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71.
The involvement of imidazoline receptors in modulation of noradrenaline release was investigated in the rabbit aorta preincubated with [3H]noradrenaline and superfused with physiological salt solution containing cocaine, corticosterone and propranolol.After blockade of 2-autoreceptors by rauwolscine, the electrically evoked tritium overflow was inhibited by various imidazolines and guanidines. The rank order of potency was BDF 7579 (4-chloro-2-isoindolinyl) guanidine) BDF 6143 (4-chloro-2-(2-imidazolin-2-ylamino)-isoindoline] > BDF 6100 [2-(2-imidazolin2-y-lamino)-isoindoline] > clonidine > ST587 (2-(2-chloro-5-trifluoromethylphenylimino) imidazolidine nitrate) cirazoline > tolazoline > idazoxan > phentolamine. Comparison of the potencies of these drugs with those previously found for the presynaptic imidazoline receptors in the rabbit pulmonary artery revealed a very good correlation. In contrast, no positive correlation was found with their affinities for the I1-and I2-imidazoline binding sites in bovine adrenal medullary membranes and with their lipophilicity (log P values). The electrically evoked tritium overflow was also inhibited by the recently identified endogenous imidazoline receptor ligand agmatine, but was not affected by amiloride. In further series of experiments, the ability of putative antagonist at presynaptic imidazoline receptors to counteract the inhibitory effect of imidazoline derivatives was determined. Amiloride, imidazole-4-acetic acid and 1-benzylimidazole did not attenuate the inhibitory effect of BDF 6143 on the electrically evoked tritium overflow. In contrast, rauwolscine antagonized the inhibitory effect of various imidazolines; rauwolscine was clearly less potent in antagonizing the effect of clonidine, BDF 6143 and cirazoline (apparent pA2 6.48–7.32) than in antagonizing that of oxymetazoline and moxonidine (apparent pA2 8.33 and 8.12, respectively). In a final series of experiments, BDF 6143 (under the conditions applied a selective agonist at presynaptic imidazoline receptors) proved to be considerably less potent in inhibiting tritium overflow evoked by high K+ than by electrical stimulation, whereas moxonidine (in rabbit aorta a selective agonist at presynaptic 2-adrenoceptors) exhibited similar potency in inhibiting the overflow evoked by both methods of stimulation.It is concluded that noradrenaline release in the rabbit aorta is inhibited via both 2-autoceptors and presynaptic imidazoline receptors which can be activated by the endogenous imidazoline receptor ligand agmatine. The occurrence of such an 2-adrenoceptor-independent mechanism is compatible with the ability of K+ ions to attenuate the inhibitory effect of an imidazoline receptor agonist but not of an 2-adrenoceptor agonist, since susceptibility to K+ ions has been suggested to be a typical feature of imidazoline recognition sites. The presynaptic imidazoline receptor in rabbit aorta appears to be identical with the previously characterized presynaptic imidazoline receptor in rabbit pulmonary artery, but differs clearly from the I1 and I2 binding sites in the bovine adrenal medulla. 相似文献
72.
目的:观察野罂粟总生物碱中八种生物碱单体心血管应的构效关系。方法:采用离体实验观察单体对KCl所致兔胸主动脉环收缩的影响,并以Ver 作对照。结果:野罂粟碱(nudicauline,Ⅰ)、瑞芙热米定(refram idine,Ⅱ)、黑龙辛甲醚(am urensinine,Ⅳ)、黑龙辛(am urensine,Ⅴ)、野罂粟醇(am uroline,Ⅵ)和七号生物碱(Ⅶ)均可使KCl量- 效曲线不平行右移,最大反应压低,其IC50分别为0.20,0.80,0.16,0.60,0.60,0.16m m ol·L- 1。结论:野罂粟碱类(Ⅱ,Ⅳ,Ⅴ,Ⅶ)对经PDC钙内流抑制效果较强,其中以Ⅱ作用最强;原阿朴菲类(Ⅵ,ⅧA,X)的抑制作用较弱 相似文献
73.
目的:探讨用于检验带膜记忆合金支架血管腔内搭桥治疗动脉瘤的模型。方法:分别以实验动物腹直肌后鞘、Dacron补片、不同口径的Dacron人血管及球囊导管材料,采用四种不同手术方法制作腹主动脉瘤模型。结果:11例动物10例模型制作成功,1例死亡,1月后造影检查发现9例的动脉瘤模型形态满意,1例动脉脉瘤扩张程度较差。结论;以腹阗甩垢鞘为材料制作动脉瘤模型具有取材方便,操作简便、不易漏血、无异物反应的优 相似文献
74.
目的研究由南五味子属药用植物分离的戈米辛J(gomisinJ,GJ)和异型南五味子丁素(heteroclitinD,HD)对血管平滑肌的作用。方法采用离体大鼠胸主动脉标本,观察他们对高钾去极化收缩和对CaCl2、NA量效曲线的影响。结果GJ和HD能抑制KCl所致的收缩,其IC50(95%可信限)分别为3.8(2.4~5.9)和7.5(1.4~39)μmol/L;GJ和HD能使CaCl2量效曲线右移,最大效应降低,其pD′2值分别为5.13±0.07和4.77±0.18;GJ和HD也可使NA量效曲线右移和最大效应降低,其pD′2值分别为3.72±0.23和3.31±0.27。结论GJ和HD能抑制KCl、CaCl2和NA产生的血管收缩,而且对CaCl2的致缩作用强于对NA的收缩作用,提示他们具有钙拮抗活性。 相似文献
75.
多脏器微栓塞病细胞综合征动物实验模型──定义、判断标准、发生机制及其与临床的关系 总被引:2,自引:0,他引:2
利用健康杂交犬制作了多脏器微栓塞病细胞综合征(POMS)模型,观察在不同时限、不同组织器官造成的病理生理改变。从中发现,钳夹腹主动脉阻断血流后,其供血器官都发生了ROMS,且不同器官的功能与结构损害有发生时间和程度的不同,但均有不同程度的微栓塞形成趋势,这有助对“多脏器衰竭”概念认识的深化。 相似文献
76.
多沙唑嗪及其手性对映体对离体兔血管α_1 受体的拮抗特性(英文) 总被引:2,自引:1,他引:2
目的 分析α1 肾上腺素受体阻断药多沙唑嗪手性对映体对兔胸主动脉和颈总动脉的选择性作用 ,以探讨作为良性前列腺增生症治疗药物的可能性。方法 测定去甲肾上腺素 (NE)诱发兔离体胸主动脉和颈总动脉收缩反应 ,并采用Schild作图法计算rac 多沙唑嗪、R 多沙唑嗪和S 多沙唑嗪的pA2 值。结果 在兔胸主动脉和颈总动脉 ,0 .0 3 ,0 .1和 0 .3μmol·L-1 的rac 多沙唑嗪、R 多沙唑嗪和S 多沙唑嗪均使NE诱发的血管收缩反应量效曲线平行右移 ,Emax不变 ;由Schild作图法计算得到的多沙唑嗪及其手性对映体的斜率值 ,经统计学分析符合竞争性拮抗。3种拮抗剂pA2 值的强度顺序为 :R 多沙唑嗪 >rac 多沙唑嗪 >S 多沙唑嗪。结论 与多沙唑嗪及其手性对映体对人前列腺组织作用的报道结果不同 ,S 多沙唑嗪对兔胸主动脉和颈总动脉α1 肾上腺素受体拮抗作用的选择性显著低于rac 多沙唑嗪和R 多沙唑嗪 相似文献
77.
巴曲酶的扩血管作用及其机制探讨 总被引:61,自引:1,他引:61
目的研究巴曲酶对血管张力的影响及其可能机制。方法离体大鼠主动脉环测定张力,主动脉薄片孵育测定NO生成、血管一氧化氮合酶(NOS)活性与L-精氨酸(L-Arg)转运。结果巴曲酶(0.1~20Bu·L-1)浓度依赖性扩张大鼠离体主动脉环,去内皮血管对巴曲酶的舒张反应明显低于内皮完整血管(P<0.01),最大舒张反应分别为40.1%±21.9%和88.1%±4.2%(P<0.01)。巴曲酶(10Bu·L-1)刺激孵育主动脉产生NO-2增加128%(P<0.01),固有型NOS(cNOS)和总NOS(tNOS)活性分别增加2.0倍和40.0%(P值均小于0.01),诱导型NOS(iNOS)活性无显著变化(P>0.05)。血管壁对L-Arg的转运呈高和低亲和两种方式,巴曲酶(10Bu·L-1)可使其最大转运速率Vmax分别增加83.8%和47.4%(P<0.01)。结论巴曲酶的内皮依赖的扩血管作用通过L-Arg/NO途径,巴曲酶增加血管壁L-Arg的转运和激活NOS,使NO生成增加 相似文献
78.
Bogaert J Kuzo R Dymarkowski S Janssen L Celis I Budts W Gewillig M 《European radiology》2000,10(12):1847-1854
Regular follow-up is required in patients with previous intervention for coarctation of the aorta to detect recoarctation
or aneurysm formation. In this study we describe the findings encountered on routine follow-up exams and we compare the use
of contrast-enhanced 3D MR angiography (CE MRA) with fast spin-echo MRI (FSE) to study the thoracic aorta after previous intervention.
In 51 consecutive patients previously treated for aortic coarctation, 74 MR studies of the thoracic aorta were performed during
a 2-year period using CE MRA and FSE MRI. The thoracic aorta was evaluated for abnormalities of course, caliber, shape, and
pathology of side branches. The CE MRA and FSE MRI studies were evaluated side by side by consensus of two reviewers evaluating
which MR technique depicted the abnormalities of the thoracic aorta the best. Of 74 exams, six clinically important abnormalities
were found: four aneurysms and two restenoses. Two small pseudoaneurysms were missed on the FSE studies. Contrast-enhanced
MRA was judged to visualize aortic abnormalities better than FSE (47 of 74 MR studies) especially for the transverse aortic
arch, coarctation site, left subclavian artery, and aortic arch configuration. For the ascending aorta and distal descending
aorta, CE MRA and FSE performed equally well. Aortic diameters measured at four levels in the first 18 MRI studies showed
no significant differences in diameter when measured by FSE or CE MRA (p = not significant). Clinically important abnormalities, such as aneurysm formation and restenosis, can be present years after
treatment for aortic coarctation. In the regular follow-up of these patients, CE MRA may provide additional diagnostic information
compared with FSE and should be included as part of the routine exam.
Received: 3 April 2000; Revised: 5 July 2000; Accepted: 7 July 2000 相似文献
79.
Congenital abnormality of the aortic arch is a diagnosis made most of the time incidentally in childhood, unless dysphagia
or respiratory disorders occur before. A case of a complex aortic arch anomaly with an aneurysm of the right subclavian artery
presenting as an isolated Horner's syndrome in an adult is reported herein. Magnetic resonance imaging led to this very unusual
diagnosis.
Received: 17 March 1999; Revised: 15 July 1999; Accepted: 13 August 1999 相似文献
80.
Mataichi Ohkubo Ken Takahashi Masahiko Kishiro Katsumi Akimoto Yuichiro Yamashiro 《Pediatrics international》2004,46(1):39-47
Abstract Background : Use of balloon angioplasty or stent implantation has been reported to be effective in relieving coarctation of the aorta. However, restenosis frequently occurs after balloon angioplasty for native aortic coarctation in small infants, and sometimes develops after stent implantation because of vessel growth. The causes of restenosis remain uncertain. The purpose of this study was to assess the histologic differences in vascular responses to angioplasty using conventional balloon, radiofrequency thermal balloon (RFTB), or stent for experimental aortic coarctation. Methods : The authors surgically created an aortic coarctation model using 14 puppies. Angioplasty using conventional balloon, RFTB, or stent was performed 1 month after the initial operation. At the acute or chronic phase after angioplasty, the animals were killed and histologic studies were performed. Results : More vascular injuries were noted in the specimens from animals undergoing conventional angioplasty than in those with RFTB or stent. However, neointimal hyperplasia was seen more often after RFTB or stent because of the proliferation of smooth muscle cells from the tunica media, caused by secretion of growth factors. Apoptosis reached a peak 1?2 weeks after angioplasty, regardless of the type of intervention. Conclusions : The authors conclude that angioplasty with RFTB or stent can provide relatively small injuries in the vessel wall for aortic coarctation, but care must be taken to prevent restenosis caused by intimal hyperplasia, because neointima hyperplasia is more frequent after RFTB or stent. 相似文献