13-正丙基巴马汀的抗心律失常作用

iv13—正丙基巴马汀(13—n—Ptopyl—Pal-matine)8mg·kg~(-1)能显著减少氯仿诱发小鼠室颤的发生率.提高哇巴因致豚鼠室早、室速、室颤及心搏停止的阈剂量。iv1、3 mg·kg~(-1)可明显减少CaCl_2诱发小鼠心律失常的发生率.缩短BaCl_2诱发大鼠心律失常的持续时间、但对乌头碱诱发大鼠心律失常无明显的对抗作用。此外,13—正丙基巴马汀还能明显提高大鼠心肌细胞膜Na~+,K~+—ATP酶的活性。     

刺乌头碱对麻醉大鼠心电图的影响及其抗实验性心律失常作用

目的与方法：给麻醉大鼠恒速ｉｖ刺乌头碱观察ＥＣＧ变化及ｉｐ小剂量刺乌头碱对动物实验性心律失常的影响。结果：ｉｖ剂量至２．５４±０．０６ｍｇ·ｋｇ－１时，ＨＲ显著减慢，Ｐ－Ｒ间期显著延长，当剂量增至４．１２～８．１９ｍｇ·ｋｇ－１时，可分别引起ＶＰ、ＶＴ、ＶＦ及ＣＡ等；经ｉｐ０．５ｍｇ·ｋｇ－１时，则能对抗乌头碱、氯化钡诱发的大鼠心律失常，显著提高哇巴因诱发豚鼠心律失常的剂量。结论：小剂量刺乌头碱具有抗心律失常作用，而大剂量又可诱发心律失常。     

苦参总碱抗实验性心律失常的作用

目的：研究苦参总碱抗实验性心律失常的作用。方法：本研究采用冠脉结扎，BaCl2肾上腺素，乌头碱，哇巴因诱发的心律失常模型。结果：苦参总碱能明显对抗大鼠冠脉结扎后诱发的早期缺血性心律失常；对BaCl2诱发的大鼠心律失常有预防和治疗作用；缩短静注肾上腺素诱发的家兔心律失常持续时间；增加乌头碱诱发大鼠心律失常的剂量；增加哇巴因诱发豚鼠心律失常的剂量。结论：苦参总碱对多种心律失常模型有预防或治疗作用，其抗心律失常机制是多方面的。     

碘杂环化合物的抗心律失常作用

碘杂环-64能防治乌头碱、氯化钡和结扎冠状动脉诱发的大鼠心律失常,推迟肾上腺素—氯仿诱发家兔心律失常的发作和缩短心律失常持续期,提高哇巴因诱发豚鼠心律失常的剂量,显著降低乙酰胆碱(Ach)—氯化钙诱发小鼠房颤(扑)的发生率。碘杂环-64减慢心率与迷走神经兴奋和β受体阻滞无关。     

莲心碱衍生物抗实验性心律失常的作用

目的:研究4种莲心碱衍生物抗心律失常的药理作用.方法:采用哇巴因、氯化钙、乌头碱3种抗心律失常模型.结果:4种莲心碱衍生物(5 mg•kg 1,iv)均能显著提高哇巴因致豚鼠、乌头碱致大鼠发生室性期前收缩(VE)、室性心动过速(VT)、心室纤颤(VF)及心脏停搏(CA)的用量,延长CaCl2诱发大鼠心律失常的出现时间,缩短生存大鼠的窦性心律恢复时间,减少死亡率.结论:4种莲心碱衍生物均有广泛的抗心律失常作用.     

苄普地尔抗心律失常作用

苄普地尔iv能明显提高乌头碱诱发大鼠心律失常用量及豚鼠心脏哇巴因中毒耐量;对BaCI_2、Adr诱发的实验性心律失常有明显对抗作用;对大鼠冠脉结扎复灌注引起的心律失常有保护作用。     

峨眉唐松草化学成分的研究

从四川产峨眉唐松草(Thalictrum omeiense W.T.Wang)根茎中分离得到八种生物碱(Ⅰ～Ⅷ),碱Ⅰ,Ⅱ,Ⅴ,Ⅶ和Ⅷ分别鉴定为oxyberberine(Ⅰ),thaliadine(Ⅱ),thalmelatidine(Ⅴ),adiantifoline(Ⅶ)和thalmineline(Ⅷ)。碱Ⅵ为新的二聚阿朴芬—苄基异喹啉类生物碱,根据理化性质和光谱数据所推定的结构如Ⅵ所示。命名为峨眉唐松草碱(methoxyadiantifoline)。碱Ⅲ和碱Ⅳ的结构尚在研究中。药理实验结果表明峨眉唐松草碱具有较明显的扩张冠状动脉作用。     

胃复安对实验性心律失常的作用

MCP有对抗氯化钡诱发大白鼠心律失常的作用;对抗氯仿-肾上腺素诱发家兔的心律失常,能提高乌头碱诱发大鼠心律失常的用量、致室颤量和致死量、但对哇巴因诱发的心律失常无影响,不能改善结扎大白鼠冠状动脉造成的缺血性心律失常。有局部麻醉作用。     

M_3受体激动剂对氯化钡诱发大鼠心律失常的保护作用

目的观察M3受体激动剂胆碱和毛果芸香碱对氯化钡诱发Wistar大鼠心律失常的保护作用。方法舌下静脉注射氯化钡诱发Wistar大鼠心律失常,分别给予胆碱和毛果芸香碱以及M3受体特异阻断剂4-二苯乙酰氧-N-甲基哌啶甲碘化物(4-DAMP)干预,观察大鼠心律失常的发生和发展情况。结果氯化钡4mg·kg-1可诱发大鼠出现明显的双向性室性心律失常,胆碱10mg·kg-1和毛果芸香碱0.2mg·kg-1均能推迟双向性室性心律失常的出现,并使心律失常的持续时间缩短(P<0.01)、严重程度减轻(P<0.01)。胆碱和毛果芸香碱的上述作用又被M3受体阻断剂4-DAMP0.12μg·kg-1部分阻断(P<0.05)。结论胆碱和毛果芸香碱通过激动心肌M3受体,对氯化钡诱发Wistar大鼠心律失常的发生和发展具有保护作用。     

山楂籽黄酮提取物抗实验性心律失常作用的研究

目的观察山楂籽黄酮提取物对三氯甲烷及乌头碱诱发的心律失常作用。方法采用三氯甲烷诱导小鼠心律失常,静注乌头碱诱发大鼠心率失常,术前5 d给予山楂籽黄酮提取物,心电图连续示波观察并记录心室颤动、室性早搏、室性心动过速的发生次数、室性早搏出现时间以及乌头碱累积消耗量。结果与模型组相比山楂籽黄酮提取物能明显降低三氯甲烷诱导的小鼠室颤发生率,且可明显增加诱发大鼠发生心律失常的乌头碱消耗量,推迟心率失常出现时间,但对降低室性早搏和室性心动过速的发生次数无明显作用。结论山楂籽黄酮提取物能明显减轻由三氯甲烷及乌头碱引起的实验性心律失常。     

Captopril potentiates the vasodepressor action of Met-enkephalin in the anaesthetized rat

The transient vasodepressor action of Met-enkephalin (10-80 micrograms kg-1, i.v.) in anaesthetized rats was significantly potentiated by the angiotensin-converting enzyme inhibitor, captopril (2 mg kg-1, i.v.); at this dose, it failed to modify the transient vasodepressor action of the non-specific vasodilator, nitroprusside (2.5, 5.0, 10 micrograms kg-1, i.v.). Captopril (2 mg kg-1, i.v.) caused a slow, progressive fall in the blood pressure of anaesthetized spontaneously hypertensive (SH) rats when compared to vehicle-treated controls. Pretreatment with naloxone (1.5 mg kg-1, i.v.) 30 min earlier failed to alter significantly the hypotensive action of captopril in anaesthetized SH rats. It was concluded that although captopril potentiated the vasodepressor action of Met-enkephalin in anaesthetized normotensive rats, potentiation of endogenous opioids does not appear to be involved in the hypotensive action of captopril in anaesthetized SH rats.     

Influence of neonatally administered capsaicin on baroreceptor and chemoreceptor reflexes in the adult rat.

1 Baroreceptor and chemoreceptor reflex activity was studied in anaesthetized adult rats which had been treated neonatally with a single injection of capsaicin (50 mg/kg s.c.). 2 Pressor responses to bilateral carotid artery occlusion were significantly lower in capsaicin-treated rats compared with vehicle-treated controls. Pressor responses to intravenously injected noradrenaline were similar in the two groups of rats. 3 Resting respiratory minute volume and tidal volume were lower in anaesthetized capsaicin-treated animals than in vehicle-treated controls, but there was no significant difference in respiratory frequency. 4 The increases in respiration evoked by intravenous administration of the peripheral arterial chemoreceptor stimulant, sodium cyanide, or by breathing a hypoxic gas mixture, were significantly lower in capsaicin-treated rats compared with the controls. 5 It is concluded that baroreceptor and chemoreceptor reflex activity are significantly reduced in anaesthetized adult rats which had been treated neonatally with capsaicin, and that this is likely to result from the destruction of unmyelinated baro- and chemoreceptor afferent fibres.     

甲基莲心碱的降压作用

甲基莲心碱对麻醉、清醒的正常大鼠,肾性、D0CA盐型高血压大鼠,麻醉猫、清醒正常家兔都能引起快速、剂量依赖性降压作用,猫椎动脉注射及脑室内注射甲基莲心碱0.6mg/kg无明显降压作用。表明甲基莲心碱是一种有效的抗高血压药,对血管平滑肌有直接扩张作用。     

TOLERANCE TO THE EFFECTS OF Δ1-TETRAHYDROCANNABINOL ON THE PRESSOR RESPONSES TO NORADRENALINE IN RATS

1. The depressor response, but not the cardiac slowing response, to the acute intravenous administration of delta 1-THC (1 mg/kg) was significantly reduced in urethane anaesthetized rats, which had been treated with daily injections of delta 1-THC (2 mg/kg, i.p.) for 10 days (P less than 0.01). 2. No significant differences in either the depressor or the negative chronotropic effects of an acute intravenous injection of delta 1-THC (1 mg/kg) were observed in anaesthetized rats which had been treated with PVP (8 mg/kg per day, i.p.) for 10 days. 3. The depressor and cardiac slowing responses to an acute intravenous dose of delta 1-THC (1 mg/kg) were not significantly different between delta 1-THC- and PVP-treated animals which had been pithed. 4. The potentiating effects of delta 1-THC on the pressor responses to intravenously administered noradrenaline were significantly reduced (P less than 0.001) in urethane anaesthetized rats which had been treated with delta 1-THC, but not in anaesthetized PVP-treated animals. 5. Tolerance to the potentiating effect of delta 1-THC on the responses to noradrenaline has also been demonstrated in anaesthetized delta 1-THC-treated rats, but not in pithed delta 1-THC treated ones. 6. It is concluded that the development of tolerance to the depressor action of delta 1-THC, and its potentiating effect on the noradrenaline pressor responses requires the presence of an intact central nervous system.     

STUDIES ON THE MECHANISM OF ACTION OF THE HYPOTENSIVE EFFECT OF KETANSERIN

Ketanserin, 0.01-3.0 mg/kg i.v., was found to cause a dose-related fall in blood pressure in anaesthetized rats. However, these decreases were only significant after 1 and 3 mg/kg doses. Subsequent administration of prazosin, 0.2 mg/kg i.v., had no significant effect on blood pressure. In the presence of ketanserin 3 mg/kg, plus prazosin 0.2 mg/kg, adenosine caused a significant dose-dependent fall in blood pressure in anaesthetized rats. Methysergide, 1 mg/kg i.v., significantly attenuated the blood pressure responses to serotonin in anaesthetized rats whereas ketanserin (1 and 3 mg/kg) had no overall effect on serotonin responses. Ketanserin, 1 and 3 mg/kg i.v., was found to antagonize the pressor effects of phenylephrine and reverse the pressor effects of adrenaline in anaesthetized rats. Responses to angiotensin II were not significantly affected by ketanserin. These results suggest that ketanserin lowers blood pressure in anaesthetized rats by blockade of alpha-adrenoceptors.     

峨眉唐松草碱对离体大鼠心肌缺血再灌注损伤的保护作用

峨眉唐松草碱(methoxyadiantifoline 5μmol/L)显著降低大白鼠离体灌流心脏缺血再灌注损伤所致心室纤颤的发生率、延长窦性心律时间、减少心肌细胞中乳酸脱氢酶的释放及丙二醛的生成,显示其具有保护心肌及抑制脂质过氧化作用,效果与维拉帕米近似。     

Influence of Various Anaesthetics on the Cardiovascular Responses to Noradrenaline in Rats before and after Guanethidine

Abstract The influence of surgical anaesthesia induced by ketamine, pentobarbital, pentobarbital-xylazine, or chloralose-urethane on blood pressure and heart rate was studied, and the effects were compared with results in conscious and pithed rats. The blood pressure was significantly decreased by pentobarbital-xylazine. The heart rate increased in all groups except in pentobarbital-xylazine anaesthetized rats. Generally, a fall in heart rate and blood pressure was observed during a two hours lasting anaesthesia as compared to the initial values. The blood pressure response to noradrenaline was significantly lowered by ketamine, pentobarbital and chloralose-urethane anaesthesia, and the response of the heart rate only by chloralose-urethane. Guanethidine 5 mg/kg intravenously significantly lowered the blood pressure in the ketamine, pentobarbital and chloralose-urethane anaesthetized groups. The guanethidine induced potentiation of the haemodynamic effects of noradrenaline was considerably influenced by the anaesthetic, the augmentation being greatest in pentobarbital and chloralose-urethane anaesthetized rats. Chloralose-urethane is considered a suitable anaesthetic in rats when studying the effects of noradrenaline and guanethidine. Following a single intraperitoneal injection a surgical anaesthesia of more than two hours' duration was obtained, and the variance of the parameters studied was less than that following administration of the other anaesthetics. It is emphasized that various effects of anaesthetics unrelated to their anaesthetic properties may obscure or even invalidate results obtained with drugs acting on the peripheral sympathetic nervous system.     

NATRIURETIC AND HYPOTENSIVE EFFECTS OF α-HUMAN ATRIAL NATRIURETIC POLYPEPTIDE IN ANAESTHETIZED DOCA-SALT HYPERTENSIVE RATS

Both natriuretic and hypotensive effects of alpha-human atrial natriuretic polypeptide (alpha-hANP) were investigated in anaesthetized DOCA-salt hypertensive rats and control rats. An intravenous injection of two doses (0.3 and 3.0 micrograms/kg body weight) of alpha-hANP produced a rapid and marked increase in natriuresis and fall in blood pressure in DOCA-salt rats. Natriuretic and hypotensive effects of alpha-hANP in DOCA-salt rats were significantly greater than those in the control rats. It is suggested that DOCA-salt rats may have an enhanced natriuretic and hypotensive responsiveness to alpha-hANP.     

Vascular actions of the prostacyclin receptor antagonist BAY 73-1449 in the portal hypertensive rat

We have investigated the actions of the postacyclin receptor antagonist BAY 73-1449 on shunt vessel development and shunt flow in the portal vein ligated portal hypertensive Wistar rat in vivo. BAY 73-1449 (0.1-1 mg/kg), given intravenously, did not significantly reduce mesenteric inflow, but significantly reduced splenic shunt vessel outflow, compared to the effects of vehicle, in anaesthetized portal vein ligated rats as measured by shunt vessel conductance. There were no differences between portal vein ligated animals treated, beginning just before portal vein ligation, with vehicle for 7 days and animals treated for 7 days with BAY 73-1449 (1-5 mg/kg, s.c.) in the degree of porto-systemic shunting, as measured by the radioactive microsphere technique in anaesthetized rats. Portal pressure was similar in animals treated with vehicle or BAY 73-1449. It is concluded that the prostacyclin receptor antagonist BAY 73-1449 can acutely reduce shunt vessel blood flow in portal hypertensive rats.     

BLOOD PRESSURE OVERSHOOT UNDER PENTOBARBITONE ANAESTHESIA FOLLOWING A SINGLE DOSE OF CLONIDINE IN RATS*

Withdrawal of chronic antihypertensive therapy with clonidine is known to produce a blood pressure overshoot. It has been reported that the same may occur after a single dose of clonidine. A single, intramuscular dose of clonidine (0.05 mg/kg) produced an overshoot in blood pressure, on the day following administration, in normotensive rats anaesthetized with sodium pentobarbitone. No rebound elevation of mean arterial pressure or of heart rate occurred in conscious, normotensive, spontaneously hypertensive or renal hypertensive rats following this dose of clonidine, nor did it occur in rats anaesthetized with ether. It is suggested that the overshoot phenomenon in rats under barbiturate anaesthesia may involve an interaction between an effect of clonidine and the barbiturate.