普鲁卡因对鼠大脑皮层锥体神经元延迟整流型钾离子通道开关动力学的影响

Na+通道是局麻药、全麻药作用的靶通道,但并非唯一通道[1]。本文运用膜片钳技术,采用内面向外式记录方法,观察了普鲁卡因对大鼠大脑皮层锥体神经元胞体上延迟整流型K+通道开/关动力学的影响。 材料与方法 一、实验方法 （一）神经元的急性分离2～5d龄的SD大鼠,雌雄不     

利多卡因对大鼠海马锥体神经元NMDA介导钙电流的影响

目的 观察不同浓度利多卡因对中枢海马锥体神经元N-甲基-D天冬氨酸(NMDA)介导钙电流的影响。方法 将已培养12-14 d的Wistar大鼠海马神经元按利多卡因浓度(10-5-10-1mol/L)分成5组,以不含利多卡因组做对照,共6组(n=6)。应用全细胞膜片钳方法,采用无间隙模式,采集记录各组大鼠海马神经元NMDA介导钙电流及各组静息电位的变化。结果 10-3、10-2、10-1组的电流密度较对照组降低(P<0.05或0.01);利多卡因浓度与电流密度呈直线负相关(r=0.76,P<0.01)。各组静息电位差异无显著性。结论 利多卡因可浓度依赖性抑制NMDA介导钙电流,低浓度利多卡因的神经保护作用可能与此有关。     

异丙酚对大鼠海马神经元钾离子通道的影响

目的 采用大鼠海马神经元作为研究对象,研究异丙酚对神经元的瞬间外向钾通道、延迟整流钾通道的影响,以探讨静脉麻醉药作用的可能机制。方法 在急性分离的大鼠海马锥体神经元上,利用全细胞膜片钳技术,记录瞬间外向、延迟整流两种钾离子通道的电流。研究异丙酚对这些通道电流幅度和通道动力学的作用。结果 异丙酚对上述通道电流均具有抑制作用,呈可逆性和浓度依赖性,并对离子通道的激活和失活曲线有一定的影响。异丙酚对瞬间外向钾通道和延迟整流钾通道作用的EC50分别为(71±18)和(37±18)μmol·-1,最大抑制率分别为52％±3％和32％±5％。结论 异丙酚对海马神经元上的瞬间外向钾电流、延迟整流钾电流有不同程度抑制作用。异丙酚对锥体神经元兴奋性的影响,可能与影响记忆功能有关。     

氯胺酮对大鼠海马锥体神经元延迟整流钾电流的影响

目的观察氯胺酮对大鼠海马锥体神经元延迟整流钾电流(IK)的影响。方法酶消化法急性分离Wistar大鼠海马锥体神经元,采用全细胞膜片钳技术测定IK。加用不同浓度(10、30、100、300、1000μmol/L)氯胺酮后,计算IK抑制率,建立氯胺酮的浓度-效应曲线,选择30 μmol/L氯胺酮作IK 稳态激活(及失活)曲线。结果10、30、100、300、1 000μmol/L氯胺酮对IK的抑制率分别为(10±4)%、(19±4)%、(31±5)%、(50±7)%、(54±8)%。IC50为(100±18)μmol/L,Hill系数为1.33±0.48。激活曲线的半数最大激活膜电位(V1/2)(1.82±0.20)mV上升到(9.30±1.03)mV(n=8,P<0.05),K从(20.4±2.3)mV移动到(16.6±4.2)mV(P>0.05);失活曲线的V1/2从(-29±4)mV下降到(-73±6) mV(P<0.01),K从(26±6)mV上升到(53±11)mV(P<0.01)。30 μmol/L氯胺酮使IK的稳态激活曲线向去极化方向明显移动;使IK的稳态失活曲线向超极化方向明显移动。结论氯胺酮对IK通道有抑制作用,氯胺酮的对中枢神经系统的作用可能与IK抑制有关。     

罗哌卡因和布比卡因对大鼠海马神经元电压门控性钾电流的影响

目的 研究罗哌卡因和布比卡因对大鼠海马神经元电压门控性钾电流的作用,从离子通道水平探讨局麻药所致中枢神经系统毒性的机理。方法 采用全细胞膜片钳技术观察罗哌卡因和布比卡因对培养大鼠海马神经元延迟整流钾电流(IK)和短暂外向钾电流(IA)的影响。结果 浓度为100、1000 μmol·L-1的罗哌卡因和布比卡因对IK的抑制率分别为8.2％±2.0％、12.3％±3.0％(P>0.05)和24％±4％、33％±6％(P<0.05)。浓度为0.1、1、10 μmol·L-1的罗哌卡因和布比卡因对IA的抑制率分别为33％±4％、44％±4％(P<0.001)和56％±4％、72％±6％(P<0.001)及86％±4％、92％±5％(P<0.01);其半数抑制浓度(IC50)分别为(0. 39±0.19)μmol·L-1和(0.14±0.05)μmol·L-1。两种药物对IA的抑制作用为非电压依赖性。结论 罗哌卡因和布比卡因对大鼠海马神经元IA均具有显著抑制作用,但罗哌卡因对IA的抑制效能明显低于布比卡因。局麻药对海马神经元IA电流的抑制作用可能是其引起中枢神经系统毒性的原因之一。     

异丙酚对大鼠顶叶皮层神经元延迟整流性钾通道电流的影响

目的 探讨异丙酚对大鼠顶叶皮层神经元延迟整流性钾通道电流(IK)的影响.方法 酶消化法急性分离Wistar大鼠顶叶皮层神经元,随机分为4组,分别为不同浓度异丙酚组(P1-4组):培养皿加入异丙酚,终浓度分别为10、30、100和300 μmol/L.于异丙酚给药前,给药后1 min时采用全细胞膜片钳技术,记录顶叶皮层神经元IK,计算IK抑制率,绘制100 μmol/L异丙酚作用下大鼠皮层神经元延迟整流性钾通道电流-电压曲线、延迟整流性钾通道激活曲线和失活曲线.结果 与给药前比较,各组给药后顶叶皮层神经元IK降低(P<0.01);异丙酚对顶叶皮层神经元IK的抑制率呈浓度依赖性(P<0.01);100 μmol/L异丙酚给药后大鼠顶叶皮层神经元延迟整流性钾通道电流-电压曲线下移,但波形、阈电位没有改变;与给药前比较,100 μmol/L异丙酚给药后延迟整流性钾通道激活和失活曲线的半数激活膜电位、曲线斜率因子差异无统计学意义(P>0.05),激活曲线向右移动大约12 mV,失活曲线向左移动大约6 mV.结论 异丙酚可抑制大鼠顶叶皮层神经元IK,且呈浓度依赖性;100 μmol/L异丙酚可减慢延迟整流性钾通道激活,加速其失活.     

异丙酚对大鼠顶叶皮层神经元延迟整流性钾通道电流的影响

Objective To investigate the effects of propofol on the delayed rectifier potassium current (IK) in acutely dissociated rat parietal conical neurons. Methods Wistar rats between 10- and 14-day old of both sexes were used. The parietal cortical neurons were acutely dissociated enzymatically. The effects of propofol (10, 30,100, 300 μmol/L) on IK were investigated by using the whole cell patch clamp technique in acutely dissociated rat parietal cortical neurons. Results IK was inhibited by propofol in a concentration-dependent manner. The four concentrations of propofol (10, 30, 100, 300 μmol/L) reduced IK by (5.2 ± 1.3)%, (13.3 ± 2.4)%,(23.9 ± 5.5)% and (42.1 ± 6.6)%, respectively (n = 6, P <0.01). The amplitude of IK was decreased at different membrane potentials after giving propefol (100 μmol/L). The V,n of the activation and inactivation curves and the slop factor (κ) had no change after giving propofol (100 μmol/L) (n = 6, P >0.05). The activation curve was shifted to the right about 12 mV, and the inactivation curve to the left about 6 mV after giving propefol (100 μmol/L).Conclusion Propefol inhibits IK of parietal cortical neurons of rats in a concentration-dependent manner, and 100 μmol/L propofol can slow the activation of the delayed rectifier potassium channel and accelerate its inactivation.     

罗库溴铵对鼠海马皮层锥体神经元乙酰胆碱受体的影响

目的 观察罗库溴铵对鼠海马皮层锥体神经元乙酰胆碱受体(AchR)通道电生理学的影响。方法应用急性分离法与膜片钳贴附式单通道记录技术,观测不同浓度罗库溴铵(0、0.05、0.1、0.2、0.4mmol·L-1)或与0.1 mmol·L-1阿托品对SD大鼠海马皮层锥体神经元胞体上AchR通道电生理学参数的作用。结果 (1)R0.05组中电导、开放概率(P0)、短时程开放时间常数(τ01)大于或长于对照组(P<0.05或0.01),长时程开放时间常数(τ02)、短时程关闭时间常数(τc1)、长时程关闭时间常数(τc2)则无统计学差异(P>0.05);其余各组6项参数均大于或长于对照组(P<0.05或0.01)。(2)同时加入罗库溴铵与阿托品,R0.05组各参数与对照组比较无统计学差异(P>0.05);其余各组6项参数(R0.1组中除τ01外)均大于或长于对照组(P<0.05或0.01)。结论 0.05～0.4 mmol·L-1罗库溴铵可不同程度致使鼠海马皮层锥体神经元AchR通道兴奋;浓度为0.05 mmol·L-1时可能主要作用于其毒蕈碱型AchR;浓度达0.1～0.4mmol·L-1时则可能以兴奋烟碱型AchR通道为主。研究结果提示,罗库溴铵一旦透过受损害的血脑屏障,可能引起中枢系统的不良反应。     

吗啡对大鼠海马锥体神经元L-型Ca2+通道电流的影响

目的观察吗啡对大鼠海马锥体神经元L-型Ca^2＋通道电流的影响。方法成年SD大鼠,体重230～270 g,麻醉后快速断头取脑,急性分离海马锥体神经元,12个海马（椎体神经元）随机分为2组（n=6）,吗啡组应用细胞贴附式膜片钳技术记录依次加入不同浓度吗啡[0（未加吗啡）、10^-8、10^-7、10^-6、10^-5mol/L]后海马锥体神经元L-型Ca^2＋通道电流及电导;纳洛酮组加入10^-5mol/L纳洛酮后30min,再依次加入上述不同浓度吗啡,记录此通道电流及电导。结果与未加吗啡比较,吗啡组10^-6、10^-5mol/L吗啡可抑制海马神经元L-型Ca^2＋通道电流,10^-5 mol/L的抑制作用更明显（P＜0．01）;预先加入纳洛酮可阻断吗啡对该通道电流的抑制作用（P＜0．01）;但L-型Ca^2＋通道电导无变化。结论通过作用于μ片受体,10^-6、10^-5 mol/L吗啡可抑制大鼠海马锥体神经元L-型Ca^2＋通道电流,10^-5mol/L的抑制作用更强。     

地氟醚对大鼠顶叶皮层神经元延迟整流钾电流的影响

目的 探讨地氟醚对大鼠顶叶皮层神经元延迟整流钾电流(Ik)的影响.方法采用酶消化法急性分离Wistar大鼠顶叶皮层神经元,接种于培养皿,采用随机数字表法,将培养皿随机分为3组(n=10),不同浓度地氟醚组(D1～3组),在培养皿中加入含0.3 mmol/L(D1组)、0.6 mmol/L(D2组)、0.9 mmol/L(D3组)地氟醚的细胞外液灌流液.于地氟醚给药前、给药后1 min时采用全细胞膜片钳技术,记录顶叶皮层神经元Ik,计算Ik抑制率,绘制0.6 mmol/L地氟醚作用下顶叶皮层神经元Ik的电流.电压曲线、激活曲线和失活曲线.结果 与给药前比较,各组给药后顶叶皮层神经元Ik降低(P＜0.01);地氟醚对顶叶皮层神经元Ik的抑制作用呈浓度依赖性(P＜0.01);0.6 mmol/L地氟醚给药后顶叶皮层神经元Ik的电流-电压曲线下移,但曲线形状和阈电位没有改变;与给药前比较,0.6mmol/L地氟醚给药后Ik的激活和失活曲线的半数激活电压和曲线斜率因子差异无统计学意义(P＞0.05).结论 地氟醚对大鼠顶叶皮层神经元延迟整流钾通道具有抑制作用,且呈浓度依赖性,而对其激活和失活速率无影响,提示地氟醚对延迟整流钾通道的抑制作用并不是通过改变该通道的兴奋性而实现的,可能与其他原因有关.

Abstract：

Objective To investigate the effects of desflurane on the delayed rectifier potassium current (Ik ) in acutely dissociated rat parietal cortical neurons. Methods Wistar rats between 10- and 14-day old of both sexes were used. The parietal cortical neurons were acutely dissociated enzymatically. The extracellular fluid saturated with 0.3,0.6 and 0.9 mmol/L desflurane was added to the culture dish, then the effects of different concentrations of desflurane on Ik were investigated by using the whole-cell patch-clamp technique in acutely dissociated rat parietal cortical neurons. Results IK was inhibited by desflurane in a concentration-dependent manner ( P ＜0.01). The V1/2 of the activation and inactivation curves and the slop factor had no change after giving 0.6 mmol/L desflurane (P ＞ 0.05). Conclusion Desflurane inhibits delayed rectifier potassium channels of parietal cortical neurons of rats in a concentration-dependent manner, and has no effect on the activation and inactivation of delayed rectifier potassium channels, indicating that the change in the excitability of the channel is not involved in the mechanism of inhibitory effect of desflurane, and the other reasons may be involved in the mechanism.     

K+ channel blocker modulation of the refractory period in spontaneously active guinea-pig ureters

The effects of various K⁺ channel blockers on the spontaneous electrical activity of the smooth muscle cells of the ureter still attached to its primary pacemaker regions were investigated using standard intracellular microelectrode recording techniques. Spontaneous action potentials in the ureter were complex, consisting of an initial rapidly rising spike which was followed by a period of membrane oscillation, a quiescent plateau phase and terminated by an abrupt repolarisation and an after-hyperpolarisation with a peak “diastolic” potential of −66 mV. This after-hyperpolarization decayed slowly over 5–20 s until the underlying triggering potentials achieved threshold for another action potential discharge. Application of the Ca²⁺-entry blocker, nifedipine (1 mu;M), blocked action potential discharge within 2–5 min, after which the membrane settled at a potential of −55 mV. 4-Aminopyridine (4-AP)(1 mM for 2 min) and Ba²⁺ (100 mu;M for 2 min) both depolarized significantly the diastolic potential. In 4-AP, this membrane depolarisation was associated with a decreased amplitude of the initial spike and an increase in the half-amplitude duration. In contrast, tetraethylammonium (TEA) (0.5 mM for 2 min) only increased the frequency and half-amplitude duration of these ureteric action potentials. Apamin (200 nM), Cs⁺ (1 mM) and glibenclamide (1 μM) had no significant effects on any parameters of the ureteric action potential. It was concluded that the refractory period of the spontaneous action potentials in the whole-mount preparation of the upper urinary tract was determined by the opening of at least three K⁺ channel populations: large conductance (‘maxi K’) Ca²⁺-activated K⁺ channels; Ca²⁺-insensitive transiently opening K⁺ (I_Kto) channels and K⁺-selective inward rectifier channels. Received: 23 July 1998 / Accepted: 7 December 1998     

K+ channel currents in rat ventral prostate epithelial cells

BACKGROUND: Electrophysiological function of the normal prostate has not been extensively studied. In particular, ion channel currents and their regulation have not been studied in freshly-isolated prostate cells. METHODS: Rat prostate secretory epithelial (RPSE) cells were isolated by collagenase treatment. Columnar epithelial cells were used for nystatin-perforated, whole-cell voltage clamp, and the intracellular Ca(2+) concentration ([Ca(2+)](i)) was measured using fura-2. RESULTS: Step-like depolarizing pulses (900 msec) starting from - 90 mV induced outwardly rectifying K(+) currents without inactivation. ACh (10 microM) or ATP (100 microM) increased the outward current and hyperpolarized the cell membrane potential. Ionomycin (0.1 microM), a Ca(2+) ionophore, induced a similar increase in the outward current. TEA (5 mM), charybdotoxin (50 nM), and iberiotoxin (30 nM) inhibited the effect of ACh (or ATP) on the outward current, whereas apamin (100 nM) had no effect. The [Ca(2+)](i) of RPSE cells was increased by ACh, ATP, and UTP. CONCLUSIONS: RPSE cells have iberiotoxin-sensitive Ca(2+)-activated K(+) channels that may play an important role in the exocrine secretions of the prostate.     

K channel expression in prostate epithelium and its implications in men with chronic prostatitis

OBJECTIVE: To investigate the effect of the Kv1.3 K(+) channel on the pathogenesis of chronic prostatitis. MATERIALS AND METHODS: The expression of the Kv1.3 K(+) channel in prostatic epithelia was detected using streptavidin/peroxidase immunohistochemistry in tissue samples from 75 men with benign prostatic hyperplasia, including 42 with and 33 without chronic inflammation. All of the men were sampled in our hospital between January 2000 and December 2003. RESULTS: There was strong and moderate immunostaining in 14 of the prostatic epithelial specimens with inflammation and in 21 from patients without inflammation, compared to 28 and 12 with low staining, respectively (chi-squared, P < 0.05). CONCLUSIONS: The expression of the Kv1.3 K(+)channel was lower in prostatic epithelial cells from patients with chronic inflammation than from those without. Opening the Kv1.3 K(+) channel could promote the efflux of K(+) from the cells, causing an increase in [K(+)] in the prostate cavity. The increase in [K(+)] can then infiltrate the stroma through the epithelial gap, exciting the nerve fibres and causing pain and other clinical symptoms.     

利多卡因对大鼠海马神经元L-型Ca2+通道电流的影响

目的 观察不同浓度利多卡因对成年大鼠海马CA1区锥体细胞L-型Ca2 通道电流的影响,以探讨其对中枢神经的作用.方法 采用酶加机械分离的方法,急性分离成年大鼠海马CA1区锥体细胞.运用膜片钳细胞贴附模式技术,记录0、2、4、8、16、32 μg/ml的利多卡因对L-型Ca2 通道电流幅度和电导的影响.结果 不同浓度的利多卡因不影响单通道的单一电流幅度,也不影响L型Ca2 通道的单通道电导.低浓度利多卡因(2、4 μg/ml)对L-型Ca2 通道的整体平均电流无明显影响;浓度为8、16、32 μg/ml时,整体平均电流分别为(0.80±0.09)、(0.67±0.07)、(0.37±0.05)pA(与对照浓度比较,P＜0.05).结论 利多卡因影响成年大鼠海马CA1区锥体细胞L-型Ca2 通道电流,随着浓度的增加表现为先兴奋后抑制.     

普鲁卡因对离体人红细胞膜ATPases活性的影响

盐酸普鲁卡因是静脉复合麻醉（ＩＢＡ）的常用药物之一。我们发现在ＩＰＢＡ下施行上腹部手 术时，术毕人红细胞膜ＡＴＰａｓｅｓ活性有所下降。本研究的目的是观察普鲁卡因对离体人红细胞膜ＡＴ－ Ｐａｓｅ活性是否有直接影响。结果；一定浓度的普鲁卡因对Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ活性有明显抑制作用，对 Ｍｇ２＋－ＡＴＰａｓｅ活性无明显作用，对Ｃａ２＋－Ｍｇ２＋－ＡＴＰａｓｅ活性有轻微保护作用。研究结果为临床合理应 用ＩＰＢＡ提供了一定的实验依据。     

罗库溴铵和维库溴铵对大鼠离体膈肌神经肌肉接头钾离子通道的影响

目的利用成年大鼠膈肌膈神经不均匀牵拉标本,探讨罗库溴铵和维库溴铵对神经肌肉接头部位钾离子通道的影响。方法成年健康Wister大鼠,快速处死制备离体大鼠膈神经肌肉标本并制成不均匀牵张膈肌膈神经标本。观察两药相当大鼠0.5×ED95剂量时的血药浓度药物对选择性钾离子通道阻断药3,4-二氨基吡啶(3,4-DAP)引起的终板电位(EPP)时程的作用。结果罗库溴铵自给药后2min起能够明显缩短由3,4-DAP引起的70%EPP时程的延长。而维库溴铵对由3,4-DAP引起的EPP时程的延长无明显影响。结论罗库溴铵能明显缩短由钾离子通道阻断药3,4-DAP引起的EPP时程延长作用。     

异丙酚和普鲁卡因对颅内压及脑灌注压的影响

目的观察异丙酚、普鲁卡因对颅内压(ICP)和脑灌注压(CPP)的影响。方法25例脑肿瘤病人随机分成异丙酚组(D组)和普鲁卡因组(P组)。局麻下钻孔于颅骨及脑膜间安置SP-2000型颅内压监护仪，连续监测ICP，同时用Colin508连续监测MAP、HR及PETCO2。静注异丙酚2mg／kg后，输注异丙酚100～150pg·kg     

七氟醚对吸入麻醉药敏感性不同的果蝇幼虫中枢神经元钾通道的影响

目的以钾通道为切入点,利用膜片钳技术探讨吸入麻醉药的作用机制。方法分离制备对吸入麻醉药敏感(S)、耐药(R)和野生(H)果蝇品系脑神经元,以膜片钳技术观察临床有效浓度七氟醚对其全细胞钾电流的影响。结果1MAC七氟醚使三品系Ⅲ型钾电流的Ipeak值显著增加:S(19±2)%>H(13±2)%>R(8±2)%;使钾电流的恢复曲线显著上移;不改变钾离子的平衡电位。2MAC七氟醚使三品系Ⅲ型钾电流的Ipeak值显著增加:S(36±4)%>H(24±2)%>R(14±1)%。3MAC的七氟醚能使Ⅲ型钾电流稳态失活曲线显著右移。结论钾离子通道可能是吸入麻醉药的中枢作用位点之一。     

氯胺酮对大鼠大脑皮质和丘脑突触体ATP酶活性的影响

目的 动态观察氯胺酮对大鼠大脑皮质和丘脑Na+-K+ATP酶和Ca2+-ATP酶活性的影响。方法 SD大鼠32只,随机分为四组:对照组、麻醉组、恢复I组和恢复Ⅱ组。对照组给予腹腔注射生理盐水10 ml·kg-1,10 min后断头;其它三组均为腹腔注射氯胺酮100 mg·kg-1。其中麻醉组在大鼠翻正反射消失后断头;恢复I组在大鼠翻正反射恢复后断头;恢复Ⅱ组在大鼠完全清醒后断头。在生理盐水冰面上分离双侧大脑皮质和丘脑,以分光光度法测大脑皮质和丘脑Na+-K+-ATP酶和Ca2+-ATP酶活性。结果大鼠腹腔注射氯胺酮后,其大脑皮质的Na+-K+-ATP酶和Ca2+-ATP酶活性分别较对照组降低32.8％和26.2％(P<0.05);丘脑的Na+-K+-ATP酶和Ca2+-ATP酶活性也分别较对照组降低31.4％和24.5％(P<0.05);大鼠翻正反射恢复后和动物完全清醒后两种ATP酶活性的变化与对照组相比差异均无统计学意义(P>0.05)。结论 Na+-K+-ATP酶和Ca2+-ATP酶活性的改变在氯胺酮全麻作用机制中可能起重要作用。