nissl-positive (neuronal) cells in the ketamine group were decreased than in the normal group. Our results also indicated that there was significantly lower expression of D1R, p-ERK1/2, and c-Fos in the IC of the U0126+Ket group, SCH23390+Ket group, and Ket+EA1 group as compared with that of the Ket group. CONCLUSIONS Ketamine addiction induces c-Fos overexpression in the IC by increasing the expression of D1R and p-ERK1/2. Acupoints EA downregulate D1R and p-ERK1/2 by reducing the overexpression of c-Fos.

[Effect of Electroacupuncture Intervention on Expressions of Nerve Growth Factor and Growth Arrest-specific Protein 7 in Ventral Posterolateral Thalamic Nucleus in Cerebral Ischemia Rats]

OBJECTIVE

To observe the effect of electroacupuncture(EA) on expressions of nerve growth factor(NGF) and growth arrest-specific protein 7(Gas 7) in the right ventral posterolateral nucleus(VPL) in the focal cerebral ischemia (FCI) rats, so as to explore its possible mechanism underlying improvement of secondary injury of FCI.

METHODS

Forty-eight Sprague-Dawley rats were randomly divided into normal group, sham operation group, model group and electroacupuncture (EA) group (n=12 in each group) by random number table.The FCI model was made by occlusion of the right middle cerebral artery (MCAO) with thread embolus.One week after MCAO, EA(2 Hz,2 V) was performed on "Baihui"(GV 20) and left "Zusanli"(ST 36) for 30 min,once daily for successively 21 days.The expressions of NGF and Gas 7 in the right VPL were detected by immunohistochemistry (n=6 in each group) and Western blot (n=6 in each group), respectively;meanwhile Nissl staining was conducted to show VPL neurons.

RESULTS

Nissl staining showed that the structure of right VPL was clear and complete,and the nuclei were centered and clear in the normal group and sham operation group;the VPL neurons were deeply stained, and the nuclei were pyknotic in the model group;the morphology of neurons in the EA group was similar to that of the normal group. The results of immunohistochemistry and Western blot were consistent. Expressions of NGF and Gas 7 proteins in the right VPL were not of significant differences between the sham operation group and the normal group (P>0.05). Compared with the normal group, the expressions of NGF and Gas 7 proteins in the VPL of the ischemic side were significantly increased in the model group(P<0.05). After treatment,the expression levels of NGF and Gas 7 proteins were further up-regulated in the EA group in comparison with the model group(P<0.05).

CONCLUSIONS

The enhanced expressions of NGF and Gas 7 in the ischemic VPL of FCI rats may be involved in the neuroprotection and repairing; EA can significantly up-regulate the expressions of NGF and Gas 7 in VPL of the ischemic side, which may contribute to its effect in improving secondary thalamic impairment of FCI.

Effects of Polysaccharide of Gastrodia Elata Blume and Electro-Acupuncture on Expressions of Brain-Derived Neurotrophic Factor and Stem Cell Factor Protein in Caudate Putamen of Focal Cerebral Ischemia Rats

Background

The aim of this study was to explore the neural protective effect of polysaccharide of Gastrodia elata Blume (PGB) and electro-acupuncture (EA) on focal cerebral ischemia rats.

Material/Methods

A total of 40 Sprague-Dawley rats were randomly divided into 5 groups (normal group, model group, PGB group, EA group and PGB+EA group). The model was prepared by middle cerebral artery occlusion (MCAO). Two week after modeling, rats were given PGB, EA, or a combination of the 2 in continuous treatment for 2 successive weeks. 14 days after modeling, expressions of BDNF and SCF protein in the caudate putamen (CPu) were detected by immunohistochemistry.

Results

Positive expression of BDNF and SCF protein was found in the right caudate putamen of each group of rats. Expressions of BDNF and SCF in the CPu of the model group were higher than normal group (P<0.05). Compared with the model group, the expressions of BDNF and SCF in the CPu of the PGB group, the EA group, and the PGB plus EA group increased significantly (P<0.05). The expressions of BDNF and SCF obviously increased in the PGB plus EA group compared to those of the EA group and the PGB group (P<0.05).

Conclusions

PGB and EA up-regulated the expressions of BDNF and SCF protein in the CPu of focal cerebral ischemia rats, and the combination of PGB+EA has a synergistic effect on the recovery from cerebral ischemia.

[Effect of Electroacupuncture plus Polysaccharide of Gastrodia elata Blume on Expression of Nestin and Brain Derived Neurotrophic Factor in the Basolateral Amygdala of Focal Cerebral Ischemia Rats]

OBJECTIVE

To observe the effect of electroacupuncture (EA) combined with administration of Polysaccharide of Gastrodia elata Blume (PGB) on stem cell proliferation in the basolateral amygdala (BLA) of focal cerebral ischemia (FCI) rats.

METHODS

A total of 40 Sprague-Dawley rats were randomly divided into normal control,model,EA, PGB and EA+PGB groups (n=8 rats in each group). The FCI model was established by occlusion of the right middle cerebral artery. EA (2 Hz, 3 V) was applied to "Baihui" (GV 20) and the left "Zusanli"(ST 36) for 30 min, once daily for 14 successive days. Rats of the PGB and EA+PGB groups were given with PGB (100 mg/kg) by gastrogavage, once daily, for14 successive days. The Zea-Longa's method was used to determine the animals' nerurological dysfunction score on day 1 and 14. The expressions of Nestin and brain derived neurotrophic factor (BDNF) of the right BLA were measured by immunohistochemical staining.

RESULTS

Following modeling, the neurological score, and the numbers of Nestin- and BDNF-immunoreaction (IR)-positive cells were significantly increased in the model group (P<0.05). Compared with the model group, the neurological scores were considerably decreased in the EA, PGB and EA+PGB groups (P<0.05), and the numbers of Nestin- and BDNF-IR positive cells were further significantly increased in the 3 treatment groups (P<0.05), and the effect of EA+PGB was notably superior to that of simple EA and simple PGB in down-regulating neurological score and up-regulating Nestin and BDNF expression (P<0.05).

CONCLUSIONS

Both EA and PGB interventions can improve FCI rats' neurological function, which may be related to their effects in up-regulating the expression of Nestin and BDNF to promote the proliferation of neural stem cells in the BLA.

[Effects of electroacupuncture intervention combined with polysaccharide of Gastrodia elata Blume on expression of nestin and cytokines of neural stem cells in the dentate gyrus of cerebral ischemia rats]

OBJECTIVE

To observe the effect of electroacupuncture (EA) of "Baihui" (GV 20) and "Zusanli" (ST 36) and EA plus polysaccharide of Gastrodia elata Blume (PGB) on neural stem cell (NSC) proliferation in cerebral ischemia (CI) rats, so as to explore its mechanisms underlying improvement of CI.

METHODS

A total of 40 SD rats were randomly divided into normal control, CI model, EA , medication (PGB) and EA + medication groups (n = 8 in each group). The CI model was established by occlusion of the middle cerebral artery (MCAO). Two weeks after modeling, rats of the medication and EA + medication groups were administrated with PGB (100 mg/kg) once daily for 2 successive weeks. EA (2 Hz, 3 V) was applied to "Baihui" (GV 20) and left "Zusanli" (ST 36) for 30 min, once daily for 2 weeks. The expression of Nestin and stem cell factor (SCF) proteins in the dentate gyrus (DG) of hippocampus was detected by immunohistochemistry.

RESULTS

Compared with the normal control group, the expression of Nestin and SCF proteins in the suprapyramidal blade (SPB) and infrapyramidal blade (IPB) of DG were significantly increased in the model group (P < 0.05). After EA intervention, the expression levels of Nestin and SCF of SPB and IPB of DG were considerably further up-regulated in both EA group and EA + medication group (P < 0.05), and the effect of EA + medication group was significantly superior to that of simple EA group and medication group (P < 0.05).

CONCLUSION

EA combined with PGB can significantly up-regulate the expression of Nestin and SCF in the hippocampal DG in CI rats, and its effects are apparently superior to those of simple EA or simple medication. It suggests that EA-induced proliferation of SCF may be one of the mechanisms underlying relieving CI.