Acta physiologica latino americana最新文献_第8页

[Mechanism of the hypotensive effect of prostaglandins A2 and E2]. [前列腺素A2、E2的降压作用机制]。

Acta physiologica latino americana Pub Date : 1981-01-01

V H Cicardo

{"title":"[Mechanism of the hypotensive effect of prostaglandins A2 and E2].","authors":"V H Cicardo","doi":"","DOIUrl":"","url":null,"abstract":"In anesthetized dogs the intravenous injection of prostaglandins (PGs) A2 and E2 (5-200 micrograms/kg) produced a dose-dependent fall (P less than 0.001) of the blood pressure with blockade of the baroreceptor reflex. The hypotension can increase the heart rate and decrease myocardial contractile force, which is neither prevented by atropine, phentolamine, diphenhydramine, verapamil nor by inhibitors of prostaglandin synthesis. Intravenous, intraaortic or intraventricular (left) injections evoked an equipotent fall of the arterial pressure. Less decrement is elicited by the intramuscular injection. The gastric route is ineffective. The intracisternal injection of high doses (20-130 micrograms/kg) of prostaglandins A2 or E2 decreases the blood pressure slightly after 5-10 minutes, probably because of prostaglandins transport across the blood-brain barrier. The blood pressure increases by stimulation of the sympathetic nerves of the spleen and of the liver, or by exogenous noradrenaline are equally significative before and after the injections of prostaglandins A2 or E2. Indomethacin and aspirin failed to affect the pressor increase produced by stimulation of the sympathetic nerves, or that of the exogenous noradrenaline in the normal dogs or in animals injected previously with PGs. It is concluded that the hypotensive action of the PGs is due to peripheric vasodilatation apparently without inactivation by the lung.","PeriodicalId":7131,"journal":{"name":"Acta physiologica latino americana","volume":"31 2","pages":"85-91"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18012675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Kinetic analysis of enzyme inhibition by substrate depletion. 底物耗尽酶抑制的动力学分析。

Acta physiologica latino americana Pub Date : 1981-01-01

J D Cortese, J C Vidal

引用次数: 0

[Theories and models of the function of the hippocampus]. [海马体功能的理论和模型]。

Acta physiologica latino americana Pub Date : 1981-01-01

N A Schmajuk, E T Segura

引用次数: 0

Excessive ingestion of iodide by the rat during pregnancy and lactation. Effects on ribonucleic acid transcription in the pups brain. 大鼠在怀孕和哺乳期间过量摄入碘。对幼犬脑内核糖核酸转录的影响。

Acta physiologica latino americana Pub Date : 1981-01-01

L Krawiec, E Ryder, G Campos

引用次数: 0

The effect of several neurotransmitter substances on nerve ending membrane ATPase. 几种神经递质对神经末梢膜atp酶的影响。

Acta physiologica latino americana Pub Date : 1981-01-01

G R Lores Arnaiz, M A Gómez de Lima

引用次数: 0

Immunogenicity of Trypanosoma cruzi in different animal species. 克氏锥虫在不同动物中的免疫原性。

Acta physiologica latino americana Pub Date : 1981-01-01

E R Rubiolo

引用次数: 0

Distribution and kinetics of hippuran 131I in rats. 河马131I在大鼠体内的分布及动力学。

Acta physiologica latino americana Pub Date : 1981-01-01

R DeLucia, P F Lara, L B Valle, R M Oliveira-Filho

引用次数: 0

Further evidence for the purinergic inhibition of adrenergic neurotransmission in the rat portal vein. 嘌呤能抑制大鼠门静脉肾上腺素能神经传递的进一步证据。

Acta physiologica latino americana Pub Date : 1981-01-01

M A Enero

{"title":"Further evidence for the purinergic inhibition of adrenergic neurotransmission in the rat portal vein.","authors":"M A Enero","doi":"","DOIUrl":"","url":null,"abstract":"The inhibition of 3H-noradrenaline (3H-NA) release by adenosine, and the possible involvement of purine receptors in the regulation of transmitter release in the portal vein were studied. The inhibitory effect of different concentrations of adenosine (10, 30, 100 and 300 microM) decreased with frequency of stimulation, but there was no marked concentration-dependence. Tetraethylammonium (TEA) enhanced the 3H-NA overflow induced by transmural stimulation. The adenosine-induced inhibition of 3H-NA overflow was antagonized by TEA. Transmural stimulation induced release of tritium from tissues prelabelled with either 3H-NA or 3H-adenine had a similar pattern of distribution. In contrast, when the rat portal vein was stimulated with (-) NA, the overflow of purine derivates was delayed and the maximum release was achieved 5 min later than the maximum induced by transmural stimulation. Phenoxybenzamine (PBA) increased 3H-NA overflow two-fold, but had no effect on the 3H-purine release induced by transmural stimulation. PBA reduced the 3H-purine release by exogenous (-) NA. These results indicate that in rat portal vein, the purine compounds have pre- and postjunctional origins and that the purine that modulates adrenergic neurotransmission might be of neuronal origin, possibly independent of adrenergic innervation.","PeriodicalId":7131,"journal":{"name":"Acta physiologica latino americana","volume":"31 2","pages":"93-103"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17377783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Increase of ionic strength for charcoal separation of B/F fractions in radioimmunoassays. 在放射免疫测定中炭分离B/F组分的离子强度增加。

Acta physiologica latino americana Pub Date : 1981-01-01

D P Udrisar, M C Camberos, E Justel, J C Cresto

引用次数: 0

Insulin binding in mouse liver cells isolated with chelating agents. 用螯合剂分离的小鼠肝细胞的胰岛素结合。

Acta physiologica latino americana Pub Date : 1981-01-01

J C Cresto, D P Udrisar, M C Camberos, J C Basabe

{"title":"Insulin binding in mouse liver cells isolated with chelating agents.","authors":"J C Cresto, D P Udrisar, M C Camberos, J C Basabe","doi":"","DOIUrl":"","url":null,"abstract":"Mouse liver cells were isolated with Ca2+ and K+ chelating agents. Cell concentrations in all experiments ranged from 2.5 X 10(5) to 1.44 X 10(6) cells/tube. The kinetics of insulin-receptor binding was studied at 2 C and 20 C. Binding of 1.67 X 10(-11) M 125I-insulin reached equilibrium at 2 C at 180 min; Ka at 50% binding was 0.736 X 10(7) M-1 sec-1. At 20 C equilibrium occurred at 30 min; Ka at 50% binding was 7.519 X 10(7) M-1 sec-1. Non-specific binding was measured by adding 16.6 microM native insulin. Kinetics studies of association point to a pure bimolecular reaction since the constant remains unaltered at different times. In studies of bound complex dissociation, insulin release from the receptor involves first order kinetics, 50% of the bound insulin becoming released during the experimental period. Dissociation was studied at 20 C only, either by dilution or addition of 16.6 microM native insulin. Both methods yielded the same result, showing the dissociation kinetics to be a first order reaction with a half-life of 101 min and Kd: 2.5 X 10(-4) sec-1. Competitive inhibition of native insulin (1.67 X 10(-10), 3.33 X 10(-10), 1.67 X 10(-9), 3.33 X 10(-9), 1.67 X 10(-8), 3.33 X 10(-8), 1.67 X 10(-7), 3.33 X 10(-7) M) against 1.67 X 10(-11) M 125I-insulin was studied in equilibrium. Heterogeneity among active binding sites was found: one population of high affinity and low capacity (2 C: K = 4.64 X 10(7) L/M, Ro = 213 X 10(-11) M; 20 C: K = 2.90 X 10(8) L/M Ro = 28.5 X 10(-11) M) and one of low affinity and high capacity (2 C: K = 6.81 X 10(7) L/M Ro: 836 X 10(-11) M; 20 C: K = 2.63 X 10(6) L/M, Ro: 1080 X 10(-11) M). The results show the use of chelating agents in the separation of liver cells to be of value in physicochemical studies of insulin-receptor interaction.","PeriodicalId":7131,"journal":{"name":"Acta physiologica latino americana","volume":"31 4","pages":"229-33"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17817918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0