Cardiovascular and neuroendocrine responses to behavioral stress after central or peripheral barodenervation in rats

The cardiovascular and neuroendocrine responses to acute behavioral stress were evaluated in rats after disruption of the baro reflexes by electrolytic lesions of the nucleus tractus solitarii (NTS) or sinoaortic denervation (SAD). Rats with NTS lesions or SAD showed significantly greater increases in mean arterial pressure (MAP) and plasma norepinephrine (NE) concentrations than control rats during a single 30-min escape-avoidance test. In addition, the increases in MAP and plasma NE concentration of NTS lesion rats were significantly greater than those of SAD rats. However, NTS lesion raats showed no increase in plasma renin activity (PRA), as observed in the other groups. Thus, disruption of the baroreflexes by NTS lesions oraugments the arterial pressure and plasma NE responses to stress. Additionally, NTS lesions appeared to eliminate the neurons or fibers of passage participating in the sympathetically mediated increase in PRA.     

不同民族冷适应水平的研究

冬季在乌鲁木齐市对维族(25名)、藏族(12名)和汉族(43名)战士及21名维族大学生的冷适应水平进行测试。以血浆CPK和FFA、尿中儿茶酚胺和VMA,以及左中指泡冰水20min的皮温作为指标。结果表明藏、维族战士的适应水平优于汉族战士及维族大学生。但进新疆2年以上的汉族战士与藏、维族问无明显差别,加强体力锻炼之后,可使某些生化指标得到改善。作者认为尿中儿茶酚胺和VMA由于测试方法简便,结果稳定,可考虑作为人群冷适应的评价指标。     

Increased catecholamine metabolism in the locus coeruleus of young spontaneously hypertensive rats

Young, 4-week-old spontaneously hypertensive rats (SHR) had significantly higher concentrations of dopamine and 3,4-dihydroxyphenylacetic acid and a faster rate of accumulation of L-dihydroxyphenylalanine after decarboxylase inhibition in the locus coeruleus than age-matched Wistar-Kyoto rats, whereas the norepinephrine levels were similar to each other. In the brainstem, these changes were restricted to the locus coeruleus and were not present in adult, 14-week-old rats with established hypertension. These results are suggestive of a noradrenergic overactivity in the locus coeruleus of young SHR, coinciding with the development of the hypertension.     

2040名健康小儿尿筛查中有关直立性蛋白尿的分析

于1987年4～6月对石家庄市2040名2～14岁的正常活动儿童进行了尿过筛检查,发现直立性蛋白尿儿童12例,占受检儿童的0.59%,直立性蛋白尿的尿蛋白定量在150mg～1g/24h,A/G 比值为3;β与γ球蛋白高于α_1 和α_2。直立性蛋白尿儿童尿内儿茶酚胺与正常儿童相比较无明显改变。对直立性蛋白尿的发病进行了讨论。     

Synthesis and release of catecholamines by the cat carotid body in vitro: Effects of hypoxic stimulation

The role of catecholamines (CAs) in cat carotid body chemoreception has been controversial. On the basis of pharmacological experiments, it would appear that endogenous dopamine (DA) may act either as an inhibitory or excitatory transmitter. Neurochemical studies on the effects of natural stimulation on the release of carotid body CAs in the cat have also been inconclusive. In the present study, we have characterized the synthesis and release of CAs in the in vitro cat carotid body preparation in response to different levels of hypoxic stimulation and have correlated these measures with the chemosensory activity of the carotid sinus nerve. The synthesis of [3H]DA and [3H]norepinephrine was linear for at least 4 h in carotid bodies incubated with their natural precursor [3H]tyrosine. Synthesis of both [3H]CAs plateaued when the [3H]tyrosine concentration in the media reached 40 microM, which is a concentration similar to that found in cat plasma. Exposure of the animals to an atmosphere of 10% O2 in N2 for 3 h prior to removal and incubation of the carotid bodies with [3H]tyrosine resulted in an approximately 100% increase in the rate of [3H]DA synthesis but no change in [3H]norepinephrine synthesis. This selective increase in [3H]DA synthesis was not detected when [3H]dihydroxyphenylalanine was used as precursor. Carotid bodies first incubated with [3H]tyrosine and later superfused with solutions equilibrated with different gas mixtures (0-100% O2 in N2) exhibited an increase in [3H]DA release and carotid sinus nerve discharge which were inversely related to the oxygen concentration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Opposite effect of simple tetrahydroisoquinolines on amphetamine- and morphine-stimulated locomotor activity in mice

Summary. Endogenous tetrahydroisoquinolines, such as 1,2,3,4-tetrahydroisoquinoline (TIQ) and 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (salsolinol), were tested for their interaction with motor effects of amphetamine and morphine in C57BL/6 mice. TIQ binding to cortical adrenergic α₁, α₂ and β receptors, striatal dopamine D₁ and D₂ receptors and cortical L-type calcium channels in the Wistar rat was also studied. Both compounds in high doses reduced the mouse locomotor activity, and in doses not affecting activity inhibited the motor stimulation induced by amphetamine, 2 or 3 mg/kg ip, but facilitated the hyperactivity induced by 10 mg/kg of morphine. TIQ did not displace ligands that are antagonists for several receptor sites (including D₁ and D₂ receptors), but displaced an agonist of α₂-adrenoceptor, clonidine. It is proposed that TIQ and salsolinol specifically antagonize the agonistic conformation of dopamine receptor and that endogenous 1,2,3,4-tetrahydroisoquinolines may play a role of natural feedback regulators of the activity of dopaminergic system. Received September 20, 2000; accepted December 6, 2000     

Direct synaptic contacts of catecholamine axons on the preganglionic sympathetic neurons in the rat thoracic spinal cord

Preganglionic sympathetic neurons were labelled by retrograde transport of horseradish peroxidase, while catecholamine axon varicosities were marked by the uptake of 5-hydroxydopamine in the intermediolateral nucleus of the rat. The direct synaptic contacts from the catecholamine axons to the preganglionic sympathetic neurons were demonstrated. Catecholamine axons formed symmetric synapses.     

实验性脑梗塞后大脑皮质内儿茶酚胺含量的测定及其荧光组织化学观察

本文对被闭塞一侧大脑中动脉的20只大白鼠大脑皮质内的儿茶酚胺(CA)进行了荧光组织化学观察与含量测定.局壮性脑梗塞三天后,双侧大脑皮质内CA膨体的数量与膨体内CA的浓度均显著减少,梗塞灶边缘区可见大量CA颗粒聚集,其荧光特征与正常皮质内的CA颗粒不同;双侧大脑皮质内的去甲肾上腺素含量显著减少,多巴胺含量无明显变化.     

Assessment of the diurnal variations in urinary homovanillic and vanillylmandelic acid excretion for the diagnosis and follow-up of patients with neuroblastoma

The diurnal variation of urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA) was studied in neuroblastoma patients and in a control group. Urinary HVA and VMA levels in four sequential 6-hour urine collections within a 24-hour period were compared. HVA and VMA levels were expressed in microgram/mg of urinary creatinine (UCr) and in mg/6h specimens. No statistically significant variations between the four time intervals were found when expressed in microgram/mg UCr or mg/6h. The small variations that exist in the excretion of HVA and VMA during different periods of the day are due to variations in renal excretion rather than variations in production. The results from this study indicate that a random urine sample should be as good as a 24-hour collection for diagnosis and follow-up of neural crest tumors.