摘要:

Abstract100 ng/kg/min bradykinin was infused into the left renal artery in anaesthetized dogs which were loaded with 10% mannitol in saline to produce a diuresis of approximately 1 ml/min. Bradykinin initially increased renal blood flow (70%), kidney volume (20%), subcapsular pressure (85%), urine PG‐excretion (410%), diuresis (80%) and decreased urine osmolarity (20%). Kidney volume, diuresis and urine osmolarity remained equally changed during continuous kinin infusion, while other parameters subsided toward the control levels. When renal blood flow was maintained constant during the infusion of bradykinin, urine PG‐excretion increased (330%), the glomerular filtration decreased (60%) and this was accompanied by decreased kidney volume, diuresis/natriuresis with unchanged urine osmolarity. Indomethacin treatment (2.5 mg/kg i.v.) decreased renal blood flow (35%) and inhibited urine PG‐excretion. Bradykinin after indomethacin showed effects which were very similar to those observed before indomethacin treatment. It is concluded that increased intratubular volume is a main determinant of bradykinin induced increase of whole kidney volume. The accompanying increase of intrarenal pressure does not apparently contribute to the kinin induced PG‐release. The vasodilation by bradykinin seems independent of released prostaglandins. The diuresis/natriuresis and decreased urine osmolarity are probably of hemodynamic

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06055.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractInsulin was released by vagal stimulation in anesthetized and eviscerated cats. The plasma insulin concentration and blood flow in the portal vein were determined concomitantly and the insulin output was calculated. Stimulation of either the right or the left cervical vagus released the same amount of insulin, whereas bilateral stimulation released twice as much. Following a stimulation that depleted the “vagally‐releasable pool”, a recovery period of 15–20 min was needed before the same maximal output could be obtained again. With shorter interstimulatory periods the amounts of insulin released were reduced. When less than 2–3 000 impulses were applied during a stimulation period, the amount of insulin released per impulse was constant. Atropine (0.2–2 mg/kg) did not reduce the vagally‐induced in

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06056.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe vasoconstrictor action of the tridecapeptide (Gln4)‐neurotensin has been studied in subcutaneous adipose tissue in the inguinal region of anesthetized dogs. Close intra‐arterial infusion of (Gln4)‐neuroten‐sin, 30–120 pmol X kg‐1b.wt. X min‐1, elicited similar vasoconstrictions in the adipose tissue on the infusion side and on the contralateral side. This suggests that (Gln4)‐neurotensin must enter the general circulation before it can elicit vasoconstriction. Removal of parts of the gastrointestinal tract did not change the vasoconstrictor response. Thus, there is no indication of release of vasoactive substances from the gastrointestinal tract by (Gln4)‐neurotensin. Infusion into the portal vein elicited the same vasoconstriction in adipose tissue as the same dose administered i.v. It is suggested that the vasoconstrictor action in adipose tissue is not caused by (Gln4)‐neurotensinper se.Instead, vasoactive substance(s) may be formed from

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06057.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractBlood flow distribution to the mucosa‐submucosa and to the muscularis in the cat small intestine was investigated with a85Kr elimination technique before and after exposing the intestinal mucosa for 30 min to cholera enterotoxin. In all experiments the toxin induced an intestinal secretion. Concomitantly, total intestinal blood flow was increased to a level 50 per cent above control 3 h after exposure. This vasodilatation reflected a doubling of mean blood flow in the mucosa‐submucosa while muscularis blood flow remained unchanged. In another series of experiments the effect of cholera toxin on intestinal capillary hydraulic conductivity was investigated by determining the capillary filtration coefficient (CFC). A slight increase in CFC was noted during the 3 h observation period but this was not more pronounced than would have been expected from the concomitant vasodilatation. It is concluded that hemodynamic changes in the intestinal mucosa may be one of the several factors that probably are involved in the pathogenesis of chol

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06058.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractHomogenate of guinea‐pig liver and human placenta, tissues known to be rich in diamine oxidase, were incubated with14C‐putrescine and the metabolites formed were determined. In the incubate of guinea‐pig liver, the major metabolites were GABA and some unidentified compound(s); Δ1‐pyrroline and14CO2were also obtained. In both the maternal and fetal parts of human placenta, radioactive GABA and the unidentified compound(s) as well as Δ1‐pyrroline were found. The results indicate that GABA is an important intermediate in putrescine metabolism. Determination of the amount of Δ1‐pyrroline is thus not well suited as a measure of the diamine oxidase activ

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06059.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractUnder optimal activation conditions we obtain an active tension‐length curve with a well‐defined plateau region. The plateau can be explained in terms of a sliding filament mechanism in which double overlap of the thin filaments does not interfere with cross‐bridge formation between thick and thin filaments of the appropriate pol

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06060.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe aim of the present work was to investigate whether prostaglandins (PGs) are synthetized and released from isolated blood‐perfused rat and cat lungs secondary to vasoconstriction induced by alveolar hypoxia. The lungs were perfused with autologous blood with constant volume inflow via the pulmonary artery in a recirculating system. They were ventilated with constant volume positive pressure, and acute alveolar hypoxia was induced by ventilation with a gas containing 2% O2. A superfusion bioassay technique was used to measure PG‐like activity in the perfusate from the lungs, the blood being re‐oxygenated before reaching the assay tissues. The oxygenator prevented the perfusate hypoxia induced by ventilation hypoxia to affect the bioassay tissues. The assay tissues were rat stomach strip, rat colon and chick rectum. They were sensitive to calibrating doses of 0.5–1 ng/ml PGE2and 1–2 ng/ml PGF2α. In another series of experiments PGs of the F‐series were measured in lung tissue from normoxic and hypoxic lungs with radioimmunoassay technique. No increase in PG‐like activity could be detected in the venous effluent by means of bioassay during hypoxia, nor was the lung tissue content of immunoactive PGF increased by hypoxia. The present findings indicate that alveolar hypoxia does not stimulate PG‐synthesis in lungs, refuting that PGs are important mediators of the pulmonary vasoconstrictor response to alveolar hypoxia. It is concluded that PGs play no significant role in producing the pressor response to

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06061.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractIt has been suggested that adenosine may be a physiologically important modulator of lipolysis. In the present study it was found that adenosine inhibited lipolysis stimulated by low (0.03 μM) concentrations of noradrenaline (NA). Lipolysis stimulated by higher concentrations (0.3 and 3 μM) of NA was inhibited to a minor degree or not at all. Theophylline (1 mM)‐induced lipolysis was inhibited by adenosine (IC60˜ 10μM). Inhibition of theophylline‐induced lipolysis was tested for several analogues of adenosine. Some N6‐sub‐stituted adenosine analogues and 2‐Cl‐adenosine were more potent inhibitors. Adenine‐nucleotides (ATP, ADP, AMP) were about equipotent with adenosine. Several adenosine analogues, including its breakdown products were considerably less potent or ineffective. None of the analogues tested inhibited the action of adenosine. Dipyridamol, dilazep and papaverine, which inhibit the uptake of adenosine into cells, caused only a slight enhancement of the antilipolytic effect of adenosine. None of the analogues inhibited the effect of adenosine. It is concluded that adenosine can inhibit lipolysis due to low, “physiological” concentrations of noradrenaline and of low concentration of theophylline via an action on a receptor structure on the cell surface which exhibits s

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06062.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractSympathetically innervated, isolated rabbit hearts were perfused according to Langendorff and the nerves were stimulated at 2, 5 or 10 Hz by equally long trains of pulses. The outflows of prostaglandin‐like substances (PLS) and of noradrenaline (NA), induced by the nerve stimulations, were followed. The sensitivity of the process of NA release to exogenous PGE1(2–6 × 10‐8M) at 2, 5 and 10 Hz was assayed. The outflow of PLS was found to be frequency‐dependent, being greater at 2 Hz than at higher discharge rates, while the outflow of NA was similar at the different frequencies. The inhibitory action of PGE, on the NA release process was more pronounced at 2 than at 10 Hz. It is concluded that the frequency‐dependence of the endogenous PGE‐mediated inhibition of the release of NA from discharging sympathetic nerves is based on 2 independent, frequency‐related mechanisms: a) a higher synthesis rate of PLS/impulse, and b) a more pronounced sensitivity of the process of NA release, at low compared to higher impul

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06063.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractMonopolar DC‐recordings were made of the gross responses from the olfactory bulb of char (Salvelinus alpinussyn.Salmo alpinusL.) and trout (Salmo truttaL.) during stimulation with different odours. The response features studied were: the magnitude and polarity of the slow potential shift, the amplitude of the induced waves and their asymmetrical waveform. Amino acids elicited the largest responses in the lateral part of the bulb. Water containing “crude fish odour” caused the largest responses in the rostral and medial parts. The results demonstrate odour specific differences in the localization of the bulb responses and the separate origin of the slow potential and the induced

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06064.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY