活血养阴颗粒对异丙肾上腺素诱导大鼠心肌缺血的保护作用

目的研究活血养阴颗粒对异丙肾上腺素造成急性心肌缺血模型大鼠的保护作用。方法采用异丙肾上腺素造成大鼠急性心肌缺血模型。结果活血养阴颗粒可对抗异丙肾上腺素所致心肌缺血大鼠的心电图T波抬高及S-T段的异常偏移,使血清乳酸脱氢酶(LDH)降低,并可增加心肌组织超氧化物歧化酶(SOD)的活力,减少丙二醛(MDA)生成。结论活血养阴颗粒对大鼠急性心肌缺血有一定的保护作用。     

Comparison of α- and β-Receptor Stimulation in the Circular and Longitudinal Muscle of the Oestrogen and Progesterone Dominated Rabbit Uterus

Abstract: Longitudinal and circular muscle strips from the progesterone-dominated rabbit uterus were stimulated in vitro with the α- and β-adrenergic agents noradrenaline and isoprenaline, and the effects were compared with results obtained from the oestrogen-dominated uterus. The spontaneous activity in oestrogen- and progesterone-dominated strips was the same. Noradrenaline caused an increase in frequency and basal tone in all strips. In the oestrogen-dominated strips the force of the induced contractions exceeded the force of the spontaneous contractions. In the progesterone-dominated strips the force of the contractions subsequent to the addition of noradrenaline was usually a little reduced. No difference between the circular and longitudinal strips was observed. Reserpine-treatment of the oestrogen-dominated animals substantially reduced the force of the noradrenaline-induced contractions. In progesterone-dominated animals reserpine treatment had no such effect. Isoprenaline produced a reduction in the force and the frequency of the spontaneous contractions. In the circular strips, the spontaneous activity was less inhibited by isoprenaline in the progesterone than in the oestrogen-dominated strips. As to the longitudinal strips, the dose-response curves were quite similar. The circular strips were much less inhibited by isoprenaline than were the longitudinal ones. It is concluded that the different reactions to adrenergic nerve stimulation in oestrogen- and progesterone-dominated rabbit uteri reported previously by other investigators, might depend on the different reactions of the muscle to α stimulation, this difference being partly explained by the higher catecholamine content of the oestrogen-dominated tissue.     

KCL CONTRACTIONS IN THE RAT INTACT AND BISECTED VAS DEFERENS: CONTRIBUTION OF ENDOGENOUS NORADRENALINE RELEASE

1 KCl produced a biphasic contraction in the intact rat vas deferens. Both components were larger and the initial rapid phasic component was faster in the prostatic portion than the epididymal portion. In some experiments the epididymal phasic response was a single slow contraction, while in others it had a mixture of fast and slow responses. 2 Phentolamine reduced the phasic response but not the tonic response of the intact vas deferens. This effect was not observed after denervation produced by chronic guanethidine treatment. 3 Both phases of the response to KC1 160 mmol/1 were substantially reduced by phentolamine in the epididymal portion. In the prostatic portion phentolamine produced only slight inhibition of the phasic component and had no effect on the tonic component. 4 Isoprenaline had no effect on the response to KC1160 mmol/1 but reduced both phases of the response to KC150 mmol/1. This effect was antagonized by propranolol. 5 It is concluded that part of the phasic component of the response to KC1 in the rat vas deferens is due to the release of noradrenaline from intramural nerves.     

心力衰竭大鼠心肌细胞端粒酶逆转录酶的表达

目的研究异丙肾上腺素(ISO)诱导的心力衰竭大鼠心肌细胞端粒酶逆转录酶(TERT)的表达意义。方法健康清洁级SD大鼠20只,随机分为对照组及心力衰竭模型组(ISO组)各10只,对照组腹腔注射生理盐水2 mL.kg-1,ISO组腹腔注射ISO30 mg.kg-1,均每日1次,连续2 d,给药结束观察48 h。检测大鼠血清肌酸激酶(CK)、乳酸脱氢酶(LDH)水平,计算心脏系数,同时检测心肌细胞超氧化物歧化酶(SOD)活性和丙二醛(MDA)水平;应用Western blotting方法检测TERT蛋白表达的变化;利用免疫组织化学方法检测TERT蛋白在心肌细胞中的定位。结果与对照组比较,ISO组大鼠血清CK、LDH明显升高(P<0.01),心肌坏死程度加重,心脏系数也显著增加(P<0.01);ISO组大鼠心肌细胞MDA明显升高(P<0.05),SOD活性显著下降(P<0.01);对照组心肌细胞未见TERT蛋白表达,ISO组大鼠心肌细胞TERT蛋白表达明显增加,免疫组织化学实验结果显示ISO组大鼠心肌细胞浆中和胞核内有TERT阳性免疫产物生成。结论心力衰竭大鼠心脏存在心肌细胞增殖,心肌细胞增殖对心功能有代偿作用。     

葶苈子水提液对动物实验性心室重构的影响

目的研究葶苈子水提液对异丙肾上腺素(ISO)诱发小鼠,L-甲状腺素(L-Thy)诱发大鼠实验性心室重构的影响。方法小鼠每天scISO2mg/kg,连续7d;大鼠每天ipL-Thy0.3mg/kg,连续10d,制备心室重构动物模型。各组小鼠每天ig葶苈子水提液6、12g/kg和美托洛尔0.06g/kg,连续7d后,检测心脏指数、血浆环磷酸腺苷(cAMP)、心肌血管紧张素(Ang)量的变化;各组大鼠每天ig葶苈子水提液4、8g/kg和卡托普利0.02g/kg10d后,检测心脏指数、血浆中醛固酮(ALD)及左心肌Ang、羟脯氨酸(Hyp)量的变化。结果模型小鼠的心脏指数、cAMP、Ang量均明显升高,给予美托洛尔0.06g/kg或葶苈子水提液12g/kg均可抑制小鼠左心室重构和肥厚,降低心脏指数和血清cAMP水平及心肌Ang的量(P<0.05)。模型大鼠也出现心肌纤维化,心脏指数、心肌Ang、血浆ALD、心肌Hyp量均明显升高,给予卡托普利0.02g/kg或葶苈子水提液4、8g/kg均可降低大鼠心脏指数和Ang、ALD及心肌Hyp水平(P<0.05)。结论葶苈子水提液具有抑制实验动物心肌肥大、心室重构的作用,其作用机制可能与抑制交感神经系统兴奋性及抑制Ang、ALD等神经内分泌因子激活有关。     

Vasodilator agents and supracollicular transection fail to inhibit cortical spreading depression in the cat

It remains an open question as to whether cortical spreading depression (CSD) is the pathophysiological correlate of the neurological symptoms in migraine with aura. In the experimental animal, CSD is an electrophysiological phenomenon mainly mediated via NMDA receptors. However, according to case reports in humans, visual aura in migraine can be alleviated by vasodilator substances, such as amyl nitrite and isoprenaline. There is also circumstantial evidence that brainstem nuclei (dorsal raphe nucleus and locus coeruleus) may play a pivotal role in the initiation of aura. In this study, CSD was elicited in alpha-chloralose anesthetized cats by cortical needle stab injury and monitored by means of laser Doppler flowmetry. Topical application of isoprenaline (0.1-1%) and amyl nitrite (0.05%) onto the exposed cortex had no effect on the elicitation or propagation of CSD. Also, after supracollicular transection, subsequent CSDs showed no differences in the speed of propagation and associated flow changes. We conclude from these data that--given CSD probably exists in humans during migraine--spreading neurological deficits during migraine aura are independent of brainstem influence and have a primarily neuronal rather than vascular mechanism of generation.     

STEREOSELECTIVE EFFECT OF PROPRANOLOL ON ANTIPYRINE METABOLISM AND ISOPRENALINEINDUCED TACHYCARDIA IN RABBITS

The effects of l-, d- and dl-propranolol on antipyrine metabolism and isoprenaline-induced tachycardia were studied in rabbits. The plasma concentration of antipyrine was assayed by Brodie's spectrophotometric method and the change of heart rate was evaluated by ECG. Both isomers of propranolol hydrochloride were administered iv (800 μg/kg) to the rabbits. d-propranolol produced an antipyrine t 1/2 of 2.67±0.77h and a cl of 0.49±0.1 l/h while its levo-form produced an antipyrine t 1/2 of 1.7±0.39h and a cl of 0.88±0.22 l/h. The differences between the half-lives and between the clearances were statistically significant (P<0.05 for t 1/2, P<0.01 for cl). The inhibitory effects of l- and d-propranolol on isoprenaline-induced tachycardia were assessed. l-propranolol yielded an ID_(50) which was only 1/88 of d-propranolol's. Our studies showed that the β-receptor blocking activity of propranolol mainly came. from its levoform while the effect on antipyrine metabolism came from its dextro-form.     

钩吻总碱Ⅰ对豚鼠肺支气管平滑肌的作用分析

用钩吻总碱I对豚鼠作实验观察,结果表明:钩吻总碱I对豚鼠肺支气管平滑肌有显著的收缩作用。异丙肾上腺素有对抗钩吻总碱I收缩豚鼠肺支气管平滑肌的作用,而苯海拉明无阻断钩吻总碱I的这一作用。     

DISSOCIATION BETWEEN CORTICOTROPHIN AND CATECHOLAMINE RESPONSES TO ISOPRENALINE IN HUMANS

1. The pituitary-adrenocortical, sympathoadrenomedullary and renin-angiotensin-aldosterone systems contribute to circulatory and metabolic homeostasis during stress. One possible site of co-ordination of these systems is the beta-adrenoceptor. 2. To determine whether circulating beta-adrenoceptor agonists can act hormonally to stimulate these systems simultaneously, plasma concentrations of corticotrophin (ACTH), noradrenaline, adrenaline and plasma renin activity were measured during graded intravenous infusions of isoprenaline in 20 people. 3. Administration of isoprenaline caused dose-related increases in noradrenaline (94% at the highest dose) and renin activity (189%), but decreases in ACTH (25%) and adrenaline (20%), findings inconsistent with simultaneous activation of these systems by circulating beta-adrenoceptor agonists.     

Biochemical studies on the cardioprotective effect of glutamine on tissue antioxidant defense system in isoprenaline-induced myocardial infarction in rats

Oxidative stress is one of the mechanisms with a central role involved in the pathogenesis of myocardial infarction. The protective effect of glutamine on myocardial antioxidant defense system was investigated during isoprenaline-induced myocardial infarction, an animal model of myocardial infarction of human beings. Levels of diagnostic marker enzymes in plasma, reduced glutathione (GSH) and lipid peroxides and the activities of glutathione peroxidase, glutathione-S-transferase, catalase and superoxide dismutase in heart tissue were determined. Injection of isoprenaline caused significant increases in the levels of diagnostic marker enzymes in plasma and lipid peroxidation in heart tissue. A parallel decline in the levels of ATP (Adenosine triphosphate) and GSH and the activities of glutathione-dependent antioxidant enzymes and antiperoxidative enzymes in heart tissue was also observed. Prior oral administration of glutamine significantly prevented isoprenaline-induced adverse effects and maintained myocardial antioxidant status at near normal status. The cardioprotective effect of glutamine is probably related to a strengthening of the myocardial membrane by its membrane stabilizing action, or to a counteraction of free radicals by its antioxidant property, or to its ability to maintain near to normal status the activities of free radical scavenging enzymes and the level of GSH, which protect myocardial membrane against oxidative damage by decreasing lipid peroxidation.