黄芩苷抗癫痫作用及对神经肽Y受体Y1在海马区表达的影响

目的:观察黄芩苷对癫痫模型行为学及海马区神经肽Y受体Y1 (NPY Y1R)表达的影响.方法:将40只成功建立癫痫模型的SD大鼠随机分为模型组、丙戊酸钠(15 mg·kg-1)组、低剂量黄芩苷(50 mg·kg-1)组和高剂量黄芩苷(100 mg·kg-1)组,另设一正常组,每组10只.治疗观察4周,记录大鼠发作潜伏期...     

左乙拉西坦对海人酸致痫大鼠血清NSE和MBP变化的影响

目的:建立海人酸(KA)致痫大鼠模型并观察癫痫大鼠血清神经元特异性烯醇酶(NSE)和髓鞘碱性蛋白(MBP)的变化及左乙拉西坦(LEV)对其水平的影响,以探讨左乙拉西坦在癫痫脑损伤中是否具有保护的作用。方法:清结级Wistar雄性4~5周龄幼鼠72只,随机分为对照组24只,立体定向右侧海马注射生理盐水,KA组24只,注射海人酸,LEV治疗组24只,注射KA造模成功前12h胃管内注入LEV200mg/kg,以后未处死大鼠均每日给药一次。分别于致痫后6h、24h、72h处死,采用ELISA法检测各组大鼠血清NSE和MBP含量。结果:(1)大鼠癫痫行为;对照组无大鼠癫痫发作,其余组均有行为学改变。LEV组幼鼠癫痫发作程度与KA组类似,但潜伏期较KA组延长。(2)血清NSE变化:KA组和LEV组血清NSE于在致痫后6h升高,24h达高峰,与对照组相比有差异(P<0.05),LEV组与KA组的NSE比较无显著差异(P>0.05)。(3)MBP变化:KA组和LEV组血清MBP于致痫后6h升高,72h达高峰,与对照组相比差异有统计学意义(P<0.05),LEV组与KA组的MBP比较无显著差异(P>0.05)。结论:KA致痫大鼠血清NSE、MBP水平显著增高,提示癫痫发作可造成一过性脑损伤,血清NSE、MBP可能作为判断癫痫脑损伤程度的敏感指标,LEV对KA致痫大鼠血清NSE、MBP水平无影响,提示LEV不能减轻亦不加重癫痫发作引起的脑损伤。     

脑源性神经营养因子对戊四氮致癫痫大鼠海马神经肽Y表达的影响

目的 研究侧脑室内注入脑源性神经营养因子(BDNF)对戊四氮(PTZ)致癫痫大鼠海马区神经肽Y(NPY)表达的影响.方法 采用PTZ制备大鼠癫痫模型.立体定向自侧脑室注入BDNF.免疫组化观察NPY在海马CA1 区的表达,放射免疫测定海马,皮层,下丘脑组织NPY匀浆浓度.结果 免疫组化显示点燃模型组阳性反应神经元增多,BDNF干预组阳性反应神经元明显增多.点燃模型组海马组织匀浆NPY的放射免疫测定浓度增高 (P＜0.05);BDNF干预组海马组织匀浆NPY的放射免疫浓度明显高于点燃模型组(P＜0.05).结论 NPY参与了癫痫的发病过程,BDNF可以增加脑组织NPY浓度.     

托吡酯对海人酸致痫大鼠海马组织P-糖蛋白和核转录因子表达的影响

目的:探讨p-糖蛋白(P-gp)和核转录因子(NF-κB)与难治性癫痫耐药机制的关系及托吡酯(TPM)对其表达的影响.方法:84只Wistar大鼠随机分成对照组24只;海人酸组(KA组)30只;TPM治疗组30只.应用KA前每天给TPM治疗组大鼠灌胃一次,至第14d灌胃后2h注射KA.分别于注射KA后6h、24h、3d...     

海人酸致痫大鼠中多药耐药相关蛋白1和主穹窿蛋白的表达及作用

目的:探讨多药耐药相关蛋白1(MRP1)和主穹窿蛋白(MVP)在难治性癫痫中的耐药机制.方法:用免疫组化法检测海人酸(KA)致痫大鼠海马组织中MRP1和MVP的表达,应用SPSS17.0软件进行统计分析.结果:KA组的MRP1和MVP的表达均比对照组明显增高(P<0.01).KA组的MRP1和MVP的表达相似,随时间段...     

拉莫三嗪对海人酸致癫大鼠血清S100β含量的影响

目的：建立海人酸致痫模型,用ELISA法检测致痫大鼠血清S100β含量的变化及拉莫三嗪对其含量的影响。方法：将72只28d龄的Wistar大鼠随机分为3组,生理盐水组24只,KA组24只,LTG组24只,KA组及LTG组大鼠分别在脑立体定位仪下于海马CA3区注射海人酸建立KA模型。LTG组在建立模型前12h进行LTG灌胃治疗2次,各组模型点燃成功后分别于6h、12h、24h、72h于右心室采血,ELISA法测定血清S100β含量值。结果：与生理盐水组比较KA组及LTG组血清S100β含量明显升高（P〈0.05）,但LTG组与KA组比较血清S100β含量无显著变化（P〉0.05）。结论：提示S100β与癫痫发作存在着密切的关系,LTG可能并不是通过降低致痫大鼠血清S100β含量而发挥抗癫痫作用。     

血清铁和铁蛋白水平在海人酸诱导的大鼠癫痫模型中的意义

目的 探讨海人酸(KA)诱导的癫痫大鼠血液中铁和铁蛋白水平的变化。方法 30只SD大鼠通过随机数字表法分为模型组和对照组(每组各15只),模型组采用一次性腹腔注射KA的方式建立癫痫大鼠模型,对照组采用腹腔注射等量生理盐水,分别于给药前1周和给药后2个月取静脉血,应用原子吸收光谱仪来测定血清铁,采用放射性标记酶联免疫分析法测定血清铁蛋白,分别观察两组大鼠血清铁和血清铁蛋白的变化。结果 模型组血清铁、血清铁蛋白含量分别为(3.502±0.475) mg/L、(29.229±1.912) μg/L,均明显高于对照组的(2.408±0.760) mg/L、(23.449±1.711) μg/L(t=1.328、19.169,P=0.018 3、0.026 7)。血清铁、血清铁蛋白与癫痫发作具有较强相关性,相关系数分别为0.633、0.732(P值分别为 0.035 0、0.013 9)。结论 KA诱导的大鼠癫痫模型血液中铁和铁蛋白水平升高,可能与海人酸诱导的癫痫发作有关。     

海马内非NMDA及GABA-A受体在青霉素致痫及电针抗痫中的作用

研究６，７ｄｉｎｉｔｒｏｑｕｉｎｏｘａｌｉｎｅ２，３ｄｉｏｎｅ（ＤＮＱＸ）和荷包牡丹碱（Ｂｉｃ）在青霉素致痫及电针抗痫中的作用．方法：Ｗｉｓｔａｒ大鼠（ｎ＝５３）海马内微量注入青霉素１μＬ（０２４μｇ），以脑电记录及其功率谱分析作为癫痫发作的指标．结果：电针和ｎｏｎＮｍｅｔｈｙｌＤａｓｐａｒｔａｔｅ（非ＮＭＤＡ）受体竞争性拮抗剂ＤＮＱＸ能部分抑制癫痫发作，电针和ＤＮＱＸ１μｇ合用时能加强对癫痫的抑制；而Ｂｉｃ可使电针对癫痫的抑制减弱．结论：海马内ＧＡＢＡＡ受体拮抗剂能部分翻转电针的抗痫作用，而电针和非ＮＭＤＡ受体拮抗剂有协同抗痫作用．     

海人酸致痫大鼠血清S100β与IL10的含量及左乙拉西坦对其含量的影响

目的:建立大鼠海人酸致痫模型,检测大鼠血清中S100β和白细胞介素(i-nterleukin,IL)-10的含量,以探讨LEV与神经保护之间的关系。方法:将96只28d龄Wistar大鼠随机分为正常对照组32只、KA组32只、左乙拉西坦(leve-tiracetamLEV)治疗组(LEV组)32只。在立体定位仪的精确定位下向右侧海马CA3区注射海人酸点燃大鼠,并观察癫痫行为分级,治疗组在KA注射前12h给予左乙拉西坦200mg/kg灌胃治疗每日一次,并分别于6h,12h,24h,72h处死各组大鼠,以免疫酶联吸附反应方法检测各组大鼠血清S100β和IL-10的含量。结果:①KA组与LEV组在KA注射后1～2h内出现痫性发作。②KA组与LEV组血清S100β含量与对照组比较,6h无明显变化(P>0.05),12h开始升高(P<0.05),24h达高峰(P<0.01),72h接近正常(P>0.05)。LEV组与KA组比较血清S100β含量在各时间点无显著差异(P>0.05)。③KA组与LEV组血清IL-10含量比较,6h开始升高(P>0.05),12h达高峰(P<0.01),24h开始下降(P<0.05),72h接近正常(P>0.05)。LEV组与KA组比较血清IL-10含量在各时间点无显著差异(P>0.05)。结论:KA致痫大鼠血清中S100β含量显著增高,其升高可能与癫痫所致的脑损伤有关,血清IL-10含量显著增高,提示IL-10与癫痫的病理生理之间存在着密切的关系,LEV对癫痫大鼠血清中S100β和IL-10的含量无影响,提示LEV不会导致脑损伤但亦不能减轻癫痫所致的脑损伤程度。     

Binding properties of three neuropeptide Y receptor subtypes from zebrafish: comparison with mammalian Y1 receptors

Neuropeptide Y (NPY) and peptide YY (PYY) are two related 36-amino-acid peptides found in all vertebrates and are involved in many physiological processes. Five receptor subtypes have been cloned in mammals (Y1, Y2, Y4, Y5, and y6). We have recently cloned three NPY/PYY receptor subtypes in zebrafish, called Ya, Yb, and Yc. Here we report on a direct comparison of the pharmacological properties of these three receptors in vitro using porcine NPY with alanine substitutions in positions 33–36 as ligands and three analogues with internal deletions: [Ahx^8–20]NPY, [Ahx^8–20, Pro³⁴]NPY, and [Ahx^5–24]NPY. In all cases, the zYc receptor was the most sensitive to the modifications of the NPY molecule and zYa was the least sensitive (except for the Arg → Ala replacement at position 33). Our data identified zYa as a receptor that can bind ligands specific for Y1, Y2, and Y4 receptors, while zYb and zYc were more Y1-like. All peptides with internal deletions bound to the zYa receptor with affinities similar to that of intact pNPY. Neither the Y1-selective antagonists BIBP3226 and SR120819A nor the Y2-selective BIIE0246 bound to any of the zebrafish receptors, although the amino acids identified as important for BIBP3226 binding were almost completely conserved. These results may prove helpful in molecular modeling of the three-dimensional receptor structure.     

环丙沙星、氧氟沙星及左氧氟沙星对大鼠致痫作用的研究

目的　观察氧氟沙星 (OFL X)和左氧氟沙星 (L VL X)对大鼠中枢神经的毒性与环丙沙星 (CPL X)毒性的差异 ,及抗痫药物对环丙沙星引发的癫痫的阻断作用。方法　 Wistar大鼠 ,随机分为 3组 ,以用药前皮层脑电图 (ECOG)其脑电图功率谱作为自身对照。颈静脉注射药物 10 0 mg/kg,记录给药后 10、2 0、30、6 0、12 0 min时的 ECOG和脑电图 ,及大鼠的行为变化 ,并在癫痫发作后静脉注射抗痫药物 ,阻断癫痫发作。结果　CPL X组大鼠中 7只 ECOG出现棘波和慢棘波 ,其中 5只大鼠 ECOG出现频发棘波 ,频发棘波能被地西泮迅速阻断。用药后 10 min脑电功率谱 δ波功率和总功率较用药前明显降低 (P<0 .0 5 ) ,之后又逐渐升高。用药后θ、α、β波功率逐渐升高 ,12 0 min时明显高于给药前 (P<0 .0 5 ) ;OFL X、L VL X组大鼠 ECOG均无异常改变 ,脑电功率谱δ、θ、α、β波功率及总功率与用药前比较均无显著性差异 (P<0 .0 5 )。但 L VL X组的 ECOG,脑电功率谱δ、θ、α、β波功率及总功率均较 OFL X组变化小。结论　 CPL X对大鼠有明显的致痫作用 ,OFL X和 L VL X无致痫作用 ,且 L VL X组大鼠 ECOG、脑电功率谱变化最小。地西泮对 CPL X引发的大鼠癫痫有阻断作用。     

Domoic acid induced seizures progress to a chronic state of epilepsy in rats

The emergence of an epilepsy syndrome in sea lions poisoned by domoic acid (DA) draws striking parallels to the single case study of temporal lobe epilepsy (TLE) that developed in an 84 yr old man one year after being poisoned by DA. To establish a basis for understanding this disease in sea lions and humans that appears to progress from DA poisoning, we have investigated the potential for a single incident of DA poisoning in rats to progress to spontaneous recurrent seizures (SRS), the hallmark of epilepsy. We have developed a DA administration protocol to induce a nonlethal status epilepticus (SE) and monitored the animals for SRS by 6 h/week of video recording. We demonstrate that a single episode of SE leads to SRS in 94% of rats (n = 23) in 6 months. These findings indicate that DA induced SE can efficiently translate to epileptic disease.     

Differential increases in brain levels of neuropeptide Y and vasoactive intestinal polypeptide after kainic acid-induced seizures in the rat

Summary Changes in immunoreactivities of neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) were investigated in the brain of rats after severe kainic acid (KA, 10 mg/kg, i.p.) induced limbic seizures. Decreased levels of both neuropeptides were observed in the frontal cortex, striatum, dorsal hippocampus and amygdala/pyriform cortex subsequently to the period of acute seizures (3 h after injection of the toxin). Then NPY increased consistently in the frontal cortex, hippocampus and amygdala/pyriform cortex. Highest levels (290% of controls) were found in the frontal cortex after two months. Anticonvulsant therapy with phenobarbital (20 mg/kg, i.p., twice daily for three weeks) partially suppressed the rise in NPY levels. Immunoreactivity of VIP increased (to 150%) in the frontal cortex only transiently 3 days after injection of kainic acid. At the subsequently examined time intervals (10–60 days after kainic acid) it declined to control values. Levels decreasing subsequently to acute seizures reflect increased release and degradation of the respective peptide. Increased NPY levels suggest upregulation of NPY/ somatostatin/GABA neurons due to the decreased seizure threshold of the animals. The early, reversible rise of VIP in the cortex points to a short-lasting activation of this peptide system contained in local cholinergic neurons. This may be a consequence either of the acute seizures or subsequent neuropathological changes. Send offprint requests to G. Sperk at the above address     

Binding of C-terminal segments of neuropeptide Y to chicken brain

The C-terminal pentapeptide amide segment of neuropeptide Y (NPY) binds specifically to chicken brain membrane preparations. The contribution of each residue of the C-terminus to this binding has been investigated through the synthesis and evaluation of a series of pentapeptide analogs. The binding of these molecules is strongly dependent on the presence of certain functional groups, in particular the guanidinium group of Arg-35 and the C-terminal aromatic amide function. The significance of these results for the binding to chicken brain tissue of NPY, pancreatic polypeptide and other potentially related neuropeptides is discussed.     

Region specific galanin receptor/neuropeptide Y Y1 receptor interactions in the tel- and diencephalon of the rat. Relevance for food consumption

The aim of this work was to determine the interactions between NPY and GAL receptor (GALR) subtypes in the hypothalamus and the amygdala using quantitative receptor autoradiography to analyze the binding characteristics of NPY-Y1 and Y2 receptor subtypes in the presence and absence of GAL. Food intake in satiated animals was evaluated after intraventricular co-injections of GAL and NPY-Y1 or Y2 agonists. The expression of c-Fos IR in both regions was also investigated. GAL decreases NPY-Y1 agonist binding in the arcuate nucleus by about 15% (p<0.01), but increases NPY-Y1 agonist binding in amygdala (18%) (p<0.01). These effects were blocked with the GAL antagonist M35. Y2-agonist binding was not modified by GAL. GAL blocked the food intake induced by the Y1 agonist (p<0.01). Co-injections of Y1 agonist and GAL also reduced the c-Fos expression induced by the Y1 agonist in the arcuate nucleus and the dorsomedial hypothalamic nucleus but increased c-Fos expression in amygdala. These results indicate the existence of antagonistic interactions between GALR and NPY-Y1 receptors in the hypothalamus and their functional relevance for food intake. In contrast, a facilitatory interaction between GALR and Y1 receptors exists in the amygdala which may be of relevance for fear related behaviour.     

Effects of butorphanol on feeding and neuropeptide Y in the rat

Butorphanol ([BT] an opioid receptor agonist/antagonist) is different from other opioid agonists in that a single dose of BT can elicit up to 12 g of chow intake in a satiated rat whereas most opioid agonists induce a mild feeding response (2-3 g). Here, we first examined whether the effectiveness of BT to elicit feeding was affected by dose, method of infusion and possible tachyphylaxis following administration. Secondly, we examined whether BT administration influenced hypothalamic NPY gene expression and peptide levels. A single dose administration of BT (4 mg/kg) significantly increased food intake at 2, 3 and 6 h after administration. However following repeated injections of BT at 4 mg/kg, the cumulative long-term intake of BT-treated rats did not differ from that of controls, indicating that the animals compensate for the increased feeding following BT injection by decreased feeding at a later time. An ascending dose schedule of repeated BT injections resulted in additional feeding. NPY gene expression in the ARC was influenced by how much food had been consumed, but not by BT. The amount of food consumed and the level of NPY mRNA were inversely correlated. This is consistent with NPY's role in normal feeding. BT treatment did not affect either NPY or leptin RIA levels. We conclude that the feeding produced by BT is sensitive to dose and dosing paradigm. Further, its mechanism of action does not appear to be mediated by NPY or leptin pathways.     

Effects of high-affinity GABAB receptor antagonists on active and passive avoidance responding in rodents with gamma-hydroxybutyrolactone-induced absence syndrome

RATIONALE: Absence seizures in man are behaviourally manifested as arrest and mild jerks mainly of facial muscles, associated in the electroencephalogram with synchronous spike and wave discharges. Gamma-hydroxybutyrolactone (GHBL) administration is currently used as an experimental model of absence seizures in rats and mice. OBJECTIVE: The aim of the present study was to examine the effects of three potent gamma-aminobutyric acid (GABA)B receptor antagonists CGP55845A, CGP62349 and CGP71982 (0.01 mg/kg) on the development of GHBL-induced absence epilepsy and in learning paradigms of active and passive avoidance tests in GHBL-treated mice and rats. METHODS: After 4 weeks of development of the absence syndrome, active and passive avoidance tests with negative reinforcement were performed. In both animal species, the absence syndrome was observed after 3 weeks of treatment in the saline group. RESULTS: The GABAB receptor antagonists CGP55845A and CGP62349 appeared to suppress the development of the absence syndrome to a greater degree in mice than in rats. CGP71982 suppressed it later than the other two antagonists (fifth week). In an active avoidance test in GHBL-treated mice, the GABAB antagonists had different effects - CGP62349 improved learning and memory retention to a greater extent than CGP55845A, whilst CGP71982 had no influence on it. In a passive avoidance test in GHBL-treated mice, the GABAB antagonists also had different effects - CGP71982 improved both learning and memory retrieval, whereas CGP55845A and CGP62349 had no effect. In the active avoidance test in GHBL-treated rats, the GABAB antagonist CGP55845A improved learning, whereas the other two, CGP62349 and CGP71982, had no effect. In the passive avoidance test the GHBL-treated rats showed an improvement in short memory retrieval. CGP55845A and CGP71982 improved this further, whilst CGP62349 had no effect. CONCLUSIONS: GHBL appeared to influence mice and rats in a different manner - rats learned the active avoidance task better than the GHBL-treated mice. The present study confirms previous data that GABAB antagonists suppress absence behaviour.     

Hyponatremia induced by antiepileptic drugs in patients with epilepsy

Introduction: Hyponatremia induced by antiepileptic drugs (AEDs) has not received sufficient attention in patients with epilepsy.

Areas covered: We reviewed articles between 1966 and 2015 about hyponatremia as an adverse effect of AEDs in patients with epilepsy. The incidence, clinical symptoms, onset times of AEDs-induced hyponatremia are discussed in detail, as are the risk factors associated with AEDs-induced hyponatremia and mechanisms underlying its development. We also briefly describe strategies for treating AED-induced hyponatremia.

Expert opinion: Carbamazepine and oxcarbazepine are the most common AEDs which induce hyponatremia in patients with epilepsy. Recently, other AEDs, such as eslicarbazepine, sodium valproate, lamotrigine, levetiracetam and gabapentin have also been reported to cause hyponatremia. Understanding the risk associated with AED-induced hyponatremia and taking effective measures to combat serum sodium imbalance induced by AED therapy are necessary.     

The modulatory effects of high affinity GABAB receptor antagonists in an active avoidance learning paradigm in rats

It has been reported that selective GABA_B receptor antagonists can enhance cognitive performance in a variety of learning paradigms. This prompted us to examine the effects of some more potent and newly synthesised GABA_B antagonists CGP 71982, CGP 62349 and CGP 55845A in an active avoidance test in rats. A two-way active avoidance test with negative reinforcement was performed for the first 5 of 12 days of antagonist administration. CGP 71982 and CGP 55845A at all doses applied (0.01–1.0 mg/kg) had an improving effect on learning, and memory retention on day 12; the rats made more avoidances in both sessions compared to controls. CGP 62349 was only active at the lowest dose tested (0.01 mg/kg). The present study confirms that GABA_B receptor antagonists can enhance cognitive performance but provides no insight into the mechanism of action of these novel antagonists. Received: 4 August 1997/Final version: 28 November 1997