GABAA receptor mediated elevation of Ca2+ and modulation of gonadotrophin-releasing hormone action in alphaT3-1 gonadotropes

gamma-amino butyric acid (GABA) is the major inhibitory neurotransmitter in the CNS, mediating fast inhibitory synaptic transmission, by activating GABAA receptors. However, these GABA-gated Cl- channels can also be excitatory, causing depolarization, and increasing Ca2+ entry via voltage-operated Ca2+ channels (VOCCs). Evidence exists for excitatory ionotropic GABA receptors in anterior pituitary cells, including gonadotropes, but these have not been directly characterized and their pharmacology remains controversial. Here we have measured the cytosolic Ca2+ concentration ([Ca2+]i) in alphaT3-1 gonadotropes, to test for expression of excitatory GABA receptors. The GABAA agonists, GABA and muscimol, both caused rapid, robust and dose-dependent increases in [Ca2+]i (EC50 values 2.7 and 1 microM), whereas the GABAB agonist, baclofen, did not. The GABAA antagonist, bicuculline, inhibited muscimol's effect, whereas the GABAB antagonist, phaclofen, did not. The neuroactive steroid 5alpha-pregnan-3alpha-ol-11,20-dione (an allosteric activator of GABAA receptors) increased [Ca2+]i, and this effect, like that of muscimol, was inhibited by picrotoxin. The muscimol effect on [Ca2+]i was blocked by the VOCC antagonist, nifedipine, or by Ca2+-free medium. When cells were pretreated with muscimol this increased the spike phase of the [Ca2+]i response to subsequent stimulation with gonadotropin-releasing hormone (GnRH). Similar amplification was seen in muscimol-pretreated cells stimulated with GnRH in Ca2+-free medium, but not when cells were pretreated with muscimol in Ca2+-free medium. The amplification was not, however, GnRH receptor-specific, because the spike response to ionomycin was also increased by muscimol pretreatment. These data provide the first direct evidence for expression of excitatory GABAA receptors, and the first demonstration of acute steroid effects, on GnRH-responsive pituitary cells. They also reveal a novel mechanism by which GABAA activation modulates GnRH action, raising the possibility that this may also influence gonadotrophin secretion from non-immortalized gonadotropes.     

Chronological changes in nonhaemorrhagic brain Infarcts with short T1 in the cerebellum and basal ganglia

Our purpose was to investigate nonhaemorrhagic infarcts with a short T1 in the cerebellum and basal ganglia. We carried out repeat MRI on 12 patients with infarcts in the cerebellum or basal ganglia with a short T1. Cerebellar cortical lesions showed high signal on T1-weighted spin-echo images beginning at 2 weeks, which became prominent from 3 weeks to 2 months, and persisted for as long as 14 months after the ictus. The basal ganglia lesions demonstrated slightly high signal from a week after the ictus, which became more intense thereafter. Signal intensity began to fade gradually after 2 months. High signal could be seen at the periphery until 5 months, and then disappeared, while low or isointense signal, seen in the central portion from day 20, persisted thereafter. Received: 1 February 1999 Accepted: 13 September 1999     

通痹灵总碱对T淋巴细胞活化CD71表达的影响

目的 :通痹灵总碱 (TBL)是从通痹灵中提取出来的总生物碱部位。本研究旨在探索TBL对T淋巴细胞活化CD71表达的影响 ,探讨通痹灵免疫调控作用的机理。方法 :对清洁级小鼠T淋巴细胞进行培养 ,体外加入通痹灵总碱 ,采用流式细胞仪检测T淋巴细胞CD71的表达率。结果 :TBL(10 0 μg mL)对ConA或PDB激活的大鼠T淋巴细胞活化表达CD3+ CD71+ 抗原有明显的下调作用 (P <0 0 1) ,并且随着剂量的增加 ,其抑制作用加强 (P <0 0 1) ,呈明显的量效关系 ;对ConA活化组的作用要强于PDB。结论 :TBL对ConA和PDB诱导活化T细胞的CD71表达率均有明显的抑制作用 ,而且呈明显的量效关系。提示对TBL在T细胞活化信号传导过程有明显作用 ,在治疗RA的过程中可能可以通过影响上游T淋巴细胞的活化 ,调节其细胞免疫机制来达到治疗RA的目的。     

金匮肾气丸对肾阳虚动物模型影响的拆方研究

建立肾阳虚动物模型 ,对金匮肾气丸进行拆方研究。结果表明 ,肾气丸能显著提高阳虚小鼠T3、T4 水平 ,其作用机理可能与调节促进下丘脑—垂体—甲状腺轴有关。     

合成鱼腥草素对巨噬细胞呼吸爆发、细胞内游离钙离子浓度及T细胞分泌白细胞介素-2的影响

目的为了进一步分析合成鱼腥草素的免疫调节作用机理 ,研究合成鱼腥草素对于巨噬细胞呼吸爆发、细胞内钙离子浓度以及T细胞分泌白细胞介素水平的影响。方法巨噬细胞分离自大鼠腹腔灌洗液。以 2′ ,7′ 二氯荧光素二乙酯作为荧光指示剂 ,采用流式细胞术检测巨噬细胞的呼吸爆发。以fura 2作为钙离子荧光指示剂采用荧光分光光度法测定细胞内钙离子浓度。利用淋巴细胞分离液采用密度梯度离心法分离外周血T细胞 ,并用尼龙毛柱加以纯化。用ELISA法测定在亚适剂量ConA、白细胞介素 1α(IL 1α)以及白细胞介素 1β(IL 1β)存在的条件下合成鱼腥草素对白细胞介素 2 (IL 2 )分泌的影响。结果合成鱼腥草素可以刺激巨噬细胞呼吸爆发 ,提高细胞内钙离子浓度水平 ,促进T细胞分泌IL 2。结论合成鱼腥草素可能具有激活巨噬细胞和T淋巴细胞的作用 ,从而部分解释合成鱼腥草素的佐剂作用以及治疗感染性疾病的作用机理。     

淋巴细胞亚群和NK细胞在脾切除术前后的动态变化

目的研究脾切除术对T细胞亚群和自然杀伤细胞(NK细胞)免疫功能的影响.方法将所收集的30例脾切除患者和30例其它腹部手术患者分为实验组和对照组.比较两组患者手术前和术后7天的T淋巴细胞亚群和(NK)活性以及免疫功能的变化.结果术后7d实验组的CD3、CD4/CD8比值和NK细胞明显低于对照组(P＜0.05),其中,CD3、CD4、CD4/CD8、NK细胞的术前术后下降程度较对照组更加明显(P＜0.01).CD8水平则无统计学意义(P＞0.05).结论脾切除术后早期细胞免疫功能严重受损,对脾破裂或良性肿瘤患者的外科治疗有指导意义.     

SARS患者白细胞、淋巴细胞和乳酸脱氢酶水平分析

目的：研究严重急性呼吸综合征(SARS)患者白细胞、淋巴细胞和乳酸脱氢酶变化，探讨其与肺损伤的关系。方法：测定SARS患者激素治疗前后白细胞、淋巴细胞和血清乳酸脱氢酶含量并与健康正常人(对照组)进行比较；将SARS患者依据临床重症诊断标准分为重症组和普通组进行以上指标的比较。结果：SARS患者的白细胞、淋巴细胞绝对值均比对照组显著减少，乳酸脱氢酶明显高于对照组；经过7～10d激素治疗后的SARS患者白细胞、乳酸脱氢酶数量显著提高，淋巴细胞绝对值无显著变化。以上3项指标重症组明显高于普通组。结论：SARS患者白细胞数量、淋巴细胞绝对值显著降低，但可恢复正常；糖皮质激素治疗仅能使白细胞数量增多，而淋巴细胞绝对值未见明显改善。SARS患者的血乳酸脱氢酶升高，其水平与肺损伤的活动性相关。     

树突状细胞瘤苗诱导的抗神经胶质瘤作用体外实验研究

目的 :研究负载自体神经胶质瘤抗原的树突状细胞 (DCs)瘤苗在体外诱导的特异性细胞毒性淋巴细胞 (CTL)对神经胶质瘤细胞的杀伤效应。方法 :以组合酶消化法从新鲜神经胶质瘤手术标本中获取神经胶质瘤细胞 ,冻融制备神经胶质瘤抗原。GM -CSF、IL -4体外诱导外周血单个核细胞 (PBMC)获得DCs并负载神经胶质瘤抗原 ,继而以其刺激自体T淋巴细胞制备神经胶质瘤抗原特异性CTL ;用CytoTox96TM检测CTL对患自身神经胶质瘤细胞体外杀伤效应。结果 :负载神经胶质瘤抗原DCs诱导的特异性CTL对患者自身神经胶质瘤细胞的杀伤率达88 17 % ,显著高于LAK细胞的杀伤率 (P<0 05)。且其对同种不同分化类型的神经胶质瘤细胞株 (P<0 01)。结论 :负载神经胶质瘤抗原的DCs体外可诱导出高效而特异的抗神经胶质瘤效应 ,提示以DCs为中心的肿瘤生物治疗作用可望提高神经胶质瘤综合治疗水平     

介入栓塞治疗对Graves病T淋巴细胞亚群的影响

目的：观察介入栓塞治疗对Graves病T淋巴细胞亚群的影响。方法：24例难治性Graves病，选择性行双侧甲状腺上、下动脉插管，并注入聚乙烯醇或(和)明胶海棉栓塞治疗，观察栓塞后3月T淋巴细胞亚群变化。结果：Graves病患者治疗前CD3^ ，CD4^ 与正常组比较差异无显著性(P＞0．05)；CD8^ 下降、CD4^ ／CD8^ 比值升高与正常组比较差异有显著性(P＜0．05)；介入栓塞治疗后CD3^ 升高、CD^ 下降，CD8^ 升高，CD4^ ／CD8^ 下降与治疗前比较差异有显著性(P＜0．05)。结论：介入栓塞治疗可引起Graves病患者T淋巴细胞亚群变化，纠正甲亢免疫调节紊乱，有利于甲亢的治愈。     

应用胰岛素泵治疗儿童及青少年1型糖尿病对糖代谢的影响

为观察应用胰岛素泵治疗儿童及青少年1型糖尿病(T1DM)对糖代谢的影响 ,随访10例胰岛素泵治疗的T1DM患儿 ,分别观察胰岛素泵治疗前、后6个月的糖化血红蛋白值(HbA1c)、胰岛素用量、严重低血糖及酮症酸中毒发生次数的变化情况。结果显示 ,胰岛素泵治疗6个月后HbA1c 显著下降 ,治疗前为8.97 %±1.69 %,治疗后为7.51 %±1.17 % (t=2.52 ,P<0.05) ;胰岛素用量无显著下降 ;未发生严重低血糖和酮症酸中毒。表明胰岛素泵治疗可有效控制血糖 ,明显降低HbA1c,减少低血糖及酮症酸中毒的发生 ,是儿童及青少年T1DM常规治疗的较好选择。