BACKGROUND: Up to now, few studies related to the mechanism of low-frequency transcutaneous electrical nerve stimulation (TENS) in relieving pain, and the effect of low-frequency TENS on the activity potential of dorsal horn cells in rats after peripheral nerve injury. OBJECTIVE: To observe the effects of low-frequency TENS on the activity potential of dorsal horn cells induced by mechanical allodynia and thermal allodynia by using animal models of peripheral nerve injury, and observe the efficacy after interfering of naloxone. DESIGN: A randomized control animal study. SETTING: Department of Neurology, Affiliated Hospital of Medical College, Yanbian University. MATERIALS: The experiment was carried out in the central laboratory of Medical College, Yanbian University between February and October 2004. Eighty male Sprague-Dawley rats were used, and 60 random selected ones were operated to separate sciatic nerve, two branch tibial nerves and sural nerves of sciatic nerve were amputated after ligation, and peroneal nerve was left as the experimental group; the other 20 rats were placed at the origin after sciatic nerve was separated, and then the skin was sutured as the control group. METHODS: ① Pain detection (Behavioral test): At 1 week postoperatively, the rats were given mechanical allodynia and thermal allodynia once every 5 seconds for 10 times, and then the frequency of foot withdrawal was detected (0%-40% for mild pain, 40%-70% for moderate pain; 70% and above for severe pain). ② The spontaneous activity potential of dorsal horn cells and that induced by mechanical allodynia and thermal allodynia were detected among the rats with moderate and severe pain in the control group and study group. ③ Low-frequency TENS of 3 mA and 10 Hz was applied to the legs of rats in the experimental group with annular electrode for 10 minute, and the membrane potential of dorsal horn cell was detected before and after stimulation. ④ At the same time of low-frequency TENS was given, rats in the experimental group were injected with naloxone via audal vein, and the membrane potential of dorsal horn cell was detected before and at 10 minutes after naloxone injection.RESULTS: Finally 80 rats were involved in the analysis of results after compensation. ① The foot withdrawal frequencies induced by mechanical allodynia and thermal allodynia in the experimental group were obviously higher than those in the control group (P ＜ 0.01). ② The membrane potential of dorsal horn cell by mechanical allodynia and thermal allodynia in the experimental group were obviously higher than those in the control group (P ＜ 0.01). ③ The membrane potential of dorsal horn cell by mechanical allodynia and thermal allodynia at 10 minutes after low-frequency TENS in the experimental group were obviously higher than those in the control group [(102.6±0.9), (136.9±1.46) impulses per 10 seconds; (175.2±1.28), (240.8±1.51) impulses per 10 seconds, P ＜ 0.01]. ④ In the experimental group, the membrane potential of dorsal horn cell by mechanical allodynia and thermal allodynia at 10 minutes after naloxone injection were obviously higher than those before injection [(174.5±0.4), (235.4±1.4) impulses per 10 seconds, P ＜ 0.01].CONCLUSION: Low-frequency TENS can effectively inhibit the activity potential of spinal dorsal horn cells induced by non-noxious stimulation,and the intravenous injection of naloxone (8 mg/kg) can recover it to the pretreatment level, indicating that low-frequency TENS may alleviate pain by stimulating central nervous system to make it secrete endogenous opium system, and acting on spinal dorsal horn cells to reduce the activity.

Objective:To investigate the effect of long-term alcohol intake on sensory information synaptic transmission of mossy fiber-granular cells in the cerebellar cortex of mice.Methods:Twenty healthy male ICR mice aged 6 to 8 weeks were divided into normal saline group(control group) and alcohol intake group(alcohol group) according to random number table, with 10 mice in each group. The mice in alcohol group were injected intraperitoneally with 20% alcohol and the mice in control group were injected with the same amount of saline for 28 days.After the injection, the scalp, muscle tissue and skull were removed in turn, and the dura mater was removed to fully expose the crus II area of cerebellum. The mice were stimulated by air blowing at 30 mm of the ipsilateral tentacle pad with a gas jet device.When the the maximal response site was determined, the NMDA receptor antagonist (D-APV), metabolic glutamate receptor 1 antagonist (JNJ16259685) and N-methyl-D-aspartic acid (NMDA) were perfused on the brain surface of mice. Each drug was perfused for 20 minutes and ACSF was used between the two drugs until the waveform was recovered. Patch clamp amplifier was used to record the changes of potential waveform in mouse cerebellar granule layer. The data were analyzed by the softwares of Clampfit 10.3 and SPSS 22.0.Results:After exposure to wind stimulation, the latency of field potential response in granular layer of mice in alcohol group (11.8±0.7)ms was significantly longer than that in the control group (10.1±0.2)ms ( t=-8.041, P<0.05), and the amplitude of N1 (1.2±0.1) MV was significantly lower than that in the control group (0.6±0.1) MV ( t=-12.728, P<0.05). Compared with the control group, the rise time of P1 waveform((4.4±0.2)ms, (3.2±0.2)ms), duration ((12.1±0.5)ms, (10.3±0.2)ms), extinction time((7.8±0.2)ms, (6.9± 0.2)ms), volume under waveform ((7.3±0.2)ms, (4.3±0.2)ms) were significantly increased in the alcohol group ( t=16.100, - 11.840, -11.673, -35.576, all P<0.05). There were no significant differences in the amplitude, half width, rise time and decay time of Roff wave between the two groups ( t=-1.909, -0.910, -0.789, 1.462, all P>0.05). When JNJ16259685 was perfused on the brain surface of mice in alcohol group, the amplitude of field potential evoked by five blowing stimuli had no significant difference compared with that before administration (all P>0.05). When D-APV was perfused into the brain surface of mice in the alcohol group, the amplitude of P1 ((42.3±1.5) Mv)was significantly lower than that before administration ((101.1±0.9)mV) and after elution ((100.1±2.2) mV) ( t=106.762, - 69.605, both P<0.05), and the area under waveform of P1 ((42.6±1.3)%) was also significantly lower than that before administration ((100.6±1.6)%) and after elution ((97.6±2.2)%) ( t=88.862, -67.791, both P<0.05).The ratio of N2 / N1 (0.3±0.1) was significantly lower than that before administration (0.4±0.1) and after elution (0.3±0.1) ( t=2.242, 2.121, both P<0.05). When NMDA was perfused on the brain surface of mice in the control group, compared with before administration and after elution, the amplitude of P1 ((110.7±3.2) mV, (100.1±0.9) mV, (102.0±1.7) mV, t=-10.173, 7.669, both P<0.05), the area under the waveform of P1 ((127.9±3.5)%, (100.0±3.1)%, (115.0±5.3)%, t=-18.698, 6.447, both P<0.05), the ratio of N2 / N1 ((0.5±0.1), (0.3±0.1), (0.3±0.1), t=-5.669, 5.669, both P<0.05) were all significantly increased. When D-APV was perfused on the brain surface of mice in control group, the field potential evoked by blowing stimuli had no significant difference compared with that before administration and after elution (all P>0.05). Conclusion:Long-term alcohol intake significantly suppresses the synaptic transmission of excitatory glutamate in MF-GC, and enhances the inhibitory response mediated by GABAA receptor in cerebellar cortex. The inhibitory component is enhanced by NMDA receptor, but not by type 1 metabolic glutamate receptor.

Objective:To investigate the effect of chronic ethanol consumption on sensory information transmission in the cerebellar molecular layer and reveal the mechanism of chronic alcoholism on sensory information transmission and integration in the cerebellar cortex.Methods:Fifty healthy male ICR mice aged 6-8 weeks were randomly divided into saline group(control group)and ethanol consumption group(alcohol group) according to the random number table, with 25 mice in each group.The mice in alcohol group were injected intraperitoneally with 20% ethanol daily, while the mice in control group were injected with the same dose of normal saline. All mice were injected intraperitoneally once a day for 28 days.Through electrophysiological technology, patch-clamp amplifier and data acquisition software were used to record the changes in cerebellar molecular layer field potential of mice in the alcohol group and control group induced by sensory stimulation.Clampfit 10.3 software was used to record and analyze the electrophysiological data. SPSS 22.0 software was used for statistical analysis. Paired t-test and one-way ANOVA were used to analyze the differences before and after treatment. Results:After giving the stimulation of wind blowing, the amplitude of P1 in alcohol group was significantly higher than that in control group ((121.31±3.5)%, (97.2±2.7)%; t=26.08, P<0.05), and the area under the P1 curve (AUC) of the alcohol group was significantly lower than that of the control group ((127.1±4.2)%, (102.2±3.5)%; t=22.95, P<0.05). There was no significant difference in N1 amplitude between the two groups (P>0.05). When L-NNA, an inhibitor of nitric oxide synthase, was perfused into the brain surface of mice, the amplitude of P1 in alcohol group was significantly lower than that before administration ((76.2±4.8)%, (103.5±3.6)%; t=22.60, P<0.05), but there was no difference of the amplitude of P1 before administration and after elution ((101.5±4.6)%) ( t=1.70, P>0.05). After the L-NNA was perfused, the AUC of P1 was significantly lower than that before administration((72.4±5.6)%, (102.7±2.66)% ( t=24. 58, P<0.05), and there was no significant difference between before administration and after elution( (100.6±3.5)%, t=1.81, P>0.05). When L-NNA was perfused into the brain surface of mice, the amplitude of P1 in control group was (104.3±1.6)% and it had no differences compared with before administration(102.2±5.6)%, t=1.84, P>0.05) and after elution(102.5±4.5)%, t=1.92, P>0.05). And the AUC of P1 in control group after perfused L-NNA had no differences compared with before administration(103.5±2.6)%, (102.5±4.6)%) and after elution((101.9±3.7)%, t=0.99, 1.81, both P>0.05). When the mouse brain surface was perfused with NO donor SNAP, the amplitude of P1 in the control group was significantly higher than that before administration( (128.2±3.4)%, (103.5±2.6)%; t=28.89, P<0. 05) and there was no difference between before administration and after elution( (105.4±4.2)% , t=1.93, P>0.05). The AUC of P1((125.4±4.4)%) was higher than before administration((104.3±4.6)% , t=16.60, P<0.05) and there was no difference between before administration and after elution(103.5±4.2)%, t=0.65, P>0.05). Conclusion:Chronic ethanol consumption significantly enhances the inhibitory response, and the enhancement of inhibitory components stems from the activation of the NO signaling pathway.

Neuropathic pain (NP) that contributes to the comorbidity between pain and depression is a clinical dilemma. Neuroinflammatory responses are known to have potentially important roles in the initiation of NP and depressive mood. In this study, we aimed to investigate the effects of paeoniflorin (PF) on NP-induced depression-like behaviors by targeting the hippocampal neuroinflammation through the toll-like receptor 4 (TLR4)uclear factor-kappa B (NF-kB) signaling pathway. We used a murine model of NP caused by unilateral sciatic nerve cuffing (Cuff ). PF was injected intraperitoneally once a day for a total of 14 days. Pain and depression-like behavior changes were evaluated via behavioral tests. Pathological changes in the hippocampus of mice were observed by H&E staining. The levels of proinflammatory cytokines in the hippocampus were detected using ELISA. Activated microglia were measured by immunohistochemical staining. The TLR4/NF-kB signaling pathwayassociated protein expression in the hippocampus was detected by western blotting. We found that the PF could significantly alleviate Cuff-induced hyperalgesia and depressive behaviors, lessen the pathological damage to the hippocampal cell, reduce proinflammatory cytokines levels, and inhibit microglial over-activation. Furthermore, PF downregulated the expression levels of TLR4/NF-kB signaling pathwayrelated proteins in the hippocampus. These results indicate that PF is an effective drug for improving the comorbidity between NP and depression.

Neuropathic pain (NP) that contributes to the comorbidity between pain and depression is a clinical dilemma. Neuroinflammatory responses are known to have potentially important roles in the initiation of NP and depressive mood. In this study, we aimed to investigate the effects of paeoniflorin (PF) on NP-induced depression-like behaviors by targeting the hippocampal neuroinflammation through the toll-like receptor 4 (TLR4)uclear factor-kappa B (NF-kB) signaling pathway. We used a murine model of NP caused by unilateral sciatic nerve cuffing (Cuff ). PF was injected intraperitoneally once a day for a total of 14 days. Pain and depression-like behavior changes were evaluated via behavioral tests. Pathological changes in the hippocampus of mice were observed by H&E staining. The levels of proinflammatory cytokines in the hippocampus were detected using ELISA. Activated microglia were measured by immunohistochemical staining. The TLR4/NF-kB signaling pathwayassociated protein expression in the hippocampus was detected by western blotting. We found that the PF could significantly alleviate Cuff-induced hyperalgesia and depressive behaviors, lessen the pathological damage to the hippocampal cell, reduce proinflammatory cytokines levels, and inhibit microglial over-activation. Furthermore, PF downregulated the expression levels of TLR4/NF-kB signaling pathwayrelated proteins in the hippocampus. These results indicate that PF is an effective drug for improving the comorbidity between NP and depression.

Ethanol is one of the most widely used and abused psychoactive substances in the world. Long-term and excessive intake of alcohol can damage the central nervous system and lead to impairment of its function. As an important component of the central nervous system, cerebellum is one of the main target organs damaged by ethanol. Acute and chronic ethanol intake can damage human motor coordination, motor learning and some cognitive functions. Its damage mechanism is generally believed to be caused by the abnormal function of cerebellar cortical neural circuit caused by ethanol intake. Combined with recent studies on the mouse model of long-term ethanol intake, this article reviews the cerebellar neural network mechanism of long-term ethanol intake from various aspects, with a view to providing research and development in behavioral movement, motor coordination, cognitive function, depression, and offers new ideas with the rise of precision medicine for treatment. People are increasingly interested in exploring the mechanism of long-term ethanol intake on the cerebellar neural network. How to improve or block the corresponding mechanism based on the mechanism of action found in existing research is an important proposition in future research.

Objective:To investigate the long-term alcohol consumption on synaptic plasticity of mossy fiber-granule cells in cerebellar cortex and motor coordination function in mice.Methods:Thirty healthy male ICR mice aged 6-8 weeks were divided into saline group (control group)and alcohol consumption group(alcohol group) according to random number table with 15 in each group. The mice in alcohol group were injected intraperitoneally with 15% ethanol (1.6 g/kg), while the mice in control group were injected with the same volum of normal saline, all mice were injected intraperitoneally once a day for 28 consecutive days. Walking obstacle test and rotating rod fatigue test were used to observe the motor coordination ability and learning ability of mice. Electrophysiological patch clamp technique was used to detect the field potential changes of long-term synaptic plasticity induced by blowing stimulation. SPSS 22.0 software was used for statistical analysis.Independent sample t-test, paired t-test and repeated measurement analysis of variance were used for comparison between the two groups before and after intervention. Results:The electrophysiological results showed that the amplitude percentage of field potential N1 wave in the control group after blowing stimulation was (130.4±3.3)%, which was higher than that before stimulation ((100.6±2.7)%) ( t=27.07, P<0.01). And the percentage of area under N1 standardized waveform after stimulation ((128.8±4.5)%) was greater than that before stimulation ((100.2±3.5)%) ( t=19.43, P<0.01). There was no significant difference in the amplitude percentage of N1 wave in alcohol group ((97.8±4.3)%) after blowing stimulation compared with that before stimulation ((99.5±5.6)%) ( t=0.93, P>0.05). And also there was no significant difference in the area percentage under N1 wave after stimulation ((96.8±3.6)%) compared with that before stimulation ((100.2±4.2)%) ( t=2.38, P>0.05). The results of walking obstacle test showed that the total number of errors (3.14±0.19) in the alcohol group was higher than that in the control group(1.52±0.29) ( t=17.87, P<0.01), and the total error time ((63.85±9.34) ms) was longer than that in the control group ((28.93±7.21) ms) ( t=11.45, P<0.01). The results of repeated measurement analysis of variance showed that there was an interaction between time and group in the falling speed and falling latency of the two groups of mice in the rotating rod fatigue experiment ( F=4.5, 455.1, both P<0.05). The drop speed of mice in the alcohol group was significantly lower than that in the control group from day 1 to 7 (all P<0.05). The fall latency of mice in the alcohol group from day 1 to 7 was shorter than that in the control group, and the difference was statistically significant (all P<0.05). Conclusion:Long-term alcohol consumption impairs synaptic plasticity in the granular layer of mice and leads to a significant decline in motor coordination and motor learning ability.

Objective:To investigate the effect of long-term chronic ethanol consumption on the spontaneous discharge activity of Purkinje cells in the cerebellar cortex of mice.Methods:Fifty 3-week-old ICR mice, regardless of gender, were divided into control group and ethanol group according to the random number table method, with 25 mice in each group. The mice in ethanol group were administered 20% ethanol (1.6 g/kg, once a day) by gavage, and the control group mice were given the same volume of 0.9% sodium chloride solution by gavage, and the gavage cycle was 28 days.The electrical activity of cerebellar Purkinje cells induced by sensory stimulation was recorded by patch clamp amplifier and data acquisition software. Statistical analysis was conducted by Clampfit 10.3 software and SPSS 22.0 software, t-test and one-way ANOVA were used to compare the data between the two groups and the data before and after intervention of each group. Results:The electrophysiological results showed that the spontaneous simple spike discharge frequency of Purkinje cells in the cerebellar cortex of mice in ethanol group was lower than that of the control group ((26.8±2.5)%, (34.6±4.7)%; t=26.08, P<0.05), and the coefficient of variation was higher than that of the control group ((27.3±3.3)%, (19.2±2.3)%; t=22.95, P<0.05). After cerebral surface perfusion of GABAA receptor antagonist, the frequency of simple peak potentials in the cerebellar cortex of ethanol mice was higher than before administration ( t=10.19, P<0.05), and the coefficient of variation was lower than before administration ( t=28.36, P<0.05). After brain surface perfusion of GABAA receptor antagonist, there was no significant change in the spontaneous simple peak discharge frequency of cerebellar Purkinje cells in the control group( P>0.05), and the coefficient of variation decreased compared to before administration ( t=6.95, P<0.05). After administering AMPA receptor antagonists on the surface of the brain, there were no significant changes in the discharge frequency and coefficient of variation in both the ethanol group and control group compared to before administration (both P>0.05). After simultaneously blocking AMPA and GABAA receptors, it was found that the spontaneous discharge frequency in ethanol group increased after administration compared to before administration((107.3±4.3)%, (99.7±3.7)%, P<0.05), and the increased value of frequency in the ethanol group was also higher than that of control group ( P<0.05). After simultaneously blocking AMPA and GABAA receptors, the coefficient of variation of the alcohol group and the control group mice were both lower than those before administration (both P<0.05), and the decrease in the alcohol group was higher than that in the control group ( P<0.05). Conclusion:Chronic ethanol exposure significantly inhibited the spontaneous discharge of Purkinje cells in the cerebellum, and the enhancement of inhibitory components was achieved by the inhibitory input mediated by GABAA receptors.