琥珀酸对大鼠化学性点燃和杏仁核电刺激性点燃的抑制作用

目的:研究琥珀酸对大鼠戊四哇化学性点燃(kindling)发作及杏仁核电刺激点燃发作的影响及作用机制.方法:建立大鼠戊四唑化学性点燃模型和杏仁核电刺激点燃癫痫模型,测定琥珀酸对点燃发作的脑电活动及行为变化指标的影响.测定琥珀酸对GABA_A受体拮抗剂印防己毒素诱发小鼠惊厥的影响.结果:琥珀酸(100-400 mg/kg,iP)对两种点燃模型有显著抑制作用,降低发作强度和全身性发作百分率(P<0.05,P<0.01),可升高杏仁核电刺激点燃大鼠的局灶性后放电阈值(P<0.05,P<0.01),以上反应呈剂量效应关系。琥珀酸可延长印防己毒素诱发小鼠惊厥的潜伏期(P<0.05,P<0.01).结论:琥珀酸对大鼠戊四唑化学性点燃和脑杏仁核电刺激点燃发作有抑制作用,其机制可能与增强GABA_A受体功能有关.     

不同钙拮抗药对大鼠杏仁核电刺激点燃模型的作用比较

目的 比较不同类型钙拮抗药对大鼠杏仁核电刺激点燃癫模型的作用及其机制。方法 采用恒定电流刺激大鼠右侧杏仁核制备大鼠杏仁核电刺激点燃慢性癫模型，观察不同类型的钙拮抗药对大鼠杏仁核电刺激点燃动物模型的后放电时程（ADD）和Racine’s分级的影响，并进行给药前后的自身对照。结果 不同类型钙拮抗药对大鼠杏仁核电刺激点燃癫发作的作用不同。尼莫地平40～80 mg·kg^-1 灌胃可抑制大鼠杏仁核电刺激点燃癫发作，降低Racine’s 分级（均P＜0.01）；地尔硫200 mg·kg^-1灌胃可抑制ADD（P＜0.05）,但对Racine’s 分级无影响（P＞0.05）;乙琥胺100～250 mg·kg^-1 灌胃对大鼠杏仁核电刺激点燃癫发作及Racine’s 分级均无抑制作用（均P＞0.05）；苯妥英钠20 mg·kg^-1 皮下注射可抑制大鼠杏仁核电刺激点燃发作，降低Racine’s分级（均P＜0.01）;丙戊酸钠500 mg·kg^-1 灌胃可抑制大鼠杏仁核电刺激点燃发作，降低Racine’s 分级（均P＜0.05）;桂利嗪20～60 mg·kg^-1灌胃可抑制大鼠杏仁核电刺激点燃癫发作，降低Racine’s 分级（均P＜0.01）。 结论 L型和T型钙通道可能参与癫发病机制，L型钙拮抗药尼莫地平具有抗癫点燃作用；较大剂量地尔硫可抑制ADD，其机制可能与阻滞L型电压依赖性钙通道（VDCC）有关; T型钙拮抗药乙琥胺对杏仁核癫点燃无抑制作用，杏仁核癫点燃发作或癫大发作与丘脑神经元低阈值T型钙通道无关；苯妥英钠、丙戊酸钠可抑制杏仁核点燃癫发作;苯妥英钠作用的T型钙通道不同于乙琥胺，该两药也可能通过其他机制抗癫;丙戊酸钠可能兼有乙琥胺和苯妥英钠对钙通道的抑制作用;桂利嗪的抗癫作用可能与阻滞多种类型的电压依赖性钙通道有关。     

香荚兰素对抗大鼠杏仁核点燃效应

用大鼠杏仁核点燃模型研究了香荚兰素的抗癫痫作用。每日一次低电流刺激杏仁基底外侧核可在第15天使大鼠产生典型的五期反应,刺激后放电显著延长。香荚兰素在不产生中枢抑制作用的剂量即可抑制点燃效应的五期反应,ED₅₀为286 mg/kg(ip),同时使刺激后放电时程比对照组下降28.6%。苯妥英钠抑制五期反应的ED₅₀为56mg/kg,也能明显缩短刺激后放电时程。本文提供了一种新型慢性实验性癲痫模型。     

吲哚醌对大鼠杏仁核点燃的抑制作用

目的：研究吲哚醌对大鼠杏仁核点燃发作的影响及其抗惊厥作用。方法：建立大鼠杏仁核点燃模型,观察发作的电生理指标和行为学变化;在小鼠最大电休克惊厥、戊四唑惊厥和氨基脲惊厥模型计数惊厥发生率。结果： ip吲哚醌50～200 mg.kg-1均可升高杏仁核点燃大鼠的局灶性后放电阈值,降低发作强度和全身性发作 (stage 5) 百分率;可剂量依赖性地对抗小鼠最大电休克发作,并能取消戊四唑惊厥和氨基脲惊厥的强直相,降低戊四唑惊厥的死亡率。结论：吲哚醌对癫痫发作有抑制作用,其机制与抑制MAO-B活性、升高发作阈值有关。     

一种新的α1A肾上腺素受体选择性拮抗剂—Sertindole

本工作分别在稳定表达α_1A,α_1B和α_1D肾上腺素受体(adrenoceptor,AR)的人胚胎肾脏细胞( human embryonic kidney 293,HEK 293)和大鼠离体血管上,用放射配体结合实验和离体血管收缩功能实验方法以确定sertindole对α₁-AR亚型的选择性拮抗作用。结果显示sertindole与克隆α_1A-AR的亲和性分别是与克隆α_1B-AR和克隆α_1D-AR的69倍和132倍。Sertindole拮抗去甲肾上腺素引起的主动脉和肾动脉收缩反应的pA₂值分别与其对α_1D和α_1A亚型的pKI值相符。分别稳定表达3种亚型受体的HEK293细胞膜标本经与sertindole预温育30min后,受体与¹²⁵IBE2254结合的B_max值显著降低,KD值无显著变化;而在 sertindole 存在条件下,α₁-AR3种亚型与¹²⁵IBE2254 结合的KD值显著增大,但B_max值无显著改变。上述结果表明sertindole为不可逆性竞争性α₁-AR拮抗剂,并有α_1A亚型选择性。     

β-淀粉样肽25-35致记忆障碍大鼠中枢双孔钾通道亚型mRNA表达的改变

目的研究聚集态β-淀粉样肽_25-35（β-AP_25-35）致记忆障碍大鼠模型中枢双孔钾通道亚型mRNA表达的变化。方法Morris水迷宫实验检验大鼠空间学习记忆能力，用RT-PCR方法检测大脑皮层和海马中3种双孔钾通道TREK-1,TREK-2和TRAAK mRNA的表达。结果在Morris水迷宫实验中，β-AP_25-35注射组大鼠d 1，d 2和d 4的潜伏期均比对照组显著延长。β-AP_25-35注射组大鼠大脑海马中TREK-1,TREK-2和TRAAK mRNA的表达比对照组明显升高；而在皮层中的表达变化不显著。结论侧脑室注射聚集态β-AP_25-35致大鼠学习记忆障碍的同时可诱发中枢双孔钾通道亚型的表达改变。     

1-(2,6-二甲氧基)-2-(3,4-二甲基苯乙氨基)丙烷盐酸盐(DDPH)拮抗α1肾上腺素受体的特性

目的　研究DDPH对α₁-肾上腺素受体(α₁-AR)及其亚型的拮抗作用。方法　放射配体结合实验和离体血管收缩功能实验。结果　DDPH对¹²⁵I-BE2254与大鼠脑皮质和脾脏α₁-AR结合呈竞争性拮抗作用。pK_I值在两者间无显著性差别, Hill系数均接近于1.0。在分别稳定表达α_1A,α_1B或α_1D-AR的克隆HEK293细胞中,其拮抗的pK_I值α_1A和α_1D比α_1B-AR高约2倍,Hill系数均接近于1.0。并拮抗去甲肾上腺素(NE)介导大鼠主动脉,肾动脉和脾脏收缩的pA₂值,在三者间无显著差别,斜率接近1.0。结论　DDPH对α₁-AR有竞争性拮抗作用,但其作用对α₁-AR亚型无选择性。     

长期饮用普萘洛尔对大鼠心脏和血淋巴细胞β肾上腺素受体效应及亚型的影响

采用放射配体结合实验，离体左心房收缩功能实验，逆转录聚合酶链反应及高效液相色谱等方法研究长期饮用普萘洛尔(70 mg·kg^-1·d^-1，8 wk)对大鼠心脏β肾上腺素受体(β-AR)及其亚型，外周血淋巴细胞β₂-AR和血浆儿茶酚胺水平的影响. 结果表明长期饮用普萘洛尔后：(1)心脏β- AR密度从对照组的41±8 pmol·g^-1蛋白上调到61±9 pmol·g^-1蛋白，CGP20712A竞争抑制曲线2位点分析结果显示为β₁和β₂-AR同等程度上调；(2)心脏β₁-AR mRNA水平不变而β₂-AR mRNA水平显著增加；(3)β-AR及其亚型介导的离体左心房正性变力效应增强，以β₂-AR的功能改变更为显著；(4)血淋巴细胞β₂-AR数目从对照组的19±7 pmol·g^-1蛋白上调至32±8 pmol·g^-1蛋白；(5)血浆去甲肾上腺素水平(0.21±0.12 μg·L^-1)明显低于对照组(0.38±0.15 μg·L^-1).     

戊四唑点燃大鼠海马、杏仁核一氧化氮合酶阳性神经元的变化

目的：探讨一氧化氮（NO）在戊四唑（PTZ）点燃发病机理中的作用,方法：每天注射PTZ建立大鼠点燃模型,运用组织化学方法观察海马,杏仁核一氧化氮合酶（NOS）阳性神经元变化,结果：点燃后海马,杏仁核内NOS阳性神经元明显增多,结论：NO促进了戊四唑点燃的形成。     

四氢原小檗碱同类物对α1肾上腺素受体的拮抗作用

用放射配体结合实验与离体血管收缩功能实验相结合的方法,研究了4种四氢原小檗碱(tetrahydroproberberine,THPB)同类物对α₁-肾上腺素受体(α₁-AR)的作用。结果显示左旋四氢巴马汀(l-THP),左旋千金藤立陡碱(l-SPD),四氢原小檗碱-18(THPB-18)和四氢小檗碱(THB)¹²⁵IBE2254¹²⁵I-2-β(4-hydroxyphenyl)-ethyaminomethyl-tetralone,¹²⁵IBE)与大鼠脑皮质α₁-AR的结合呈竞争性拮抗作用,pK_I值分别为5.54±0.36,5.56±0.47,5.75±0.56和6.01±0.60,Hill系数接近于1.0。并拮抗苯肾上腺素(phenylephrine,PE)介导大鼠主动脉的收缩,pA₂值分别为5.48±0.58,5.66±0.54,5.64±0.34和5.45±0.76,斜率与1.0无显著性差别。结果提示,4种四氢原小檗碱同类物对α₁-AR均有非亚型选择性拮抗效应,且亲和性相同。     

Characterization of beta-adrenoceptor mediated smooth muscle relaxation and the detection of mRNA for beta1-, beta2- and beta3-adrenoceptors in rat ileum.

1. Functional and molecular approaches were used to characterize the beta-AR subtypes mediating relaxation of rat ileal smooth muscle. 2. In functional studies, (-)-isoprenaline relaxation was unchanged by CGP20712A (beta1-AR antagonist) or ICI118551 (beta2-AR antagonist) but shifted by propranolol (pKB=6.69). (+/-)-Cyanopindolol, CGP12177 and ICID7114 did not cause relaxation but antagonized (-)-isoprenaline relaxation. 3. BRL37344 (beta3-AR agonist) caused biphasic relaxation. The high affinity component was shifted with low affinity by propranolol, (+/-)-cyanopindolol, tertatolol and alprenolol. CL316243 (beta3-AR agonist) relaxation was unaffected by CGP20712A or ICI118551 but blocked by SR58894A (beta3-AR antagonist; pA2 = 7.80). Enhanced relaxation after exposure to forskolin and pertussis toxin showed that beta3-AR relaxation can be altered by manipulation of components of the adenylate cyclase signalling pathway. 4. The beta-AR agonist RO363 relaxed the ileum (pEC50=6.18) and was blocked by CGP20712A. Relaxation by the beta2-AR agonist zinterol (pEC50=5.71) was blocked by SR58894A but not by ICI118551. 5. In rat ileum, beta1-, beta2- and beta3-AR mRNA was detected. Comparison of tissues showed that beta3-AR mRNA expression was greatest in WAT>colon=ileum >cerebral cortex>soleus; beta1-AR mRNA was most abundant in cerebral cortex > WAT > ileum = colon > soleus; beta2-AR mRNA was expressed in soleus > WAT > ileum = colon > cerebral cortex. 6. These results show that beta3-ARs are the predominant beta-AR subtype mediating rat ileal relaxation while beta1-ARs may produce a small relaxation. The beta2-AR agonist zinterol produces relaxation through beta3-ARs and there was no evidence for the involvement of beta2-ARs in relaxation despite the detection of beta2-AR mRNA.     

尼卡地平对大鼠杏仁核点燃效应的抑制作用(英文)

目的:探讨钙通道阻滞剂尼卡地平对大鼠杏仁核点燃的作用及机制。方法:恒定电流每日一次刺激大鼠右侧杏仁核,观察尼卡地平对杏仁核点燃发展和发作的影响,测定点燃大鼠脑内各种氨基酸神经递质的含量。结果:腹腔注射尼卡地平2mg·kg~(-1)显著延缓杏仁核点燃发展进程(P<0.01);尼卡地平2-20mg·kg~(-1)剂量依赖性抑制大鼠杏仁核点燃发作,升高发作阈值(ADT),降低Racine分级;20mg·kg~(-1)尼卡地平显著提高杏仁核点燃大鼠脑内抑制性氨基酸神经递质GABA的含量(P<0.05)。结论:尼卡地平对大鼠杏仁核点燃的发展和发作有抑制作用,其机制可能与阻断电压依赖性钙通道及增强GABA系统功能有关。     

MK-801与抗癫痫药合用对大鼠杏仁核点燃的影响

目的在大鼠杏仁核点燃模型研究MK-801(地佐西平)及其联合用药的抗癫痫作用。方法建立大鼠杏仁核慢性电刺激点燃模型,测定不同剂量的MK-801对点燃模型各项指标的影响,探讨MK-801与其他抗癫痫药的协同作用,用氨基脲诱发的小鼠惊厥模型测定MK-801抗惊厥作用。 结果MK-801(0.1～0.25 mg·kg^-1)可剂量依赖性抑制杏仁核点燃,缩短后放电时程,降低Racine's分级;在对点燃均无明显影响的剂量下,MK-801(0.05 mg·kg^-1)与抗癫痫药(苯巴比妥、丙戊酸及尼卡地平)合用可缩短后放电时程或降低Racine's分级。MK-801(0.1～0.25 mg·kg^-1)显著降低小鼠氨基脲诱发的发作潜伏期、惊厥发生率和死亡率。结论MK-801具有抑制大鼠杏仁核点燃的作用,增强苯巴比妥、丙戊酸及尼卡地平的抗癫痫活性,为临床的合并用药提供实验依据。     

beta(1)-Adrenoceptors compensate for beta(3)-adrenoceptors in ileum from beta(3)-adrenoceptor knock-out mice

1. This study examines beta(1)-, beta(2)- and beta(3)-adrenoceptor (AR)-mediated responses, mRNA levels and radioligand binding in ileum from beta(3)-AR knock-out (-/-) (KO) and wild type (+/+) (FVB) mice. 2. In KO and FVB mice, SR59230A (100 nM) (beta(3)-AR antagonist) antagonized responses to (-)-isoprenaline in both KO and FVB mice. (-)-Isoprenaline mediated relaxation of ileum was antagonized weakly by ICI118551 (100 nM) (beta(2)-AR antagonist). Responses to (-)-isoprenaline were more strongly antagonized by CGP20712A (100 nM) (beta(1)-AR antagonist), propranolol (1 microM) (beta(1)-/beta(2)-AR antagonist), carvedilol (100 nM) (non-specific beta-AR antagonist), and CGP12177A (100 nM) (beta(1)-/beta(2)-AR antagonist) in ileum from KO than in FVB mice. 3. Responses to CL316243 (beta(3)-AR agonist) in ileum from FVB mice were antagonized by SR59230A (100 nM) but not by propranolol (1 microM) or carvedilol (100 nM). CL316243 was ineffective in relaxing ileum from KO mice. 4. CGP12177A had no agonist actions in ileum from either KO or FVB mice. 5. beta(1)-AR mRNA levels were increased 3 fold in ileum from KO compared to FVB mice. This was associated with an increased maximum number of beta(1)-/beta(2)-AR binding sites (B(max)). beta(2)-AR mRNA levels were unaffected while no beta(3)-AR mRNA was detected in KO mice. 6. In mouse ileum, beta(3)-ARs and to a lesser extent beta(1)-ARs are the predominant adrenoceptor subtypes mediating relaxation in ileum from FVB mice. In KO mice beta(1)-ARs functionally compensate for the lack of beta(3)-ARs, and this is associated with increased beta(1)-AR mRNA and levels of binding.     

大鼠骨骼肌细胞不存在功能性β3—肾上腺素受体

AIM: To determine the functional role of beta 3-adrenoceptors (beta 3-AR) in rat skeletal muscle cells. METHODS: Nonselective beta-AR agonist isoprenaline (isoproterenol, Iso), beta 3-AR agonist CGP12177A which is a beta 1-/beta 2-AR antagonist and selective beta 3-AR antagonist SR59230A on cAMP accumulation was studied in primary cultured rat skeletal muscle cells. RESULTS: Iso stimulated cAMP accumulation in a concentration-dependent manner with EC50 of 1.51 nmol.L-1 and propranolol inhibited cAMP accumulation stimulated by Iso with KB of 3.47 nmol.L-1. CGP12177A had no effect on cAMP accumulation but inhibited cAMP production induced by Iso. SR59230A 10 nmol.L-1 did not inhibit cAMP production induced by Iso. CONCLUSION: The functional beta 3-AR are not present or at least not coupled to adenylyl cyclase activity in skeletal muscle cells.     

Desensitization of alpha 2A-adrenoceptor signalling by modest levels of adrenaline is facilitated by beta 2-adrenoceptor-dependent GRK3 up-regulation

(1) Adrenaline (ADR) and noradrenaline (NA) can simultaneously activate inhibitory alpha(2)- and stimulatory beta-adrenoceptors (AR). However, ADR and NA differ significantly in that ADR is a potent beta(2)-AR agonist while NA is not. Only recently has the interaction resulting from the simultaneous activation of alpha(2)- and beta(2)-AR been examined at the cellular level to determine the mechanisms of alpha(2)-AR regulation following concomitant activation of both alpha(2)- and beta(2)-ARs by chronic ADR. (2) This study evaluates beta(2)-AR regulation of alpha(2A)-AR signalling following chronic ADR (300 nM) and NA (1 and 30 micro M) treatments of BE(2)-C human neuroblastoma cells that natively express both beta(2)- and alpha(2A)-ARs. (3) Chronic (24 h) treatment with ADR (300 nM) desensitized the response to the alpha(2A)-AR agonist, brimonidine, in BE(2)-C cells. Addition of the beta-AR antagonist, propranolol, blocked the ADR-induced alpha(2A)-AR desensitization. Unlike ADR, chronic NA (1 micro M) treatment had no effect on the alpha(2A)-AR response. However if NA was increased to 30 micro M for 24 h, alpha(2A)-AR desensitization was observed; this desensitization was partially reversed by propranolol. (4) Chronic ADR (300 nM) treatment reduced alpha(2A)-AR binding levels, contributing to the alpha(2A)-AR desensitization. This decrease was prevented by addition of propranolol during ADR treatment. Chronic NA (30 micro M), like ADR, treatment lowered specific binding, whereas 1 micro M NA treatment was without effect. (5) Chronic ADR treatment produced a significant increase in GRK3 levels and this was blocked by propranolol or GRK2/3 antisense DNA treatment. This antisense DNA, common to both GRK2 and GRK3, also blocked chronic ADR-induced alpha(2A)-AR desensitization and down-regulation. (6) Acute (1 h) ADR (300 nM) or NA treatment (1 micro M) produced alpha(2A)-AR desensitization. The desensitization produced by acute treatment was beta-AR independent, as it was not blocked by propranolol. (7) We conclude that chronic treatment with modest levels of ADR produces alpha(2A)-AR desensitization by mechanisms that involve up-regulation of GRK3 and down-regulation of alpha(2A)-AR levels through interactions with the beta(2)-AR.     

Pharmacological characterization of the β-adrenoceptor that mediates the relaxant response to noradrenaline in guinea-pig tracheal smooth muscle

Pharmacological characteristics of beta-adrenoceptors (beta-ARs) mediating noradrenaline-induced relaxation were investigated in guinea-pig tracheal smooth muscle. The inhibitory effects of several types of beta-AR antagonists on noradrenaline-induced relaxation against histamine contraction were scrutinized with Schild plot analysis. The concentration-response curve for noradrenaline obtained in the absence of phentolamine and uptake inhibitors was competitively antagonized by all of the beta-AR antagonists used in this study (propranolol, bupranolol, atenolol, butoxamine and ICI-118,551). However, their pA2 values were markedly less than the expected values for beta1-AR and beta2-AR. On the other hand, pA2 values of ICI-118,551 (6.85) determined in the presence of phentolamine suggested a contribution of a beta1 -AR rather than beta2 -AR. In the presence of phentolamine and uptake inhibitors (desipramine and deoxycorticosterone), the Schild plot for atenolol was a better fit, with two distinct straight lines. The pA2 values of atenolol provided by the regression were: approximately 7.0, which corresponds to the expected beta1-AR value, and approximately 6.5, which was 3 times less than the expected value for beta1 -AR, and thus the possible presence of two classes of beta1 -AR (beta1(Low) and beta1(High)) was suggested. This view was also supported by Schild plot analysis for propranolol, which fit two straight lines each with a slope of 1.0. The present findings indicate that beta1 -ARs contributing to noradrenaline-elicited relaxation in guinea-pig tracheal smooth muscle exhibit diverse pharmacological characteristics and may be subdivided into at least two classes with distinct affinities for atenolol. Under physiological conditions, beta1(Low) rather than beta1(High) seems to play a more significant role in noradrenaline-regulated airway smooth muscle tone.     

Modafinil exerts a dose-dependent antiepileptic effect mediated by adrenergic alpha1 and histaminergic H1 receptors in mice

Epilepsy is characterized by neuronal hyperexcitability and hypersynchronization. Disruption of electroencephalographically (EEG) synchronized epileptiform discharges may be a possible therapy for epilepsy. In the present study, to clarify the role of EEG desynchronization on epilepsy, we investigated the effect of modafinil, a potent wake-promoting substance with EEG desynchronization activity, on epilepsy in mice and clarified the receptors involved in the suppression of seizure caused by maximal electroshock (MES) and pentylenetetrazol (PTZ) kindling models. Modafinil given at 22.5, 45, and 90 mg/kg, i.p. significantly decreased the incidence of tonic hindleg extension in MES seizure models, and protected against PTZ-induced convulsive behaviors in a dose-dependent manner. In addition, modafinil at 180 mg/kg exerted an antiepileptic effect in the MES model; however, at the same dosage it increased the seizure stage in the PTZ-kindling model. The antiepileptic effect in both MES and PTZ models was antagonized by the adrenergic alpha(1) receptor antagonist terazosin, but not by the adrenergic alpha(2) receptor antagonist yohimbine or by dopaminergic receptor antagonists, SCH-23390 (for D(1) receptors) and haloperidol (for D(2) ones). Pyrilamine, a histaminergic H(1) receptor antagonist, counteracted the antiepileptic action of modafinil in the PTZ induced-kindling model, but not in the MES seizure model. Taken together, the present findings indicate that modafinil exerted its antiepileptic effect via adrenergic alpha(1) and histaminergic H(1) receptors, and might be of potential use in the treatment of epilepsy.