GABA-Mediated Presynaptic Inhibition in Crayfish Primary Afferents by Non-A,Non-B GABA Receptors

GABAergic presynaptic inhibition has been investigated in primary afferents using an in vitro preparation of the crayfish, Procambarus clarkii. Presynaptic terminals of a leg proprioceptor, the coxo-basal (CB) chordotonal organ, were impaled in the neuorpil of the 5th thoracic ganglion. Pressure ejection of small volumes of the GABAA or GABAB receptor agonists, muscimol and 3-aminopropylphosphinic acid (3-APA), both induce depolarizing responses in the impaled CB sensory terminal. These depolarizations are not blocked by the specific GABAA and GABAB receptor antagonists, SR-95531 and phaclofen, but they are abolished by picrotoxin. Both muscimol- and 3-APA-induced depolarizations are carried by an increase in conductance to Cl-. The presynaptic increase in conductance to Cl- by GABA receptor activation leads to a depression of sensory synaptic transmission through a shunting of the incoming spikes. Monosynaptic EPSPs elicited in motor neurons by CB sensory nerve stimulation are depressed by muscimol and 3-APA. GABA-mediated presynaptic modulation occurs in crayfish primary afferents which can adjust the gain of reflexes. These results show that GABA-activated Cl- channels can induce a modulation of synaptic transmission, but also that the distinction between GABAA and GABAB receptors, as in vertebrates, is not applicable to the crustacean primary afferents.     

Residual effects of prolonged cannabis administration on exploration and DRL performance in rats

Chronic oral administration of cannabis extract to rats (daily ⁹ dose 20 mg/kg) was examined for its residual effect on open field activity and DRL (differential reinforcement of low-rate responding) performance, following a 2–3-month drug-free period. Locomotor activity during the latter part of an open field test was markedly increased in rats previously treated for either 6 months or 3 months with the drug. The same treatments also produced a significant impairment on a DRL-20 task relative to control subjects' performance. These and other findings (impaired maze learning and facilitated two-way shuttle box avoidance) might mean that cannabis produces long-lasting hippocampal, dysfunction in rats.     

中药载体制剂的研究进展

总结近年来中药载体制剂的研究工作和文献报道，综述了有关脂质体、微粒、毫微粒、乳剂等作为载体在中药制剂中的应用。     

中药和天然药靶向制剂的研究进展

靶向制剂可以提高靶组织的药理作用强度和降低全身的不良反应 ,是一种比较理想的给药方式 ,为第四代的药物剂型。采用脂质体作为药物载体是研究的重点 ,磁靶向 ,酶靶向制剂也是研究热点。此外 ,口服结肠靶向给药系统 (OCDDS)也是靶向制剂的一个重要部分 ,其是经口服将药物运送到回盲肠后释放并发挥局部或全身的治疗作用。中药靶向制剂的研究在我国还仅处于试探阶段 ,目前中药和天然药物的靶向制剂的研究大多数是以天然单一有效成分为原料药物 ,而用中药有效部位研制的靶向制剂屈指可数 ,这与制定中药有效部位的质量标准及制剂工艺难度大有关。中药新剂型和新技术的开展是中药国际化的关键 ,需要有组织地开展多学科合作 ,靶向制剂是中药今后发展的一个重要课题。     

口腔溃复平膜剂的研究

目的：优选口腔溃复平膜剂（黄柏，龙胆草，青黛等）最佳处方。建立膜剂中盐酸小檗碱含量的测定方法。方法：以膜剂外观和融化时间为指标。采用L9（3^4)正交试验筛选处方，反相液相色谱法测定膜剂中盐酸小檗碱的含量。结果：膜剂最佳处方为：中药提取液40mL,PVA0.588:PVA1788为4：1.5，甘油含量8%，CMC-Na0.25g；测定方法中盐酸小檗碱的平均回收率为97.7%。结论：膜剂的外观（包括可塑性，粘附性及抗拉强度）和融化时间等指标均符合质量标准的要求，采用反相液相色谱法可有效控制溃复平膜剂中盐酸小檗碱的含量。     

甲硝唑阴道泡腾片生产工艺的研究

目的　简化甲硝唑阴道泡腾片 (Ⅰ )的生产工艺。方法　采用非水制粒法 ,酸碱组分混合制备Ⅰ ,并按照《中国药典》2 0 0 0年版稳定性实验指导原则进行稳定性考察。结果　用非水制粒法制备的Ⅰ通过稳定性加速实验后仍符合《中国药典》2 0 0 0年版的质量要求。结论　用非水制粒法制备Ⅰ是简便可行的。     

中药炮制机理初探

开展中药炮制机理研究，揭示其炮制内涵变化实质，是确定中药饮片最佳炮制工艺，制定饮片质量标准，提高临床治疗疗效，发展炮制学科理论水平的关键。     

尼索地平微球的制备

采用溶剂挥发法制备了尼索地平微球 ,考察了制备工艺中影响微球质量的 5个主要因素 ,筛选出较理想的处方和工艺。所得微球形态圆整 ,表面光滑 ,粒径 (18.2± 3.8) μm,载药量 2 1.2 % ,包封率 85 .4 %。     

聚维酮碘泡腾栓的研制与应用

目的：研制聚维酮碘泡腾栓，并考察其临床疗效。方法：采用正交设计，筛选聚维酮碘泡腾栓的最优处方，并对该处方进行了稳定性研究、局部刺激性研究和临床疗效研究。结果：本栓剂以聚氧乙烯单硬脂酸S—40为基质，枸橼酸和碳酸氢钠为泡腾散，具有载药量大、刺激性小、起效快、渗透性强、临床疗效良好等优点。结论：本制剂设计合理，稳定性好，可满足临床需要。     

苯并吡喃-4-酮衍生物的合成及其趋骨性探讨

目的 根据具有趋骨性的化合物的共同特征，设计并合成苯并吡喃-4-酮类化合物，检测它们的趋骨性。方法 以苯并吡喃-4-酮为核心，设计并合成了6个在其3位、5位、6位有酚羟基、甲氧基、羧基、酯基、甲氧羰甲氧基等基团的衍生物，用羟基磷灰石吸附实验检测其趋骨性。结果 所有合成的目标化合物的结构均经过IR，^1H—NMR和MS确认。结论 部分设计的苯并吡喃-4-酮衍生物具有比四环紊更好的趋骨性。