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OBJECTIVE@#To observe the direct intervention effects of electroacupuncture (EA) and non-steroid anti-inflammatory drugs (NSAIDs) on pain memory, and to explore their effects on cAMP/PKA/cAMP pathway in anterior cingulate gyrus (ACC).@*METHODS@#Fifty clean healthy male SD rats were randomly divided into a control group, a model group, an indomethacin group, an EA group and a sham EA group, 10 rats in each group. Except the control group, the pain memory model was established in the remaining four groups by twice injection of carrageenan at foot; 0.1 mL of 2%λ-carrageenan was subcutaneously injected at the left foot of rats; 14 days later, when the pain threshold of rats of each group returned to the basic level, the second injection was performed with the same procedure. The rats in the EA group were treated with EA at bilateral "Zusanli" (ST 36) for 30 min; the rats in the indomethacin group was treated with indomethacin intragastric administration with the dose of 3 mg/kg; the rats in the sham EA group was treated with EA without electricity at the point 0.3 mm forward "Zusanli" (ST 36) with the depth of 2 mm for 30 min; the rats in the control group was not given any invention. All the above interventions were performed 5 h, 1 d, 2 d and 3 d after the second injection of 2% λ-carrageenan. The left-side paw withdrawal thresholds (PWT) were observed before the first injection, 4 h, 3 d, 5 d after the first injection, before the second injection and 4 h, 1 d, 2 d, 3 d after the second injection. Three days after the second injection, the number of positive cells of cAMP, p-PKA, p-CREB and the number of positive cells of protein co-expression in the right ACC brain area were detected by immunofluorescence, and the relative protein expression of p-PKA and p-CREB were detected by Western blot.@*RESULTS@#Compared with the control group, the PWTs in the model group decreased significantly 4 h, 3 d and 5 d after the first injection and 1 d, 2 d and 3 d after the second injection (<0.05); compared with the control group, the positive expression of cAMP, p-PKA and p-CREB in the right ACC brain area in the model group increased significantly (<0.05), and the number of positive cells of the co-expression of cAMP/p-PKA and p-PKA/p-CREB also increased significantly (<0.05). Compared with the model group, indomethacin group and sham EA group, the PWTs in the EA group were increased significantly 1 d, 2 d and 3 d after the second injection (<0.05); compared with the model group, indomethacin group and sham EA group, the positive expression of p-PKA and p-CREB in the right ACC brain area in the EA group decreased significantly (<0.05), and the number of positive cells of co-expression of cAMP/p-PKA and p-PKA/p-CREB was decreased significantly (<0.05). Compared with the model group and sham EA group, the positive expression of cAMP in the right ACC brain area was decreased in the EA group (<0.05).@*CONCLUSION@#EA have a direct intervention effect on pain memory, which have significant advantage over NSAIDs in the treatment of chronic pain. The advantage effect of EA on pain memory may be related to the inhibition of cAMP/PKA/CREB pathway in ACC area.
Subject(s)
Animals , Male , Rats , Anti-Inflammatory Agents, Non-Steroidal , Therapeutic Uses , Cyclic AMP , Metabolism , Cyclic AMP Response Element-Binding Protein , Metabolism , Cyclic AMP-Dependent Protein Kinases , Metabolism , Electroacupuncture , Gyrus Cinguli , Metabolism , Pain Threshold , Random Allocation , Rats, Sprague-Dawley , Signal TransductionABSTRACT
Objective To perform a comparative study on membrane electrical properties of visceral and somatic nociceptive neurons of anterior cin?gulate gyrus(ACG)in cats,so as to provide the experimental basis for elucidating the mechanism of differences in perceptual qualities between vis?ceral pain and somatic pain from the membrane electrical aspects. Methods A total of 77 adult cats,female or male,weighting 2.0 to 3.5 kg were selected for the study. According to the properties of the greater splanchnic nerve(GSN)or saphenous nerve(SN)evoked responses of neurons in ACG and effect of morphine on the evoked responses,visceral nociceptive neurons(VNNs)having the long latency(≥50 ms)GSN evoked re?sponses or somatic nociceptive neurons(SNNs)having the long latency(≥50 ms)SN evoked responses were detected. With a glass microelectrode in vivo,a series of polarizing current of different intensity from-5 nA to+5 nA with a 50 ms duration were injected to these neurons in ACG,and the membrane electrical responses of these neurons were recorded. Finally,the membrane electrical parameters of these neurons were calculated. Re?sults Totally 254 VNNs and 172 SNNs were recorded in ACG. GSN evoked response threshold of VNNs were higher than SN evoked response threshold of SNNs. Compared with SNNs,the membrane resistance,the membrane capacity and the time constant of VNNs were larger. Conclusion Our data proved that there are some differences in the membrane electrical properties between VNNs and SNNs in ACG,which might be the mem?brane electrical basis for differences in perceptual qualities between visceral pain and somatic pain.
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Objective Based on the literatures published between 2005 and 2014,review the correlation between reward/loss of brain structure and neural network,and its relationship with physical and mental ailments,aim to reveal the neural structure and network of behavioral decision mechanism.Methods By retrieving literatures on PubMed,ScienceDirect,CNKI and Wanfang database in September 2014,we used decision making,reward,loss aversion and so on as the key words.Results Totally 40 papers were enrolled,the result reviewed the clinic meaning and the brain structure and neural network of the reward/loss process in decision making.Conclusion Most studies found the reward/loss decision making mechanism of the brain structure and the physical and mental ailments caused by the two systems imbalance,but related to the precise decision making neural mechanism has yet to be studied further.
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Objective To investigate the effects of GR82334 caudal veins injection(iv)or intrathecal injection(ith)on the increase of dopamine (DA)content in rats anterior cingulate gyrus(ACG)induced by heavy current stimulation of saphenous nerve(SN). Methods Totally 42 male Wi-star rats were randomly divided into six groups,including control group,sham stimulation group,SN stimulation group,GR82334(ith)group,NS (ith)group,GR82334(iv)group,and NS(iv)group. At the end of the study,rats of different groups were sacrificed,then the right side ACG were collected and weighted. ACG samples were then homogenized with 0.1 mol/L perchloric acid solution. After spinning at 10 000 r/min(4℃)for 20 min,20μL of the supernatant were harvest from each sample. High performance liquid chromatography electrochemical detection was used to mea-sure DA content. Results Heavy current stimulation of SN caused obvious increase of the DA content in ACG. GR82334(iv or ith)antagonized the significant increase of DA content in ACG induced by the stimulating SN. However,GR82334(ith)did not completely antagonized the increase of DA content in ACG induced by electric stimulating SN. Conclusion The results indicated that there is connection between SN and the dopami-nergic nervous system in ACG,and SN afferent nociceptive signals can activate ACG dopaminergic neurons to release DA. Peripheral and central NK-1 receptors are involved in the process of significant increase of DA content in ACG induced by SN afferent signals. However,there are other central paths of SN information input to ACG to induce obvious increases of DA content,in which other neurotransmitters and receptors may be involved.
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OBJECTIVES: Posttraumatic stress disorder(PTSD) has been primarily associated with emotional problems. Recently, however, the impact of PTSD on cognitive processes has interested a growing number of researchers. The current study is aimed at investigating the cognitive aspects of PTSD at both behavioral and neurological levels. METHODS: We recruited individuals with PTSD who survived the Daegu subway explosion in 2003 as well as non-PTSD individuals as a control group. To evaluate the inhibitory processes and the neural mechanisms, we had these individuals perform the negative priming task simultaneously with functional MRI scanning. RESULTS: Behaviorally, the negative priming effect was intact in the control group but was not evident in the PTSD group. In the imaging results, only the PTSD group showed the negative priming effect (i.e., increased activation of the negative priming condition as opposed to the neutral condition) in the dorsolateral prefrontal cortex, anterior cingulate cortex, and inferior temporal gyrus. The PTSD group also showed increased activity for the positive priming condition as opposed to the neutral condition in the claustrum. These results confirm and extend the previous findings that the integrity of the ACC is compromised in the trauma survivors due to disrupted white matter tract. CONCLUSIONS: The current results suggest that deteriorated performance of the PTSD group may be due to the functional problem as well as the structural abnormalities.