托吡酯对青霉素诱发大鼠痫性放电和海马区相关递质含量的影响

目的　观察托吡酯对大鼠皮层定位注射青霉素诱发惊厥模型的对抗作用,并探讨其作用机制。方法　建立大鼠皮层定位注射青霉素诱发惊厥模型,观察两种剂量托吡酯ig给药对青霉素诱发痫性发作的程度和海马区痫性放电的潜伏期、痫波发放频率及痫波最高波幅的影响;采用HPLC法测定惊厥大鼠海马区Glu、Asp、Gly、GABA含量的变化。结果　两种剂量托吡酯(110, 440mg·kg-1,ig)均可减轻大鼠惊厥发作的程度,延长痫性放电的潜伏期,减少痫波发放频率,减小放电最高波幅,与模型组比较,差异均具有显著性(P<0 05或P<0 01)。同时,均可使大鼠海马区Glu含量降低,GABA含量升高,与模型组比较差异均有显著性 (P<0 05或P<0 01)。结论　托吡酯可明显抑制皮层定位注射青霉素诱发的痫性发作和痫性放电, 产生抗惊厥作用。其作用机制可能与加强GABA抑制功能和限制Glu兴奋功能有关。     

探讨睾酮对大鼠癫痫发作的影响机制

目的 探讨睾酮对大鼠癫痫发作的影响机制.方法 应用反相高效液相色谱仪测定正常对照组(A组)、正常致痫组(B组)、阉割组(C组)、阉割致痫组(D组)、阉割后加小剂量睾酮致痫组(EL组)及阉割后加大剂量睾酮致痫组(EH>组)大鼠海马和皮质中谷氨酸(Gh)、天门冬氨酸(Asp)、γ-氨基丁酸(GABA)及甘氨酸(Gly)的含量变化.结果 各组大鼠海马氨基酸含量:D组Asp、Gh、Gly及GABA的含量较A、B及C组明显高,P<0.05.EL组和EH组Asp、Glu及GABA的含量较D组明显低,P<0.05.皮质:D组Asp、Glu及GABA的含量较A、B及C组明显高.P<0.05.EL和EH组Gh及GABA的含量较D组明显低,P<0.05.结论 睾酮的抗痫部分机制可能是由于其可使致痫大鼠脑组织内兴奋性氨基酸含量降低所致.     

茯苓总三萜对青霉素诱发惊厥模型海马氨基酸含量的影响

茯苓的主要成分为茯苓多糖和三萜类,有抗炎和免疫调节等作用.但茯苓三萜类的抗惊厥作用未见报道.为此,本实验用大鼠皮层定位注射青霉素诱发惊厥模型观察了茯苓总三萜的抗惊厥作用及其对痫样放电的影响,同时用高效液相色谱技术测定Glu、Asp、Gly和GABA神经递质含量,从而探讨其作用机制.     

L-精氨酸对局灶性脑缺血大鼠脑组织氨基酸含量的影响

目的观察L-精氨酸对脑缺血大鼠纹状体、海马、皮层中天门冬氨酸(Asp)、谷氨酸(Glu)、甘氨酸(Gly)、γ-氨基丁酸(GABA)含量的影响,探讨L-精氨酸对大鼠脑缺血组织的保护作用及其作用机制。方法采用线栓法复制大鼠中脑动脉梗塞(MCAO)模型,缺血后给予L-精氨酸治疗。相应时间断头取脑,然后测定脑梗死体积、脑组织中氨基酸的含量。结果L-精氨酸组脑梗死体积较缺血组明显缩小;与假手术组比较,缺血组纹状体、海马、皮层中Asp、Glu、Gly、GABA含量显著增加,给予L-精氨酸治疗后,缺血后2、6h治疗组Asp、Glu的含量明显降低,Gly、GABA含量明显升高。结论L-精氨酸降低脑组织中兴奋性氨基酸的含量及升高抑制性氨基酸的含量可能是保护脑缺血的重要机制。     

半夏生物总碱和钩藤生物总碱抗小鼠、大鼠惊厥的协同作用（英文）

目的研究半夏生物总碱（PTA）和钩藤生物总碱（UTA）抗惊厥的协同作用,并探讨其相互作用机制。方法采用小鼠最大电休克惊厥试验和急性毒性试验检测PTA和UTA单用和三种比例（1：1,1：4,4：1）配伍的抗惊厥作用及毒性效应,并采用bliss’s法分别计算它们的ED50和LD50。用等效线法评价其协同作用并计算各组配伍的受益指数（BI）。制备大鼠运动皮层定位注射青霉素惊厥模型,同时采用高效液相色谱法（HPLC）测定海马区癫痫相关递质Glu、Asp、Gly、GABA的含量。结果半夏、钩藤生物总碱4：1配伍的抗惊厥作用呈现协同,而毒性呈现相互拮抗,是PTA和UTA合用的最佳比例。而两药1：4和1：1比例配伍尽管在最大电休克惊厥试验中抗惊厥作用呈现协同,但是在毒性试验中毒性效应却呈现相加。PTA和UTA单用和4：1合用,均可明显减少海马Glu的水平,增加GABA的水平,且4：1合用组的GABA水平要比两单药组高。但对Asp、Gly无明显影响。结论PTA和UTA以4：1合用时抗癫痫效应协同、毒性拮抗。两药合用的抗惊厥作用机制可能与其同时降低Glu能神经的兴奋性,并协同提高GABA能神经功能有关。     

中药复方抗痫灵对戊四氮致痫大鼠血清中谷氨酸、氨基丁酸的影响

目前大多研究认为,癫痫是脑内抑制性神经递质氨基丁酸(GABA)与兴奋性神经递质谷氨酸(Glu)作用失衡,神经元兴奋性升高,异常放电所致痫性发作.本实验通过观察中药复方抗痫灵对戊四氮致痫大鼠血清中的Glu、GABA含量变化的影响,从分子水平探讨癫痫的发病机制,从而为中药复方抗痫灵在临床的应用提供了科学的理论与实验依据.     

藏药七十味珍珠丸对惊厥小鼠脑内氨基酸含量的影响

目的　观察七十味珍珠丸的抗惊厥作用及作用机制。方法　七十味珍珠丸ig给药,使用硫代氨基脲制成惊厥小鼠模型,测定惊厥开始时间、致死率;采用高压液相色谱仪测定小鼠脑内抑制性氨基酸γ氨基丁酸(GABA)、甘氨酸(Gly)和兴奋性氨基酸谷氨酸(Glu)、天门冬氨酸(Asp)的含量。结果　七十味珍珠丸对硫代氨基脲所致惊厥的开始时间,具有显著延迟作用,可明显减少小鼠致死率。有升高惊厥小鼠脑内GABA ,降低脑内Glu含量的作用趋势,但无显著差异(P>0.05) ,而对Glu/GABA的比值,却有明显的降低作用(P<0.05、P<0.01) ,使Glu/GABA保持正常动物的水平,即维持中枢神经系统兴奋和抑制状态平衡的作用,阻止惊厥发生。结论　该药具有抗惊厥作用,其作用机制可能是通过调节脑内兴奋性和抑制性氨基酸的平衡来实现的     

左乙拉西坦对热性惊厥大鼠治疗作用的研究

目的观察左乙拉西坦对热性惊厥大鼠的治疗作用。方法通过热水浴建立热性惊厥大鼠模型,将40只SD幼龄热性惊厥大鼠随机分为模型组及左乙拉西坦低、中、高剂量组[100、200、300 mg/(kg·d)],分别于造模前灌胃,造模后进行47℃热水浴试验,每天惊厥1次,共惊厥5 d。观察每组大鼠惊厥潜伏期、惊厥持续时间、惊厥级别。采用TUNLE法检测各组大鼠海马神经元凋亡情况。试剂盒法检测海马组织中含半胱氨酸的天冬氨酸水解酶(Caspase 3)活性及谷氨酸(Glu)含量,Western blot检测γ-氨基丁酸(GABA蛋白)表达量。结果与模型组比较,左乙拉西坦低、中、高剂量组中大鼠惊厥潜伏期延长,惊厥持续时间缩短,惊厥严重程度降低,海马神经元凋亡率降低,Caspase 3活性及Glu含量降低,GABA表达量提高,差异均有统计学意义(P<0.01)。结论左乙拉西坦对热性惊厥大鼠具有显著治疗作用,可能与抑制神经元凋亡及调节Glu与GABA表达量有关。     

海洛因使大鼠背侧海马功能和Glu/GABA递质系统紊乱

目的探讨海洛因依赖对大鼠背侧海马神经元功能以及海马谷氨酸(Glu)和γ-氨基丁酸(GABA)递质系统的影响。方法按剂量逐日递增原则,1日2次,连续9 d皮下注射海洛因建立其依赖SD大鼠模型。采用玻璃微电极细胞外记录大鼠海马神经元自发放电,比较放电形式和频率的变化。并用氨基酸自动分析仪测定大鼠海马Glu和GABA含量。结果海洛因依赖组大鼠背侧海马神经元放电以中频(51.02%)、单个不匀(61.22%)为主,对照组则以低频(58.70%)为主,形式分布均一(P<0.05);海洛因对腹侧海马神经元放电无影响(P>0.05);依赖大鼠海马Glu含量下降,GABA含量增加(P>0.05),Glu/GABA比值低于对照组(P<0.05)。结论海洛因更易损伤大鼠背侧海马神经元功能;Glu/GABA递质系统的紊乱可能是海洛因损害大鼠学习记忆能力的机制之一。     

胡椒碱抗实验性癫痫作用及其作用机制分析

目的　研究胡椒碱的抗惊厥作用和作用机制。方法以不同的物理和化学方法引起小鼠和大鼠不同类型的惊厥 ,形成不同类型的实验性动物癫痫模型 ,预先ip不同剂量的胡椒碱 ,观察其有无抗惊厥作用。利用荧光分光光度计和氨基酸自动分析仪 ,分别测量小鼠脑内单胺类神经递质和氨基酸含量和大鼠脑片3H Glu释放实验分析其作用机制。结果　胡椒碱对多种实验性癫痫动物模型均有不同程度的对抗作用 ;对癫痫大发作动物模型MES、小发作动物模型Met和小鼠脑室注射 (icv)KA形成的颞叶性癫痫模型对抗作用较强 ,但对士的宁引起的强直性惊厥、3 巯基丙酸、荷包牡丹碱和兴奋性氨基酸引起的阵挛性惊厥均无明显的对抗作用。胡椒碱可明显增加小鼠脑内单胺类神经递质 5 HT的含量和明显降低Glu和Asp含量 ,并能降低 (Glu +Asp) /GABA的比值。 1× 10 -6 mol·L-1的胡椒碱对大鼠大脑皮层脑片预载的3H Glu的释放有明显的抑制作用。结论　胡椒碱有较强的抗惊厥作用。是一种广谱抗惊厥药。其机制可能与其增加动物脑内 5 HT和降低Glu及Asp的含量和阻断KA 受体有关     

Presynaptic inhibition by clonidine of neurotransmitter amino acid release in various brain regions.

The release of endogenous aspartic acid (Asp), glutamic acid (Glu) and gamma-aminobutyric acid (GABA) was investigated in synaptosomes prepared from various regions of the rat brain. The basal release of Asp, Glu and GABA from various regions was 12-35, 24-107 and 15-43 pmol/min per mg protein, respectively. Exposure to a depolarizing concentration of KCl (30 mM) resulted in 1.7 to 3.6-fold increases in Asp, Glu and GABA release. When clonidine (10(-4) M) was added to the perfusion medium, the K(+)-evoked overflow of both Asp and Glu was inhibited by 50-90% in the anterior cortex, thalamus and hypothalamus. Clonidine inhibited the K(+)-evoked Glu overflow by 30-40% in the posterior cortex and hippocampus. No significant effects were observed in the other brain regions (olfactory bulb, striatum, midbrain, cerebellum, pons, medulla oblongata). The inhibitory effects of clonidine were counteracted by an alpha 2-adrenoceptor antagonist, rauwolscine. The data suggest that the basal and K(+)-evoked release of Asp, Glu and GABA from nerve terminals is different in rat brain regions and that the presynaptic alpha 2-adrenoceptors which regulate the release of excitatory amino acids are mainly distributed in the anterior cerebral cortex, thalamus and hypothalamus of the rat brain.     

Interstrain differences in the content of excitatory and inhibitory amino acids in the brain of DBA/2J, Balb/c and C57BL/6 mice: characteristics of the effect of a dipeptide antipsychotic drug dilept

We have performed a comparative study of the content of glutamate (Glu), aspartate (Asp), taurine (Tau), glycine (Gly) and gamma-amino-butyric acid (GABA) in the cortex, hippocampus, and striatum of the DBA/2J, Balb/c and C57BL/6 mice brain. The levels of Glu, Tau and GABA in DBA/2J hippocampus was lower than those in other experimental strains. These findings are consistent with published data on the specific neurophysiological properties of DBA/2J (neuroleptic sensitive prepulse inhibition, deficit), thus allowing this strain to be used in modeling schizophrenia. Taking into account these facts, in the next step we investigated the effects of dilept, the new neurotensine-derived dipeptide with antipsychotic activity (GZR-123, methyl ester of N-caproyl-L-prolyltyrosine), on the content of neurotransmitter acids in DBA/2J mice brain structures. In a dose of 0.8 mg/kg (i.p.) dilept induced a statistically significant increase in the levels of Glu, Tau and GABA in striatum of DBA/2J, as well as insignificant increase in the levels of these amino acids in the cortex. These effects are quite similar to those described for the parent peptide neurotensine, in case of its intracerebral administration. The results of our study prove the necessity of the further development of dilept as a potential antipsychotic drug.     

γ-氨基丁酸对急性不完全性全脑缺血大鼠脑组织氨基酸和钙离子含量的影响(英文)

目的　进一步探讨γ 氨基丁酸 (GABA)类药物对脑缺血保护作用的机制。方法　结扎双侧颈总动脉制备大鼠不完全性全脑缺血模型 ,高效液相法和原子吸收分光光度法分别测定脑组织氨基酸和钙离子含量。结果　脑缺血 4h显著增加大鼠海马和皮层区的谷氨酸 (Glu)和天冬氨酸 (Asp)含量及海马GABA含量 ,增高皮层细胞钙离子水平和含水量。脑缺血前 30min给予GABA 10 0mg·kg- 1,iv ,能逆转缺血诱导的Glu和Asp等兴奋性氨基酸释放增加 ,减轻脑组织含水量。此外尚能增加内源性GABA含量。结论　外源性给予GABA可逆转脑缺血诱导的兴奋性氨基酸释放 ,升高抑制性氨基酸水平 ,减轻脑水肿     

Effects of gamma-aminobutyric acid (GABA) agonists and GABA uptake inhibitors on pharmacosensitive and pharmacoresistant epileptiform activity in vitro.

1. Lowering of the extracellular Mg(2+)-concentration induces various patterns of epileptiform activity in combined rat entorhinal cortex-hippocampal brain slices. After a prolonged period of exposure to Mg(2+)-free medium seizure-like events in the entorhinal cortex change to a state of late recurrent discharges which cannot be blocked by clinically available antiepileptic drugs. This late epileptiform activity thus represents a useful model to test the effects of new anticonvulsant substances. 2. A mechanism possibly underlying the development of sustained seizure-like activity is the loss of synaptically released gamma-aminobutyric acid (GABA). Drugs which increase the amount of GABA available in presynaptic endings might thus be useful in the treatment of these therapeutically complicated forms of epilepsy. 3. Therefore, we studied the effects of various substances increasing GABA-mediated inhibition on early and late forms of epileptiform activity. GABA and the GABAA receptor agonist muscimol blocked both the pharmacosensitive discharges in the hippocampus and entorhinal cortex as well as the late recurrent discharges in the medial entorhinal cortex. The GABAB receptor agonist baclofen blocked the recurrent short discharges very potently, but did not consistently block seizure-like events and late recurrent discharges in the entorhinal cortex. 4. GABA uptake blockers showed a differential potency to block the various discharge patterns. Whereas nipecotic acid and beta-alanine suppressed all forms of epileptiform activity albeit at high concentrations (1-5 mM), tiagabine was much more potent in blocking the hippocampal recurrent short discharges and the seizure-like events in the medial entorhinal cortex, but could not block the late recurrent discharges. 5. Our data support the idea that prolonged neuronal overactivity might result in a loss of synaptically available GABA. Selective block of uptake into glia cells or substitution of the transmitter may therefore be an efficient strategy for the treatment of severe prolonged epileptic discharges whereas block of neuronal GABA uptake fails to counteract synchronized discharges in this situation.     

卡马西平对青霉素点燃惊厥大鼠脑内GABA_A受体mRNA表达的作用

目的研究两种剂量卡马西平对青霉素慢性点燃大鼠的抗惊厥作用及对脑内GABAA受体mRNA表达的影响,从基因水平探讨卡马西平抗惊厥的作用机制。方法采用腹腔注射(ip)青霉素(3×106U.kg-1.d-1)慢性点燃大鼠惊厥模型,两种剂量卡马西平(50,100mg.kg-1×13d)ig给药,以痫性发作潜伏期和Racine惊厥行为分级标准为判定药效指标,观察卡马西平的抗惊厥作用。运用RT-PCR技术测定大鼠脑内GABAA受体mRNA表达量,分析卡马西平抗惊厥作用的新机制。结果两种剂量卡马西平ig给药后,均可使青霉素慢性点燃大鼠痫性发作的潜伏期延长,与模型对照组相比差异有统计学意义(P<0.01),同时使惊厥大鼠的发作程度均较模型对照组减轻。青霉素慢性点燃大鼠脑内GABAA受体mRNA表达减少,与正常对照组比较,差异有统计学意义(P<0.01);两种剂量卡马西平预防性干预组的GABAA受体mRNA表达量分别与模型对照组相比,差异均无显著性。结论两种剂量卡马西平对青霉素慢性点燃的惊厥发作均有明显的对抗作用,但抗惊厥机制与GABAA受体的基因表达无关。     

Sigma sites mediate DTG-evoked hypothermia in rats

The alkaloid ricinine isolated from the plant Ricinus communis, when administered to mice at high doses, induces clonic seizures accompanied by electroencephalographic alterations in the cerebral cortex and hippocampus. The lethal nature of ricinine-induced seizures is considered to be a good model for the study of the events that cause death during clonic seizures, particularly those related to respiratory spasms. The initial signs (pre-seizure period) were marked by exophthalmus and decreased locomotor behavior. Animals killed during the preseizure period presented an increased utilization rate (HVA/DA) of dopamine (DA), an increased concentration of noradrenaline (NA), and a decreased concentration of glutamate (Glu), glutamine (Gln), taurine (Tau), and serotonin (5-HT) in the cerebral cortex. The seizure period is characterized by the occurrence of hind limb myoclonus and respiratory spasms, which are followed by death. Alterations in the cerebral cortex concentration of these neurotransmitters persisted during the seizure period. These alterations are only partially observed in the hippocampus, mainly during the seizure period. The present results suggest that an increased release of Glu in the cerebral cortex can be implicated in the genesis of the ricinine-induced seizure and that it triggers many anticonvulsive mechanisms, like the release of Tau, DA, 5-HT, and NA.     

长期给酒精后大鼠不同脑区氨基酸类递质变化及吡拉西坦的作用

目的·· :观察长期给酒精后大鼠不同脑区氨基酸类递质的变化 ,探讨吡拉西坦的作用。方法·· :以SD大鼠为实验材料 ,连续每天给20%酒精 (10ml·kg-1,ig,每日1次 )6周 ,使其产生酒依赖 ,一组于给酒精第5周 (在继续给酒精的同时 )开始给吡拉西坦 (200mg·kg-1,im,每日2次 ) ,连续1周。采用高效液相色谱电化学检测法分别测定大鼠小脑、大脑皮层、海马和丘脑中的谷氨酸及γ -氨基丁酸含量。结果··:连续给酒精6周后 ,小脑、大脑皮层和海马中的谷氨酸水平均有所降低 ,小脑中的变化显著(P<0.05) ;γ -氨基丁酸水平除小脑中有明显降低(P<0.05)外 ,其余3区无显著性变化 ;谷氨酸与γ -氨基丁酸的比值在海马中显著降低(P<0.01)。吡拉西坦治疗组丘脑的谷氨酸水平明显提高(P<0.05) ,小脑和大脑皮层的γ -氨基丁酸水平明显降低(P<0.01) ,小脑、大脑皮层、海马3脑区中谷氨酸和γ -氨基丁酸的比值显著升高(P<0.01)。结论·· :连续给酒精对大鼠不同脑区谷氨酸和γ -氨基丁酸的含量以及二者的比值均有不同影响 ,吡拉西坦可在不同程度上逆转酒精的作用     

Regional rat brain benzodiazepine receptor number and gamma-aminobutyric acid concentration following a convulsion.

1 Following administration to rats of an electroconvulsive shock (ECS) which resulted in a major tonic-clonic seizure, no changes in [3H]-diazepam binding characteristics were observed in cortex or hippocampus with either a well washed membrane preparation or a crude synaptosomal preparation. 2 No changes were observed in [3H]-diazepam binding in any other brain region examined 30 min after an ECS. 3 Thirty min following an ECS, regional brain gamma-aminobutyric acid (GABA) concentrations increased in hippocampus, cortex and hypothalamus. Only in the hippocampus did the increase occur within 5 min of the seizure. 4 Similar increases in GABA concentration were seen after a bicuculline-induced seizure but not after seizure induced by flurothyl; both treatments produced a tonic-clonic seizure. 5 Pretreatment of the rats with (+)-propranolol 5 min before the ECS abolished the tonic extension and prevented the brain GABA concentration changes that occur 30 min after the seizure. 6 No increase in GABA concentration was seen in hippocampus, cortex and hypothalamus 30 min after the final ECS of a course of 10 ECS given once daily for 10 days. In contrast a marked increase in striatal GABA concentration was observed. 7 These changes in GABA biochemistry following a seizure are discussed in relation to the post-ictal rise in seizure threshold that is occurring at the same time.