摘要:

AbstractA series of adrenergic α‐and β‐blockers have been found to decrease the release rate of nor‐adrenaline from a suspension of bovine splenic nerve granules incubated in phosphate buffer at pH 7.5. The same blockers also inhibited the uptake of noradrenaline in partially depleted nerve granules in the presence of ATP—Mg++. It is tentatively suggested that the interactions of the adrenergic blocking agents with uptake mechanisms for noradrenaline in the nerve granules and at the receptor level in effector cells involve certain common

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03426.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractAn attempt has been made to define the types of muscle fibres present in the iliofibularis muscle ofXenopus laevis.Histochemical studies were carried out on cross sections of the muscle. The variation between cells in the content of lipids, DPN‐diaphorase and succinic dehydrogenase was noted, and on this basis the fibres were classified into three main groups. Single, living fibres representing the histochemical groups were selected and their contractile behaviour in response to electrical stimulation and the application of ACh was studied. The findings indicated a relationship between the histochemical and functional properties of the muscle fibres. Fibres with a moderate content of lipid and enzymes (pale fibres) were fast fibres which fatigued rapidly on maintained stimulation. Fibres with a high content of lipid and enzymes (dark fibres) were fast fibres which did not fatigue rapidly. Fibres containing no lipid and no DPN‐diaphorase or succinic dehydrogenase (clear fibres) were slow fibres. Staining of the end‐plates on the fibres showed that fast fibres had end‐plates of varying gross morphology and with high cholinesterase activity, whereas slow fibres had ‘en grappe’ end‐plates with very low cholineste

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03427.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractIn 23 expts. the plasma, concentrations of protein and inulin were measured in blood collected simultaneously from an artery, from the subcapsular, and from the deep veins of the cat kidney. These concentrations allow a calculation of the filtration fractions of the plasma flows supplying, partly the superficial cortex and partly the deep cortex plus medulla. A filtration fraction averaging 0.34 was found for the plasma supplying the superficial cortex. The filtration fraction of the plasma, supplying the deep cortex and the medulla was lower; the ratio: filtration fraction in deep area/filtration fraction in superficial area (FFD/FFs) was usually 0.70 to 0.95 and the average (0.85) was significantly lower than 1.00 (p<0.001). The existence in the deep parts of the kidney of various vessels through which the plasma (blood) may by‐pass the capillary tufts of juxtamedullary glomeruli provides the possibility of accounting for the observed deviation of FFD/FFs from 1,00 without resorting to the assumption of (basically) different filtration fractions for plasma entering glomerular tufts in deep and superficial glomeruli. A by‐pass of a magnitude sufficient to account for the deviation may also account for a medullary plasma flow as reported by oth

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03428.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractIn 23 expts. in cats the plasma concentrations of protein, inulin, and glucose have been measured in blood collected simultaneously from an artery and from subcapsular and deep veins of the kidney. For each venous drainage area it is possible to calculate the ratio: reabsorption rate/filtration rate on the basis of the protein and inulin concentrations in the venous plasma relative to those of the arterial plasma. In the superficial cortex the ratio between the reabsorption rate and the filtration rate was approximately 0.75, significantly lower than 1.00 (p<0.001). In the deep cortex plus medulla the ratio between reabsorption rate and filtration rate was approximately 1.35. The ratio was significantly higher than 1.00 (p<0.001).From the protein, inulin, and glucose concentrations it is possible to calculate the ratio: reabsorbed amount/filtered amount of glucose of the superficial cortex and of the deep cortex plus medulla. The ratio was significantly higher than 1.00 (1.13) in the superficial and lower than 1.00 (0.89) in the deep cortex plus medulla (p<0.001). The results agree with the renal anatomy. A relatively complicated pattern emerges for the drainage of the reabsorbate from different tubule segments to the vein systems.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03429.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractOxygen consumption of isolated working rat hearts at 32° C was found to be 0.56ml/min per g dry weight or about 13ml/min per 100g wet weight. Oxygen consumption during experimental asystolia varied from 0.16ml/min per g dry weight for hearts arrested with high potassium to 0.38ml/min per g dry weight for hearts arrested with citrate. Adrenaline increased the oxygen consumption in asystolic as well as in working hearts. The effect of adrenaline on basal QO2was blocked with the adrenergic β‐receptor blocking agents propranolol and dichloroisopropylamino‐ethanol, but not with the α‐receptor blocking agent phentolamine. Mechanisms through which adrenaline might affect cardiac oxygen consumption during asystolia are discussed, and it is proposed that the calorigenic effect reflects an increased utilization of ATP by several separate processes which directly or indirectly are stimulated by ad

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03430.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractThe effect of prolonged elevation of venous outflow pressure on the intestinal filtration capacity was studied on cats. Increases of venous outflow pressure produced a filtration of fluid from the capillaries, but the filtration rate decreased gradually with time and often a new isovolumetric state was reached. In order to study the factors causing this decrease of filtration capacity, pointing to a shift of the Starling equilibrium, an indirect method was used, consisting of stepwise raising and lowering the venous pressure. During this procedure the rate of net fluid transfer upon a given venous pressure level could differ very much, depending on whether this pressure level was reached from a lower or from a higher venous outflow pressure. The transcapillary forces, responsible for these differences of net fluid transfer, amounted to often more than 10mm Hg. This means that some factor, or factors, involved in the Starling equilibrium, must have changed by this amount. It is suggested that increasing tissue pressure is the most important counterforce during outward filtration, caused by a sudden rise of the venous outflow pressure. Evidently, the small intestine is quite well protected against edema, in spite of a very big transcapillary filtration capacity.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03431.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractFor the present work the urinary excretion of noradrenaline, adrenaline and 3‐methoxy‐4‐hydroxymandelic acid in 18 healthy young persons during a sauna bath were studied. The average basal excretion of noradrenaline was 30.6 ± 3.4ng/min, and due to the influence of sauna it rose to 46.6 ± 4.1ng/min. Average adrenaline excretion during basal activity was 7.0 ± 0.7ng/min, and in the sauna 9.6 ± 1.1ng/min, while the figures for excretion of 3‐methoxy‐4‐hydroxy‐mandelic acid were 4.2 ± 0.3μg/min

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03432.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractIn unanaesthetized spinal cats, injected with 1‐DOPA, volleys in the flexor reflex afferents (FRA) evoke a long latency, long lasting dorsal root potential (DRP). Measurements of excitability of ispilateral primary afferent terminals show a corresponding depolarization of Ia, but not Ib or cutaneous, afferent terminals. Volleys in the FRA have no effect on Ia afferent terminals in the normal acute spinal cat, presumably because the neuronal pathway transmitting the effect from the FRA to Ia afferents is inhibited by activity in another pathway from the FRA. Results are presented showing that after intravenous injection of DOPA volleys in the FRA can inhibit transmission from the FRA to Ia afferents. It is suggested that this inhibitory effect from the FRA also is responsible for the hyperpolarization of Ia afferent terminals that sometimes is evoked from the FRA after DOPA and is probably caused by a removal of depolarizatio

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03433.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractAfter injection of DOPA in unanaesthetized spinal cats volleys in the flexor reflex afferents (FRA) evoke a late long lasting Contralateral dorsal root potential. Measurements of excitability of contralateral afferent terminals show a corresponding depolarization of Ia, but not of Ib or cutaneous afferent terminals. Results are also presented showing that transmission from the FRA to contralateral Ia afferent terminals can be inhibited from the FRA.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03434.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractMonoamine oxidase (MAO) activity was determined in fractions obtained from bovine splenic nerve with both dopamine (DA) and noradrenaline (NA) as substrates. DA was found to be a much better substrate for MAO than NA. The bulk of the MAO in this preparation was found in the nerve granule fraction, which by electron microscopic evaluation seemed to be largely free from mitochondrial contamination. These findings suggest that bovine splenic nerve in addition to mitochondrial bound MAO also contains a form of MAO, with a substrate preference for DA, which seems to be associated with the nerve granules.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03435.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY