免疫抑制剂在反复胚胎种植失败患者中的应用价值研究

目的： 观察免疫抑制剂环孢素A在反复胚胎着床失败患者中的临床疗效，探索免疫抑制剂在辅助生殖中的应用价值。方法： 回顾性分析2016年1月至2018年1月在某院行体外受精-胚胎移植助孕治疗的97例反复胚胎着床失败患者的临床资料，根据再次行胚胎移植时是否应用环孢素A将患者分为研究组54例，对照组43例。比较2组患者胚胎着床率、临床妊娠率，观察外周血淋巴细胞免疫表型变化，以及不良事件发生情况。结果： 采用χ²检验比较组间差异，研究组胚胎着床率（28.89%）、临床妊娠率（46.3%）均高于对照组（11.11%，23.26%），差异有显著性（P<0.05）；治疗后CD3⁺T细胞、CD4⁺T细胞占淋巴细胞的比率下降，但差异无显著性；治疗后活化的CD3⁺T细胞比率（CD3⁺HLA-DR⁺）、B淋巴细胞（CD3^-CD19⁺）较治疗前无显著性（P>0.05），CD8⁺T细胞占淋巴细胞的比率上升、CD4⁺/CD8⁺比值下降，NK细胞（CD3^-CD16⁺CD56⁺）占淋巴细胞的比率明显下降，差异有显著性（P<0.05）。2组患者治疗过程中均未出现严重不良事件。结论： 免疫抑制剂环孢素A能增加反复着床失败患者的胚胎着床率，提高临床妊娠率，促使外周血免疫细胞分布向有利于胚胎着床方向偏移，免疫抑制剂在辅助生殖中的应用值得进一步开展研究。     

桂枝茯苓胶囊通过MAPK信号通路介导T淋巴细胞下调ICAM-1、HE4表达抑制子宫肌瘤细胞增殖、迁移和侵袭

目的：探究桂枝茯苓胶囊对子宫肌瘤大鼠细胞增殖、迁移和侵袭、MAPK信号通路和T淋巴细胞水平的影响。方法：60只大鼠随机分为对照组、子宫肌瘤组和子宫肌瘤+GZFLc组（n=20）。通过注射苯甲酸雌二醇和黄体酮构建子宫肌瘤模型。桂枝茯苓胶囊灌胃干预,剂量为1 000 mg·kg^-1。检测各组小鼠激素水平、子宫系数、雌二醇（E2）、孕酮（P）、促卵泡激素（FSH）、细胞间黏附分子1（ICAM1）、附睾蛋白4（HE4）、Ki67、基质金属蛋白酶2（MMP2）、ERK1/2、p38 MAPK蛋白表达量。通过流式细胞术检测CD3⁺比例和CD4⁺/CD8⁺水平。结果：3组大鼠上述指标比较差异有统计学意义（P<0.05）。子宫肌瘤组大鼠血清中E2[（782.45±65.38） pg·mL^-1]、P[（57.11±5.84） ng·mL^-1]和FSH[（6.24±0.61） IU·L^-1]、子宫系数（15.36±1.92）、ICAM1（1.82±0.15）、HE4（1.19±0.12）、Ki67（0.74±0.07）、MMP2（0.62±0.06）、ERK1/2（1.28±0.11）、p38 MAPK（1.10±0.10）水平显著高于对照组,CD3⁺[（34.58±2.35）%]和CD4⁺/CD8⁺（1.17±0.22）水平显著低于对照组（P<0.05）。子宫肌瘤+GZFLc组的E2[（437.62±41.49） pg·mL^-1]、P[（46.52±4.57） ng·mL^-1]、FSH[（4.85±0.46） IU·L^-1]、子宫系数（8.25±1.04）、ICAM1（0.76±0.07）、HE4（0.71±0.07）、Ki67（0.32±0.03）、MMP2（0.27±0.03）、ERK1/2（0.52±0.05）和p38 MAPK（0.56±0.05）水平显著低于子宫肌瘤组,CD3⁺（42.44±3.76）和CD4⁺/CD8⁺（1.85±0.31）水平显著高于子宫肌瘤组（P<0.05）。结论：桂枝茯苓胶囊可抑制子宫肌瘤的增殖迁移和侵袭,抑制MAPK通路,提高CD3⁺、CD4⁺/CD8⁺的水平。     

蒽环类药物联合紫杉醇治疗局部晚期乳腺癌患者的临床疗效及其对免疫功能的影响

目的 观察蒽环类药物联合紫杉醇治疗局部晚期乳腺癌患者的临床疗效及其对免疫功能的影响。方法 选取2019年1月—2021年1月南华大学附属长沙中心医院收治的局部晚期乳腺癌患者78例,采用随机数字表法分为对照组和试验组,各39例。对照组患者采用蒽环类药物治疗,试验组患者在对照组基础上采用紫杉醇化疗,2组均连续治疗4个疗程。比较2组临床疗效,治疗前后T淋巴细胞亚群[CD₃⁺细胞分数、CD₄⁺细胞分数、CD₈⁺细胞分数、CD₄⁺/CD₈⁺细胞比值]、肿瘤标志物[血管内皮生长因子(VEGF)、癌胚抗原(CEA)]水平,不良反应。结果 试验组总有效率为74.36%,高于对照组的51.28%(χ²=4.446,P=0.035)。治疗4个疗程后,对照组CD₃⁺细胞分数低于治疗前,CD₄^+<...     

吉林省不同产地白屈菜药效学的比较

目的： 探讨吉林省不同产地白屈菜的药效成分含量及其止咳平喘作用,确定白屈菜的最优产地,指导临床更加合理的使用白屈菜。方法： 采用HPLC法测定9个产地白屈菜中白屈菜红碱的含量,通过观察诱咳模型小鼠咳嗽潜伏期、咳嗽次数、炎症因子IL-1、IL-6水平;哮喘模型豚鼠哮喘潜伏期、行为学评分、气道黏多糖含量、CD4⁺/CD8⁺变化及肺组织病理学改变,评价不同产地白屈菜的药效作用差异。结果： 9组不同产地的白屈菜浓缩液均能延长小鼠咳嗽潜伏期,降低3 min内咳嗽次数（P<0.05或P<0.01）,延长豚鼠哮喘潜伏期,降低行为学评分（P<0.05或P<0.01）;其中靖宇产白屈菜控制小鼠咳嗽发生的潜伏期、3 min内咳嗽次数、豚鼠发生哮喘潜伏期、哮喘发生的行为状态、气道黏多糖含量及CD4⁺/CD8⁺值明显优于其他8组（P<0.05或P<0.01）。结论： 不同产地的白屈菜均有止咳平喘作用,但作用效果不同,其中靖宇地区产白屈菜在治疗咳嗽、哮喘症状方面具有一定的优势。     

超高效液相色谱-质谱联用法检测人全血中氯喹、羟氯喹、阿比多尔及其临床应用

目的: 建立并验证一种人全血中氯喹、羟氯喹、阿比多尔的检测方法,并将其用于临床检测。方法: 全血样本经氯化铵裂解和乙腈蛋白沉淀后,采用液相-串联质谱联用仪测定。色谱柱为BEH C₁₈,以含0.5%甲酸乙腈溶液-0.5%甲酸水溶液为流动相梯度洗脱,流速为0.4 mL·min^-1,电喷雾正离子模式,多反应监测。结果: 氯喹、羟氯喹、阿比多尔在8~1 600 ng·mL^-1线性关系良好;批内和批间精密度(RSD)均在12.71%以内,批内和批间准确度(RE)均在-7.12%~13.51%;提取回收率均在76.50%~92.49%;内标归一化的基质因子变异系数(RSD)均小于15%;在多种储存条件下,处理前后的样品稳定性良好。结论: 该方法专属性强,准确度高,重复性好,可用于3种药物治疗药物监测及中毒检测。     

CYP3A5基因多态性与他克莫司血药浓度以及有效性与安全性的系统评价

目的： 系统评价CYP3A5基因多态性与肾移植受者术后他克莫司（FK506）血药浓度有效性、安全性的相关性,为临床提供循证依据。方法： 计算机检索Ovid Medline、Ovid EMBase、Cochrane Library、CNKI、CBM、VIP和WanFang Data,检索时限均从建库至2019年2月20日,对纳入的每项研究进行偏倚风险评价,并对其进行系统评价。结果： 共纳入21个研究,系统评价结果显示：（1）术后1年内,CYP3A5 ^*1/^*1基因型肾移植患者剂量调整血药浓度低于CYP3A5 ^*1/^*3基因型肾移植患者,CYP3A5 ^*1/^*3基因型肾移植患者剂量调整血药浓度低于CYP3A5 ^*3/^*3基因型肾移植患者,CYP3A5 ^*1/^*1基因型肾移植患者剂量调整血药浓度低于CYP3A5 ^*3/^*3基因型肾移植患者;（2）术后1年内,CYP3A5表达者（CYP3A5 ^*1/^*1+^*1/^*3）急性排斥反应发生率高于CYP3A5非表达者（CYP3A5 ^*3/^*3）;（3）术后3个月内,除高胆固醇血症外,CYP3A5表达者各不良反应发生率均低于CYP3A5非表达者。结论： 他克莫司个体化用药分为起始剂量和维持剂量两个阶段。起始剂量通过基因检测技术确定CYP3A5基因分型来预测,维持剂量根据TDM结果进行调整,达到目标浓度后定期进行治疗药物监测,以提高临床疗效并减少不良事件的发生。     

全营养素联合放化疗治疗局部晚期直肠癌的效果及其对免疫功能的影响

目的 观察全营养素联合放化疗治疗局部晚期直肠癌的效果及其对免疫功能的影响。方法 选取2020年6—12月华润武钢总医院肿瘤科收治的66例局部晚期直肠癌患者作为研究对象,按照随机数字表法分为对照组和观察组,各33例。对照组患者术后采用常规放化疗方案治疗,观察组患者在对照组基础上予以全营养素治疗。比较2组治疗2周后的营养状况,术前及术后1、2周免疫功能指标[CD₃⁺、CD₄⁺、CD₄⁺/CD₈⁺及自然杀伤细胞(NKC)分数]。结果 治疗后,观察组营养状况优于对照组(u=2.023,P=0.043)。术后1周,观察组CD₃⁺、NKC分数较其术前升高,对照组CD₃⁺较术前降低(P<0.05);术后2周,观察组CD₃⁺、CD₄⁺、CD_...     

基于MAPK通路探讨蒿藤胶囊对Ⅱ型胶原诱导性关节炎大鼠的免疫抑制机制

目的：探讨蒿藤胶囊对Ⅱ型胶原诱导性关节炎模型（CIA）大鼠的免疫抑制机制。方法：采用弗氏完全佐剂与Ⅱ型胶原混合后乳剂诱导大鼠关节炎模型,每周检测大鼠右后足关节肿胀百分率;末次给药后,观察关节滑膜的病理变化,采用流式细胞术检测蒿藤胶囊对外周血中CD4⁺ T淋巴细胞的影响,酶联法检测蒿藤胶囊对血清中TNF-α、IL-17、IL-6、IL-21及IL-22的影响,PCR法测定蒿藤胶囊对脾脏组织中JNK、p38、ERK mRNA表达的影响,免疫组化测定蒿藤胶囊对脾脏组织中JNK、p38、ERK蛋白表达的影响,Western blot法测定关节滑膜中JNK、ERK蛋白表达。结果：蒿藤胶囊0.193 g·kg^-1在给药14 d时可显著缓解CIA大鼠的关节肿胀率,降低病理学评分及血清炎症因子IL-17、IL-6的水平,抑制CD4⁺ T淋巴细胞升高,下调脾脏组织JNK、p38、ERK mRNA及JNK、ERK蛋白的表达并下调关节滑膜中JNK、ERK蛋白表达。结论：蒿藤胶囊治疗CIA大鼠的免疫抑制机制可能与下调脾脏组织与关节滑膜中JNK、ERK表达,降低外周血中CD4⁺ T淋巴细胞的比例与血清炎症因子IL-17、IL-6的水平有关。     

三种常用高效抗逆转录病毒治疗方案疗效的比较

目的：比较替诺福韦酯（tenofovir disoproxil fumarate,TDF）+拉米夫定（lamivudine,3TC）+依非韦伦（efavirenz,EFV）、替诺福韦酯+拉米夫定+克力芝（lopinavir/ritonavir,LPV/r）、齐多夫定（zidovudine,AZT）+拉米夫定+依非韦伦3种高效抗逆转录病毒治疗（highly active anti-retroviral therapy,HAART）方案的疗效。方法：回顾性收集2011年1月至2021年4月在广西中医药大学附属瑞康医院治疗的HIV感染者/艾滋病患者220例,按治疗方案分为3组,其中TDF+3TC+EFV （A组）136例、TDF+3TC+LPV/r （B组）53例、AZT+3TC+EFV （C组）31例。比较不同组治疗1年、2年后的CD4⁺、CD8⁺T细胞计数和病毒载量（HIV RNA）的变化,并计算各组的用药成本。结果：治疗1年和2年后,各组CD4⁺T细胞计数、CD4⁺/CD8⁺T细胞比值均显著升高（P<0.05）;CD8⁺T细胞计数均有所下降,其中A组治疗前后差异有统计学意义（P<0.05）;HIV RNA在最低检测限以下的患者达96%以上;病毒学指标和免疫学指标的组间差异均无统计学意义（P>0.05）。结论：TDF+3TC+EFV、TDF+3TC+LPV/r、AZT+3TC+EFV三种方案的疗效相近,其中,TDF+3TC+EFV有成本低、安全性高的优势。     

帕博利珠单抗联合白蛋白结合型紫杉醇及卡铂致严重视神经病变1例

<正>2021年中国临床肿瘤学会(CSCO)指南将紫杉醇/白蛋白结合型紫杉醇+铂类+帕博利珠单抗三联方案作为Ⅳ期无驱动基因肺鳞癌一线治疗的Ⅰ级推荐^[1],三联方案获益优于紫杉醇/白蛋白结合型紫杉醇+铂类^[2],疗效不受程序性死亡因子1(programmed death 1,PD-1)表达影响^[3-4] 。三联方案临床应用广泛，获益良好，其引起的不良反应也应得到重视，以保证患者用药安全。     

Inhibition of P-type ATPases by [(dihydroindenyl)oxy]acetic acid (DIOA), a K+ -Cl- cotransporter inhibitor

[(Dihydroindenyl)oxy]acetic acid (DIOA) has been used as a potent inhibitor of K⁺–Cl⁻ cotransporter (IC₅₀ = 10 μM). Here we found that DIOA inhibited activities of P-type ATPases such as dog kidney Na⁺,K⁺-ATPase (IC₅₀ = 53 μM), hog gastric H⁺,K⁺-ATPase (IC₅₀ = 97 μM) and rabbit muscle Ca²⁺-ATPase (IC₅₀ = 127 μM). In the membrane preparation of the LLC-PK1 cells stably expressing rabbit gastric H⁺,K⁺-ATPase, DIOA inhibited activities of the endogenous Na⁺,K⁺-ATPase (IC₅₀ = 95 μM) and the exogenous H⁺,K⁺-ATPase (IC₅₀ = 75 μM). 5-Nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB), a Cl⁻ channel blocker, had no effects on the DIOA-elicited inhibition of the P-type ATPases. These findings suggest that lower concentration of DIOA (< 20–30 μM) should be used for evaluation of the activity of K⁺–Cl⁻ cotransporter without affecting the activities of coexisting Na⁺,K⁺-ATPase and/or H⁺,K⁺-ATPase in cells.     

Interaction between theophylline and ouabain in the rabbit heart: Effect on (Na + K)-ATPase

In electrically stimulated rabbit ventricular strips, theophylline (0.3–30 M) antagonized the increased contractility produced by ouabain (0.8 μM). Initial velocity of specific [³H]ouabain binding to homogenates prepared from the muscle strips was used to determine the fraction of binding sites occupied by ouabain. Theophylline decreased the binding of ouabain to (Na⁺ + K⁺)-ATPase. It is concluded that the effect of theophylline on ouabain-induced positive inotropism may be mediated by decreased ouabain binding to (Na⁺ + K⁺)-ATPase.     

Similarities of the in vivo and in vitro effects of mercuric chloride on H]ouabain binding and potassium activation of Na/K-ATPase in isolated rat cerebral microvessels

A previous study revealed that a single i.p. administration of 6 mg/kg body wt. of mercuric chloride (MC) durably inhibits the rat cerebral microvascular Na⁺/K⁺-ATPase activity [1]. In this study, cerebral microvessels isolated 18 h after MC treatment were compared to those obtained from control rats and subsequently treated or not treated with MC in vitro, with regard to: (a) ³H]ouabain binding to, and (b) K⁺-activation kinetics of, the Na⁺/K⁺-ATPase. Microvessels from MC-treated rats showed a decrease of ³H]ouabain binding down to 62% of the control binding, and the same degree of inhibition was attained in microvessels treated in vitro with 5 μM MC. Analysis of the K⁺-activation kinetics of Na⁺/K⁺-ATPase revealed a decrease of V_max from the control value of 13.1 to 7.67 μmol/mg/h in microvessels from MC-treated rats and 6.07 μmol/mg/h in microvessels treated in vitro with 5 μM MC, with no change in K_m in either case. The similarity of the effects of in vivo and in vitro treatments suggests that the inhibition of the cerebromicrovascular Na⁺/K⁺ATPase following in vivo administration of MC results from a direct interaction of Hg⁺ with the enzyme.     

Effects of [Na] and [Ca] on the responses to milrinone in rat cardiac preparations

In the present investigation we have studied the influence of changing the [Ca²⁺] and [Na⁺] on the cardiac responses to milrinone in various preparations of rat heart. Milrinone (5 × 10⁻⁵ to 8 × 10⁻⁴ M) produced a dose-dependent positive chronotropic effect on right atrium and a positive inotropic effect on left atrium and papillary muscle of the rat. A decrease in [Ca²⁺] (from 2.2 to 1.1 mM) or an increase in [Na⁺] (from 120 to 60 mM) increased the milrinone-induced inotropic effect in left atrium and papillary muscle. However, in right atrium the chronotropic effect of milrinone was significantly decreased under these conditions. Opposite changes to milrinone-induced responses were observed when [Ca²⁺] was increased (to 3.3 mM) or when the [Na⁺] was decreased to 60 mM. Nifedipine (3 × 10⁻³ M), a selective Ca²⁺ channel blocker, significantly inhibited the chronotropic response to milrinone in right atrium. However, the inotropic response to milrinone was found to be significantly greater in the presence of nifedipine. A veratridine-induced positive inotropic effect in the left atrium was also significantly increased in the presence of nifedipine. Tetrodotoxin (TTX, 1 × 10⁻⁶ M), a fast sodium channel blocker, significantly reduced the inotropic response to milrinone in left atrium and papillary muscle. A milrinone-induced dose-dependent increase in the baseline tension was observed in the right atrium which was abolished in low [Ca²⁺] and significantly increased in high [Ca²⁺]. Our data suggest the possibility that milrinone increases Ca²⁺ influx in the right atrium to cause the chronotropic effect. Milrinone also may possess an action like veratridine, involving an increased influx of Na⁺ through fast Na⁺ channels in left atrium and papillary muscle, and this action is possibly involved in the positive inotropic effect.     

The Protective Action of Tetrodotoxin and (±)-Kavain on Anaerobic Glycolysis, ATP Content and Intracellular Na and Ca of Anoxic Brain Vesicles

Because recent reports point to Na⁺ channel blockers as protective agents directed against anoxia-induced neuronal damage including protection of anaerobic glycolysis, the influences of tetrodotoxin (TTX) and (±)-kavain on anoxic rat brain vesicles were investigated with respect to lactate synthesis, vesicular ATP content and cytosolic free Na⁺ and Ca²⁺ ([Na⁺]_i, [Ca²⁺]_i), both of the latter determined fluorometrically employing SBFI and FURA-2, respectively. After anoxia, basal lactate production was increased from 2.9 to 9.8 nmol lactate/min/mg protein. Although lactate synthesis seemed to be stable for at least 45 min of anoxia, as deduced from the linearity of lactate production, the ATP content declined continuously with a half life (τ ) af 14.5 min, indicating that anaerobic glycolysis was insufficient to cover the energy demand of anoxic vesicles. Correspondingly, [Na⁺]_i and [Ca²⁺]_i increased persistently after anoxia by 22.1 mmol/l Na⁺ and 274.9 nmol/l Ca²⁺, determined 6.3 min after onset. An additional stimulation of vesicles with veratridine accelerated the drop of ATP (τ = 5.1 min) and provoked a massive Na⁺ overload, which levelled off to 119 mmol/l Na⁺ within a few minutes. Concomitantly, [Ca²⁺]_i increased linearly with a rate of 355 nmol Ca²⁺/l/min. Despite the massive perturbation of ion homeostasis, lactate production was unaffected during the first 8 min of veratridine stimulation. However, complete inhibition of lactate synthesis took place 30 min after veratridine was added. The Na⁺ channel blockers TTX and (±)-kavain, if applied before anoxia, preserved vesicular ATP content, diminished anoxia-induced increases in [Na⁺]_i and [Ca²⁺]_i and prevented both the veratridine-induced increases of [Na⁺]_i and [Ca²⁺]_i and the inhibition of lactate production. The data indicate a considerable Na⁺ influx via voltage-dependent Na⁺ channels during anoxia, which speeds up the decline in ATP and provokes an increase in [Ca²⁺]_i. A massive Na⁺ and Ca²⁺ overload induced by veratridine failed to influence lactate synthesis directly, but initiated its inhibition. © 1997 Elsevier Science Ltd. All rights reserved.     

Action of the Na ionophore monensin on vascular smooth muscle of guinea-pig aorta

The effects of the Na⁺ ionophore monensin on contractile responses were investigated in guinea-pig aorta in normal and high K⁺ solutions. In normal K⁺ (5.4 mM) solution, monensin (2 × 10⁻⁵ M) produced a rapid increase in tension followed by slow relaxation. This contraction was markedly inhibited by phentolamine (10⁻⁵ M) or prazosin (10⁻⁶ M) and was accompanied by an increase in tritium efflux from tissue preloaded with [³H]norepinephrine. In the presence of phentolamine, monensin (1–2 × 10⁻⁵ M) or ouabain (1−2 × 10⁻⁵ M) caused only a small and slowly developing contraction. Simultaneous application of these agents caused a more rapid and greater contraction. Either monensin or ouabain gradually increased cellular Na⁺ and decreased cellular K⁺ content. When monensin was applied simultaneously with ouabain, there was a rapid increase in cellular Na⁺ and loss of cellular K⁺. In high K⁺ (65.4 mM) solution, monensin (10⁻⁶ M) slightly reduced the increased tension level but when external glucose was omitted monensin markedly inhibited the contraction. A significant decrease in tissue ATP content was observed only when monensin was applied in glucose-free solution. Similarly, hypoxia (N₂ bubbling) markedly inhibited the high K⁺ contraction and decreased the tissue ATP content only in the absence of glucose. These results suggest that monensin produces a neurogenic contraction due to the release of endogenous catecholamines and also produces a myogenic contraction by a decrease in transmembrane Na⁺ and K⁺ gradients when the Na⁺ and -K⁺ pump is inhibited by ouabain, and that monensin inhibits aerobic energy metabolism of vascular smooth muscle.     

Na,K-ATPase activity is selectively increased in thalamus in thiamine deficiency prior to the appearance of neurological symptoms

The relationship between progression of neurological status and the activities of both Na⁺,K⁺- and Mg²⁺-dependent-ATPase (adenosine 5′-triphosphate phosphohydrolase) was investigated in brain regions of pyrithiamine-induced thiamine deficient rats. Thalamic Na⁺,K⁺-ATPase activity was selectively increased by 200% (P < 0.01) prior to the appearance of symptoms of thiamine deficiency and normalized in symptomatic rats. This selective transitory activation precludes a mediation by brain soluble fraction Na⁺,K⁺-ATPase modifiers as does the unaltered distribution in regional high-affinity [³H]ouabain binding densities observed throughout the time-course used in these experiments. Na⁺,K⁺-ATPase maintains cellular ionic gradients and has been implicated in neurotransmitter uptake and release mechanisms. The fact that the increased thalamic Na⁺,K⁺-ATPase activity coincides with the early alterations in serotonin metabolism observed in similarly treated animals and the concomitantly early increase in glucose utilization previously observed in the thalamus of thiamine-deficient rats is discussed.     

CGP37157 modulates mitochondrial Ca homeostasis in cultured rat dorsal root ganglion neurons

The effects of 7-chloro-3,5-dihydro-5-phenyl-1H-4,1-benzothiazepine-2-on (CGP37157), an inhibitor of mitochondrial Na⁺/Ca²⁺ exchange, on depolarization-induced intracellular free Ca²⁺ concentration ([Ca²⁺]_i) transients were studied in cultured rat dorsal root ganglion neurons with indo-1-based microfluorimetry. A characteristic plateau in the recovery phase of the [Ca²⁺]_i transient resulted from mitochondrion-mediated [Ca²⁺]_i buffering. It was blocked by metabolic poisons and was not dependent on extracellular Ca²⁺. CGP37157 produced a concentration-dependent decrease in the amplitude of the mitochondrion-mediated plateau phase (IC₅₀=4±1 μM). This decrease in [Ca²⁺]_i was followed by an increase in [Ca²⁺]_i upon removal of the drug, suggesting that Ca²⁺ trapped in the matrix was released when the CGP37157 was removed from the bath. CGP37157 also inhibited depolarization-induced Ca²⁺ influx at the concentrations required to see effects on [Ca²⁺]_i buffering. Thus, CGP37157 inhibits mitochondrial Na⁺/Ca²⁺ exchange and directly inhibits voltage-gated Ca²⁺ channels, suggesting caution in its use to study [Ca²⁺]_i regulation in intact cells.     

Vesicular site of action of lithium ion in choline-calcium stimulated adrenergic nerve endings of rat heart

Reports from this laboratory have suggested that the secretion of norepinephrine (NE) in slices of ventricle from the rat heart, incubated in a medium of choline and Ca²⁺ (Ch⁺-Ca²⁺) deprived of Na⁺, is mediated by the outward transport of NE (blocked by cocaine) from synaptic vesicles fused or attached to the axolemma. Lithium (and reserpine), block the Mg²⁺-ATP-stimulated uptake of NE by isolated synaptic vesicles (Slotkin, Seidler, Whitmore, Salvaggio, and Lau, 1978). Hence, a hypothesis to be tested was that lithium ions would increase secretion of NE stimulated by Ch⁺-Ca²⁺. By contrast, amines mobilized by lithium ions (or reserpine) in control nerves would be deaminated. Experiments showed that lithium-Krebs increased the excretion of [³H]deaminated metabolites of [³H]NE. A much smaller quantity of [³H]NE was released by a process that was independent of Ca²⁺ and weakly inhibited by cocaine. When combined with Ch⁺Ca²⁺, lithium ions, in concentrations that were known to block uptake in isolated vesicles, induced a Ca²⁺-dependent secretion of [³H]amines. A small quantity of [³H]deaminated metabolites was excreted. Both processes were strongly inhibited by both cocaine and desipramine. Both reserpine (Bogdanski, 1982) and lithium ions blocked the inhibitory effect of exogenous ATP (2 mM) on secretion induced by Ch⁺−Ca²⁺. This effect indicated a proximity of vesicles to the axolemma. The effects of lithium ions could be explained by the hypothesis if lithium prevented storage of [³H]NE in vesicles by blocking the Mg²⁺ + ATP-dependent amine pump in vesicle membranes.     

The effect of trimethyltin on acetylcholine release in the guinea-pig trachea

The purpose of the present work was to characterise the effects of trimethyltin on the release of acetylcholine from parasympathetic nerves and its effect on the postjunctional cholinergic stimulation of a smooth muscle. The guinea-pig trachea has been used as a model. Prejunctionally, trimethyltin (3.0 × 10⁻³ M) significantly enhanced in a reversible manner the high K⁺ (75 mM) evoked release of endogenous acetylcholine and [³H]acetylcholine. The evoked release of endogenous acetylcholine and [³H]acetylcholine was released from a pool of acetylcholine being independent of extraneuronal Ca²⁺ in the presence, but not in the absence of trimethyltin. The effect of trimethyltin on the release was not inhibited by low Ca²⁺ (0 mM and 1.0 × 10⁻⁴ M) or by Ca²⁺ channel blockers (verapamil, 1.0 × 10⁻⁴ M, flunarizine, 1.0 × 10⁻⁴ M, ω-conotoxin GVIA, 2.0 × 10⁻⁷ M and ω-agatoxin, 2.0 × 10⁻⁷ M). The present results also demonstrate that trimethyltin induce emptying of a non-vesicular, probably a cytoplasmic storage pool of acetylcholine, since AH5183 (2.0 × 10⁻⁵ M), an inhibitor of the translocation of acetylcholine into synaptic vesicles, and -latrotoxin (1.0 × 10⁻⁸ M), a toxin from black widow spider venom inducing vesicle depletion, had no inhibitory effects on the release of [³H]acetylcholine evoked by trimethyltin (3.0 × 10⁻³ M). The release of [³H]acetylcholine was moreover enhanced by trimethyltin when the vesicular uptake of [³H]acetylcholine was inhibited by AH5183, probably as a result of a higher cytoplasmic concentration of [³H]acetylcholine. Trimethyltin also reduced the neuronal uptake of [³H]choline and this was probably due to a depolarising effect of trimethyltin on the cholinergic nerve terminals. A similar depolarisation induced by trimethyltin was observed during patch clamping of GH₄ C₁ neuronal cells. Postjunctionally, trimethyltin had no effect by itself or on the carbachol-induced smooth muscle contraction, indicating that trimethyltin did not have a general depolarising effect on smooth muscle cells or an effect on muscarinic receptors. Furthermore, the reduced electrical field-induced contraction and the subsequent increase in the basal smooth muscle tension that was observed by addition of trimethyltin was activity-dependent, and was most probably due to emptying of a nervous non-vesicular storage pool of acetylcholine, followed by rapid hydrolysis of acetylcholine by acetyl- and pseudocholinesterases.