摘要:

AbstractThe recovery of total radioactivity,14C‐histamine and14C‐methylhistamine in extracts of wholeMyxine glutinosawas determined after s.c. injection of14C‐histamine. 24 hrs after injection the same parameters were determined in single organs. Total radioactivity declined very slowly, 10 days after administration 71% was recovered. At that time14C‐histamine and14C‐methylhistamine amounted to 44% and 1% respectively of the given dose. The liver was the most efficient organ in extracting radi

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04810.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractMitotic homeostasis in the erythron appears to be controlled by a humoral feedback mechanism consisting of a tissue‐specific mitotic inhibitor, the erythrocytic chalone, and a tissue‐specific mitotic stimulator. The present report is an account of the way in which these two regulatory factors affect RNA synthesis in normal rat bone marrow cellsin vitro. The responses were measured in terms of3H‐uridine incorporation into the target cells. The primary action of the erythrocytic chalone on3H‐uridine incorporation was manifested as a rapid and strong inhibition. The initial inhibition was reversible and was followed, after a few hours' incubation, by an increased rate of3H‐uridine incorporation, which ultimately led to complete compensation of the inhibition. The tissue specificity of these findings was demonstrated indirectly by means of polycythemic target bone marrow, on which the erythrocytic chalone had only a negligible effect. The effect of the mitotic stimulator on3H‐uridine incorporation in the cells was invariably a stimulation, which showed a slight tendency to increase with incubation time. The results demonstrate that the effects of the mitotic regulatory factors are not restricted to DNA metabolism alone but can also be elicited within other metabolic processes

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04811.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe efferent activities in the thick and thin “accessory” axons in the dorsal nerve of the crayfish abdomen have been studied during reflex activation from the same and neighbouring segments. The reflex input was either adequate stimulation of the slowly or the rapidly adapting stretch receptor or electrical stimulation of the afferent fibres from the receptors. The results support Eckert's finding (1961a) that the thick accessory nerve is reflexly activated from both the slowly and the rapidly adapting receptors. The thick accessory nerve is most effectively activated ipsilaterally while the thin accessory nerve predominantly participates in crossed refle

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04812.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe effect of PGE1on the uptake of glucose and the release of FFA and glycerol before and after sympathetic nerve stimulation (4 cps) was investigated in perfused canine subcutaneous adipose tissuein situ. Glucose uptake was significantly increased by PGE1at all concentrations used (5 times 10‐10to 7 times 10‐7M in blood). The effect of PGE1on the release of FFA and glycerol in unstimulated adipose tissue was inconsistent. Increases as well as decreases were observed. Lipolysis, as measured by glycerol release, induced by nerve stimulation was inhibited dose‐dependently. A 50 per cent inhibition was produced by approximately 1.2 times 10‐7M PGE1. Stimulated FFA release was also inhibited but there was no clear dose‐response relationship. It is concluded that PGE1has similar effects in canine subcutaneous adipose tissue with an intact blood supply as are known to be produce

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04813.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThere is little information about the possible role of the pulmonary vascular bed as a variable blood depot. An evaluation of the degree of blood mobilization from this vascular compartment after a blood loss has therefore been attempted. Rats were given labelled erythrocytes and albumin, and immediately after a standardized blood loss the circulation was arrested by immersing the animals in liquid nitrogen. The lungs and tissue samples from liver and skeletal muscles were removed, and their blood contents evaluated. Values found in the tissues of the bled animals were compared with those from a group of non‐bled control animals. In a group of animals bled 12% of their total blood volume the mean pulmonary blood volume was reduced by 25%, while the muscle and liver blood contents were reduced by about 10% only. This difference was even more pronounced in a group of animals bled 24% of their total blood volume. The reduction in pulmonary blood volume was in the former group equal to 27% of the lost blood. This was more than the amount of blood contributed from the whole mass of skeletal muscle. In the bled animals the weight of the lung tissue proper was considerably reduced, indicating that there had been a reduction also in lung tissue wate

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04814.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractIn vivosulfate incorporation into tissues of small animals, as a metabolic research tool, has been previously handicapped since convenient micromethods for sulfate determination were lacking. A double isotope method for determination of the inorganic sulfate pool applicable to very small animals is presented and evaluated. It is based on a principle which makes blood samples unnecessary. Phenol injectedi.v.is converted to phenyl sulfate in the viscera and the circulating inorganic sulfate pool of the animal participates in this reaction.3H‐phenol and35S‐sulfate mixed with suitable amounts of carrier are given to the animals and the tagged phenyl sulfate formed is isolated from the urine by thin‐layer radio‐chromatography. Its3H/35S ratio together with the specific activities of the injection mixture yield all necessary values for calculation of the size of the sulfate pool. Simultaneously the incorporated amount of sulfate into a defined portion of costal cartilage is measured after correction for the individual sulfate pool values.In 20 g N.M.R.I. mice the total miscible sulfate pools were about 300–400 μg SO4/mouse and the sulfate incorporation during the 30 min experimental period reached 200–400 nanogram SO4per 5 pairs of cartilaginous ribs including their osteochondral junctions. The size of the sulfate pool increased with increasing body wegiht at different ages both in N.M.R.I. and in obese‐hyperglycemic mice. The sulfate incorporation rates showed markedly different values in different mouse strains investigated a

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04815.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe mechanisms underlying the generation of activity in the afferent nerve branches within the muscle spindle have been studied in isolated frog spindles. Repetitive stimulation at given frequencies and strengths caused a disintegration of the synchronous activity of the spindle as revealed by a decomposition of the impulse into small abortive spikes of different amplitudes. The breakdown of synchronous activity was preceded by a stage during which the impulse appeared gradually later but then remained steady at a given delay. The isolated receptor potential exhibited a latency shift closely similar to that of the impulse response under repetitive stimulation. Treatment of the spindle with tetrodotoxin at critical concentrations caused a decomposition of the impulse similar to that with repetitive stimulation. It could be shown in these spindles that synchronization of the activity within the spindle is related to the amount of depolarization of the sensory endings. The mechanisms for generation of activity in the spindle are discussed in relation to the structural organization of the branches of the afferent fibre. It is concluded that the anatomical and functional properties of the spindle provide the basis for a synchronization of the activity of its different parts during the response to an applied stretch.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04816.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe rates of incorporation of3H‐acetate and35S‐sulfate into chondroitin sulfate of mouse costal cartilage were studied by anin vitro‐incubation technique. Cartilage specimens from two different regions of costal cartilage prepared from growing mice, were incubated for varying periods of time. Chondroitin sulfate was isolated, after proteolytic digestion of the tissues, by repeated precipitation with cetylpyridinium chloride. The average incorporation rates, which were followed during 24 hrs, showed a marked decrease after 2 hrs of incubation and then remeained essentially constant. During the entire incubation period much more exogenous sulfate than acetate was incorporated into the segments. Considerably more exogenous sulfate and acetate were incorporated into the lateral segments of the cartilage, including the osteochondral junctions, than into the medial segments. It is concluded that chondroitin sulfate is synthetized at a higher rate in the vicinity of the osteochondral junction than in other portions of mouse costal cart

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04817.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe influence of desmethylimipramine (DMI) on the cardiovascular responses to i.v. injected noradrenaline (NA), adrenaline, metaraminol and isoprenaline, as well as to some chemically unrelated pressor agents (angiotensin, vasopressin, and the vasopressin analogue felypressin), was studied in anesthetized dogs and cats. The cardiovascular effects of NA were potentiated very markedly by moderate doses of DMI (0.1–1.0 mg/kg). The responses to adrenaline and metaraminol were only slightly potentiated. In the case of adrenaline, DMI was slightly more effective in enhancing the pressor action of this amine after partial β‐blockade (propranolol). In analogy with the carotid occlusion response, the effect on the peripheral vascular resistance elicited by electrical stimulation of the lumbar sympathetic nerves was not significantly potentiated by DMI.A method of “delayed autoperfusion” was developed to record reflex vasomotor counter‐regulation. DMI was found to reduce the activity of this counter‐regulation suggesting that this may be one way in which this drug potentiates the cardiovascular effects of the non‐catecholamine

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04818.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractWhen the extracellular Na+was replaced by lithium (Li+) the frequency of the impulses elicited by stretching the stretch receptor of crayfish was changed and then inhibited. This effect was not due to the lack of extracellular Na+. Higher firing rate facilitated and low extracellular K+delayed the Li+effect. Ouabain alone (10‐4M) changed the impulse activity in a similar manner to Li+replacement. Ouabain (10‐5M) decreased the rate of recovery during wash‐out after Li+replacement. The Li+‐induced increase in the frequency of the impulse activity was probably the result of a lower intracellular K+concentration, the block of the spike activity being due to the accumulation of Li+in the cell. The Na+pump participated in the recovery of the spike activity after Li+repl

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04819.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY