脑型肌酸激酶同功酶在脑血管病中的意义 Ⅱ.急性脑血管病患者血清和脑脊液中CKBB变化及与CT片上病损大小的关系

用改良的ELISA检测25例正常对照组和32例急性脑血管病患者的血清和脑脊液(CSF)中的脑型肌酸激酶同功酶BB(creatine kinase isoenzyme BB)浓度。32例急性脑血管病患者CSF CKBB平均水平为16.62±8.3ng/ml,明显高于对照组(7.5—4.8ng/ml)。发病24h内CSFCKBB轻微增高,24～48h达高峰,以后下降,7天左右尚未恢复正常。病初CSF CKBB水平明显高于恢复期。9例高血压性脑出血的血肿出血量(按CT片上血肿大小计算)与患者CSF CKBB有密切关系(r=0.8127,P<0.01)。血肿体积(X)与CSF CKBB浓度(y)的回归方程y—7.945±0.872X。     

Activation of guinea pig eosinophil respiratory burst by leukotriene B4: role of protein kinase C

Leukotriene B4 (LTB4) and the protein kinase C activator, 4-beta-phorbol dibutyrate (PDBu), both induced a pronounced and concentration-dependent stimulation of hydrogen peroxide (H2O2) generation by purified guinea pig peritoneal eosinophils in the concentration range 1 nM-1 microM. The LTB4 response was inhibited competitively by the specific LTB4 receptor antagonist, U-75302, with a KB of 25 nM, while the concentration-response curves for both stimuli were shifted rightwards (3.8-fold and 2.8-fold for LTB4 and PDBu, respectively) by the competitive protein kinase C inhibitor, 1-O-hexadecyl-2-O-methylglycerol at a concentration of 300 microM. LTB4 appears, therefore, to induce respiratory burst in eosinophils via a receptor-mediated mechanism involving protein kinase C.     

KN-93抑制脊髓背角C-纤维诱发电位LTP的诱导和早期维持

[目的]探讨钙-钙调蛋白依赖性蛋白激酶Ⅱ(CaMKⅡ)在脊髓背角C-纤维诱发电位长时程增强(LTP)的诱导和维持中的作用。[方法]用钨丝微电极在脊髓腰膨大部背角浅层神经元细胞外记录C-纤维诱发电位,强直刺激坐骨神经诱导背角C-纤维诱发电位的LTP。在LTP诱导前后,在暴露的脊髓表面局部给予CaMKⅡ的选择性抑制剂KN-93,观察C-纤维诱发电位的变化。[结果]50μmol/L的KN-93不影响脊髓背角C-纤维诱发电位的幅度,但可完全阻断脊髓背角LTP的诱导(n=6)。KN-93呈时间依赖性翻转脊髓背角LTP。在LTP诱导后30min,50μmol/L的KN-93对LTP的早期表达无影响(n=4),而100μmol/L的KN-93在用药后,LTP逐渐降低,于3h降至对照水平(n=6);在LTP诱导后1h脊髓局部给予100μmol/L的KN-93,7例动物中有5例LTP被抑制;但同样浓度的KN-93,在LTP诱导后3h,不能翻转业已建立的LTP(n=5),且增加KN-93的浓度至200μmol/L也不能抑制脊髓背角LTP。[结论]CaMKⅡ参与脊髓背角C纤维诱发电位LTP的诱导和早期维持,但KN-93对晚期LTP无抑制作用。     

Role of tyrosine kinase activity in cardiac slow delayed rectifier channel modulation by cell swelling

 We studied the effects of cell swelling on membrane currents of canine ventricular myocytes using the whole-cell patch-clamp method. Cell swelling was induced by lowering the osmolarity of the bath solution to 60% of control. Cell width and currents were measured simultaneously. Cell swelling induced little or no change in the L-type Ca, the inward rectifier, and the transient outward currents, but a marked increase in the slow delayed rectifier current (I _Ks) was seen. We further examined the role of protein kinase activities in I _Ks modulation by cell swelling. This modulation was not affected by inhibiting serine/threonine kinases using H-8. On the other hand, the modulation was inhibited by genistein (a protein tyrosine kinase inhibitor) although not by daidzein (an inactive analogue of genistein). Our data suggest that in canine ventricle cell swelling can increase protein tyrosine kinase activity, which can augment I _Ks and contribute to changes in membrane electrical activity observed under these conditions. Received: 20 September 1996 / Received after revision and accepted: 5 December 1996     

Accentuated antagonism by angiotensin II on guinea-pig cardiac L-type Ca-currents enhanced by β-adrenergic stimulation

 To examine mechanism(s) underlying the accentuated antagonism by angiotensin II (A-II) on twitch tension, we recorded L-type Ca²⁺ currents (I _Ca,L) using conventional patch-clamp techniques in single, guinea-pig, ventricular myocytes. I _Ca,L was recorded by a step-pulse protocol after eliminating K⁺ conductances (internal Cs⁺ plus tetraethylammonium chloride and K⁺-free extracellular solution). A-II (100 nM) did not affect basal I _Ca,L, but inhibited I _Ca,L that had been enhanced (approximately 200% of control) by (ISO, isoproterenol 100 nM). The inhibitory action of A-II was concentration dependent (concentration eliciting 50% inhibition 88±9 pM, n=41) and the ISO-enhanced component of I _Ca,L was completely blocked by A-II at concentrations above 10 nM. CV-11974 (500 nM), an A-II type-1 receptor (AT₁) antagonist, prevented the inhibitory action of A-II. Pre-incubation with pertussis toxin (PTX) abolished the inhibitory effect of A-II. A-II also inhibited the I _Ca,L enhanced by histamine (500 nM) and forskolin (1 μM), but failed to affect I _Ca,L enhanced by intracellular cyclic adenosine monophosphate (1 mM). The inhibitory action of A-II may therefore involve AT₁ receptors/PTX-sensitive, guanine nucleotide-binding (G) proteins (Gi)/adenylate cyclase and partially explains the A-II-dependent accentuated antagonism of inotropy.     

肾上腺髓质素对内皮素促家兔气道平滑肌细胞增殖的抑制作用

在体外培养的家兔气道平滑肌细胞（ＡＳＭＣ）上，观察肾上腺髓质素（ＡＭ）对内皮素（ＥＴ）促ＡＳＭＣ增殖的影响及丝裂素活化蛋白激酶（ＭＡＰＫ）活性的变化。以探讨ＡＭ对ＡＳＭＣ增殖的调控。结果显示１０－８ｍｏｌ／ＬＥＴ－１显著刺激ＡＳＭＣ３Ｈ－ＴｄＲ参入及ＭＡＰＫ激活（Ｐ＜０．０１）。ＡＭ（１３－５２）呈剂量依赖地抑制ＥＴ－１的上述作用（Ｐ＜０．０５，Ｐ＜０．０１）。单独应用ＡＭ（１３－５２）对ＡＳＭＣ３Ｈ－ＴｄＲ参入及ＭＡＰＫ活性无明显影响。表明ＡＭ（１３－５２）可抑制ＡＳＭＣ对ＥＴ－１的增殖反应，其机理可能涉及ＭＡＰＫ活性的抑制。     

The effects of phorbol esters with different biological activities on protein kinase C

The sapintoxins are a series of naturally occurring fluorescent phorbol esters with a range of selective biological activities (e.g. pro-inflammatory but non-tumour promoting). Their ability to activate protein kinase C (PKC) in vitro has been studied. Both tumour promoting and non-promoting phorbol derivatives activate the enzyme in vitro at low concentrations. 12-deoxyphorbol-13-phenylacetate-20 acetate (DOPPA) acts as a partial agonist in the activation of protein kinase C. Structurally distinct phorbol esters may therefore preferentially activate different forms of protein kinase C. α-sapinine, a biologically inactive compound, binds to protein kinase C without stimulating the enzyme and prevents subsequent activation by phorbol esters such as 12-O-tetradecanoyl phorbol-13-acetate (TPA).     

Chronic lithium treatment increases the phosphorylation of a 64-kDa protein in rat brains

Despite the wide clinical use of lithium in the treatment of manic depressive illness there is no adequate explanation for its mechanism of action. In the light of lithium's suggestive effects on the second messenger system in the brain, we studied the effects of chronic dietary lithium treatment (achieving blood levels in the therapeutic range) on protein phosphorylation in different areas of rat brain. An increase in the phosphorylation of a 64-kDa membrane-associated protein was evident in the lithium-treated rats compared to controls. This increase was observed only under basal phosphorylating conditions and was abolished when the phosphorylation was performed in the presence of Ca²⁺ or Ca²⁺ and calmodulin. The possibility that this 64-kDa protein affected by lithium is the beta-subunit of the calmodulin-dependent protein kinase or a different protein which co-migrates with it is discussed.     

人T淋巴母细胞（Jurkat）移动性的研究

利用人Ｔ淋巴母细胞（Ｊｕｒｋａｔ）细胞系作为研究对象。企图探探索细胞外基质成份及肌醇磷脂细胞信息传递系统与细胞移动的关系。研究结果表明：当细胞被伏波醇酯（ＰＭＡ）处理过后，其粘连性与移动件对纤维连结蛋白（ＦＮ）底物的反应在已是高水平的基础上有更进一步提高的作用。与ＦＮ刊相反的是，未经ＰＭＡ处理处的Ｊｕｒｋａｔ细胞对层粘连蛋白（Ｌｍ）底物却无明显的粘连性及移动性增加的反应，尽管在ＰＭＡ处理过４小时内亦无任何的增强。但是，当ＰＭＡ作用于细胞２４一４８小时后则明显池增加其Ｌｍ底物的粘连性及移动性反应，表明了其明显的协同作用。分别用抗ＦＮ、抗Ｌｍ及蛋白激酶Ｃ抑制剂Ｓｔａｕｒｏｓｐｒｉｎｅ（ＳＰ）时均起到特异性的抑制作用。可见，协同作用的产生是通过蛋白激酶Ｃ激活后的－段时间内，使细胞表面Ｌｍ受体密度增加而对底物Ｌｍ反应增强所致。