糖尿病大鼠输精管平滑肌收缩超反应性及钙通道特征

为对解糖尿病对输精管平滑肌功能的影响及其机理，我们比较了链脲菌素（streptozotocin)所致糖尿病大鼠及其同龄对照组大鼠输精管平滑肌对电场刺激，氯化钾，去氧肾上腺素的反应及钙通道的改变，电场刺激引起的收缩反应是单收缩之后继以连续性收缩，糖尿病组单收缩幅度较大，两组连续收缩几乎相同。1μmol/L Bay K8644使糖尿病鼠输精管产生单收缩，对照组无影响。氯化钾引起的收缩和钙内流在两组都强，但在1μmol/L Bay K8644存在时，糖尿病组比对照组增加明显。10μmol/L去氧肾上腺素引起的收缩可完全被0．1μmol/L硝苯啶阻断。100μmol/L新霉素在对照组可完全抑制去氧肾上腺素引起的收缩，但在糖尿病组只能部分抑制，并使单收缩增强，用钙通道拮抗剂配体[^3H]PN200-110所做的结合实验表明，对照或糖尿病组钙通道的亲和力和结合位的数量都滑有明显的不同，在输精管可溶性成分中，蛋白激酶C含量在糖尿病组是对粗的两倍。这些结果提示在没有神经病变及钙通道数量不变吓，氯化钾增强链脲菌素所致糖尿病大鼠输糖管的收缩反应部分是由于钙通道开放的概率和蛋白激酶C活性增强所致。     

苦参碱对大鼠输精管的作用与激活钙通道的关系

哌唑嗪(10 μmol·L~(-1)),硝苯地平(50nmol·L~(-1))可竞争性拮抗苦参碱收缩大鼠离体输精管,pA_2值分别为5.1和9.29,维拉帕米(1 μmol·L~(-1))可非竞争性拮抗苦参碱,pD_2为6.07。苦参碱可增强CaCl_2和KCl收缩输精管的作用,对KCI的增强作用更显著,提示苦参碱是一钙通道激动剂。     

超氧阴离子对牛主动脉平滑肌细胞收缩性的影响

目的观察超氧阴离子对培养的牛动脉平滑肌细胞内钙及收缩性的影响。方法原代培养牛动脉平滑肌,使用数字荧光显微镜技术测定细胞内钙,采用胶原凝胶收缩方法分析收缩性。结果超氧阴离子对高钾溶液及A-23187诱导的钙内流无明显影响(P>0.05),但可使凝胶收缩面积减小。超氧阴离子可使高钾诱导的胶原凝胶收缩面积从18.32%±2.11%减小至5.13%±0.45%(P<0.01),使A-23187诱导的胶原凝胶收缩面积从17.16%±1.10%减小至4.31%±0.04%(P<0.01)。结论超氧阴离子可明显抑制牛主动脉平滑肌细胞收缩性,但对电压依赖性钙通道引起的钙内流及A-23187诱导的细胞内钙变化无影响。     

糖尿病大鼠病程的不同时期主动脉平滑肌对苯肾上腺素的收缩反应(英文)

目的:研究随着糖尿病的发生发展,大鼠主动脉平滑肌对苯肾上腺素等激动剂收缩反应的变化及其可能机制。方法:用链尿菌素诱导糖尿病后,在第2、6、12周,取主动脉环进行实验观察。结果:苯肾上腺素的浓度依赖性收缩反应曲线,与对照相比:在第2周,低浓度时(0.01-0.03μmol·L~(-1))明显增加(P<0.01),最大反应无明显变化;在第6周,各浓度点均显著增加,且最大收缩反应增加约40％;然而,在第12周1)苯肾上腺素10μmol·L~(-1)引起的最大收缩反应趋向降低(P<0.05),2)在无Ca~(2 )液,也较对照明显减小(P<0.05),3)在无Ca~(2 )液,在尼非地平1μmol· L~(-1)和苯肾上腺素10μmol·L~(-1)存 在下,复Ca~(2 )引起的收缩在两组间的差异未见显著性,4)在正常Krebs’液,环匹阿尼酸10μmol·L~(-1)引起的收缩反应较对照也显著减小(P<0.001)。结论:(1)在糖尿病的第2周,平滑肌α_1-肾上腺素能受体的敏感性增加。(2)糖尿病大鼠主动脉平滑肌对苯肾上腺素收缩反应的异常变化,与通过电压依赖性钙通道的Ca~(2 )内流大小、胞内功能性Ca~(2 )池大小及其胞内Ca~(2 )池耗竭后所引起的充电性内流变化密切相关。     

输精管结扎术并发症的B超诊断及其临床价值

目的：探讨B超在输精管结扎术并发症中的诊断价值。方法：应用Aloka SSD-1100型超声诊断仪，主要探头为7．5MHz凸型探头，患者取仰卧位，充分暴露阴囊，使阴茎朝向腹侧，从不同角度扫查两睾丸及精索。作前列腺及精囊检查时，患者适度充盈膀胱，用3．5MHz探头在耻骨联合上缘进行多方面检查。结果：诊断附睾郁积症30例，痛性结节18例，精索附睾炎6例，前列腺精囊炎5例，阴囊血肿2例，精索血肿3例。结论：B超检查不仅能对病变的内部性质、程度作出诊断，而且对病变的部位、大小作出准确的诊断，检查简便易行，易被患者所接受。     

兰尼定对大鼠平滑肌细胞的肾上腺素能作用(英文)

电场刺激后释放的内源性去甲肾上腺素可引起大鼠输精管的双相收缩。初始的短暂收缩可被30μmol/L兰尼定和2μmol/L硝苯啶减弱,而后继的收缩部分可被2μmol/L硝苯啶消除,但被30μmol/L兰尼定增强。 外加的去甲肾上腺素也可产生输精管的双相收缩,这两相都能被2 μmol/L硝苯啶抑制,兰尼定30μmol/L可使两个相的收缩都减弱50％。我们推测兰尼定的结合位点在输精管的内质网。兰尼定对α-肾上腺素能刺激的不同相的作用不一致,表明对α-肾上腺素能的刺激一收缩偶合有两种方式。     

氨茶碱调节大鼠支气管平滑肌L型钙通道的活动性

目的 探讨氨茶碱对大鼠支气管平滑肌细胞L型钙通道(L-L_(Ca))的作用。方法 将20只大鼠随机分为2组,A组为正常对照组(n=10),B组为氨茶碱组(n=10),观测大鼠支气管平滑肌细胞L-L_(Ca)在正常时及给予氨茶碱治疗后的变化。结果 氨茶碱治疗后大鼠的L-L_(Ca)与正常对照组大鼠通道开放概率相比差异有显著性(P<0.05)。氨茶碱组通道开放时间常数(τ_(O1)和τ_(O2))不变,关闭时间常数(T_(c1)和T_(c2))延长,与正常对照组相比差异有显著性(P<0.05)。大鼠L-钙通道的活动经氨茶碱治疗后活动减弱,表现为通道开放时间常数不变,关闭时间常数延长。结论 氨茶碱通过缩短L-L_(Ca)的开放时间来抑制支气管平滑肌细胞的收缩,可显著抑制大鼠L-L_(Ca)的活动,促进大鼠支气管平滑肌细胞的舒张。     

福辛普利钠对糖尿病大鼠血管反应性的影响

目的观察福辛普利钠对糖尿病大鼠血管反应性的影响。方法建立链脲左菌素所致的糖尿病大鼠血管体外灌注模型,以八导生理记录仪检测大鼠肠系膜血管反应持续时间及灌注压的变化。结果糖尿病大鼠肠系膜血管对去甲肾上腺素的反应持续时间分别为(9.50±3.1)与(5.1±2.1)s(P<0.01),最高灌压显著降低由(5.15±0.82)kPa降至(7.52±0.90)kPa(P<0.01);口服福辛普利钠8周的糖尿病组大鼠血管反应性无明显改变。结论福辛普利钠为血管紧张素转换酶(ACE)抑制剂,有保护内皮细胞依赖性血管舒张作用,使糖尿病大鼠血管反应性异常减轻。     

钙通道阻滞剂对大鼠肝细胞钙释放激活的钙电流的影响(英文)

目的:研究钙通道拮抗剂对大鼠肝细胞钙释放激活的钙电流(I_(CRAC))的影响,方法:应用全细胞膜片箝技术。结果:I_(CRAC)的电流峰值是(-0.41±0.09)nA(n=15),反转电位约为0 mV,维拉帕米(Ver),地尔硫(艹卓)(Dil)和硝苯地平(Nif)显著降低I_(CRAC),不影响它的反转电位,Ver 5 μmol·L~(-1)的抑制率是40％±12％(n=3),Ver 50 μmol·L~(-1)使,CRAC的幅值从(-0.49±0.12)nA降到(-0.20±0.09)nA(n=5,P<0.01),抑制率为57％±15％,Dil和Nif 50 μmol·L~(-1)分别从(-0.43±0.10)nA(n=5),(-0.32±0.08)nA(n=5)降到(-0.29±0.07)nA(P<0.01),(-0.27±0.08)nA(P<0.01),抑制率分别为31％±11％,19％±7％,I_(CRAC)的幅值大小依赖细胞外钙浓度。I_(CRAC)在含台氏液1.8 mmol·L~(-1)中电流幅值为(-0.21±0.08)nA(n=3,P<0.01),结论:这三种钙通道拮抗剂有效抑制,I_(CRAC)并且通过抑制I~(CRAC)减少肝细胞钙超载。     

染料木黄酮对豚鼠结肠平滑肌细胞L型钙通道的影响(英文)

目的研究酪氨酸激酶抑制剂染料木黄酮(GST)对豚鼠结肠平滑肌细胞L型钙通道电流的作用。方法木瓜蛋白酶法分离单个豚鼠结肠平滑肌细胞,应用全细胞式膜片钳技术记录L型钙通道电流。结果 GST(10 ~100μmo·lL-1)浓度依赖性地阻断L型钙通道电流,其作用可被洗脱,半数有效抑制浓度为(39.9±3.6)μmol·L-1。GST可使L型钙通道的稳态失活曲线向超极化方向左移约10 mV(P<0.01),对其斜率没有影响。GST的无活性拟似物大豆异黄酮对L型钙通道电流的作用明显小于GST。酪氨酸磷酸酶抑制剂原钒酸钠可阻断GST对钙通道电流的抑制作用。结论 GST可通过酪氨酸激酶途径抑制豚鼠结肠平滑肌L型钙通道。     

Effects of T-type calcium channel blockers and thalidomide on contractions of rat vas deferens

Background and purpose:

In rat vas deferens, nerve mediated-contractions to a single electrical stimulus consist of an early purinergic and a later adrenergic component with differing sensitivities to L-type calcium channel blockers. We have investigated the effects of the T-type calcium channel blockers mibefradil and (1S, 2S)-2-[2-[[3-(1H-benzimidazol-2-yl)propyl]methylamino]ethyl]-6-fluoro-1,2,3,4-tetrahydro-1-(1-methylethyl)-2-naphthalenyl cyclopropanecarboxylic dihydrochloride (NNC 55-0396) against contractions in rat vas deferens. In addition, the actions of thalidomide were examined.

Experimental approach:

Prostatic and epididymal portions of rat vas deferens were stimulated with a single electrical stimulus every 5 min, and mouse whole vas deferens was stimulated with 40 pulses at 10 Hz every 5 min.

Key results:

Both mibefradil and NNC 55-0396 (100 µM) produced inhibition of contractions of epididymal portions (42 ± 13%, n= 7, and 43 ± 4%, n= 15, of control respectively). However, both agents produced small inhibitions of responses in prostatic portions, presumably by L-type calcium channel block. Thalidomide (100 µM) inhibited contractions in epididymal (55 ± 4% of control, n= 17) but not in prostatic portions of rat vas deferens. Thalidomide (10–100 µM) also inhibited contractions in mouse vas deferens.

Conclusions and implications:

The T-type calcium channel blockers mibefradil and NNC 55-0396 block particularly the adrenoceptor-mediated, nifedipine-resistant response to nerve stimulation in rat vas deferens, and this may suggest that this component involves T-type calcium channels. In addition, thalidomide has actions that resemble those of the T-type calcium channel blockers, in that it blocks nifedipine-resistant contractions in epididymal portions.     

Possible role of disturbed Na+ homeostasis in mouse vas deferens contractile hyperreactivity after imunological sensitization

In the present study we have investigated the involvement of sensitized mice immunoglobulins and some electrophysiological alterations that participate to the antigenic sensitization-induced hyperreactivity of isolated mouse vas deferens. Active sensitization was performed by subcutaneous injection of egg albumen. Contractile responses to noradrenaline were isometrically recorded in the isolated vas deferens. Low external Na⁺-induced contractions and rapid cooling contractures were evaluated. Resting membrane potential (Er) and intracellular Na activity were measured in control and actively sensitized vas deferens by using conventional KCl-filled and Na⁺-sensitive microelectrodes respectively. Active sensitization-induced hyperreactivity to noradrenaline was reproduced by in vitro passive sensitization of control vas deferens with sensitized mice immunoglobulins. The inhibition of the nitric oxide synthesis by N-nitro-L-arginine methyl ester (L-NAME) did not change control vas deferens reactivity in vitro to noradrenaline and acetylcholine. Rapid cooling contractures, performed after lowering external Na⁺ concentration, were not altered by active sensitization. However, sensitization increased significantly the strength of the low external Na⁺-induced contractions. In control vas deferens Er was a mean of –49.2±0.3 mV (mean ±SEM). Sensitization resulted in reduction of Er by 14 mV. In sensitized preparations, relative insensitivity of Er to ouabain, external K⁺ removal and cooling were observed. The intracellular Na⁺ activity was increased by about 40% in sensitized vas deferens. It is concluded that sensitization-induced hyperreactivity is mediated by immunoglobulins and produced smooth muscle cells depolarisation. The low Er of sensitized muscle may be partly the result of an increase in membrane permeability to Na⁺ which could interfere with intracellular Ca²⁺ homeostasis. Received: 26 May 1998 / Accepted: 22 July 1998     

雷藤氯内酯醇抑制人精子Ca~（2＋）内流及对大鼠胸主动脉、输精管收缩的影响

雷藤氯内酯醇（Ｔｒｉｐｃｈｌｏｒｏｌｉｄｅ，Ｔ４）由雷公藤中分离的单体，除有增强抗炎、免疫抑制作用外，还增强雄性抗生育活性。Ｔ４经大鼠口服，可致附睾尾精子活率和密度明显下降而不育。精子活力主要受Ｃａ２＋等调控，为了探讨Ｔ４抑制精子活力的作用机制，我们观察了Ｔ４对人射出精子Ｃａ２＋内流的作用和对离体大鼠胸主动脉及输精管收缩的影响。结果指出，Ｔ４Ｉ抑制人射出精子对Ｃａ２＋摄取，但不影响由去甲肾上腺素和高Ｋ＋依赖Ｃａ２＋支持而诱发的大鼠胸主动脉和输精管的自发收缩。提示，Ｔ４抑制人射出精子Ｃａ２＋内流，导致精子膜内外Ｃａ２＋梯度浓度失去动态平衡，可能是Ｔ４抑制精子活力的重要机理之一。但Ｔ４不影响离体大鼠胸主动脉和输精管的收缩，可能有选择性的作用在附睾部位。     

Calcium mobilization and phosphatidylinositol turnover in vas deferens smooth muscle of diabetic rats

The study concerned Ca2+ channels that are receptor-operated by norepinephrine (NE) and mediate hyper-reactivity of vas deferens smooth muscle from rats with streptozotocin (STZ)-induced diabetes, and the mediatory responses of these channels, such as tension development, Ca2+ uptake and phosphatidylinositol (PI) turnover. The contractile responses induced by adrenoceptor agonists were significantly greater in diabetic rat vas deferens than in the controls. A greater Ca2+ uptake was induced by 10(-5) M NE in strips from diabetic rats than in the controls. The uptake of Ca2+ was completely inhibited by 10(-6) M prazosin but not by 10(-5) M verapamil. Enhancement of Ca2+ release by 10(-5) M NE was faster and greater in diabetic muscles than in the controls. The accumulation of [3H]inositol phosphates was increased 4-fold in the controls and 7-fold in diabetic muscles by 10(-5) M NE. This increase was completely inhibited by 10(-6) M prazosin but not by 10(-6) M yohimbine. The data suggest that vas deferens smooth muscle hyper-reactivity in diabetic rats is due to increased PI turnover mediated by alpha 1-adrenoceptors, to the release of intracellular bound Ca2+ and to an increase of Ca2+ uptake through receptor-operated Ca2+ channels.     

比格犬前列腺增生模型中输精管病理变化

目的　探讨前列腺增生症中输精管的增生机制。方法　丙酸睾酮 (TP)诱导比格犬前列腺增生模型建立后 ,获取输精管组织 ,利用放射免疫分析法检测输精管组织中的双氢睾酮 (DHT)含量 ,组织经石蜡固定包埋切片 ,显微图像分析技术分析输精管管腔大小及上皮细胞高度 ,流式细胞术检测输精管组织凋亡率 ,免疫组织化学技术检测输精管组织中前列腺特异抗原 (PSA)、前列腺酸性磷酸酶 (PAP)、Bcl 2及P5 3蛋白表达 ,2 %的琼脂糖凝胶电泳观察输精管组织的凋亡情况。结果　输精管组织中DHT含量随TP剂量增大而增加 ,但无统计显著性差异。输精管管腔面积随TP增加增大 (P <0 .0 1 ) ,输精管上皮细胞高度也随TP增高 (P <0 .0 1 )。流式细胞术结果中 ,对照组细胞凋亡率高于 0 .8及 7.5mg·kg-1TP组(P <0 .0 1 )。免疫组化结果中 ,PSA ,PAP和Bcl 2表达没有明显差异 ,但各组P5 3表达均低于对照组 (P <0 .0 5 )。琼脂糖凝胶电泳结果中 ,对照组中可以看到 2 0 0bp整数倍的DNA片段 ,其他组则没有观察到类似现象。结论　DHT促进输精管增生 ,这种增生与凋亡抑制有关     

Changes in electrophysiological properties and noradrenaline response in vas deferens of diabetic rats

The purpose of this study was to study changes in the sympathetic nerves of the vas deferens in 10-week-old streptozotocin-induced diabetic rats. To assess the activity of autonomic neurons, we recorded the amplitude and frequency of spontaneous junction potentials in vasa deferentia from age-matched controls and streptozotocin-induced diabetic rats. No change in the resting membrane potential of the smooth muscle of the vas deferens was found in streptozotocin-induced diabetic rats. The frequency of spontaneous junction potentials was significantly increased in the streptozotocin-induced diabetic rats and their amplitude was also markedly increased. The dose–response curve for the contractile response of the vas deferens to noradrenaline was significantly shifted to the right and the apparent affinity (pD₂ value) was significantly decreased in streptozotocin-induced diabetic rats. These results suggest that degeneration of sympathetic neurons may occur in the vas deferens of 10-week streptozotocin-induced diabetic rats and that the greater amplitude of the spontaneous junction potentials may be related to an increase in Ca²⁺ mobilization, though the increase in Ca²⁺ mobilization does not lead to an enhanced contractile response.     

Inhibition by the putative potassium channel opener pinacidil of the electrically-evoked release of endogenous dopamine and noradrenaline in the rat vas deferens

Summary The effect of pinacidil on the release of endogenous noradrenaline and dopamine from the sympathetic innervation of the rat vas deferens was examined. Amine release was evoked by electrical stimulation (1, 2, 5 and 10 Hz) or by depolarization with high potassium (75 mmol/l) in the medium. Dopamine and noradrenaline were measured by means of high pressure liquid chromatography with electrochemical detection.Pinacidil (1, 5, 10 and 50 mol/l) produced a concentration-dependent inhibition of the electrically stimulated (2 Hz) overflow of noradrenaline and dopamine. Only pinacidil 50 mol/l increased the spontaneous loss of dopamine and noradrenaline. The inhibitory effects of pinacidil (5 mol/l) on amine overflow were also observed at other frequencies of stimulation (1, 5 and 10 Hz). The magnitude of the inhibitory effect on noradrenaline release was approximately the same at all frequencies (63% to 56% reduction); for dopamine, the higher the frequency of stimulation, the greater the inhibitory effect of pinacidil (up to 73% reduction). When the preparations were continuously stimulated for 70 min at 2 Hz, pinacidil (5 mol/l) reduced the overflow of dopamine and noradrenaline during the first 40 or 30 min of stimulation only. The addition of phentolamine (1 mol/l) to the perifusion medium slightly reduced the inhibitory effect of pinacidil on amine overflow, but the inhibition by pinacidil remained statistically significant. Tetraethylammonium (10 mmol/l) completely abolished the inhibitory effect of pinacidil (10 mol/l). Pinacidil (5 mol/l) did not reduce the potassium-evoked release of the amines.The results demonstrate that pinacidil impairs transmitter release from the sympathetic innervation of the rat vas deferens, probably as a consequence of the opening of potassium channels. Send offprint request to P. Soares-da-Silva at the above adress     

Effect of normorphine and enkephalin on spontaneous potentials in the vas deferens.

Spontaneous excitatory junction potentials were recorded intracellularly from the smooth muscle of the mouse vas deferens. Exposure of the vas deferens to either normorphine (1 muM) or methionine-enkephalin (0.5 muM) did not alter the frequency or amplitude distribution of the spontaneous potentials. The possible mechanisms by which the narcotic agonists depress the release of noradrenaline on nerve stimulation without inhibiting the spontaneous release of noradrenaline are discussed.     

Abolition of neurally evoked motor responses of the vas deferens by 6-hydroxydopamine

Contractions of isolated guinea-pig or rat vasa deferentia evoked by stimulation through ring electrodes were abolished after incubation with 6-hydroxydopamine?HBr. After this treatment it was no longer possible to demonstrate the presence of fluorescent nerves by the Falk-Hillarp technique and most preparations became supersensitive to noradrenaline. It is concluded that the motor innervation of rat and guinea-pig vasa deferentia is noradrenergic.