7-甲氧基-4′-羟基-3′-二乙胺甲基异黄酮(MHDF)对大鼠血流动力学和主动脉的作用

本实验观察了MHDF对整体大鼠血流动力学和离体大鼠胸主动脉的作用。结果表明iv MHDF(3～12.8 mg/kg)能降低大鼠左心室±dp/dt_(max),V_(max),V_(pm)和LVSP,延长T-dp/dt_(max),减慢心率。MHDF还能舒张大鼠胸主动脉,ED_(50)为6.5×10~(-6)mol/L;非竞争拮抗NA和CaCl_2致主脉收缩,pD_2′为3.11±0.21和3.73±0.07;抑制高K~ 致主动脉收缩,IC_(50)为1.76×10~(-5)mol/L。提示MHDF对血管的作用与α受体阻断剂不同,而可能与钙拮抗有关。     

萘甲异喹对离体豚鼠心肌的作用

萘甲异喹(NI)呈浓度依赖性地降低离体豚鼠心房收缩力和频率。其拮抗豚鼠左房肌Iso正性肌力作用的PD2₂′值为5.4,Ver为5.8。NI10μmol/L明显降低豚鼠乳头肌收缩力;缩短快反应APD,以对APD₂₀影响最大,但不影响APA和V_max。对高K⁺去极化慢反应动作电位,NI产生浓度依赖性负性肌力作用,同时明显降低APA,V_max,缩短APD;提高细胞外液Ca²⁺浓度可使其抑制作用逆转。结果提示NI具有钙通道阻滞作用。     

粉防己碱,小檗胺等四氢异喹啉类生物碱对大鼠脑内M-胆碱受体的作用

用放射受体结合方法,研究了36种四氢异喹啉类生物碱及其半合成衍生物对大鼠脑内M-胆碱受体的结合特性。实验发现,粉防己碱对M-胆碱受体的亲和力最高,其K_i值为7.3×10^-8mol/L。小檗胺、四氢黄连碱和半合成原小檗碱衍生物B₁亦具有较高亲和力,K_i值分别为1.9×10^-7,6.8×10^-7和8.1×10^-7mol/L。四氢小檗碱半合成原小檗碱衍生物B₂,B₃,B₄,B₅,B₆和半合成小檗胺衍生物E₁及半合成蝙蝠葛碱衍生物D₁对M-胆碱受体的亲和力为中等强度,K_i值在1～2×10^-6mol/L之间。实验结果提示,某些四氢异喹啉类生物碱的药理作用可能与M-胆碱受体有关。     

大鼠肝微粒体中芬氟拉明对映体氧化代谢的立体选择性研究

目的建立大鼠肝微粒体孵育液中l-和d-芬氟拉明的对映体选择性测定的方法,并用于研究芬氟拉明Ⅰ相代谢的立体选择性。方法将dl-芬氟拉明与大鼠肝微粒体孵育后,采用柱前衍生化毛细管气相色谱-氢火焰离子化检测法进行对映体的分离,测定时间反应曲线和酶动力学参数。结果单个对映体的线性范围是1～50μg/mL;l-和d-芬氟拉明的方法平均回收率分别为92.4%和95.5%,检测限和定量限分别为0.1μg/mL和1.0μg/mL,方法精密度为RSD<10%(n=6)。l-和d-芬氟拉明的K_m,V_max,Cl_int值分别为(0.15±0.01)和(0.27±0.02)μmol.mL^-1,(4.99±0.52)和(9.53±0.87)nmol.g^-1.min^-1,(33.3±3.0)和(35.3±3.1)mL.min^-1.g(蛋白)^-1。结论方法准确可靠,已用于l-和d-芬氟拉明在大鼠肝微粒体孵育液中的代谢及其动力学研究;结果表明,芬氟拉明在大鼠的Ⅰ相代谢具有对映体选择性。     

心喘灵(XC-1)及其衍生物XC-2对肾上腺素受体及动脉平滑肌的作用

本文用放射配基结合法研究了心喘灵(XC-1)及其衍生物XC-2对肾上腺素受体的亲和力,用离体器官方法观察了二者对α受体功能的影响,用酶分析法研究了两药对β受体功能的影响。两药各种作用强度相近,对大鼠脑皮层细胞膜α受体有中等强度亲和力(Ki10^-6mol/L),对兔主动脉和大鼠肛尾肌α₁受体均有中等强度阻断作用,但对大鼠输精管突触前α₂受体只有微弱的阻断作用。二药抑制由ISO激动的腺苷酸环化酶活性的IC₅₀均为3.6×10^-5mol/L。此外,二者都能拮抗CaCl₂,KCl和5-HT引起的主动脉条收缩反应并有直接扩张血管的作用。     

赛庚啶对离体犬心肌肌质网Ca2+,Mg2+—ATP酶活性和45Ca2+摄取功能的影响

当赛庚啶浓度在8×10^-6mol/L～2×10^-4mol/L之间时,该药对正常犬心肌肌质网Ca²⁺,Mg²⁺—ATP酶活性几乎没有影响,仅在10^-3mol/L时对该酶活性才有一定的抑制作用(抑制率为39.85%,P<0.01)。正常犬心肌肌质网的⁴⁵Ca²⁺摄取过程有明显的时间依赖性,至第30 min,其⁴⁵Ca²⁺摄取量可达312.79±22.25 nmol/mg protein.赛庚啶对心肌肌质网的~(45)Ca²⁺摄取有一定的抑制作用,其IC₅₀为1.94×10^-4mol/L。     

变价态唐松草新碱—PVC膜离子选择电极的研制及解离常数的测定

本文研制了以四苯硼—唐松草新碱缔合物为电活性物质的变价态唐松草新碱—PVC膜电极。电极膜按电活性物质:PVC:DBP为1:8:8组成。该电极在pH 5.0～6.0,Ⅰ=0.05的NaCl—HCl溶液中Nernst响应范围为1×10^-3～1×10^-5mol/L。电极斜率为58.2 mV/logc。检测限为2.5×10^-6mol/L。用直接电位法考察了TDH⁺,TDH₂CF⁺⁺共存时溶液pH和电极斜率S的关系。用S—pH关系,测定了25℃,Ⅰ=0.05时的Ka₁值为(2.5±0.2)×10^-4,用E—pH关系,测定了25℃,Ⅰ=0.05时的Ka₂值为(8.1±0.9)×10^-8。     

示波极谱法测定片剂和尿液中别嘌醇的含量

用二阶导数示波极谱法研究了别嘌醇的测定方法。在pH5.5 HAc-NaAc缓冲溶液和0.50 mol/L H₂SO₄溶液中,浓度与波高分别在3×10^-7～1×10^-4mol/L和5×10^-7～1×10^-4mol/L内呈现良好的线性关系,检测下限分别可达8×10^-8mol/L(0.011 ppm)和3×10^-7mol/L(0.041ppm)。测定了片剂和尿液中别嘌醇的含量。初步探讨了电极反应的性质。     

新类型酸性色素定量胺类化合物的研究:羊毛罂粟蓝测定胺类药物

前报报道了自70种色素中研究选出测定胺类的两种色素之一:二甲苯蓝(XC)⁽¹⁾,本文报道另一种色素:羊毛罂粟蓝(EG)。经研究得出:EG对亲脂性较大的胺,苯乙托品(Ⅰ)⁽²⁾的检出限为15ng/ml,苯乃辛(Ⅱ)⁽²⁾为20 ng/ml,其吸收系数(E_{1cm^1%)(Ⅰ为36.89×10²,Ⅱ为24.36×10²)为溴百里酚蓝(BTIJ)的4.6～5.9倍。EG—胺配合物的氯仿液呈绿蓝色,λmax635.5nm。测定时色素浓度应为2×10^-3mol/L。检量线在0～7(Ⅰ)与0～10(Ⅱ)μg/ml为直线。EG—胺配合物的分子比在EG浓度为2×10^-3mol/L时,EG:Ⅱ=1:1;2×10^-4mol/L时则为0.5:1。Ⅰ则在EG浓度不同时分子比基本不变,为1.3:1。用EG测定Ⅰ或Ⅱ0.2μg/ml时,CV在±5%以内;2.5,5.0,10.0μg/ml时为±1～2%。EG与XC一样,为文献上尚未用来测定胺类的新类型酸性色素,属同一类,其基本构造为:}     

抗痫灵的电化学行为及吸附伏安法研究

抗痫灵在0.20 mol/L H₂SO₄底液、富集电位-0.70 V(vs Ag/AgCl)、扫速100 mV/s等条件下,用吸附伏安法得一灵敏的还原峰,峰电位-0.94 V,峰电流与抗痫灵浓度在3.0×10^-9～1.0×10^-8mol/L(富集时间t_ac=120 s),1.0×10^-8～7.0×10^-8mol/L(t_ac=90 s),7.0×10^-8～7.0×10^-7mol/L(t_ac=60 s),7.0×10^-7～3.0×10^-6mol/L(t_ac=45 s)范围内成线性关系,检测限可达1.0×10^-9mol/L,并用于片剂及病人尿样的测定,得到满意的结果。以多种电化学手段研究抗痫灵的电化学行为及反应机理。实验表明属不可逆吸附波。测得扩散系数D为7.7×10^-6cm²/s,电极反应速率常数k₁为1.5×10^-3cm/s,电极反应电子数n为2,电子转移系数α=0.52。抗痫灵的还原基团为分子中碳碳双键。     

Vascular actions of 17beta-oestradiol in rat aorta and mesenteric artery

1. It has been proposed that the cardiovascular protective actions of 17beta-oestradiol may involve calcium antagonistic actions. We have examined the effects of 17beta-oestradiol on contractions to noradrenaline and KCl in male rat small mesenteric artery and aorta. 2. In rat mesenteric artery, 17beta-oestradiol (10 microM) significantly reduced the maximum contraction to noradrenaline (67.7 +/- 5.8% of control) and KCl (38.8 +/- 3.1% of control) without affecting potency. 3. In rat aorta, 17beta-oestradiol (10 microM) also significantly reduced contractions to noradrenaline (77.5 +/- 4.8% of control), and the effects were mimicked by droloxifene (10 microM). The effect of oestrogen was not prevented by the protein synthesis inhibitor cycloheximide (10 microM). In experiments carried out in calcium-free solution in which calcium stores were depleted, 17beta-oestradiol (10 microM) significantly reduced the contraction to calcium restoration in rat aorta. 4. In aorta from female rats, 17beta-oestradiol (10 microM) significantly reduced contractions to noradrenaline (73.6 +/- 10.8% of control), but this effect of oestrogen was not prevented by cycloheximide (10 microM). 5. In summary, 17beta-oestradiol diminishes the maximum contractile response to noradrenaline in both rat small mesenteric artery and aorta, an effect which at least in the aorta is mimicked by the oestrogen receptor antagonist/partial agonist droloxifene, and may be due to restriction of calcium entry by a nongenomic action.     

Antihypertensive effect of the new calcium antagonist (+-)-3-(benzylmethylamino)-2,2-dimethylpropyl-methyl-4-(2-fluoro-5- nitrophenyl)-1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate hydrochloride in rats.

The antihypertensive effect of TC-81 ((+-)-3-(benzylmethylamino)-2,2-dimethylpropyl-methyl-4-(2-f luoro-5- nitrophenyl)-1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate hydrochloride), a new calcium antagonist, was investigated in normotensive and hypertensive rats. By oral administration, the antihypertensive activity of TC-81 (ED20% in spontaneous hypertensive rats (SHR), DOCA-salt hypertensive rats and renal hypertensive rats were 0.37, 0.32, and 0.38 mg/kg p.o., respectively) was 7-14 times more potent in conscious hypertensive rats in comparison with nicardipine. Duration of the antihypertensive effect of TC-81 was about 2 times longer than that of nicardipine, and the response was elicited more slowly than that of nicardipine at an equipotent dose. Similar results were observed by intravenous injection, but the potency of TC-81 was only 3 times higher than that of nicardipine in anesthetized rats. Tolerance of the antihypertensive effect of TC-81 in long-term daily dosing and the rebound phenomenon after discontinuance of the treatment were not observed in hypertensive rats. TC-81, at a concentration of 10(-10)-3 x 10(-9) mol/l, inhibited the KCl-induced contraction of isolated rat vascular preparations. Moreover, TC-81 inhibited the norepinephrine-induced contraction of isolated SHR aorta preparation, but in isolated normotensive rat aorta, TC-81 inhibited the norepinephrine-induced contraction very little. From these observations, TC-81 can be characterized as having a strong, long-lasting, and slow-onset antihypertensive activity, especially by oral administration. Therefore, this new calcium antagonist may be useful for long-term antihypertensive therapy.     

pH对大鼠离体胸主动脉环静息张力的影响及机制

目的观察pH改变对大鼠离体胸主动脉环静息张力的影响,探讨其可能的作用机制。方法采用离体血管张力实验方法,观察pH改变对大鼠离体胸主动脉环静息张力的的影响。观察静息状态下外钙内流和内钙释放在pH=9.5收缩大鼠离体胸主动脉环中的作用,以及孵育钙通道阻断剂维拉帕米(VEP,10-5 mol.L-1)、Na+/Ca2+交换阻断剂KB-R7943(10-6 mol.L-1)、Na+/H+交换抑制剂氨氯吡咪(AM,10-4 mol.L-1)对pH=9.5时大鼠离体胸主动脉环收缩的影响。结果胞外酸性环境下随pH值逐渐降低,大鼠离体胸主动脉环静息张力无明显改变;碱性环境下随pH值逐渐增加,其静息张力明显升高,其中pH=8.5、pH=9.0、pH=9.5、pH=10.0时的Emax分别为(11.79±6.83)%、(30.25±3.57)%、(92.24±5.73)%、(110.85±7.78)%。外钙内流和内钙释放均参与pH=9.5时的胸主动脉环收缩,VEP可部分阻断其收缩。KB-R7943和AM对pH=9.5时大鼠离体胸主动脉环收缩有减弱作用(P<0.01),其Emax分别为(48.33±5.75)%、(32.12±4.45)%。结论胞外碱性环境下,大鼠离体胸主动脉环静息张力随pH值增大而明显升高,此作用依赖外钙内流和内钙释放,与Na+/Ca2+交换和Na+/H+交换均有关。     

Effects of Ba(2+) on norepinephrine-induced contraction of rat thoracic aorta in vitro

The aim of this study was to examine the effect of exogenously applied BaCl(2) on the norepinephrine-induced contraction of the rat thoracic aorta. Exogenously applied BaCl(2) (0.3-1 mmol/l) slightly elevated the norepinephrine-induced sustained contraction of the rat thoracic aorta in the absence of nicardipine (1 micromol/l). In the aortic preparation pretreated with nicardipine (1 micromol/l), exogenous BaCl(2) (0.1-3 mmol/l) did not elevate the norepinephrine-induced sustained contraction, but the high concentration of BaCl(2) (10 mmol/l) slightly inhibited the norepinephrine-induced tone. In a Ca(2+)-free Krebs bi- carbonate solution (KBS) containing norepinephrine (1 micromol/l) or a Ca(2+)-free K(+)-rich (60 mmol/l) KBS, exogenously applied BaCl(2) (1-30 mmol/l) caused a sustained contraction of the rat thoracic aorta, and this sustained contraction was completely inhibited by nicardipine (1 micromol/l). Exogenous CaCl(2) (0.1-3 mmol/l) also caused a sustained contraction of the aortic preparation in a Ca(2+)- free KBS containing norephinephrine (1 micromol/l), but such a sustained contraction was partly inhibited by nicardipine (3 micromol/l). These results indicate that Ba(2+) elevates the norepinephrine-induced tone of the rat isolated thoracic aorta by permeating voltage-dependent Ca(2+) channels in the absence of nicardipine, but that Ba(2+) has a minor modification on the norepinephrine-induced sustained contraction of the nicardipine-pretreated preparation.     

Vasorelaxing effect in rat thoracic aorta caused by denudatin B, isolated from the Chinese herb, magnolia fargesii

Denudatin B is an antiplatelet agent isolated from the flower buds of Magnolia fargesii. We studied the effects of denudatin B on the vasoconstriction of rat thoracic aorta induced by high potassium (K+) solution, norepinephrine (NE) and caffeine, and to elucidate its mode of action. The contraction of rat aorta caused by high K+ (60 mM) and cumulative concentrations of CaCl2 (0.03-3 mM) was inhibited concentration dependently by denudatin B with an IC50 of 21.2 micrograms/ml. NE (3 microM)-induced phasic and tonic contractions of rat aorta were inhibited by pretreatment with denudatin B (10-100 micrograms/ml). The relaxing action of denudatin B persisted in denuded aorta, in Ca2(+)-free and EGTA (2 mM)-containing medium. The vasorelaxing effects were not affected by indomethacin (20 microM), hemoglobin (10 microM) or methylene blue (50 microM) and were not accompanied by PGI2 formation. In quin-2/AM-loaded cultured rat vascular smooth muscle cells, denudatin B (100 micrograms/ml) inhibited the increase of intracellular calcium caused by NE (3 microM) in the presence or absence of extracellular calcium. Denudatin B did not affect the caffeine (10 mM)-induced contraction and the increase in intracellular calcium. Denudatin B (100 micrograms/ml) increased the cGMP, but not the cAMP level in intact and denuded aorta. The 45Ca2+ influx induced in rat aorta by high K+ (60 mM) or NE (3 microM) was markedly inhibited by denudatin B in a concentration-dependent manner. These results indicate that denudatin B relaxed vascular smooth muscle by inhibiting the Ca2+ influx through voltage-gated and receptor-operated Ca2+ channels; its effect to increase cGMP may enhance the vasorelaxation.     

Pimaradienoic acid inhibits vascular contraction and induces hypotension in normotensive rats

The present investigation was designed to investigate the effect of the diterpene ent-pimara-8(14),15-dien-19-oic acid (pimaradienoic acid, PA) on smooth muscle extracellular Ca(2+) influx. To this end, the effect of PA on phenylephrine- and KCl-induced increases in cytosolic calcium concentration ([Ca(2+)](c)), measured by the variation in the ratio of fluorescence intensities (R340/380 nm) of Fura-2, was analysed. Whether bolus injection of PA could induce hypotensive responses in conscious normotensive rats was also evaluated. PA inhibited the contraction induced by phenylephrine (0.03 or 10 micromol L(-1)) and KCl (30 or 90 mmol L(-1)) in endothelium-denuded rat aortic rings in a concentration dependent manner. Pre-treatment with PA (10, 100, 200 micromol L(-1)) attenuated the contraction induced by CaCl(2) (0.5 nmol L(-1) or 2.5 mmol L(-1)) in denuded rat aorta exposed to Ca(2+)-free medium containing phenylephrine (0.1 micro mol L(-1)) or KCl (30 mmol L(-1)). Interestingly, the inhibitory effect displayed by PA on CaCl(2)-induced contraction was more pronounced when KCl was used as the stimulant. Phenylephrine- and KCl-induced increases in [Ca(2+)](c) were inhibited by PA. Similarly, verapamil, a Ca(2+)-channel blocker, also inhibited the increase in [Ca(2+)](c) induced by either phenylephrine or KCl. Finally, bolus injection of PA (1-15 mg kg(-1)) produced a dose-dependent decrease in mean arterial pressure in conscious normotensive rats. The results provide the first direct evidence that PA reduces vascular contractility by reducing extracellular Ca(2+) influx through smooth muscle cellular membrane, a mechanism that could mediate the hypotensive response induced by this diterpene in normotensive rats.     

Role of the carboxylic group in the antispasmodic and vasorelaxant action displayed by kaurenoic acid

The present work describes the investigation of the role of the carboxylic group in the structure-activity relationship of the diterpene ent-kaur-16-en-19-oic acid (kaurenoic acid, KA) in inhibiting rat aorta contraction. For this purpose the methylation of the C-19 carboxyl group of KA was carried out. The effects of the obtained ent-methyl-kaur-16-en-19-oate (KAMe) were compared with those induced by KA. Vascular reactivity experiments showed that KA (50 and 100 microM) concentration-dependently inhibited KCl-induced contraction in both endothelium-intact and denuded rat aortic rings. On the other hand, KAMe attenuated KCl-induced contraction at 100 microM, but not at 50 microM. KA also reduced CaCl(2)-induced contraction in Ca(2+)-free solution containing KCl (30 mM). Again, KAMe produced a less accentuated reduction in CaCl(2)-induced contraction than that induced by the acid KA. KAMe (1-450 microM) concentration-dependently relaxed KCl-pre-contracted rings (percentages of relaxation 82.57 +/- 1.65 and 70.55 +/- 4.71, respectively) with denuded endothelium. Similarly, the relaxation induced by KA on phenylephrine (Phe)-pre-contracted rings (73.06 +/- 3.68%) was more pronounced than that found for KAMe (53.68 +/- 4.75%). Pre-incubation of denuded rings for different periods with KA and KAMe showed that the equilibrium periods required by each compound to achieve its maximal inhibitory response on KCl-induced contraction are different. Collectively, our results provide functional evidence that methylation of the C-19 carboxyl group of KA reduces but does not abolish the antispasmodic activity displayed by KA. Additionally, we showed that the equilibrium period is a critical step for the inhibitory effect displayed by kaurane-type diterpenes.     

Effects of nonsteroidal antiestrogens in the in vitro rat uterus.

We have studied the effect of nonsteroidal antiestrogens on rat uterine contractions induced by oxytocin (8 nmol/l), methacholine (10 mumol/l), prostaglandin F2 alpha (1 mumol/l), KCl (60 mmol/l) and CaCl2 (6 mmol/l). In a concentration-dependent way, the antiestrogens tamoxifen, clomiphene, nafoxidine and ethamoxytriphetol inhibited the amplitude and frequency of the oxytocin-induced contractions and the contraction produced by CaCl2. At a concentration of 30 mumol/l the four drugs inhibited the contractions induced by methacholine and prostaglandin F2 alpha. They also relaxed the tonic contraction to KCl in a concentration-dependent way. This action was partially counteracted by CaCl2 (0.1-10 mmol/l). Bay k 8644 (0.3 nmol/l to 3 mumol/l) only partially reversed the inhibition by ethamoxytriphetol (0.1 mmol/l) of CaCl2 (6 mmol/l)-induced contractions. The steroidal antiestrogen, ICI 164,384, which lacks agonist activity, had an inhibitory effect (44 +/- 4%, n = 7) on KCl-induced contractions only at a concentration of 0.1 mmol/l. However, the quaternary analogue of tamoxifen (tamoxifen ethyl bromide) produced 86 +/- 3% relaxation of the KCl-induced contracture (IC50 1.52 +/- 0.1 mumol/l, n = 10) and this effect was counteracted by addition of CaCl2. Taken together the results indicate that the inhibitory effects of nonsteroidal antiestrogens on rat uterine contractions could be mediated by an action to block Ca2+ entry through an agonist action on extracellular estrogen receptors.