Subtype determination of soma-dendritic α2-autoreceptors in slices of rat locus coeruleus

The aim of the study was to subclassify the soma-dendritic α₂-autoreceptors in the locus coeruleus (LC) of the rat by means of antagonists. To this end, the frequency of spontaneous action potentials was recorded extracellularly from single LC neurones in brain slices. The neurones fired spontaneously at an average rate of 1 Hz. The selective α₂-adrenoceptor agonist 5-bromo-6-(2-imidazolin-2-ylamino)-quinoxaline (UK 14,304) and noradrenaline decreased the action potential discharge with IC₅₀ values of 5 and 510 nM, respectively. The concentration-inhibition curves of UK 14,304 and noradrenaline were shifted to the right by phentolamine (0.15 μM) and rauwolscine (0.15 μM) but not by prazosin (1 μM). Apparent K _d values of phentolamine were 17 nM (against UK 14,304) and 20 nM (against noradrenaline). Apparent K _d values of rauwolscine were 47 nM (against UK 14,304) and 70 nM (against noradrenaline). (+)-Oxaprotiline (1 μM) suppressed the firing of the neurones within 10 to 33 min. In the continued presence of oxaprotiline, phentolamine and rauwolscine restored firing with EC₅₀ values of 120 and 250 nM, respectively. Prazosin (1 μM) again was ineffective. All three antagonist affinity estimates – against UK 14,304, exogenous noradrenaline and endogenous noradrenaline (that accumulates in the extracellular space in the presence of oxaprotiline) – yield an affinity order phentolamine > rauwolscine >> prazosin, prazosin being ineffective even at a concentration of 1 μM. These findings identify the soma-dendritic α₂-autoreceptors of the LC as the rat variant of the α_2A/D-adrenoceptor, i.e. α_2D. Not only presynaptic but also soma-dendritic α₂-autoreceptors may at least predominantly be α_2A/D throughout the nervous system. Received: 3 March 1997 / Accepted: 21 April 1997     

侧脑室注射东莨菪碱和酚妥拉明对幼兔分辨学习的影响

目的 探讨东莨菪碱和酚妥拉明对幼兔分辨学习的影响。方法 将30只比利时纯种幼兔从生后13日龄随机分为三组：东莨菪碱组、酚妥拉明组和生理盐水对照组，观察不同日龄各组幼兔的分辨学习能力。结果 幼兔分辨学习的正确反应一般始于生后15日龄。侧脑室注射东莨菪碱对16日龄以前幼兔分辨学习无明显影响，对17日龄以后幼兔分辨学习产生明显抑制作用。侧脑室注射酚妥拉明对13—23日龄幼兔分辨学习均有明显抑制作用。结论 幼兔生后发育过程中学习能力的发展具明显的阶段性，其原因可能与神经递质系统的发育成熟有关。     

酚妥拉明与多巴胺治疗难治性肺炎20例

目的 :观察酚妥拉明与多巴胺治疗难治性肺炎的疗效。方法 :对 2 0例难治性肺炎的患儿 ,在常规治疗的基础上 (予抗生素、止咳化痰、超声雾化、拍背 ) ,用酚妥拉明和多巴胺静点 ,每日 1次。结果 :总有效率 90 %。结论 :酚妥拉明与多巴胺治疗难治性肺炎疗效好、价格低、副作用小 ,值得临床推广     

Renal hemodynamics and renal O2 uptake during hypoxia in the anesthetized rabbit

Summary The effects of hypoxic hypoxia on renal hemodynamics and metabolism have been studied in anaesthetized mechanically ventilated rabbits. Acute hypoxia (F₁O₂=0.10,PaO₂=35 torr) induces at constant mean arterial pressure a 45% decrease in RBF, GFR, and whereas free water clearance increases. These alterations were still apparent 50 min after resuming normal arterial oxygenation. In order to assess the role of the stimulation of catecholamine release in these observations, two other sets of experiments were performed: 1) the animals were ventilated with the same hypoxic gas mixture but after adrenergic blockade (phentolamine: 0.2 mg·kg·min^–1 i.v.), 2) hypoxia was induced by ventilating the animals with CO (F_ICO=0.002) at constantPaO₂. Increase in renal vascular resistance and reduction of renal O₂ uptake were still observed. This indicates that adrenergic stimulation cannot fully explain the renal vasoconstriction encountered in hypoxia. The role of a local vasoactive factor, especially that of the renin angiotensin system is discussed. The apparent O₂ cost of Na reabsorption was not greatly modified by any type of hypoxia and the Na:O₂ ratio remained close to the value observed in normoxic animals. This indicates that the kidney may adapt to hypoxia by reducing its O₂ demand keeping unaltered its tubular function and basal O₂ needs.     

普萘洛尔、酚妥拉明对由去甲肾上腺素诱导的家兔肠系膜微血管运动的影响

应用显微录像静画步进法观察家兔肠系膜局部施加去甲肾上腺素（NA）后，诱寻出微动脉周期性、节律性的血管运动及静脉注入普萘洛尔、酚妥拉明对其产生的影响，以期探讨血管运动产生机制及其与α－，β－肾上腺素受体的关系。结果：在家兔颈动脉平均血压为11．40±0．89kPa的条件下，局部施予NA0．8μg于肠系膜观察域，引起微动脉的血管运动，其频率：0．109±0．006Hz，振幅：5．51±0．42μm。同一视野的微静脉和毛细血管未出现血管运动。血管运动的振幅在同一支微动脉上分布不均，呈节段性。普萘洛尔0．1mg／ml·kg-1、0.5mg／ml·kg-1组的内径、血压、血管运动频率及振幅无明显改变，1．0mg／ml·kg-1组的血压无明显变化，内径减小，血管运动频率增加，振幅减小。静脉注入酚妥拉明0．5mg／ml·kg－1及1．0mg／ml·kg-1，颈动脉血压降低，血管内径增加，血管运动频率减少，振幅降低，血管运动被抑制。结论：上述结果表明生理条件下，局部施加NA可以诱导出家兔肠系膜微动脉血管运动，并且血管运动的发生与NA及α－，β-肾上腺素受体有一定关系。     

Comparative cardiovascular effects of SNP,ATP and phentolamine during norepinephrine-induced hypertension in dogs

There has been no study comparing the advantage and disadvantage of various antihypertensive agents during surgery for pheochromocytomas because the study is difficult in clinical setting. In the present experiments using dogs, after increasing the arterial blood pressure with norepinephrine, we decreased it to the baseline with sodium nitroprusside (SNP), adenosine triphosphate (ATP), or phentolamine (PE) and compared the hemodynamic changes. A hyperdynamic state was found with ATP and with PE, but not with SNP. The norepinephrine-induced pulmonary hypertension could be successfully treated with SNP, but not with ATP or PE. The reason for these differences are thought to be the different vasodilative properties on peripheral arteries and veins. We conclude that agents that dilates the arteries and veins should be used to regulate the arterial pressure during surgical removal of a pheochromocytoma.(Murata K, Takahashi H, Ikeda K: Comparative cardiovascular effects of SNP, ATP and phentolamine during norepinephrine-induced hypertension in dogs. J Anesth 5: 396–403, 1991)     

酚妥拉明治疗小儿支气管哮喘

目的　为了观察酚妥拉明治疗小儿支气管哮喘的疗效。方法　对 2 0 0 1年 2月～ 2 0 0 2年 3月收治的支气管哮喘 14 0例 ,随机分为两组 ,其中治疗组 80例 ,对照组 60例 ,治疗组静脉滴注酚妥拉明 ,对照组静脉滴注氨茶碱。两组综合治疗相同。结果　治疗组总有效率为 95% ,明显高于对照组的 66 67% ,且平均住院天数治疗组为 8± 2 3 5d ,较对照组的 10± 3 2 6d为短 ,两组差异有非常显著意义。结论　酚妥拉明对缓解小儿支气管哮喘症状有明显治疗作用     

酚妥拉明与多巴胺伍用治疗慢性肺心病心力衰竭

目的：总结酚妥拉明与多巴胺伍用治疗慢性肺心病心力衰竭的疗效。方法：30例肺心病顽固性心衰患者，均在抗感染、吸氧、利尿、强心等综合治疗后，心衰无好转时加用酚妥拉明与多巴胺静脉滴注，每日一次，连用7至10天。用药前后记录血压、心率、尿量。结果：一疗程后心率明显减慢，尿量明显增加与治疗前相比有非常显著差异(P＜0．01)。血压与治疗前无明显差异(P＞0．05)。总有效率达86．6％(显效46．6％，有效40％)。结论：酚妥拉明与多巴胺伍用治疗慢性肺心病顽固性心衰，疗效确切，副作用少，在临床上有一定的使用价值。     

Myocardial injury following endogenous catecholamine release in rabbits

Catecholamines (CAT) given in large doses produce cardiomyopathic changes in several animal species. This study was designed to determine if endogenous release can also induce cardiac injury. Rabbits were infused with doses of tyramine (TYR), ranging from 200 to 500 micrograms/min/kg, i.v. for 90 min. Arterial pressure and heart rate were measured, as were total CAT concentrations, blood gases, pH and glucose. Two days later the animals were killed and cardiac injury assessed using a histological scoring system. All data were compared with controls given saline. Initial CAT averaged 452 pg/ml, rose to 2890 pg/ml after starting TYR, 500 micrograms/min/kg, and remained elevated for the duration of infusion. Circulating CAT levels were a function of TYR dose, and bore a linear relationship to the histological score (P less than 0.001). Development of lesions was unaltered by beta 1 blockade with practolol, but sharply reduced by alpha blockade with phentolamine (P less than 0.01). Pretreatment with insulin also reduced lesion formation, but diabetic (alloxan) rabbits showed no greater CAT injury. It is concluded that endogenous release of CAT induces myocardial injury in the rabbit in a dose-dependent manner. This is unrelated to myocardial O2 demand, and microvascular pathology was absent. Activation of alpha adrenergic pathways is likely the dominant or exclusive mechanism.     

酚妥拉明治疗小儿肺炎的临床效果观察

目的探究酚妥拉明治疗小儿肺炎的临床效果。方法选取100例2013年3月至2014年3月在我院儿科就诊的确诊小儿肺炎的患儿,随机分成对照组和试验组,分别给予常规治疗和常规治疗基础上给予酚妥拉明静脉滴注治疗,比较两组的临床疗效。结果对照组患儿症状消失时间明显长于试验组患儿,住院时间也明显长于试验组患儿,试验组患儿治疗总有效率86%(43例患儿有效),明显高于对照组患儿治疗总有效率60%(30例患儿治疗有效),对照组患儿发热,呕吐,低血压等并发症发生率为18%(9例),明显高于试验组患儿并发症发生率4%(2例),均有P<0.05,差异有统计学意义。结论酚妥拉明治疗小儿肺炎临床疗效良好,可以明显缩短病程和住院时间,提高治疗有效率,同时减少并发症的发生,建议临床上推广使用酚妥拉明治疗小儿肺炎。