Hypothermic effects of N-n-propylnorapomorphine in mice: Antagonism by neurotransmitter receptor blockers

Six receptor blockers were compared in mice for their ability to alter hypothermia induced by the dopamine agonist N-n-propylnorapomorphine (NPA). The dopamine antagonist haloperidol inhibited NPA-induced hypothermia whereas phentolamine, propranolol, sotalol, atropine, cyproheptadine, or naloxone (alpha-adrenergic, beta-adrenergic, muscarinic cholinergic, serotonergic, and opiate antagonists, respectively) failed to inhibit it. The degree of antagonism of the hypothermic effect of NPA induced by haloperidol pretreatment suggests that the hypothermic response may serve as a useful model of specific dopaminergic activity of aporphines. Hypothermia induced by NPA and other aporphines may supplement the measure of aporphine-induced stereotypic cage-climbing previously reported to be specifically dopaminergic.     

Propranolol and morphine

The morphine blocking and anticonvulsant effects of propranolol were investigated in mice. Three different convulsant procedures (electroshock, pentylenetetrazol and thebaine) were used. In addition, LD₅₀'s of morphine after different doses of propranolol were done. Sotalol was used as a control drug to check which of the effects of propranolol could be regarded as due to beta blockade.Morphine LD₅₀ in mice is not altered by pretreatment with propranolol. The anticonvulsant characteristics of propranolol are different from those of sotalol, the former acting mainly on the tonic phase of the seizures. This study does not support the hypothesis that propranolol is a morphine antagonist but reinforces the idea that propranolol has definite central nervous system effects.     

索他洛尔治疗中老年室性早搏的疗效观察

目的　观察索他洛尔对中老年患者室性早搏的治疗效果。方法　根据治疗前后动态心电图监测室性早搏减少的百分比判定疗效 ,同时观察对最快心率、最慢心率、平均心率及 Q- Tc间期的影响 ;对治疗前后的心功能变化进行了监测。结果　索他洛尔治疗中老年人室性早搏总有效率为 65.2 % ;对冠心病合并室性早搏疗效显著 ,并且可减慢窦性心律及延长 Q- Tc间期 ;1 60～ 2 4 0 mg/d治疗 3～ 4w对心功能无影响。结论　索他洛尔是一种有效的治疗室性早搏的抗心律失常药物 ,对冠心病合并的室性早搏效果明显 ,极少数人因心率下降及 Q- Tc间期延长而停止治疗     

Sharply timed and lateralised events at time of establishment of long term memory

In the chick long term memory is known suddenly to become more resistant to disturbance 25 minutes after training. This was investigated using two bead pecking tasks: training involved either presentation of an ill-tasting bead (causing inhibition of spontaneous pecking) or habituation by prolonged presentation. Retention tests revealed two brief periods of improved recall, centred at 25 and at 30-32 minutes after learning. The first appeared to be associated with systems fed by the left eye and the second with right eye systems. In a final experiment memory formation in right or left hemisphere was directly disturbed by intracranial injection of the amnesic beta-antagonist sotalol. The first (and perhaps also second) period of improved recall was associated with interaction between the hemispheres. Right- and left-eyed birds differed markedly, both in the character of such interaction and in the outcome of learning.     

心电图U波与左心室中层心肌关系的实验研究

利用单相动作电位记录技术,同步记录16只兔子左心室心外膜下、中层和心内膜下心肌的单相动作电位,以索他洛尔作为工具药,研究心电图U波的起源.结果发现①应用索他洛尔1.5 mg/kg后心电图上出现U波,随着索他洛尔剂量的增加,U波更加明显.②索他洛尔明显延长中层心肌的复极时程,心外膜下心肌的复极时程与体表心电图T波的顶点相一致,而中层心肌的复极时程与U波的终点相一致.提示U波的产生可能是由于中层心肌复极延迟所致.     

索他洛尔与比索洛尔对持续性房颤电复律后窦性心律维持的比较

目的比较持续性房颤电复律后应用索他洛尔、比索洛尔维持窦性心律的疗效及安全性。方法1999-01~2001-01以持续性房颤在我院住院且病历资料完整的患者116例,成功电复律后配对随机进入索他洛尔组和比索洛尔组。随访1 a,每半月检测一次心电图,临床观察终点为房颤复发。结果索他洛尔组63.1%、比索洛尔组56.9%在随访的1 a中维持着窦性心律,差异无显著性(P>0.05);两组房颤的复发时间分别为51±87 d4、6±89 d,差异无显著性(P>0.05);比索洛尔组未出现室速,索他洛尔组3.4%发生了尖端扭转性室速,且都发生在首次用药的24 h内。结论持续性房颤转复窦性心律后服用比索洛尔(5 mg/d)与索他洛尔(160 mg/d)都可有效地维持窦性心律,但比索洛尔更安全。     

索他洛尔治疗室性期前收缩的疗效及对QTc离散度的影响

目的　观察索他洛尔治疗室性期前收缩的疗效及对QTc离散度的影响。方法　 38例室性期前收缩患者 ,给予索他洛尔 80～ 2 0 0mg/d ,治疗 4周。分析治疗前、后的 2 4h动态心电图及常规心电图。结果　治疗有效率为 6 8.4 % ,治疗前、后室性期前收缩分别为 (2 36± 10 6 )次 /h和 (77± 4 1)次 /h ,两者比较有显著差异 (P <0 .0 1)。并缩短QTc离散度 ,不良反应少 ,耐受性好。结论　索他洛尔是一种安全、有效的抗心律失常药物。     

从索他洛尔电生理作用评价其抗心律失常作用

从索他洛尔 (sotalol)电药理和电生理作用探索其抗心律失常机制。方法 :①采用经典的微电极方法和膜片钳技术观察sotalol对豚鼠心肌细胞动作电位时程 (APD)和膜离子流的作用 ;②运用心内膜单相动作电位 (MAP)技术观察sotalol对狗APD、有效不应期 (ERP)的影响 ;③监测药物浓度与QT间期关系。结果 :①索他洛尔对内向整流性钾流、钠内流、慢钙内流无影响 ,仅对延迟整流性钾流 (IK)有抑制作用 ;②索他洛尔可延长APD ,呈反转使用依赖 ;③静脉注射索他洛尔后 ,QTc ,APD90 和心室ERP均延长 ,缺血区心肌与非缺血区心肌对索他洛尔的反应一致 ;④QT间期随血药浓度升高而延长 ,血药浓度随剂量增大而上升。结论 :索他洛尔阻滞IK 外流、延长APD ,呈反转使用依赖。索他洛尔延长QTc与血药浓度呈正相关。因此 ,如能掌握索他洛尔特性 ,本药还不失为一安全有效的Ⅲ类抗心律失常药物。     

索他洛尔对兔心肌电生理的影响

目的探讨索他洛尔口服后对兔左心室心肌细胞电生理的影响及其发生机制。方法建立冠状动脉灌注的兔左心室楔形心肌模型,应用心电图同步记录技术和浮置玻璃微电极技术,观察索他洛尔口服后兔内外两层心肌动作电位时程(action potential duration,APD)、Q-T间期及跨壁复极离散度(transmural dispersion of repolarization,TDR)的变化以及心律失常的发生。结果索他洛尔组兔内、外膜心肌细胞的APD、Q-T间期及TDR在不同刺激周长下均较对照组延长,且以内膜延长为主(均P0.05)。索他洛尔组兔心律失常发生率较对照组升高(P0.05)。结论索他洛尔可明显延长兔内、外膜心肌细胞的APD、Q-T间期,并可增大兔心肌细胞的TDR,在兔子模型中,应用索他洛尔容易导致心律失常发生。