家鸽顶盖脑片中Ⅱ g—j亚层神经元对乙酰胆碱的反应

在家鸽的离体顶盖脑片上，用玻璃微电极记录了顶盖Ⅱg-j亚层神经元对灌流乙酰胆碱所产生的反应，结果如下：在顶盖IIg-j亚层记录到66个神经元的自发放电，根据其放电特征，将它们分为3种形式：单个放电，丛状放电和连续放电，其中的46个神经元单位中有34个（34／46）对 酰胆碱产生自发放电增频反应；4个单位（4／46）的自发放电被乙酰胆碱抑制；8个单位（8／46）对乙酰胆碱无反应，在20个对乙酰胆碱产生增频反应的神经元单位中，有14个单位（14／20）的自发放电被阿托品所抑制，乙酰胆碱和阿托品的作用还具有可逆性的重复性，以上结果提示：在家鸽顶盖IIg-j亚层中可能有胆碱能纤维到达并存在乙酰胆碱敏感神经元。     

Ultrastructural localisation of substance P and choline acetyltransferase in endothelial cells of rat coronary artery and release of substance P and acetylcholine during hypoxia

Substance P and choline acetyltransferase have been localised in a small proportion of endothelial cells of rat coronary arteries using electron microscopic immunocytochemistry. During a hypoxic period of 1 min, coronary vasodilatation was produced in the Langendorff heart preparation and increased levels of substance P and acetylcholine were released into the perfusate. The possibility that these substances are released from endothelial cells during hypoxia and contribute to the hyperaemic response is discussed.     

组织胺在兔十二指肠纵肌收缩中的作用及递质间的相互关系

以家兔离体十二指肠纵肌方向的张力为指标，观察了乙酰胆碱（Ａｃｈ）、去甲肾上腺素（ＮＥ）、组织胺（Ｈｉｓｔａｍｉｎｅ）对十二指肠的作用，探讨了组织胺对Ａｃｈ，ＮＥ的调制作用．实验表明，在正常情况下兔离体十二指肠收缩活动比较规律，并出现梭形波，纵肌的张力变化呈现周期性．Ａｃｈ对十二指肠的作用依其剂量的不同而不同．ＮＥ通过β抑制性受体对十二指肠产生抑制作用，而β兴奋性受体和α兴奋性受体介导兴奋．组织胺对十二指肠的作用与肠的机能状态有关，Ｈ１型受体介导兴奋．阈下剂量的组织胺可激活ＮＥ的α受体使ＮＥ表现为兴奋作用，对Ａｃｈ具有调制作用     

Effect of Calcium on Spontaneous Quantal Transmitter Secretion from ACh-Loaded Myocytes

Introduction Transmitter secretion requires specialized secretory or- ganelles, the synaptic vesicles, for the packaging, stor- age, and exocytotic release of the transmitters[1,2]. The neurotransmitter acetylcholine (ACh) is released at the neuromuscular…     

"补肾活血"对老年鼠脑乙酰胆碱代谢的影响

为研究“补肾活血”对老年鼠脑乙酰胆碱(Ach)代谢的影响，将老年大鼠分别用补肾益精、行气活血、补肾活血方剂灌胃30d，采用高效液相色谱技术检测大鼠脑内Ach摩尔质量浓度、分光光度法检测胆碱乙酰转移酶(ChAT)和胆碱酯酶(AChE)的活性．研究发现老年大鼠脑内Ach摩尔质量浓度、ChAT活性显著低于青年鼠，AChE活性显著高于青年鼠；补肾益精、行气活血、补肾活血均可改善老年鼠脑内Ach代谢，补肾活血法明显优于补肾益精法、行气活血法．     

OA诱导大鼠基底核Ach降低及τ蛋白过度磷酸化

研究了磷酸酯酶(proteinphosphatase，PP)对胆碱能神经元功能的影响，将PP抑制剂岗田酸(okadaic acid，OA)注入大鼠双侧Meynert基底核，并经免疫印迹检测r(tau)蛋白磷酸化程度、经微渗透结合HL,PC检测Ach、经Morris水迷宫检测大鼠的空间记忆能力，结果发现，Meynert基底核注射OA后，Ach水平降低，τ蛋白在Sei-198／Sei-199／Set-202，Ser-396／Ser-404位点发生过度磷酸化，并伴有大鼠空间记忆障碍，本研究结果提示PP活性降低可能参与了神经元纤维缠结形成、胆碱能神经元功能及认知功能障碍，在AD发病机制中起重要作用。     

Neuromuscular synaptogenesis: clustering of acetylcholine receptors revisited

Clustering of neurotransmitter receptors in the postsynaptic membrane is critical for efficient synaptic transmission. During neuromuscular synaptogenesis, clustering of acetylcholine receptors (AChRs) is an early sign of postsynaptic differentiation. Recent studies have revealed that the earliest AChR clusters can form in the muscle independent of motorneurons. Neurally released agrin, acting through the muscle-specific kinase MuSK and rapsyn, then causes further clustering and localization of clusters underneath the nerve terminal. AChRs themselves are required for agrin-induced clustering of several postsynaptic proteins, most notably rapsyn. Once formed, AChR clusters are stabilized by several tyrosine kinases and by components of the dystrophin/utrophin glycoprotein complex, some of which also direct postnatal synaptic maturation such as formation of postjunctional folds. This review summarizes these recent results about AChR clustering, which indicate that early clustering can occur in the absence of nerves, that AChRs play an active role in the clustering process and that partly different mechanisms direct formation versus stabilization of AChR clusters. Received 10 April 2002; received after revision 4 June 2002; accepted 10 June 2002