丁基苯酞抑制低氧低糖诱导的大鼠皮质神经细胞凋亡

目的：以原代培养的大鼠胎鼠皮质神经元低氧低糖再复氧为模型,研究丁基苯酞对神经细胞凋亡的抑制作用。方法：用流式细胞术检测DNA含量及凋亡细胞百分率,透射电镜观察细胞形态学变化,DNA琼脂糖凝胶电泳和原位末段标记(TUNEL)检测DNA断裂。 结果：丁基苯酞能减轻细胞核形态的改变,减少DNA断裂和阳性细胞数,使低氧低糖诱导的神经细胞凋亡百分率明显下降,凋亡峰显著降低。 结论：丁基苯酞对低氧低糖诱导的大鼠皮质神经细胞凋亡有抑制作用。     

左旋丁基苯酞对低糖氧造成神经元损伤的保护作用

目的探讨新药左旋丁基苯酞（1-NBP）对低糖低氧造成的神经细胞坏死和凋亡的保护作用，并从线粒体和细胞内钙角度对其可能的作用机制进行研究。方法：以低糖低氧造成原代培养神经细胞的损伤模型，采用Hoeehest 33824（Hoe）、Ppropidium iodide（PI）、Fluo-3／AM和Rhodamine-123（Rhod）对细胞进行荧光染色，分别测定不同损伤条件下神经细胞的坏死、凋亡、细胞内游离钙和线粒体膜电位的变化，并对1-NBP的保护作用进行观测。结果原代培养神经元的的坏死和凋亡的发生率在低糖氧处理3h后即出现明显升高，     

丁基苯酞对低糖低氧诱导的大鼠皮层神经细胞损伤的保护作用

为进一步探讨丁基苯肽对神经的保护作用,用原代培养大鼠皮层神经细胞的方法,以LDH和细胞形态等指标,观察了l-丁基苯酞(l-NBP)和d-丁基苯酞(d-NBP)对低糖低氧诱导的大鼠皮层神经细胞损伤的保护作用。结果表明:l-NBP和d-NBP能剂量依赖性地抑制低糖低氧诱导的大鼠皮层神经细胞内LDH的释放,降低细胞死亡率,并能改善受损细胞的形态;此外还能明显减轻低糖低氧诱导的神经细胞内粗面内质网脱颗粒及多聚核糖体解聚。提示:NBP对低糖低氧诱导的大鼠皮层神经细胞损伤有明显保护作用。     

中药962对神经细胞内钙升高的血清药理学研究

目的:探讨中药复方962的小鼠血清制品(含药血清)对线粒体损伤造成的神经细胞内游离钙升高的影响及其作用机制。方法:用3-nitropropionicacid(3-NPA)和1-methyl-4-phenyl-1,2,3,6-tetrahydro-pyridine(MPTP)造成胎鼠神经细胞内钙升高模型。用Fura-2/AM作细胞内钙的荧光指示剂,观察中药复方962的含药血清对神经细胞内游离钙升高的抑制作用,同时利用内钙释放剂Thapsigargin、外源性谷氨酸和KCl作工具药,对含药血清的作用环节进行分析。结果:不同剂量和不同处理时间的含药(962)血清对MPTP和3-NPA造成的神经细胞内钙增高都有明显的抑制作用,而且表现出良好的量效关系。在MPTP和3-NPA模型中,作用最强的分别是给药3d和14d得到的血清。含药血清能抑制谷氨酸和KCl引起的细胞内钙增高,大剂量下对Thapsigargin造成的内钙升高也有抑制作用。结论:中药复方962对MPTP和3-NPA造成的神经细胞内钙增高有抑制作用,在两种模型中起效的主要成分份不同,可能分别为原药/早期代谢产物和后期代谢产物/活性因子。作用机制主要是抑制细胞外钙内流,大剂量对细胞内钙库的释放也有影响。     

TMB-8对去甲肾上腺素和BHQ引起新生大鼠单个脑细胞内游离钙增高的影响

应用AR-CM-MIC阳离子测定系统,研究TMB-8对体外新生SD大鼠单个脑细胞内游离钙的抑制作用及其机制。结果表明,在无细胞外钙情况下,静息[Ca²⁺]i为79±13nmol·L^-1。TMB-810,30μmol·L^-1能明显降低静息[Ca²⁺]i。TMB-8100μmol·L^-1对高钾去极化引起的[Ca²⁺]i显著增高无明显影响。在细胞外钙为1.3mmol·L^-1时,去甲肾上腺素诱导的细胞内[Ca²⁺]i升高可部分被TMB-8抑制;TMB-8(30μmol·L^-1)对BHQ引起的[Ca²⁺]i的升高无明显抑制作用。而当细胞外液[Ca²⁺]i为0时,TMB-8几乎完全抑制了去甲肾上腺素和BHQ的作用。提示TMB-8降低脑细胞内游离钙的作用机制是通过促使细胞内钙进入肌浆网以抑制内钙的释放,并通过饱和肌浆网内Ca²⁺间接地阻滞细胞膜钙通道。     

小檗碱对培养大鼠神经细胞内游离Ca2+的影响

以Fura-2/AM为细胞内钙离子的荧光指示剂,用AR-CM-MIC阳离子测定系统,直接测定了体外培养的新生大鼠神经细胞内游离钙([Ca²⁺]i)值,并观察了小檗碱(Ber)的影响。结果表明,Ber对神经细胞静息[Ca²⁺]i无明显影响,Ber1～100μmol·L^-1能剂量依赖地抑制去甲肾上腺素和H₂O₂引起的[Ca²⁺]i升高,其IC₅₀分别为39.9和17.9μmol·L^-1。高剂量Ber(10～100μmol·L^-1)能抑制高K+引起的[Ca²⁺]i升高。姐果提示,Ber对去甲肾上腺素,高K⁺及H₂O₂引起的[Ca²⁺]i升高的抑制作用可能是其抗脑缺血作用机制之一。     

小檗碱对培养大鼠神经细胞内游离Ca^2＋的影响

以Ｆｕｒａ２／ＡＭ为细胞内钙离子的荧光指示剂，用ＡＲＣＭＭＩＣ阳离子测定系统，直接测定了体外培养的新生大鼠神经细胞内游离钙（［Ｃａ２＋］ｉ）值，并观察了小檗碱（Ｂｅｒ）的影响。结果表明，Ｂｅｒ对神经细胞静息［Ｃａ２＋］ｉ无明显影响，Ｂｅｒ１～１００μｍｏｌ·Ｌ－１能剂量依赖地抑制去甲肾上腺素和Ｈ２Ｏ２引起的［Ｃａ２＋］ｉ升高，其ＩＣ５０分别为３９．９和１７．９μｍｏｌ·Ｌ－１。高剂量Ｂｅｒ（１０～１００μｍｏｌ·Ｌ－１）能抑制高Ｋ＋引起的［Ｃａ２＋］ｉ升高。姐果提示，Ｂｅｒ对去甲肾上腺素，高Ｋ＋及Ｈ２Ｏ２引起的［Ｃａ２＋］ｉ升高的抑制作用可能是其抗脑缺血作用机制之一。     

丁基苯酞的体内代谢转化研究

大鼠po丁基苯酞(NBP),定时收集尿液,经酶水解、提取浓缩、衍生化处理后用GC/MS分析。在给药后0～24h及24～48h尿中,NBP原药含量很低,主要以代谢物形式存在,依次为γ-羟基、β-羟基与3-羟基取代物。NBP体内代谢结果与肝微粒体中代谢结果基本一致。     

丁基苯酞及其光学异构体的抗惊厥作用

ｌ－丁基苯酞是从芹菜籽中分离出的有效成分。ｄｌ－丁基苯酞（ｄｌ－３－ｎ－ｂｕｔｙｌｐｐｈｔｈａｌｉｄｅ），简称ＮＢＰ，又名芹菜甲素，是我所人工合成的消旋体〔１〕。于澍仁等〔２〕研究表明ｌ－ＮＢＰ和ｄｌ－ＮＢＰ对最大电休克，最小电休克、戊四唑惊厥和原发...     

应用Fura-2/AM检测分离的神经细胞内游离钙及其变化

本文以酶法制备新生大鼠脑细胞悬液,运用近年来发展起来的Fura-2技术,检测此神经细胞内游离钙(以下简写为[Ca²⁺]i)及其变化。结果表明:在静息状态下,其[Ca²⁺]i为240±5nmol/L。高钾去极化可使[Ca²⁺]i成倍增加.钙拮抗剂verapamil和Ilifedipinc能阻断高钾升高[Ca²⁺]i的作用。实验结果证明了所制备的神经细胞悬液的可用性及建立的Fura-2测定[Ca²⁺]i方法的可靠性。     

CR1409拮抗缩胆囊素升高细胞内Ca~(2+)的作用

CR1409是一种新合成的缩胆囊素(CCK)受体拮抗剂。本文使用荧光指示剂Fura-2作为细胞内钙离子的探测物,在离体的大白鼠胰腺细胞研究OR1409对CCK引起细胞内钙离子浓度升高的拮抗作用。结果表明:10μmol/L CR1409完全抑制1nmol/L CCK的作用,半效抑制浓度为0.37μmol/L,比另一种拮抗剂双丁酰环鸟嘌呤核苷(db cGMP)强100倍。随着CR1409浓度的递增,使CCK升高细胞内钙离子浓度的量效曲线右移,根据Schild方法计算,pA_2值为6.93(r=0.992)。CR1409对氯氨甲酰胆碱和蛙皮素无拮抗作用。实验结果证明CR1409是一种效力较强的、特异性的和竞争性的CCK受体拮抗剂。     

银耳多糖对小鼠脾细胞内游离钙离子浓度的影响

为进一步探讨银耳多糖(TP)免疫调节作用的机制,建立了特异性荧光探针Fura-2测定脾细胞内游离钙离子浓度的方法,观察TP对脾细胞内游离钙离子浓度的影响。结果表明,TP在一定剂量范围内可以剂量依赖方式增加脾细胞内游离钙离子的浓度,并与ConA有协同作用。在外钙为零时,TP对内钙释放无影响,钙通道阻断剂维拉帕米(verapamil 10μg·mL^-1)可阻断TP升高脾细胞内游离钙离子浓度的作用。     

银杏内酯B对大鼠中性白细胞花生四烯酸代谢酶和细胞内钙水平的影响

目的　观察银杏内酯B对大鼠中性白细胞花生四烯酸代谢酶及细胞内钙水平的影响。方法　反相高效液相色谱及Fura-2/AM荧光指示剂法。结果　银杏内酯B在0.1-10μmol·L^-1范围内,使花生四烯酸释放量降低10.9%-22.2%;0.1-50μmol·L^-1时,LTB₄和5-HETE生成量分别降低29.4%-88.6%和26.2%-89.3%;在0.1-100μmol·L^-1使PAF和fMLP刺激引起的细胞内游离钙浓度分别降低13.9%-51.4%和2.2%-36.6%。结论　银杏内酯B能抑制体外大鼠中性白细胞花生四烯酸代谢酶的活性及细胞内游离钙浓度的升高。     

丁基苯酞对局灶性脑缺血大鼠软脑膜微循环障碍的影响

目的：观察消旋、左旋及右旋丁基苯酞（dl-,l-,d-3-n-butylphthalide,dl-,l-,d-NBP）对局灶性脑缺血大鼠软脑膜微循环障碍的影响。方法：用插线法造成大鼠局灶性脑缺血模型,并用体外显微摄像技术及微循环图象处理系统观察大鼠软脑膜微动脉管径及红细胞流速的变化。结果：dl-,l-和d-NBP对正常大鼠脑微动脉管径无明显影响,MCAO术前1 h预防给药,dl-,l-NBP和尼莫地平可明显增加局灶性脑缺血大鼠软脑膜微动脉管径及血流速度,而d-NBP则加重软脑膜微循环障碍。MCAO术后20 min治疗给药,dl-和l-NBP仍可明显逆转局灶性脑缺血大鼠软脑膜微循环障碍,而d-NBP及尼莫地平作用不明显。结论：改善脑微循环状态是 dl-和l-NBP发挥抗脑缺血作用的重要药理机制之一。     

体外液压冲击伤对大鼠神经细胞内游离钙和pH值的影响

目的研究体外液压冲击伤后大鼠神经细胞内游离钙和pH值的变化及其药物的保护作用。方法培养新生乳鼠的大脑皮层神经细胞,给予2.5kPa,20ms的液压冲击伤,通过激光扫描共聚焦显微镜检测伤后单个神经细胞内游离［Ca²⁺］i和pH值的变化,并分别给予尼莫地平和D-AP-5,观察药物对上述变化的影响。结果伤后细胞内［Ca²⁺］i迅速升高,持续12h达高峰,随后逐渐下降,48h接近正常;pH值下降较慢,于12h达低谷,48h未恢复正常。尼莫地平和D-AP-5均可明显抑制细胞内［Ca²⁺］i的升高和pH值的下降。结论可根据液压冲击伤后神经细胞内游离［Ca²⁺］i及pH值的变化规律指导用药。     

EFFECTS OF PHENOXYBENZAMINE ON RESPONSES TO SOME RECEPTOR AGONISTS AND CALCIUM IN VITRO

Noradrenaline-induced contractions of the rabbit and rat isolated aorta and guinea-pig spleen strips were inhibited by concentrations of phenoxybenzamine which did not affect responses to calcium. This may suggest a specific action on alpha-adrenoceptors. However, analysis of noradrenaline concentration-effect curves in guinea-pig spleen indicated that 1 mumol/l phenoxybenzamine should have reduced the available receptor population to 6% of control, but data from radioligand binding experiments on the same tissues using [3H]-prazosin indicated a reduction of the receptor population to only 82% of control. The reduced responsiveness observed in the organ bath study after phenoxybenzamine pretreatment, whilst not apparently related to effects on voltage-dependent calcium channels, could be due to the actions of phenoxybenzamine on other (non-receptor) processes such as receptor-operated calcium channels. Maximal contractile responses to histamine in rabbit isolated aorta but not those in guinea-pig isolated ileal preparations, were depressed by concentrations of phenoxybenzamine which depressed responses to calcium. Phenoxybenzamine produced parallel rightward shifts of curves to carbachol in guinea-pig ileal preparations but only depressed maximal responses to the agonist in higher concentrations which reduced responses to calcium. On the basis of the results obtained with calcium it is possible that the effects of phenoxybenzamine on receptor-mediated responses could be produced through the actions of this antagonist at less specific sites such as voltage-dependent calcium channels for histamine in rabbit aorta and carbachol in guinea-pig ileum. For alpha-receptor mediated responses in aortic and splenic strip preparations and for histamine-mediated responses in guinea-pig ileum, the actions of phenoxybenzamine may reflect an interaction of the antagonist with receptor-operated calcium channels.     

EFFECT OF COLFORSIN ON HUMAN NEUTROPHIL SUPEROXIDE PRODUCTION AND INTRACELLULAR CALCIUM MOBILIZATION

1. The effects of dibutyryl cyclic AMP (cAMP), isoproterenol and colforsin (forskolin) were evaluated on respiratory burst in human polymorphonuclear neutrophils (PMN). 2. Dibutyryl cAMP showed a dose-dependent inhibition of n-formyl-methionyl-leucyl-phenylalanine (FMLP)-induced superoxide production by human PMN. 3. Administration of isoproterenol induced a dose-dependent inhibition of FMLP-induced superoxide production by human PMN, and the inhibition was blocked by propranolol. 4. Administration of colforsin induced a dose-dependent inhibition of FMLP-induced superoxide production by human PMN, and the inhibition could not be blocked by propranolol. 5. Incubation with colforsin caused a significant increase in the cAMP level in human PMN. 6. Pretreatment with colforsin caused a dose-dependent inhibition in the elevation of intracellular free calcium (monitored by fura-2 fluorescence), which was observed in human PMN stimulated with FMLP. 7. These results suggest that cAMP is an inhibitory factor of superoxide production and intracellular calcium mobilization in human PMN stimulated with FMLP.     

EFFECTS OF A CONTINUOUS INFUSION OF DOPAMINE ON THE VENTILATORY AND CAROTID BODY RESPONSES TO HYPOXIA IN CATS

1. We investigated how a continuous infusion of dopamine (DA; 5μg/kg per min), which is often used clinically, would affect the ventilation and carotid chemoreceptor neural activity in anaesthetized cats. 2. In anaesthetized, spontaneously breathing cats, tidal volume (Vt) and respiratory frequency (f) were continuously monitored at five levels of inspired oxygen (P10₂= 110,130, 150, 170, 760mmHg) during Da or saline infusion. Vt and f were sampled for 1 min after 3 min exposure to each level of P10₂. Time control study was also performed. 3. DA infusion significantly lowered V_T under both normoxia and hypoxia in seven of eight cats. Respiratory frequency was not affected by DA infusion. Depression of ventilation during post-hypoxic hyperoxia was augmented by DA infusion. Chemodenervntion abolished the ventilatory response to hypoxia and DA did not further affect the ventilatory response to hypoxia. 4. In a second group of artificially ventilated cats, carotid chemoreceptor neural activity was recorded at five levels of arterial oxygen tension. DA infusion significantly depressed carotid chemoreceptor neural activity during normoxia and hypoxia in six of seven cats. 5. These findings suggest that changes in ventilation during low dosage of DA infusion closely correlate with carotid body neural output. A predominant effect of this dosage of DA (5 μg/kg per min) was depression in the ventilatory response to hypoxia due to an inhibition of carotid body neural output.