摘要:

Abstract:The renal effects of bumetanide, a new potent diuretic, were studied in ten patients with latent congestive heart failure. Following the intravenous administration of 3 mg bumetanide the glomerular filtration rate (GFR) and renal plasma flow (RPF) showed initial, statistically significant increments over control values, and subsequent statistically significant reductions. This biphasic pattern was unrelated to the diuresis and natriuresis which were sustained for a longer period. The pathophysiological mechanisms involved in the changes of GFR and RPF are discussed and it is suggested that the initial rise in GFR and RPF is primarily due to a vasodilating effect of bumetanide.

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03527.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:Stereotyped behaviour including gnawing was elicited in mice by L‐DOPA given after various doses of the decarboxylase inhibitor Ro 4–4602, The gnawing was estimated quantitatively. The effect of various drugs including reserpine, FLA‐63, spiramide and α‐methyltyrosine on the gnawing was studied and it is concluded that the gnawing is influenced by both dopamine and noradrenaline in the brain. The relation of noradrenergic brain mechanisms to gnawing seems to be com

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03528.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:Histamine release and lactate content were concomitantly determined in samples of isolated rat mast cells. Histamine release induced by exogenous ATP or compound 48/80 was inhibited by antimycin A (0.2 μM). Glucose (0.60 mM) restored the release induced by compound 48/80 but not that induced by ATP. ATP but not compound 48/80 inhibited the accumulation of lactate in suspensions of mast cells containing glucose (0.60 mM). ATP induced inhibition of lactate accumulation and release of histamine within the same concentration range. However, the time courses for the two processes were different. Antimycin A (0.2 μM) enhanced the accumulation of lactate, an effect which was counteracted by ATP. 0.05 mM ATP or more reduced the lactate accumulation to the same values as those found in the absence of antimycin A. The inhibitory action of ATP on glycolysis may explain the observed inability of glycolytic substrates to restore the ATP‐induced histamine release blocked by inhibitors of oxidative metabol

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03529.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:In order to investigate whether the energy dependence of histamine release induced by compound 48/80 from isolated rat mast cells reflects an increased utilization of ATP during the release process, the ATP content in samples of mast cells was determined 5 sec. before and 25 sec. after the addition of compound 48/80. No change in the ATP content was found when histamine release was induced from cells with an intact energy metabolism. However, when the cells had been preincubated for 1 min. with antimycin A to inhibit oxidative production of ATP, histamine release was accompanied by a greater reduction (P<0.005) in the ATP content than that observed in the control samples. In contrast, when corresponding experiments were performed with chlorpromazine or n‐decylamine as releasing agent, the ATP content was not lower in the samples in which histamine release had been induced than in the controls, regardless of whether antimycin A was present or not. The results indicate that histamine release from rat mast cells induced by compound 48/80, but not by chlorpromazine or n‐decylamine, is accompanied by an increased utilization of ATP in the ce

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03530.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:Pretreatment of isolated rat mast cells with antimycin A (0.03 μM or more) inhibited histamine release induced by subsequent exposure to compound 48/80 or exogenous ATP. When the mast cells were simultaneously exposed to antimycin A (0.1 μM) and the releasing agents, compound 48/80, but not ATP, released histamine. In contrast, exogenous ATP, but not compound 48/80, induced histamine release from cells which after pretreatment with antimycin A were diluted to an ineffective concentration of the inhibitor with a solution containing the releasing agent. The different effects of antimycin A on histamine release induced by compound 48/80 and exogenous ATP can be explained by the difference in the time courses between the release reactions. The ATP content in mast cells was gradually reduced during treatment with antimycin A (0.2 μM) so that after 3 min. only about 30 % of the original content remained. Concomitantly, the ability of the cells to release histamine when exposed to compound 48/80 decreased. This suggests that histamine release induced by compound 48/80 is dependent on the ATP content in the cells at the time of exposure to the releasing age

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03531.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:Antimycin A (0.2 μM) reduced the ATP content in isolated rat mast cells to 25–30 % of the original value. Pyruvate (4.9 mM) did not restore the ATP content in antimycin A‐treated cells, indicating a complete block of oxidative ATP production. 82–97 % of the glucose which disappeared from suspensions of mast cells in the presence of antimycin A was recovered as lactate. Therefore, the rate of lactate accumulation in suspensions of antimycin A‐treated cells was used as a measure of the cellular ATP production rate. Maximal accumulation occurred with 1.1 mM glucose. Incubation with glucose (0.51 mM) for 2.5 min. completely restored the ability of mast cells pretreated with antimycin A to release histamine when exposed to compound 48/80. Concomitantly, the ATP content in the cells was restored to a steady‐state level of about 75 % of the original value. 0.29 mM glucose partially restored the histamine release as well as the ATP level whereas 0.13 mM glucose did not affect either of these parameters. The turnover time of ATP at steady‐state was about 30 sec. with all three concentrations of glucose, which indicates that the rate of ATP utilization by the cells is directly proportional to the ATP content. The present study supports the view that histamine release induced by compound 48/80 is dependent on the ATP content in the mast cells at the time of exposure to co

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03532.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:Histamine release from rat mast cells was induced by the simultaneous presence of ATP and calcium in the incubation medium. The minimum concentration of calculated free ATP necessary for histamine release was 1–2 μM. The amount of histamine released as well as the rate of the release increased when the concentration of free ATP was raised. The gradual inhibition of the release observed with increasing concentrations of CaCl2and MgCl2could be ascribed to decreasing concentrations of free ATP by the formation of CaATP and MgATP complexes. By pretreating the cells with ATP before the addition of CaCl2less free ATP was required during the calcium‐dependent secretory phase. It is concluded that free ATP and free calcium (or/and possibly CaATP complex) interact on the rat mast cells since the lowering of the concentration of one factor could, within certain limits, be compensated for by increasing concentrations of the other with regard to the magnitude of the secretory response of the mast c

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03533.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:The tissue concentrations of digoxin were measured in 13 cadavers who before death had been on the maintenance digoxin therapy. Tissue samples were taken from 5 different parts of the heart, from skeletal muscle, liver and kidney. Digoxin was extracted by dichlormethane and measured by radioimmunoassay. Whole blood digoxin was measured by the same method. The appropriate recovery studies showed good extraction. The highest heart digoxin concentration was found in the septal muscle (mean 132 ± S. D. 65 ng/g) and the lowest in the left auricle (43 ± 26 ng/g). The heart concentrations were in good correlation with the whole blood concentration — the best correlation was found with the ventricular muscle (r = 0.86). The skeletal muscle concentration was about 15 % of the heart concentration (20 ± 13 ng/g) and the correlation with the whole blood was poorer (r = 0.54). The kidney concentration (123 ± 65 ng/g) was approximately the same as that of the heart and the liver concentration was 68 ± 51 ng/g. The results indicate a linear correlation between blood and

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03534.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:The formation of 3,4‐DOPA from m‐tyrosinein vivois demonstrated. The kinetic aspects of DOPA accumulation in the brain after central and peripheral inhibition of the 1‐aromatic amino acid decarboxylase are considered. It is concluded that the excess DOPA accumulation after administration of m‐tyrosine is due to the uptake from the blood of DOPA generated in the liver. This exogenous DOPA is shown to be much less exposed to brain decarboxylase than DOPA generated in the brain. The possibility that the pharmacological effects of m‐tyrosine can at least partly be explained by dopamine generation from DOPA is

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03535.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY