尼莫地平抑制缺血再灌注后成年大鼠脑内神经发生

目的：观察尼莫地平（Nimodipine）对大鼠脑缺血再灌注后海马齿状回神经发生的影响并探讨其相关机制。方法：采用四动脉阻断法诱导大鼠全脑缺血,缺血20min前腹腔内注射尼莫地平或脑室内注射细胞外信号调节激酶（extracellular signal-regulated kinase,ERK）的抑制剂U0126;免疫组化Brdu标记法检测脑内海马神经发生;Western Blot法检测海马组织ERK、磷酸化ERK（p-ERK）蛋白的表达。结果：尼莫地平抑制脑缺血再灌注后海马部位的神经发生的同时也抑制了脑缺血再灌注后海马齿状回p-ERK的表达;海马部位神经发生在U0126组与U0126＋尼莫地平联合给药组差异无统计学意义。结论：尼莫地平显著抑制脑缺血再灌注后海马齿状回的神经发生,其机制与下调p—ERK表达密切相关。     

苦参碱对人横纹肌肉瘤RD细胞MAPK/ERK信号通路的影响

目的探讨苦参碱对人横纹肌肉瘤（RMS）RD细胞ERK通路的影响。方法取对数生长期的细胞,随机分为对照组（含细胞无药物）及3个药物干预组（分别为U0126 10μmol组、苦参碱1.0 mg/mL组和U0126 10μmol与苦参碱1.0 mg/mL共同作用组）。蛋白质印迹法（Western blotting）检测p44/p42MAPK（ERK1/2）及Phospho-p44/p42MAPK（p-ERK1/2）的表达;反转录聚合酶链反应（RT-PCR）方法检测erk m RNA的表达。最后采用SPSS 16.0统计软件进行单因素方差分析。结果 Western blotting法检测ERK1/2、p-ERK1/2的表达,对照组（U0126 10μmol组,苦参碱1.0 mg/mL组及U0126 10μmol与苦参碱1.0 mg/mL共同作用组）的灰度值分别为：2.84±0.03、2.64±0.03、2.14±0.01、2.10±0.02及1.76±0.15、1.37±0.19、1.21±0.24、1.19±0.22。与对照组比较,苦参碱1.0 mg/mL组及苦参碱与U0126共同作用组对ERK1/2、p-ERK1/2蛋白表达量明显降低,差异均有统计学意义（P〈0.01）;RT-PCR方法检测erk m RNA的表达,对照组（U0126 10μmol组,苦参碱1.0 mg/mL组及U0126 10μmol与苦参碱1.0 mg/mL共同作用组）的灰度比值分别为0.59±0.04、0.57±0.04、0.25±0.02和0.18±0.01,苦参碱1.0 mg/mL组及苦参碱与U0126共同作用组erk m RNA的表达量较对照组明显降低,差异均有统计学意义（P〈0.01）。结论苦参碱在体外环境下作用RMS-RD细胞,可抑制erk m RNA的表达及ERK1/2蛋白磷酸化的活性。     

栀子苷通过抑制VPO1/ERK1/2信号通路减轻糖尿病心肌病大鼠的心肌细胞凋亡

目的:探讨栀子苷(geniposide,GE)改善大鼠糖尿病心肌病的作用及其具体机制。方法:24只成年雄性SD大鼠,随机分为3组:正常组(Control组,8只)、糖尿病心肌病组(DCM组,8只)、糖尿病心肌病组+栀子苷组(DCM+GE组,8只),采用高脂饲料联合链脲佐菌素(STZ)构建糖尿病心肌病大鼠模型,应用次氯酸(HOCl)诱导H9C2损伤模型。干预12周后,HE和Masson染色观察心脏组织病理学改变;TUNEL法检测大鼠心肌细胞凋亡水平;免疫组化检测及Western blot检测法检测VPO1/ERK1/2信号通路及凋亡相关蛋白表达水平。给予次氯酸刺激心肌细胞后,Western blot检测法检测ERK1/2、p-ERK1/2、Bcl-2、Bax蛋白表达水平的改变。给予ERK1/2酶抑制剂U0126后,用Western blot检测法再次检测ERK1/2、p-ERK1/2、Bcl-2、Bax蛋白表达水平的改变。结果:HE及Masson染色显示,与Control组相比,DCM组出现心肌纤维排列紊乱、心肌胶原含量明显增多,而DCM+GE组心肌损伤情况明显改善(P<0.05)。与Control组相比,DCM组心肌细胞凋亡水平及Bax/Bcl-2比值明显增加,而DCM+GE组心肌凋亡情况得到明显好转(P<0.05)。免疫组化和Western blot结果显示,在DCM组中VPO1、p-ERK1/2蛋白表达水平升高,而DCM+GE组中VPO1、p-ERK1/2蛋白表达水平得到了抑制(P<0.05)。进一步对H9C2细胞行HOCl干预发现,与Control组相比,次氯酸组出现p-ERK1/2蛋白表达水平及Bax/Bcl-2比值增加,而加入ERK1/2酶抑制剂U0126后p-ERK1/2蛋白表达水平及Bax/Bcl-2比值下降(P<0.05)。结论:栀子苷通过抑制VPO1/ERK1/2信号通路抑制心肌细胞凋亡从而改善糖尿病引起的心肌损伤。     

ERK1/2在胶质瘤中的表达及意义

目的 探讨细胞外信号调节激酶1/2(ERK1/2)在人脑胶质瘤中的表达及其与胶质瘤的发生发展的关系.方法 收集具有明确病理分级的胶质瘤标本48例,WHO I～Ⅱ级15例,Ⅲ级21例,Ⅳ级12例;另取8例正常脑组织作正常对照.用免疫组织化学染色检测ERK1/2和磷酸化ERK1/2(p-ERK1/2)表达水平.结果 在胶质瘤组织中,ERK1/2和p-ERK1/2表达均增高,且与胶质瘤恶性程度呈正相关;在Ⅲ、Ⅳ级胶质瘤中,ERK1/2和p-ERK1/2表达水平显著强于I、Ⅱ级胶质瘤.结论 ERK1/2在胶质瘤组织中表达水平与胶质瘤的恶性程度有关.     

比索洛尔预处理通过调控ERK1/2途径抑制缺氧/复氧诱导的心肌细胞凋亡和纤维化

目的 探讨比索洛尔预处理对缺氧/复氧诱导的心肌细胞凋亡和纤维化的影响,并分析分子机制。方法 构建缺氧/复氧细胞模型,将H9c2细胞分为对照组、模型组、比索洛尔组、细胞外信号调节激酶（ERK1/2）通路激活剂（LM22B-10）组。采用酶联免疫吸附测定法（ELISA）检测细胞中乳酸脱氢酶（LDH）和肌酸激酶同工酶（CK-MB）水平,CCK-8法检测细胞活力,流式细胞术检测细胞凋亡水平,免疫印迹法（Western blotting）法检测凋亡蛋白、纤维化蛋白和ERK1/2信号通路蛋白表达。结果 与模型组比较,比索洛尔组H9c2细胞中LDH和CK-MB水平、细胞凋亡率,切割型半胱氨酸天冬氨酸蛋白水解酶-3（cleaved Caspase-3）、B淋巴细胞瘤-2相关蛋白（Bax）、I型胶原（Col I）、III型胶原（Col III）、α-平滑肌肌动蛋白（α-SMA）、基质金属蛋白酶9（MMP-9）蛋白表达以及磷酸化细胞外信号调节激酶1/2（p-ERK1/2）/（ERK1/2）比值显著降低;细胞活力,B淋巴细胞瘤2（Bcl2）、金属蛋白酶组织抑制因子1（TIMP-1）蛋白表达显著升高（P<0.05）。与比索洛尔组比较,LM22B-10组H9c2细胞中LDH和CK-MB水平、细胞凋亡率,Cleaved Caspase-3、Bax、Col I、Col III、α-SMA、MMP-9蛋白表达以及（p-ERK1/2）/（ERK1/2）比值均显著升高,细胞活力,Bcl-2、TIMP-1蛋白表达均显著降低（P<0.05）。结论 比索洛尔预处理通过抑制ERK1/2信号通路活化减轻缺氧/复氧诱导的心肌细胞凋亡和纤维化。     

二甲双胍对高糖诱导的肾小管上皮细胞TGF-β/ERK/MMP-9通路及上皮间质转化的影响

目的探讨二甲双胍对高糖诱导的肾小管上皮HK-2细胞上皮间质转化(EMT)的影响及其机制。方法以0、7.5、15.0、30.0、60.0、120.0mmol/L二甲双胍作用48h后,采用噻唑蓝(MTT)法检测HK-2细胞活力以筛选合适的二甲双胍作用浓度;将体外培养的HK-2细胞分为对照组(5.5 mmol/L D-葡萄糖)、高渗组(24.5 mmol/L甘露醇和5.5 mmol/L D-葡萄糖)、高糖组(30 mmol/L D-葡萄糖)、高糖+7.5 mmol/L二甲双胍组(30 mmol/L D-葡萄糖+7.5 mmol/L二甲双胍)和高糖+15 mmol/L二甲双胍组(30 mmol/L D-葡萄糖+15 mmol/L二甲双胍),倒置显微镜观察各组HK-2细胞形态,免疫印迹法(Western blotting)检测各组HK-2细胞中α-平滑肌肌动蛋白(α-SMA)、E-钙黏附蛋白(E-cadherin)、转化生长因子-β(TGF-β)、细胞外信号调节激酶(ERK)、磷酸化(p)-ERK、基质金属蛋白酶9(MMP-9)蛋白表达水平,实时荧光定量PCR(qRT-PCR)检测α-SMA、E-cadherin、TGF-β、ERK、MMP-9 mRNA表达水平。结果与对照组相比,30.0、60.0mmol/L二甲双胍作用后HK-2细胞活力明显升高,120.0mmol/L二甲双胍作用后HK-2细胞活力明显降低(P0.05),而7.5、15.0mmol/L二甲双胍作用后HK-2细胞活力差异无统计学意义(P0.05);与对照组比较,高渗组细胞形态无明显改变,且细胞中α-SMA、E-cadherin、TGF-β、MMP-9蛋白和mRNA表达水平以及p-ERK/ERK蛋白、ERK mRNA表达水平差异均无统计学意义(P0.05),但高糖组细胞失去原有形态变为长梭形,且细胞中α-SMA、TGF-β蛋白和mRNA表达水平以及p-ERK/ERK蛋白、ERK mRNA表达水平明显升高,而MMP-9、E-cadherin蛋白和mRNA表达水平明显降低(P0.05);与高糖组比较,高糖+7.5mmol/L二甲双胍组、高糖+15.0mmol/L二甲双胍组细胞形态由长梭形逐渐变成圆形或椭圆形,且α-SMA、TGF-β蛋白和mRNA表达水平以及p-ERK/ERK蛋白、ERK mRNA表达水平明显降低,而MMP-9、E-cadherin蛋白和mRNA表达水平明显升高(P0.05),且高糖+15.0 mmol/L二甲双胍组细胞上述指标变化幅度大于高糖+7.5 mmol/L二甲双胍组。结论二甲双胍可抑制高糖诱导的肾小管上皮HK-2细胞EMT,其作用机制可能与抑制TGF-β/ERK/MMP-9通路活化有关。     

活性氧激活的ERK1/2通路在化学性缺氧损伤PC12细胞中的作用

目的探讨胞外信号调节激酶1/2(ERK1/2)在化学性缺氧损伤PC12细胞中的作用。方法应用化学性低氧模拟剂氯化钴(CoCl2)处理PC12细胞建立化学性缺氧损伤模型。应用细胞计数试剂盒-8(cell counting kit-8,CCK-8)比色法检测细胞存活率;罗丹明123(Rh123)染色荧光显微镜照像检测线粒体膜电位(MMP);流式细胞术检测凋亡细胞百分比;Western blot法测定caspase-3、ERK1/2和p38MAPK蛋白的表达水平。结果应用600μmol.L-1处理PC12细胞60 min可使磷酸化(p)ERK1/2的表达明显升高;在600μmol.L-1CoCl2处理PC12细胞前,应用500μmol.L-1N-乙酰半胱氨酸(NAC,为活性氧的清除剂)预处理1 h可抑制CoCl2对p-ERK1/2表达的上调作用;在600μmol.L-1CoCl2处理PC12细胞前,应用10μmol.L-1U0126(ERK1/2抑制剂)预处理2 h可保护PC12细胞对抗CoCl2引起的损伤,使细胞存活率升高,凋亡细胞数目和cleaved caspase-3表达及线粒体膜电位(MMP)丢失均减少;10μmol.L-1U0126预处理还能抑制CoCl2对p-p38MAPK表达的上调作用。此外,应用20μmol.L-1SB203580(p38MAPK抑制剂)预处理能抑制CoCl2对p-ERK1/2表达的上调作用。结论活性氧激活的ERK1/2通路介导CoCl2对PC12细胞的损伤作用,并与p38MAPK通路存在相互的的激活作用。     

ERK1/2通路在4-AP诱导大鼠肺动脉收缩中的作用

目的探讨细胞外信号调节激酶-1/2(ERK1/2)通路在4-氨基吡啶(4-aminopyridione,4-AP)阻断正常大鼠肺动脉平滑肌细胞(PASMCs)膜上电压依赖性钾通道(KV)所引起的肺动脉收缩中的作用。方法取正常鼠肺动脉制作肺动脉环,分别加入4-AP(KV通道阻断剂),PD98059/U0126+4-AP,比较肺动脉收缩的变化。同时培养肺动脉平滑肌细胞进行Western blot分析4-AP对ERK1/2的影响。结果①在血管环试验中,4-AP引起的肺动脉收缩有浓度依赖性;加入20mmol.L-1PD98059或2μmol.L-1U0126可以抑制4-AP引起的肺动脉收缩。②4-AP可刺激PASMCs ERK1/2蛋白磷酸化;③U0126可抑制4-AP引起的ERK1/2蛋白磷酸化。结论ERK1/2通路参与4-AP阻断正常大鼠肺动脉平滑肌细胞膜上电压依赖性钾通道(KV)引起肺动脉收缩。     

黄腐醇诱导胃癌细胞焦亡的作用机制

目的 探讨黄腐醇对人胃癌细胞系SGC-7901焦亡的作用及其可能机制。方法 用DMSO(对照组)和不同浓度黄腐醇10、20和40μmol/L处理SGC-7901细胞,采用细胞集落实验检测细胞集落形成,细胞划痕实验观察细胞迁移,流式细胞术检测细胞内活性氧(ROS)水平,Western blot法检测加斯德明E-N端(GSDME-N)和Caspase-3蛋白表达。采用ROS清除剂N-乙酰-L-半胱氨酸(NAC)5 mmol/L、细胞外信号调节激酶(ERK)抑制剂U0126 10μmol/L或p38抑制剂达马莫德(BIRB)10μmol/L预处理SGC-7901细胞后再加入黄腐醇40μmol/L,采用Western blot法检测GSDME-N蛋白表达,倒置显微镜下观察细胞焦亡的形态学变化。结果 与对照组相比,黄腐醇呈浓度依赖性地抑制SGC-7901细胞集落形成、细胞迁移和Caspase-3蛋白表达,上调ROS水平和GSDME-N蛋白表达(P<0.05);而用NAC、U0126或BIRB预处理后,GSDME-N蛋白表达降低,细胞焦亡数目减少(P<0.05)。结论 黄腐醇可能通过升...     

新藤黄酸诱导人鼻咽癌细胞CNE-1凋亡以及对p-p38和p-ERK1/2蛋白的影响

目的探讨新藤黄酸对人鼻咽癌细胞CNE-1凋亡的作用以及对磷酸化p38、p-ERK1/2蛋白的影响。方法倒置显微镜观察新藤黄酸不同时间和不同浓度处理CNE-1细胞形态变化;采用四甲基偶氮唑蓝(MTT)比色法检测不同浓度新藤黄酸(0.25、0.5、1.0、2.0、4.0和8.0μmol.L-1)处理24 h、48 h和72 h对人鼻咽癌细胞CNE-1增殖的抑制作用;新藤黄酸作用CNE-1细胞24 h后的IC50为2.34μmol.L-1,再结合倒置显微镜观察的结果故选用2.0μmol.L-1作为药物作用浓度。Annexin V-FITC/PI双染流式细胞仪检测细胞凋亡率,并应用透射电子显微镜检测细胞凋亡形态改变及线粒体损伤;Western blot检测p-p38、p38、ERK1/2和p-ERK1/2蛋白和线粒体凋亡相关蛋白Cytochrome C和Caspase-3蛋白的表达。结果新藤黄酸对人鼻咽癌细胞CNE-1生长和增殖有抑制作用,并随着新藤黄酸浓度的增加或作用时间的延长细胞活力明显下降。通过电镜可见2.0μmol.L-1新藤黄酸作用CNE-1细胞后细胞体积皱缩变圆,细胞核发生典型核染色质固缩等细胞凋亡形态学的变化;与control组相比包括对线粒体的损伤。Western blot表明p-p38蛋白表达有所上调,特别是在短时间(120 min)内,p-ERK1/2蛋白表达呈现时间依赖性下降;而p38和ERK1/2表达则基本不变。Cytochrome C和Caspase-3蛋白表达也呈现时间依赖性增加。结论新藤黄酸能诱导人鼻咽癌细胞CNE-1凋亡,增强Cytochrome C和Caspase-3蛋白表达,同时对p-p38和p-ERK1/2蛋白也有影响。     

Glutamate-mediated spinal reflex potentiation involves ERK 1/2 phosphorylation in anesthetized rats

The extracellular signal-regulated kinase (ERK) cascades are suggested to contribute to excitatory plasticity in the CNS, including the spinal cord. This study investigated whether the ERK involves in the repetitive stimulation-induced spinal reflex potentiation (SRP) in the pelvic nerve-to-external urethra sphincter reflex activities. External urethra sphincter electromyogram in response to pelvic afferent nerve test stimulation (TS, 1/30 Hz) or repetitive stimulation (RS, 1 Hz) was recorded in anesthetized rats. TS evoked a baseline reflex activity, whereas RS produced SRP in associated with significant ERK 1/2 phosphorylation. RS-induced SRP and ERK 1/2 phosphorylation were both abolished by pretreatment of U0126 (MEK inhibitor). Intrathecal CNQX (AMPA receptor antagonist) attenuated, while AP5 (NMDA receptor antagonist) abolished the RS-induced SRP and ERK 1/2 phosphorylation. Pretreated U0126 abolished the SRP elicited by glutamatergic agonists including glutamate, NMDA and AMPA. Intrathecal H89 and BIS7 (PKA and PKC inhibitors, respectively) both abolished the RS- and glutamate agonist-induced SRP as well as ERK 1/2 phosphorylation. In addition, forskolin and PMA (PKA and PKC activator, respectively) induced SRP, which were both abolished by pretreated U0126. Saline distension, mimicking the storage phase of the urinary bladder, induced SRP and ERK 1/2 phosphorylation. In conclusion, activated ERK 1/2 may produce SRP in the pelvic nerve-to-external urethra sphincter reflex activity, which is essential for urine continence. In addition, blockage of spinal ERK 1/2 activation decreases the physiological function of the urethra, indicating that phosphorylation of the ERK 1/2 cascade may represent a novel target for the treatment of patients with neurological incontinence of spinal origin.     

Activation of ERK2 in basolateral amygdala underlies the promoting influence of stress on fear memory and anxiety: Influence of midazolam pretreatment

Exposure to emotionally arousing experiences elicits a robust and persistent memory and enhances anxiety. The amygdala complex plays a key role in stress-induced emotional processing and in the fear memory formation. It is well known that ERK activation in the amygdala is a prerequisite for fear memory consolidation. Moreover, stress elevates p-ERK2 levels in several areas of the brain stress circuitry. Therefore, given that the ERK1/2 cascade is activated following stress and that the role of this cascade is critical in the formation of fear memory, the present study investigated the potential involvement of p-ERK2 in amygdala subnuclei in the promoting influence of stress on fear memory formation and on anxiety-like behavior. A robust and persistent ERK2 activation was noted in the Basolateral amygdala (BLA), which was evident at 5 min after restraint and lasted at least one day after the stressful experience. Midazolam, a short-acting benzodiazepine ligand, administered prior to stress prevented the increase in the p-ERK2 level in the BLA. Pretreatment with intra-BLA infusion of U0126 (MEK inhibitor), but not into the adjacent central nucleus of the amygdala, attenuated the stress-induced promoting influence on fear memory formation. Finally, U0126 intra-BLA infusion prevented the enhancement of anxiety-like behavior in stressed animals. These findings suggest that the selective ERK2 activation in BLA following stress exposure is an important mechanism for the occurrence of the promoting influence of stress on fear memory and on anxiety-like behavior.     

Analgesic effect of paeoniflorin in rats with neonatal maternal separation-induced visceral hyperalgesia is mediated through adenosine A1 receptor by inhibiting the extracellular signal-regulated protein kinase (ERK) pathway

Paeoniflorin (PF), a chief active ingredient in the root of Paeonia lactiflora Pall (family Ranunculaceae), is effective in relieving colorectal distention (CRD)-induced visceral pain in rats with visceral hyperalgesia induced by neonatal maternal separation (NMS). This study aimed at exploring the underlying mechanisms of PF's analgesic effect on CRD-evoked nociceptive signaling in the central nervous system (CNS) and investigating whether the adenosine A₁ receptor is involved in PF's anti-nociception. Results: CRD-induced visceral pain as well as phosphorylated-extracellular signal-regulated protein kinase (p-ERK) and phospho-cAMP response element-binding protein (p-CREB) expression in the CNS structures of NMS rats were suppressed by NMDA receptor antagonist dizocilpine (MK-801) and ERK phosphorylation inhibitor U0126. PF could similarly inhibit CRD-evoked p-ERK and c-Fos expression in laminae I-II of the lumbosacral dorsal horn and anterior cingulate cortex (ACC). PF could also reverse the CRD-evoked increased glutamate concentration by CRD as shown by dynamic microdialysis monitoring in ACC, whereas, DPCPX, an antagonist of adenosine A₁ receptor, significantly blocked the analgesic effect of PF and PF's inhibition on CRD-induced p-ERK and p-CREB expression. These results suggest that PF's analgesic effect is possibly mediated by adenosine A₁ receptor by inhibiting CRD-evoked glutamate release and the NMDA receptor dependent ERK signaling.     

右美托咪啶通过ERK1/2 MAPK信号通路缓解七氟醚神经毒性

目的研究右美托咪啶对中枢神经系统发育期七氟醚神经毒性的影响,以及ERK1／2MAPK信号通路在其中所起的作用。方法对离体培养7d的海马神经细胞及出生后7d的Sprague-Dawley幼鼠进行七氟醚处理（3％,6h）,制备七氟醚神经毒性模型。分别给予右美托咪啶或右美托咪啶＋U0126处理后,应用流式细胞仪及TUNEL染色检测细胞凋亡;应用免疫印迹检测total ERK1／2、Phospho-ERK1／2、Bax及Bcl-2的蛋白表达水平;应用Morris水迷宫检测实验动物的空间学习记忆功能变化。结果3％七氟醚处理6h使海马神经细胞凋亡增加（P=0．007）,应用右美托咪啶则可明显缓解七氟醚神经毒性（P=0．032）。七氟醚处理可降低Phospho-ERK1／2及Bcl-2的蛋白表达（P〈0．05）,增加Bax的蛋白表达（P〈0．05）;右美托咪啶可增加Phospho-ERK11／2及Bcl-2表达（P〈0．05）,降低Bax表达水平（P〈0．05）。右美托咪啶的神经保护作用可被U0126所逆转。此外,右美托咪啶还明显缓解发育期七氟醚处理引起的空间学习记忆功能异常。结论右美托咪啶可缓解七氟醚神经毒性,其机制可能与ERK1／2MAPK信号通路有关。     

PTK,ERK and p38 MAPK contribute to impaired NMDA-induced vasodilation after brain injury

N-Methyl-D-aspartate (NMDA)-induced pial artery dilation is reversed to vasoconstriction following fluid percussion brain injury (FPI). This study investigated the contribution of activation of protein tyrosine kinase (PTK) and the extracellular signal-regulated kinase (ERK) and p38 isoforms of mitogen-activated protein kinase (MAPK) in impaired vasodilation to NMDA after fluid percussion brain injury in pigs equipped with a closed cranial window. NMDA (10(-8), 10(-6) M)-induced vasodilation was reversed to vasoconstriction following fluid percussion brain injury, but such responses were partially restored by genistein (4',5,7-trihydroxy isoflavone), U0126 [1,4-diamino-2,3-dicyano-1,4-bis (0-aminophenylmercapto)butadiene] and SB203580 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)-1H-imidazole], PTK, ERK and p38 MAPK inhibitors (9+/-1% and 16+/-1%, sham control; -6+/-2% and -11+/-3%, fluid percussion brain injury; and 3+/-1% and 6+/-1%, fluid percussion brain injury-genistein, respectively). However, the robustness of the protection to NMDA dilation was significantly greater for U0126 vs. SB203580 (4+/-1% and 7+/-1% vs. 1+/-1% and 1+/-2%). Similar results were observed for glutamate. These data show that PTK, ERK and p38 MAPK activation contribute to impaired NMDA cerebrovasodilation after fluid percussion brain injury. These data suggest that activation of the ERK isoform of MAPK contributes to such impairment more than the p38 MAPK isoform.     

Erk activation in the amygdala and hippocampus induced by fear conditioning in ethanol withdrawn rats: Modulation by mk-801

The extracellular signal-regulated kinase (ERK) pathway, which can be activated by NMDA receptor stimulation, is involved in fear conditioning and drug addiction. We have previously shown that withdrawal from chronic ethanol administration facilitated the formation of contextual fear memory. In order to explore the neural substrates and the potential mechanism involved in this effect, we examined: 1) the ERK1/2 activation in the central (CeA) and basolateral (BLA) nuclei of the amygdala and in the dorsal hippocampus (dHip), 2) the effect of the NMDA receptor antagonist MK-801 on fear conditioning and ERK activation and 3) the effect of the infusion of U0126, a MEK inhibitor, into the BLA on fear memory formation in ethanol withdrawn rats.Rats made dependent via an ethanol-containing liquid diet were subjected to contextual fear conditioning on day 3 of ethanol withdrawal. High basal levels of p-ERK were found in CeA and dHip from ethanol withdrawn rats. ERK activation was significantly increased both in control (60 min) and ethanol withdrawn rats (30 and 60 min) in BLA after fear conditioning. Pre-training administration of MK-801, at a dose that had no effect on control rats, prevented the increase in ERK phosphorylation in BLA and attenuated the freezing response 24 h later in ethanol withdrawn rats. Furthermore, the infusion of U0126 into the BLA, but not the CeA, before fear conditioning disrupted fear memory formation. These results suggest that the increased fear memory can be linked to changes in ERK phosphorylation, probably due to NMDA receptor activation in BLA in ethanol withdrawn rats.