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Objective:To evaluate the effect of edaravone on the extracellular signal-regulated kinase (ERK)-cAMP responsive element binding protein (CREB) signaling pathway in the hippocampus of aged rats with postoperative cognitive dysfunction (POCD).Methods:Sixty SPF healthy male Sprague-Dawley rats, aged 20 months, weighing 650-700 g, were divided into 4 groups ( n=15 each) using a random number table method: control group (group C), POCD group (group P), edaravone group (group E) and ERK inhibitor group (group I). The rats received laparotomy under 3% sevoflurane anesthesia to prepare POCD model in P, E and I groups. Edaravone 3 mg/kg was intraperitoneally injected at 30 min before operation in E and I groups, ERK inhibitor PD98059 0.3 mg/kg was injected via the tail vein in group I. The open field test was performed at 3 days after operation to evaluate the spontaneous activity of rats, then Morris water maze test was performed to evaluate the cognitive function of rats on 3-7 days after operation. The rats were sacrificed after the end of Morris water maze test, and hippocampal tissues were obtained for determination of the expression of phosphorylated ERK (p-ERK), phosphorylated CREB (p-CREB), synaptophysin and postsynaptic density protein 95 (PSD-95) (by Western blot) and dendrite length and density of dendrites in hippocampal CA1 area (using Golgi staining). Results:Compared with group C, the escape latency was significantly prolonged after operation, the number of crossing the original platform was reduced, the expression of p-ERK, p-CREB, synaptophysin and PSD-95 was down-regulated, and the dendritic length and density of hippocampal neurons were reduced in group P ( P<0.05). Compared with group P, the escape latency was significantly shortened, the number of crossing the original platform was increased, the expression of p-ERK, p-CREB, synaptophysin and PSD-95 was up-regulated, and the dendritic length and density of hippocampal neurons were increased in group E ( P<0.05). Compared with group E, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-ERK, p-CREB, synaptophysin and PSD-95 was down-regulated, the dendritic length of hippocampal neurons was shortened, and the density of hippocampal neurons was decreased in group I( P<0.05). Conclusions:The mechanism by which edaravone improves POCD may be related to activating ERK/CREB signaling pathway and changing synaptic plasticity in hippocampal CA1 region in aged rats.
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Objective:To evaluate the effect of surgery under propofol anesthesia during mid-pregnancy on the cognitive function and hippocampal histone deacetylase 2 (HDAC2)-cAMP response element-binding protein (CREB)-N-methyl-D-aspartate (NMDA) receptor 2B subunit (NR2B)-containing NMDA receptor (NR2B) signaling pathway in the offspring rats.Methods:Thirty healthy Sprague-Dawley rats at 14 days of gestation were divided into 3 groups ( n=10 each) using a random number table method: propofol anesthesia group (P group), surgery under propofol anesthesia group (S group) and control group (C group). In S group, propofol 20 mg/kg was injected via the caudal vein, and then propofol was continuously infused at a rate of 20 mg·kg -1·h -1 to maintain anesthesia for 4 h, and exploratory laparotomy was performed. Group P received no exploratory laparotomy and the other treatments were similar to those previously described in group S. The equal volume of normal saline was given instead in group C. The learning and memory of the offspring rats was assessed using Morris water maze test on postnatal day 30. The expression of HDAC2, phosphorylated CREB (p-CREB), NR2B, brain-derived neurotriphic factor (BDNF) and phosphorylated tyrosine kinase B (p-TrkB) in offspring′s hippocampi was evaluated by Western blot. Apoptosis in hippocampal neurons was detected by TUNEL staining. Results:Compared with group C, the escape latency was significantly prolonged, the frequency of crossing the original platform was decreased, the time spent in the second quadrant was shortened, the expression of HDAC2 was up-regulated, the expression of p-CREB, NR2B, BDNF and p-TrkB was down-regulated, and the apoptosis rate of the hippocampal neurons was increased in P and S groups ( P<0.05). Compared with P group, the escape latency was significantly prolonged, the frequency of crossing the original platform was decreased, the time spent in the second quadrant was shortened, the expression of HDAC2 was up-regulated, the expression of p-CREB, NR2B, BDNF and p-TrkB was down-regulated, and the apoptosis rate of the hippocampal neurons was increased in S group ( P<0.05). Conclusions:Surgery under propofol anesthesia during mid-pregnancy can decrease the cognitive function of offspring rats, and the mechanism is related to the regulation of HDAC2-CREB-NR2B signaling pathway and the promotion of apoptosis in hippocampal neurons.
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Objective:To evaluate the role of protein kinase A (PKA)-cyclic adenosine monophosphate response element binding protein (CREB) signaling pathway in sevoflurane-induced reduction of cardiopulmonary bypass (CPB)-induced cognitive impairment in rats.Methods:Forty healthy male Sprague-Dawley rats, aged 4 months, weighing 300-350 g, were divided into 4 groups ( n=10 each) using a random number table method: control group (group C), group CPB, CPB+ sevoflurane group (group CS) and CPB+ sevoflurane+ PKA inhibitor H89 group (group CSH). After H89 5 μl was injected into the lateral ventricle in group CSH, the rats in group CS and group CSH were exposed to 2.4% sevoflurane for 1 h, and then the CPB model of beating heart without blood priming for 60 min was developed in CPB, CS and CSH groups.The autonomic movement ability was evaluated using the open field test at 2nd day after CPB.Morris water maze test was used to assess the cognitive function at 3rd day after CPB.The rats were sacrificed after the Morris water maze test, the brain was removed and the hippocampal tissues were isolated for determination of the apoptosis rate of hippocampal neurons (by flow cytometry) and expression of PKA, phosphorylated CREB (p-CREB) and brain-derived neurotrophic factor (BDNF) (by Western blot). Results:There was no significant difference in movement speed, distance and time of staying at the central region among the four groups ( P>0.05). Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the time of staying at the original platform quadrant was shortened, the apoptosis rate of hippocampal neurons was increased, and the expression of PKA, p-CREB and BDNF was down-regulated in the other three groups ( P<0.05). Compared with group CPB, the escape latency was significantly shortened, the number of crossing the original platform was increased, the time of staying at the original platform quadrant was prolonged, the apoptosis rate of hippocampal neurons was decreased, and the expression of PKA, p-CREB and BDNF was up-regulated in group CS ( P<0.05), and no significant change was found in the indexes mentioned above in group CSH ( P>0.05). Compared with group CS, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, and the time of staying at the original platform quadrant was shortened, the apoptosis rate of hippocampal neurons was increased, and the expression of PKA, p-CREB and BDNF was down-regulated in group CSH ( P<0.05). Conclusions:Sevoflurane can reduce the apoptosis in hippocampal neurons by activating PKA-CREB signaling pathway, and thus reducing the cognitive impairment induced by CPB in rats.
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Abstract Alzheimer's disease is a neurodegenerative condition that causes changes in memory and cognition, in addition to behavioral disorders, and most commonly affects the elderly. Several studies in the literature have presented therapeutic measures in an attempt to interfere with the pathogenic mechanisms of the disease and to mitigate its clinical manifestations. Some factors, such as excitotoxicity, cholinergic dysfunctions, oxidative stress, tau protein hyperphosphorylation, changes in amyloid-beta peptide metabolism, herpes viruses, apolipoprotein E, glycogen synthase kinase 3, insulin resistance, and the endocannabinoid system seem to be related to pathophysiology of Alzheimer's disease. Given this, a literature review was carried out to address the molecular mechanisms associated with the pathophysiological hypotheses previously mentioned, aiming to better understanding their underlying causes and contributing to possible pharmacological strategies about treatment of the disease.
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Objective:To evaluate the role of p38 mitogen-activated protein kinase (MAPK)/cyclic adenosine monophosphate response element-binding protein (CREB) signaling pathway in tetramethylpyrazine-induced reduction of hippocampal inflammatory responses in mice with sepsis-associated encephalopathy (SAE).Methods:Sixty healthy male C57BL6 mice, weighing 24-27 g, were divided into 4 groups ( n=15 each) using a random number table method: sham operation group (group Sham), sepsis group (group Sep), tetramethylpyrazine group (group TMP) and p38 MAPK inhibitor SB203580 group (group SB). The model of SAE was established by cecal ligation and puncture in anesthetized mice.Tetramethylpyrazine 10 mg/kg was injected intraperitoneally once a day at 3 days before the establishment of the model in TMP group, and SB203580 2.0 mg/kg was intraperitoneally injected at 30 min after the establishment of the model in SB group.The equal volume of normal saline was given intraperitoneally in Sham and Sep groups.At 1 day after operation, cognitive function was assessed by Morris water maze, and the escape latency and ratio of time spent in the target quadrant were recorded.The animals were sacrificed after the test, and hippocampal tissues were taken for determination of the contents of interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α) and IL-6 (by enzyme-linked immunosorbent assay) and for detection of the expression of phosphorylation of p38 MAPK, GSK3 and CREB and expression of brain-derived neurotrophic factor (BDNF) (by Western blot). Results:Compared with group Sham, the escape latency was significantly prolonged, the ratios of time spent in the target quadrant were decreased, the contents of IL-1β, TNF-α and IL-6 were increased, the phosphorylation of hippocampus p38 MAPK was increased, the phosphorylation of GSK3 and CREB were decreased, and the expression of BDNF was down-regulated in Sep, TMP and SB groups ( P<0.05). Compared with group Sep, the escape latency was significantly shortened, the ratios of time spent in the target quadrant were increased, the contents of IL-1β, TNF-α and IL-6 were decreased, the phosphorylation of hippocampus p38 MAPK was decreased, the phosphorylation of GSK3 and CREB were increased, and the expression of BDNF was up-regulated in TMP and SB groups ( P<0.05). Compared with group TMP, no significant change was found in the parameters mentioned above in group SB ( P>0.05). Conclusion:p38 MAPK/CREB signaling pathway is involved in the process of tetramethylpyrazine-induced reduction of hippocampal inflammatory responses in mice with SAE.
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Objective:To evaluate the role of extracellular signal-regulated kinase 1/2 (ERK1/2)/cyclic adenosine monophosphate response element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF) signaling pathway in dexmedetomidine-induced inhibition of propofol-caused apoptosis in isolated hippocampal neurons of fetal rats.Methods:Pregnant Sprague-Dawley rats at 16 days of gestation were sacrificed, and the fetal rats were taken out, and hippocampal neurons of fetal rats were obtained and primarily cultured in vitro for 7 days.The neurons were divided into 9 groups ( n=12 each) using a random number table method: control group (group C), fat emulsion group (group I), dimethyl sulfoxide (DMSO) group, dexmedetomidine group (group D), propofol group (group P), propofol plus dexmedetomidine group (group PD), PD98059 plus propofol plus dexmedetomidine group (group PDP), MH89 plus propofol plus dexmedetomidine group (group HDP), and KG501 plus propofol plus dexmedetomidine group (group KDP). Group C received no treatment.In group I, 20% fat emulsion was added, and the neurons were incubated for 30 min, and 0.25% DMSO was added in group DMSO, and the neurons were incubated for 30 min.Dexmedetomidine at a final concentration of 10 μmol/L was added, and the neurons were incubated for 30 min in group D. Propofol at a final concentration of 100 μmol/L was added, and the neurons were incubated for 3 h in group P. In group PD, dexmedetomidine at a final concentration of 10 μmol/L was added, the neurons were incubated for 30 min, propofol at a final concentration of 100 μmol/L was added, and the neurons were incubated for 3 h. In PDP, HDP and KDP groups, 25 μmol PD98059 (p-ERK1/2 inhibitor), 10 μmol H89 (p-CREB inhibitor) and 25 μmol KG501 (CREB inhibitor) were added, respectively, the neurons were incubated for 30 min, dexmedetomidine at a final concentration of 10 μmol/L was added, the neurons were incubated for 30 min, and propofol at a final concentration of 100 μmol/L was added, and the neurons were incubated for 3 h. The cell ultrastructure was observed with the transmission electron microscope, the apoptosis in neurons was detected by flow cytometry, the expression of ERK1/2, CREB and BDNF mRNA was detected by quantitative real-time polymerase chain reaction, and the expression of p-ERK1/2, CREB, p-CREB, BDNF and cleaved caspase-3 was detected by Western blot. Results:Compared with group C, the apoptosis rate was significantly increased, the expression of p-ERK1/2 and p-CREB was down-regulated, and the expression of cleaved caspase-3 was up-regulated in P, PD, PDP, HDP and KDP groups, and the expression of BDNF was significantly down-regulated in P, PDP, HDP and KDP groups ( P<0.05). Compared with group P, the apoptosis rate was significantly decreased, the expression of p-ERK1/2, p-CREB and BDNF was up-regulated, and the expression of cleaved caspase-3 was down-regulated in group PD ( P<0.05). Compared with group PD, the apoptosis rate was significantly increased, the expression of p-ERK1/2, p-CREB and BDNF was down-regulated, and the expression of cleaved caspase-3 was up-regulated in PDP, HDP and KDP groups ( P<0.05). Conclusion:The ERK1/2/CREB/BDNF signaling pathway is involved in dexmedetomidine-induced inhibition of propofol-caused apoptosis in isolated hippocampal neurons of fetal rats.
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Objective:To investigate the effects of upregulation of cAMP response element binding protein (CREB) on proliferation, invasion and natural killer (NK) cell killing activity of esophageal adenocarcinoma.Methods:23 patients with esophageal cancer treated in Shaanxi Provincial People′s Hospital from March 2017 to December 2019 were selected. The protein expression of CREB in esophageal adenocarcinoma and adjacent normal tissues was detected by immunohistochemistry; Esophageal adenocarcinoma cell line TE-10 was cultured in vitro. TE-10 cells transfected with si-NC were set as the control group and TE-10 cells transfected with si-CREB were set as the si-CREB group. Western blot was used to detect the protein level of CREB, MHC class Ⅰ chain-related A (MICA) and MHC class Ⅰ chain-related B (MICB); Flow cytometry was employed to detect the expression of MICA and MICB; clone formation experiment and Transwell were used to detect the proliferative and invasive ability of TE-10 cells; lactate dehydrogenase (LDH) releasing assay was used to detect cytotoxicity of NK cells against TE-10 cells. Results:The expression of CREB in esophageal adenocarcinoma tissue was higher than that in normal tissues adjacent to cancer; the protein level of CREB in esophageal cancer cell TE-10 was higher than that of human normal esophageal epithelial cells HEEC ( P<0.05). The proliferative and invasive ability of TE-10 cells in the si-CREB group was significant lower than that in the control group ( P<0.05), while the expression of MICA and MICB, the killing rate of NK cells on TE-10 cells was significant higher than that in the control group ( P<0.05). Conclusions:CREB was highly expressed in esophageal adenocarcinoma tissues and cells. Silencing CREB could inhibit the proliferation and invasion of esophageal adenocarcinoma cells, and enhance the killing sensitivity of NK cells to esophageal adenocarcinoma cells by up-regulating the expression of MICA and MICB.
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BACKGROUND: The pain-relief properties of tricyclic antidepressants can be attributed to several actions. Recent observations suggest that adenosine is involved in the antinociceptive effect of amitriptyline. The A3 adenosine receptor (A3AR) is the only adenosine subtype overexpressed in inflammatory and cancer cells. This study was performed to investigate the role of A3AR in the anti-nociceptive effect of amitriptyline. METHODS: Spinal nerve-ligated neuropathic pain was induced by ligating the L5 and L6 spinal nerves of male Sprague-Dawley rats. The neuropathic rats were randomly assigned to one of the following three groups (8 per group): a neuropathic pain with normal saline group, a neuropathic pain with amitriptyline group, and a neuropathic pain with amitriptyline and 3-ethyl-5-benzyl- 2-methyl-4-phenylethynyl-6-phenyl-1,4-(±)-dihydropyridine-3,5-dicarboxylate (MRS) group. Amitriptyline or saline was administered intraperitoneally and 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(±)-dihydropyridine-3,5-dicarboxylate (MRS-1191), an A3AR antagonist, was injected subcutaneously immediately before amitriptyline administration. The level of extracellular signal-regulated kinase P44/42 (ERK1/2), cyclic AMP response element-binding protein (CREB), and proinflammatory cytokines were assessed using immunoblotting or reverse-transciption polymerase chain reaction. RESULTS: Amitriptyline increased the mechanical withdrawal threshold of the neuropathic rats. The level of phospho-ERK1/2 and phospho-CREB proteins, and proinflammatory cytokines produced by spinal nerve ligation were significantly reduced by amitriptyline administration. However, the use of MRS-1191 before amitriptyline administration not only reduced the threshold of mechanical allodynia, but also increased the signaling protein and proinflammatory cytokine levels, which were reduced by amitriptyline. CONCLUSIONS: The results of this study suggest that the anti-nociceptive effect of amitriptyline involves the suppression of ERK1/2 and CREB signaling proteins, and A3AR activation also affects the alleviation of the inflammatory response.
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Animals , Humans , Male , Rats , Adenosine , Amitriptyline , Antidepressive Agents, Tricyclic , Cyclic AMP Response Element-Binding Protein , Cytokines , Hyperalgesia , Immunoblotting , Ligation , Neuralgia , Phosphotransferases , Polymerase Chain Reaction , Rats, Sprague-Dawley , Receptors, Purinergic P1 , Spinal NervesABSTRACT
Objective To evaluate the role of cyclic adenosine monophosphate-protein kinase A-cAMP response element-binding protein (cAMP-PKA-CREB) signaling pathway in hypoxic preconditioninginduced reduction of propofol-induced central neurotoxicity in the developing rats.Methods A total of 70 SPF male Sprague-Dawley rats,aged 7 days,weighing 10-15 g,were divided into 7 groups (n=10 each) using a random number table method:normal saline group (N group),propofol group (P group),hypoxic preconditioning plus propofol group (HP group),hypoxic preconditioning plus propofol plus PKA inhibitor H89 group (HPH group),propofol plus PKA agonist SP-CAMP group (PS group),normal saline injected via the lateral cerebral ventricle group (NI group),and 5％ dimethyl sulfoxide (DMSO) injected via the lateral cerebral ventricle group (DI group).In P group,propofol 50 mg/kg was intraperitoneally injected,and an increment of propofol 50 mg/kg was given after recovery of righting reflex.The equal volume of normal saline was given instead in N group.In HP group,hypoxic preconditioning (rats were subjected to 5 cycles of 10-min hypoxia of 8％ O2 and 1O-min normoxia of 21％ O2) was performed,and propofol was intraperitoneally injected at 2 h after the end of hypoxic preconditioning and the method was similar to those previously described in P group.In HPH group,H89 5 μmol/5 μl was injected via the lateral cerebral ventricle,and 30 min later the other treatment was similar to those previously described in HP group.In PS group,SP-CAMP 20 nmol/5 μl was injected via the lateral cerebral ventricle,and 30 min later propofol was injected using the method previously described in P group.In NI and DI groups,5 μl normal saline and 5％ DMSO were injected via the lateral cerebral ventricle,respectively.Rats were immediately sacrificed after the righting reflex was recovered,brains were removed and hippocampi were isolated and cut into sections which were stained with haematoxylin and eosin for determination of PKAc and p-CREB positive cells (by i mmuno-histochemistry) and expression of cleaved caspase-3,Bcl-2,Bax,PKAc and posphorylated (p-CREB) protein (by Western blot).Results Compared with N group,the expression of cleaved caspase-3 and Bax was significantly up-regulated,the expression of Bcl-2,PKAc and p-CREB was downregulated,and the percentage of PKAc and p-CREB positive cells was decreased (P＜0.05),hippocampal cells had irregular arrangement,and cells was atrophied in P group.Compared with P group,the expression of cleaved caspase-3 was significantly down-regulated,the expression of Bcl-2,PKAc and p-CREB was up-regulated,and the percentage of PKAc and p-CREB positive cells was increased in HP and PS groups,and the expression of Bax was down-regulated (P＜0.05),the hippocampal cells were arranged neatly,the cytoplasm was abundant,and the nuclei were visible in HP group.Compared with HP group,the expression of cleaved caspase-3 was significantly up-regulated,the expression of Bcl-2,PKAc and p-CREB protein was down-regulated and the percentage of PKAc and p-CREB positive cells was decreased (P＜0.05),the cells had irregular arrangement and shrinked,and nuclear condensation was found in cells in HPH group.Conclusion The mechanism by which hypoxic preconditioning reduces propofol-induced central neurotoxicity may be related to activating cAMP-PKA-CREB signaling pathway in the developing rats.
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Objective To evaluate the effect of sevoflurane on hippocampal cyclic AMP (cAMP)-protein kinase A (PKA)-cAMP response element-binding protein (CREB) signaling pathway in aged rats.Methods Sixty healthy aged male Sprague-Dawley rats,aged 18 months,weighing 600-750 g,were divided into control group (C group,n =30) and sevoflurane group (group Sev,n =30) using a random number table method.Group Sev inhaled 2％ sevoflurane for 4 h.Group C inhaled the mixture of 50％ air and oxygen (2 L/min) for 4 h.Morris water maze test was performed on 1-6 days before anesthesia and at 1 day after the end of anesthesia (at the corresponding time points in group C).The animals were sacrificed and hippocampi were removed at 1,3 and 7 days after anesthesia (at the corresponding time points in group C) for determination of the hippocampal cAMP content (using enzyme-linked immunosorbent assay) and expression of hippocampal CREB,phosphorylated CREB (p-CREB) and PKA (using Western blot),and the p-CREB/CREB ratio was calculated.Results Compared with group C,the escape latency and swimming distance were significantly prolonged,the frequency of crossing the original platform was decreased,the time of staying at the original platform quadrant was shortened at 1 day after the end of anesthesia,and the expression of hippocampal cAMP and PKA was down-regulated at 1,3 and 7 days after the end of anesthesia,and the expression of CREB and p-CREB was down-regulated and p-CREB/CREB ratio was decreased at 1 day after the end of anesthesia in group Sev (P＜ 0.05).Conclusion The mechanism of sevoflurane-induced postoperative cognitive dysfunction may be related to inhibiting hippocampal cAMP-PKA-CREB signaling pathway in aged rats.
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Objective To evaluate the effect of sevoflurane on hippocampal calcium/calmodulindependent protein kinase Ⅱ (CaMK Ⅱ)/cyclic adenosine monophosphate response element-binding protein (CREB) signaling pathway in aged rats.Methods Sixty pathogen-free healthy male Sprague-Dawley rats,aged 18 months,weighing 600-750 g,were divided into 2 groups (n=30 each) using a random number table:control group (group C) and sevoflurane group (group Sev).Group Sev inhaled 2％ sevoflurane in the mixture of 50％ air and oxygen (2 L/min) for 4 h.Group C inhaled the mixture of 50％ air and oxygen (2 L/min) for 4 h.Morris water maze test was performed on 6 days before anesthesia and 1 day after anesthesia.The escape latency,swimming distance,frequency of crossing the original platform and time of staying at the platform quadrant Ⅱ were recorded.On 1,3 and 7 days after anesthesia,the rats were sacrificed,and the hippocampus was obtained for determination of the expression of CaMK Ⅱ,phosphorylated CaMK Ⅱ,CREB and phosphorylated CREB by Western blot.Results Compared with group C,the escape latency and swimming distance were significantly prolonged,the frequency of crossing the original platform was decreased,and the time of staying at the platform quadrant Ⅱ was reduced on 5th day of training and 1 day after anesthesia,and the expression of CaMK Ⅱ,phosphorylated CaMK Ⅱ,CREB and phosphorylated CREB was down-regulated after anesthesia in group Sev (P＜ 0.05).Conclusion Sevoflurane leads to cognitive decline through inhibiting hippocampal CaMK Ⅱ/CREB signaling pathway in aged rats.
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Objective To evaluate the relationship between hippocampal cyclic adenosine monophosphate response element-binding protein(CREB)/brain-derived neurotrophic factor(BDNF)signaling pathway and cognitive dysfunction in rats with chronic pathological pain.Methods Thirty-two healthy adult male Sprague-Dawley rats,weighing 220-250 g,were divided into 3 groups using a random number table:control group(group C,n=8),sham operation group(group S,n=8)and chronic pathological pain group(group CP,n=16).Chronic pathological pain model was established by injecting cobra venom 0.4 mg(4 μl)into the sheath of the infraorbital nerve.The mechanical pain threshold was measured at 3 days before establishment of the model(baseline)and 4 days and 1,2,3,4 and 8 weeks after establishment of the model.Morris water maze test was performed to evaluate the spatial learning and memory abilities at 5 and 9 weeks after establishment of the model.Eight rats were sacrificed at 5 and 9 weeks after establishment of the model in CP group,and rats were sacrificed after the end of Morris water maze test at 9 weeks after establishment of the model in C and S groups.The hippocampi were isolated for determination of the expression of phosphorylated CREB and BDNF in the hippocampal tissues using Western blot.Results Compared with group C,the mechanical pain threshold was significantly decreased at each time point after establishment of the model,the escape latency was prolonged at 5 and 9 weeks after establishment of the model,the rate of time of staying at the target quadrant was decreased,the frequency of crossing the original platform was decreased,and the expression of phosphorylated CREB and BDNF was down-regulated at 9 weeks after establishment of the model in group CP(P0.05).Conclusion The mechanism underlying cognitive dysfunction may be related to inhibited activation of CREB/BDNF signaling pathway in the hippocampus of rats with chronic pathological pain.
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@#Objective To explore the effects of electroacupuncture at Shenting (DU24) and Baihui (DU20) on cognitive dysfunction after stroke. Methods Forty-five Sprague-Dawley rats were randomly divided into control group (n=15), model group (n=15) and electroacupuncture group (n=15). The latter two groups were occluded their middle cerebral artery for two hours and reperfused. The electroacupuncture group accepted electroacupuncture at Shenting and Baihui 24 hours after modeling for seven days. They were assessed with Morris water maze once a day since the second day of intervention. Their brains were stained with TTC staining to measure cerebral infarction volume after treatment, while the expression of cyclic AMP response element binding protein (CREB) and phosphorylation (p-CREB) in hippocampal CA1 area were detected with immunohistochemistry. Results The escape latency and swimming distance of place navigation shortened in the electroacupuncture group compared with those in the model group (P<0.05) from the fourth day of intervention. The number of cross platform of spatial probe increased (P<0.05). The infarction volume was less in the electroacupuncture group than in the model group (P< 0.05), with increased expression of CREB and p-CREB in hippocampal CA1 area (P<0.05). Conclusion Electroacupuncture at Shenting and Baihui can increase the expression of CREB and phosphorylation in hippocampal CA1 area in rats after cerebral ischemia-reperfusion, to protect the neurons from ischemia and improve the learning and memory function.
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OBJECTIVE To investigate the effect of injection of β2-adrenergic receptor agonist clenbuterol into the infralimbic cortex(IL) on drug-seeking behavior triggered by conditioned cues. METHODS Adult male SD rats were trained to self-administer heroin under a FR1 schedule for consecutive 14 d,followed by 2-h extinction training. Cue-induced heroin seeking was measured for 2 h. Clenbuterol was microinjected bilaterally into the IL(8 ng/side)of rats 15 min prior to reinstatement test. Meanwhile,locomotor activity was detected 15 min after clenbuterol or artifial cerebrospinal fluid(mod?el group) was microinjected bilaterally into IL. Western blotting was used to detect the expression of phosphorylated cyclic AMP response element-binding protein(p-CREB)in the prelimbic cortex(PL), IL,nucleus accumbens core (NACc) and shell (NACsh) of rats immediately after reinstatement test. RESULTS After heroin administration training for 14 consecutive days,these animals exhibited reliable heroin self-administration,indicated by the increase in active nose poke responses and infusions. The rats that had received infusion of clenbuterol into the IL had significantly lower active pokes (8 ± 3)than those in model group(45±10)in cue-induced reinstatement(P<0.01),but there was no significant differ?ence between clenbuterol group and vehicle group in the locomotor activity. The expression of p-CREB in either IL or NACsh was significantly decreased in clenbuterol group compared with model group(P<0.01,P<0.05),but significantly increased in NACc(P<0.01). CONCLUSION Microinjection of clenb?uterol into the IL can attenuate the cue-induced reinstatement of heroin-seeking behavior in rats. The underlying mechanism might be related to the regulation of p-CREB expression in the NACc and NACsh.
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Objective To investigate the relationship between spinal neuronal microRNA 212 (miR-212) and phosphorylation of cAMP response element-binding protein (CREB) in a mouse model of bone cancer pain (BCP).Methods Thirty-two male SPF C3H/HeJ mice, aged 4-6 weeks, weighing 20-25 g, were randomly divided into 4 groups (n=8 each) using a random number table: sham operation group (group S), BCP group, BCP + intrathecal negative control locked nucleic acid (LNA) group (group BC) , and BCP + intrathecal miR-212 antisense LNA group (group BL).After the mice were anesthetized with intraperitoneal pentobarbital sodium, 20 μl of α minimal essential medium containing NCTC 2472 cells 2×105 was injected directly into the medullary cavity of the distal femur.In BC and BL groups, negative control LNA and miR-212 antisense LNA 12 pmol/5 μl were intrathecally injected, respectively, once a day for 7 consecutive days, starting from day 14 after inoculation.In S and BCP groups, the equal volume of DNAse/RNAse-free water was given instead.The number of spontaneous flinches (NSF) and mechanical paw withdrawal threshold (MWT) were measured on 1 day before inoculation and 4, 7, 10, 14 and 21 days after inoculation.The mice of each group were sacrificed after measurement of pain threshold on 21 days after inoculation, and the lumbar enlargement segments of the spinal cord were harvested to detect the expression of phosphorylated CREB (p-CREB) and CREB using Western blot.Results Compared with group S, the MWT was significantly decreased, and the NSF was increased on 7-21 days after inoculation, and the expression of p-CREB was up-regulated in BCP, BC and BL groups.Compared with group BCP, the MWT was significantly increased, and the NSF was decreased on 21 days after inoculation, and the expression of p-CREB was down-regulated in group BL, and no significant change was found in the parameters mentioned above in BC group.There was no significant difference in the expression of CREB between the four groups.Conclusion Spinal neuronal miR-212 is involved in the maintenance of BCP probably by promoting phosphorylation of CREB in mice.
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Objective To evaluate the effect of sevoflurane anesthesia on the expression of phosphorylated cAMP response element-binding protein (p-CREB) in the hippocampal neurons of developing rats.Methods Thirty-two healthy male Sprague-Dawley rats, aged 7 days, weighing 10-15 g, were equally and randomly divided into either control group (group C) or sevoflurane anesthesia group (group Sev) using a random number table.Group C inhaled 30％ oxygen for 6 h.Group Sev inhaled 3％ sevoflurane for 6 h.Eight rats in each group were sacrificed immediately after the end of oxygen or sevoflurane inhalation, and the hippocampus was removed for determination of the expression of p-CREB.The rats at ages 2 months underwent Morris water maze test.The rats were then sacrificed, and the hippocampus was removed for determination of the expression of p-CREB by Western blot.Results Compared with group C, the escape latency and swimming distance were significantly prolonged, the frequency of crossing the original platform was decreased, the percentage of the time of staying at the quadrant Ⅱ was decreased, and the expression of p-CREB in hippocampal neurons was down-regulated in group Sev.Conclusion The mechanism of sevoflurane anesthesia-induced neurotoxicity is related to inhibition of p-CREB expression in hippocampal neurons of developing rats.
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Objective Beta platelet-derived growth factor receptor ( PDGFR-β)-mediated signaling plays a key role in mor-phine tolerance , but its molecular mechanisms are not yet completely understood .The present study aims to investigate whether the ex-tracellular signal-regulated kinase ( ERK) and cyclic AMP response element binding protein ( REB) signaling pathways are involved in the development of PDGFR-βactivation-induced morphine tolerance in rats . Methods Thirty-six adult male SD rats were randomly divided into six groups of equal number:normal saline (20μL), morphine (15μg), morphine +imatinib (morphine 15μg +ima-tinib 10μg), morphine +PDGF-BB (morphine 15μg +PDGF-BB 10 ng), imatinib (10μg), and PDGF-BB (10 ng), all treated intrathecally at 20μL once daily for 7 consecutive days .Paw withdrawal latency ( PWL ) was measured 1 d before and 30 min after medication at 1, 3, 5, and 7 days, respectively, followed by calculation of the maximal possible effect of analgesia (MPE).On the 8th day, PWL was again obtained from all the rats at 30 min after intrathecal injection of morphine (15μg).Then, all the animals were sacrificed and the L4-5 segment of the spinal cord was isolated for determination of the expressions of ERK , phosphorylated ERK ( p-ERK) , CREB, and phosphorylated CREB ( p-CREB) by Western blot. Results At 5 and 7 days after medication, MPE was significant decreased in the morphine group ([52.90 ±8.20] and [15.12 ±3.80] %) and the morphine +PDGF-BB group ([43.51 ±5.42] and [14.81 ±3.60] %) as compared with (100.00 ± 0.00) %in both groups at 1 day (P<0.05), but had no significant changes in the morphine +imatinib group at 1, 3, 5, and 7 days.After intrathecal injection of morphine on the 8th day, MPE was (16.22 ±2.51) %in the morphine group, (15.22 ±3.50) %in the morphine +PDGF-BB group, and (35.21 ±4.51) %in the PDGF-BB group, all remarkably lower than (100.00 ±0.00) %in the control group (P<0.05).There were no significant differences in the expression levels of ERK and CREB among the six groups.The expressions of spinal p-ERK and p-CREB were markedly increased in the morphine , morphine +PDGF-BB, and PDGF-BB groups as compared with the control group (P<0.05), but significantly decreased in the morphine +imatinib group in compari-son with the morphine group, (P<0.05). Conclusion The PDGFR-βsignaling pathway plays an important role in the develop-ment of tolerance to morphine-induced analgesia and its underlying mechanisms may be associated with the activation of the ERK and CREB pathways .
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PURPOSE: Pelvic irradiation for the treatment of cancer can affect normal cells, such as the rapidly proliferating spermatogenic cells of the testis, leading to infertility, a common post-irradiation problem. The present study investigated the radioprotective effect of rolipram, a specific phosphodiesterase type-IV inhibitor known to increase the expression and phosphorylation of the cyclic adenosine monophosphate response element-binding protein (CREB), a key factor for spermatogenesis, with the testicular system against pelvic irradiation. MATERIALS AND METHODS: Male C57BL/6 mice were treated with pelvic irradiation (2 Gy) and rolipram, alone or in combination, and were sacrificed at 12 hours and 35 days after irradiation. RESULTS: Rolipram protected germ cells from radiation-induced apoptosis at 12 hours after irradiation and significantly increased testis weight compared with irradiation controls at 35 days. Rolipram also ameliorated radiation-induced testicular morphological changes, such as changes in seminiferous tubular diameter and epithelial height. Additionally, seminiferous tubule repopulation and stem cell survival indices were higher in the rolipram-treated group than in the radiation group. Moreover, rolipram treatment counteracted the radiation-mediated decrease in the sperm count and mobility in the epididymis. CONCLUSIONS: These protective effects of rolipram treatment prior to irradiation may be mediated by the increase in pCREB levels at 12 hours post-irradiation and the attenuated decrease in pCREB levels in the testis at 35 days post-irradiation in the rolipram-treated group. These findings suggest that activation of CREB signaling by rolipram treatment ameliorates the detrimental effects of acute irradiation on testicular dysfunction and the related male reproductive functions in mice.
Subject(s)
Animals , Humans , Male , Mice , Adenosine Monophosphate , Apoptosis , Cyclic AMP Response Element-Binding Protein , Epididymis , Germ Cells , Infertility , Phosphorylation , Rolipram , Seminiferous Tubules , Sperm Count , Spermatogenesis , Stem Cells , TestisABSTRACT
Objective To evaluate the effects of dexmedetomidine on the expression of phosphor-cAMP response element binding protein (p-CREB) in isoloated hippocampal neurons of fetal rats.Methods SpragueDawley rats on 16-18 days of gestation were sacrificed and the fetal rats were obtained.The hippocampi of fetal rats were isolated and hippocampal neurons were seeded in culture medium for 8 days.The cells were then divided into 4 groups (n =12 each) using a random number table:control group (group C),dexmedetomidine 0.001 μmol/L group (group D1),dexmedetomidine 0.010 μmol/L group (group D2),and dexmedetomidine 0.100μmol/L group (group D3).In D1.3 groups,dexmedetomidine with the final concentrations of 0.001 μmol/L,0.010 μmol/L,and 0.100 μmol/L was added to the culture medium,respectively,and then the cells were incubated for 3.5 h.The apoptosis in hippocampal neurons was detected by flow cytometry.The expression of p-CREB in hippocampal neurons was determined by RT-PCR and Western blot.Results Compared with group C,apoptosis rate was significantly decreased and the expression of p-CREB was up-regulated in D1.3 groups.Conclusion Dexmedetomidine inhibits apoptosis in isolated hippocampal neurons of fetal rats by up-regulating the expression of p-CREB.
ABSTRACT
Objective To evaluate the effects of dexmedetomidine on the activity of cAMP response element binding protein (CREB) and c-fos in the spinal dorsal horn in a rat model of neuropathic pain.Methods Fifty-four adult male Wistar rats,aged 6-8 weeks,weighing 180-220 g,were randomly divided into 3 groups (n =18 each):sham operation group (group S),chronic neuropathic pain group (group C) and dexmedetomidine group (group D).The animals were anesthetized with intraperitoneal 10％ chloral hydrate 350 mg/kg.The sciatic nerve was exposed and 4 ligatures were placed on the right sciatic nerve at 1 mm intervals with 4-0 silk thread in C and D groups.In group D,dexmedetomidine 50 μg/kg was injected intraperitoneally once a day starting from the end of operation until 1 day before the animals were sacrificed,while the equal volme of normal saline was injected instead of dexmedetomidine in S and C groups.Paw withdrawal threshold to mechanical stimulation with yon Frey filament (MWT) and paw withdrawal latency to thermal stimulation (TWL) were measured on 1 day before operation and 3,7 and 14 days after operation.The animals were sacrificed after measurement of MWT and TWL.Their lumbar segments (L4-6) of the spinal cord were removed for measurement of the expression of phosphorylated CREB (pCREB) and c-fos by immunohistochemistry.Results Compared with group S,MWT was significantly decreased,TWL was shortened,and the expression of pCREB and c-fos was up-regulated on 3,7 and 14 days after operation in C and D groups (P ＜ 0.05).Compared with group C,MWT was significantly increased,TWL was prolonged,and the expression of pCREB and c-fos was down-regulated on 3,7 and 14 days after operation in group D (P ＜ 0.05).MWT was significantly lower,and TWL was shorter on 3,7 and 14 days after operation than on 1 day before operation in C and D groups (P ＜ 0.05).MWT was significantly lower,TWL was shorter,and the expression of pCREB and c-fos was higher on 7 and 14 days after operation than on 3 days after operation in C and D groups (P ＜ 0.05).MWT was significantly higher,TWL was longer,and the expression of pCREB and c-fos was lower on 14 days after operation than on 7 days after operation in C and D groups (P ＜ 0.05).Conclusion The mechanism by which dexmedetomidine reduces neuropathic pain is related to inhibition of the activity of CREB and c-fos in the spinal dorsal horn of rats.