桂枝汤有效部位A对体温双向调节作用机理研究——对下丘脑三磷酸肌醇和钙调蛋白含量的影响

桂枝汤有效部位Ａ（Ｆｒ．Ａ）对酵母致热大鼠下丘脑三磷酸肌醇（ＩＰ３）和钙调蛋白（ＣａＭ）的降低及安痛定诱致低体温大鼠下丘脑ＩＰ３和ＣａＭ含量的升高均有明显的逆转效应，即使高体温大鼠下丘脑ＩＰ３和ＣａＭ升高，低体温大鼠ＩＰ３和ＣａＭ降低，分别使之趋向正常。结果提示，Ｆｒ．Ａ对体温的双向调节有中枢神经细胞内信息传递系统ＩＰ３和ＣａＭ参予。     

Reversible depression of action potentials and force production in frog single muscle fibres by calmodulin-inhibitors

The effects of the calmodulin-inhibitors trifluoperazine, thioridazine and zaldaride maleate on the responses to electrical stimulation in isolated frog skeletal muscle fibres were investigated. All three drugs initially reduced the amplitude of the action potentials but potentiated twitch force. This was followed by a total loss of action potentials and force production. However, the resting membrane potential was not changed. The effects were completely reversible upon removal of the drugs. These results suggest that an intact calmodulin system is required for normal function of the sarcolemmal sodium channels of frog skeletal muscle.     

Myosin light chain kinase: functional domains and structural motifs

Conventional myosin light chain kinase found in differentiated smooth and non-muscle cells is a dedicated Ca²⁺/calmodulin-dependent protein kinase which phosphorylates the regulatory light chain of myosin II. This phosphorylation increases the actin-activated myosin ATPase activity and is thought to play major roles in a number of biological processes, including smooth muscle contraction. The catalytic domain contains residues on its surface that bind a regulatory segment resulting in autoinhibition through an intrasteric mechanism. When Ca²⁺/calmodulin binds, there is a marked displacement of the regulatory segment from the catalytic cleft allowing phosphorylation of myosin regulatory light chain. Kinase activity depends upon Ca²⁺/calmodulin binding not only to the canonical calmodulin-binding sequence but also to additional interactions between Ca²⁺/calmodulin and the catalytic core. Previous biochemical evidence shows myosin light chain kinase binds tightly to actomyosin containing filaments. The kinase has low-affinity myosin and actin binding sites in Ig-like motifs at the N- and C-terminus, respectively. Recent results show the N-terminus of myosin light chain kinase is responsible for filament binding in vivo. However, the apparent binding affinity is greater for smooth muscle myofilaments, purified thin filaments, or actin-containing filaments in permeable cells than for purified smooth muscle F-actin or actomyosin filaments from skeletal muscle. These results suggest a protein on actin thin filaments that may facilitate kinase binding. Myosin light chain kinase does not dissociate from filaments in the presence of Ca²⁺/calmodulin raising the interesting question as to how the kinase phosphorylates myosin in thick filaments if it is bound to actin-containing thin filaments.     

凝血酶对牛主动脉内皮细胞表达组织因子活性的影响

目的 :探讨凝血酶对内皮细胞表达组织因子 (TF)活性的作用及其机制。方法 :实验材料为第 4～ 8代新生牛主动脉内皮细胞 ,采用一期凝固法检测细胞冻融液中的TF活性。结果及讨论 :凝血酶可促进血管内皮细胞表达TF活性 ;凝血酶对内皮细胞的这种刺激作用可能具有Ca2 + /CaM依赖性 ,且可能与细胞内cAMP浓度有关。     

赛庚啶对大鼠垂体-肾上腺皮质轴作用及机制的研究

目的　研究赛庚啶 (cyproheptadineCyp)对大鼠垂体 肾上腺皮质轴内分泌功能及机制的影响。方法　用放射免疫分析法 (RIA)观察Cyp对大鼠血清ACTH、可的松水平的影响。用电镜及荧光定量PCR技术 ,观察Cyp对ACTH细胞、肾上腺皮质束状带细胞超微结构及钙调素 (calmodulinCaM)mRNA在垂体、肾上腺皮质基因表达的影响。结果　Cyp 2 3、4 6mg·kg- 1 ·d- 1 ,ig,连续用药 1 4d ,可使大鼠血清ACTH和可的松含量降低 (P <0 0 5 ,P <0 0 1 )。组织形态电镜观察 ,该药亦可引起大鼠垂体ACTH细胞、肾上腺皮质束状带细胞超微结构的退行性改变。同时发现CaMmRNA在垂体、肾上腺皮质的基因表达较对照组减少 (P <0 0 5 ,P<0 0 1 )。结论　Cyp对大鼠垂体 肾上腺皮质轴分泌功能有抑制作用 ,其机制可能与抑制CaMmRNA在垂体、肾上腺皮质的基因表达有关     

钙调素免疫原的制备及检测

目的　研究钙调素免疫原的制备。方法　以碳化二亚胺法将钙调素—卵清蛋白偶联物作为免疫原 ,采用常规免疫方法免疫BALB/C小鼠 ,酶联免疫吸附法 (ELISA)检测抗体效价。结果　用钙调素—卵清蛋白偶联物腹腔注射的BALB/C小鼠经 2次体内免疫后测血清中的抗体效价均为阳性。结论　将钙调素和卵清蛋白进行偶联来作为抗原是成功的。     

抗钙调素自身抗体的测定与临床应用

自人脑中提取钙调素,用戊二醛共价交联抗原法将其包被于聚苯乙烯反应板微孔,建立了检测循环抗钙调素自身抗体的间接 ELISA 法。此法特异性、精密度较好。100名正常人抗钙调素活性((?)±s)为7.56±2.68U/ml,SLE(n=32),RA(n=28),肝炎(n=43)、慢性肾炎(n=22)抗钙调素的活性与阳性率均显著高于正常对照组。     

Modulation of Cardiac Na+ and Ca2+ Currents by CaM and CaMKII

Sarcolemmal sodium (Na) and calcium (Ca) currents are fundamentally involved in shaping the cardiac action potential. Alterations in Na or Ca currents can change action potential characteristics and therefore might result in cardiac arrhythmias. Also, these ions contribute to excitation-contraction coupling and therefore are important in myocyte shortening and contractility of the heart. This review article summarizes how sarcolemmal Na and Ca channels are regulated with an emphasis on the novel role of Ca-dependent proteins Calmodulin (CaM) and especially Ca/CaM-dependent protein kinase II (CaMKII) to modulate sarcolemmal Na and Ca channels in the heart.     

Interaction of calmodulin with synthetic deletion peptides of melittin

The 26-residue peptide melittin present in bee venom has been shown to bind calmodulin tightly. In this study we synthesized the following series of deletion peptides of melittin by the solid-phase method: Mel12, Mel13, Mel 14, Mel 15, Mel15F. The results of this study show that the deletion peptides Mel 14 and Mel 15 have almost the same binding activity as the intact native peptide. Each deletion peptide forms a 1:1 complex with calmodulin according to electrophoresis analysis. When the tryptophanyl residue of Mel15 was replaced by the phenylalaninyl residue, the dissociation constant of the peptide—calmodulin complex increased. This shows the importance of the tryptophanyl residue for binding to calmodulin.     

The relationship between alterations of calcium and calmodulin levels in the cerebral cortex and the blood following brain in

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