摘要:

AbstractThe time course of innervation by nerve implants of the fast contracting flexor digitorum longus and the slow contracting soleus muscles were studied by the recorcling of isometric twitch tensions in response to stimulation of the implanted nerve and by histochemical visualization of newly‐formed end‐plates. When a foreign motor nerve was implanted into a muscle 30 days prior to sectioning of the original nerve supply, synaptic contacts were established 4–8 days after the section of the nerve, while, with simultaneous implantation and denervation, 16 days were required for the implanted nerve to innervate the muscle. Implantation of the nerve which normally innervates the flexor digitorum longus muscle into the soleus altered the contraction and relaxation speeds of the soleus muscle towards those of a fast contracting muscle, the change being apparent as soon as 4–8 days following sectioning of the original nerve. In muscles with nerve implants and intact normal innervation hypertrophy occurred, amounting to 20–30 per cent within

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04469.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractExperiments were carried out in the isolated, perfused cat spleen to assess the capacity of the mechanisms of synthesis of noradrenaline to keep pace with the loss of noradrenaline by overflow from the organ, during prolonged periods of electrical nerve stimulation. The organ was pretrcated with the monoamine oxidase inhibiting drug nialamide to block deamination of noradrenaline. Phenoxybenzamine or cocaine+ Hydergin were added to the perfusion fluid in order to inhibit reuptake of noradrenaline liberated from the nerves, and to facilitate washout of noradrenaline in the extracellular fluid by preventing the vasoconstriction response.De novosynthesis of noradrenaline was found to proceed at a rate comparable to the highest values described in the literature. However, the discharge of noradrenaline from the neurons in response to nerve stimulation, as reflected by the peak overflow of noradrenaline from the organ, occurred at an approximately ten times higher rate. The results imply that the major mechanism for the maintenance of a constant noradrenaline level in the neuron from one moment to the next, during periods of increased nerve activity, is notde novosynthesis, but rather an almost quantitative reuptake of the noradrenaline liberated from the neurons.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04470.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractIn 6 internationally successful endurance athletes measurements of oxygen uptake, and pulmonary diffusion capacity at maximal bicycle exercise were performed at sea level and after 3 weeks stay at 2250 m altitude (Mexico City). Maximal oxygen uptake was 10–17%lower at altitude and this reduction was related to the ratio at sea level between DLCO/max Vo2, The findings demonstrated that there is a physiological basis not only for a more marked reduction of max Vo2in welltrained groups at altitude but also for the observed large differences in performance at altitude between athletes of equal capability at sea leve

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04471.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractTwo bee venom fractions, F I and F II, obtained by gel filtration, and compound 48/80, were shown to release histamine from skin and lung tissue of the rat. F I is the phosphatidase A containing fraction, and F II contains a basic polypeptide. Dose‐response relationships, the time course of the histamine release, and the influence of enzyme inhibitors were studied. The results with F II and compound 48/80 were similar, suggesting that the two substances activate the same kind of release mechanism. It is concluded that F II is not related to the earlier described bee venom polypeptides melittin and aparnin. The mode of action of phosphatidase A was distinctly different from that of F II or compound 48/80. The results are consistent with the assumption that it acts in a “non‐specific.” way by hydrolysing tissue phosphatides to lyso compounds, which in turn damage the

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04472.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractSlices from normal, atrophied and postganglionically sympathectomized rat salivary glands were incubated with labeled dopamine or noradrenaline. The catabolism of dopamine proceeded at a higher rate than that of noradrenaline. This phenomenon is proposed to be due to the higher affinity of dopamine for monoamine oxidase, the extraneuronal part of which being very important. The major catabolites of dopamine were found to be the phenolic acids dihydroxy‐phenylacetic acid and homovanillic acid. Exogenously added noradrenaline was primarily catabolized to normetanephrine, whereas the major metabolites of newly synthesized noradrenaline from dopamine were the phenolic glycols 3,4‐dihydroxyphenylglycol and 3‐methoxy‐4‐hydroxyphenylglycol, supporting the view that intraneuronally formed noradrenaline initially is metabolized by intraneuronal monoamine oxidase prior to its O‐methylation by catechol‐O‐methyl transferase. Atrophy reduced the levels of all 3‐O‐methylated products, especially those of the methoxylated amines, whereas sympathectomy increased the amounts of these amines and diminished the deaminated products. Thus, catechol‐O‐methyl transferase is localized to the parenchymal cells in the salivary glands. In contrast to the dopamine metabolism, the catabolism of noradrenaline was more affected by postganglionical sympathectomy than by atrophy. The data from the present study demonstrate the importance of the amine concentrating mechanism of the adrenerg

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04473.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe activity of glyceradehyde‐3‐phosphate dehydrogenase, phosphoglycerate kinase and adenylate kinase was determined at the surface of intact red cells, suspended in isotonic sodium chloride or isotonic sodium chloride containing 6 % Dextran. The surface‐bound phosphoglycerate kinase activity was found to be 4.5 %of the total phosphoglycerate kinase activity of the cell. The corresponding figures for glyceraldehyde‐3‐phosphate dehydrogenase and adenylate kinase were 3.1 % and 2.0 %, respectively. The extent of hemoglobin leakage into the assay medium did not exceed 1 % in any case. The suspending medium, after the cells had been removed, contained no glyceraldehyde‐3‐phosphate dehydrogenase or phosphoglycerate kinase activity, whereas part of the adenylate kinase activity had been eluted f

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04474.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractSingle‐unit impulses were recorded with semi‐microelectrodes from muscular portions of peripheral limb nerves in awake human subjects. Thirteen units were studied. Four of them could not be activated by mechanical peripheral stimuli but they fired steadily during sustained voluntary contractions. They were considered to be either motor fibres or proprioceptor units, having high thresholds to mechanical stimuli. The other nine units were shown to be proprioceptors which had their end organs located in deep structures of the leg or the forearm. They were divided into three groups on the basis of their responses to local mechanical stimuli, passive movements, and voluntary contractions. Possible relations between each group of units and various anatomical types of proprioceptors are discussed. Some of the units had characteristics which suggested that they were muscle spindle afferents. The findings reported in this investigation and in an earlier investigation, dealing with multi‐fibre discharges in muscle nerves, indicate that the muscle spindle afferent discharge is increased during voluntary contractions and thus, that the fusimotor system is engaged in voluntary motor

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04475.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractIsolated rat peritoneal mast cells were exposed to d‐tubocurarine, and the release of histamine was studied under various conditions. The proposal is made that d‐tubocurarine although a monomer induces histamine release by a mechanism similar to that one triggered by the polymer synthetic amine compound 48

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04476.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractA device is described for sudden application of a mechanical load to the brain in animals by displacing a column of fluid within a plunger system towards its connection with a hole in the skull. Velocity and displacement of the piston, moving the fluid into the skull cavity, were varied in a series of experiments in rabbits. Simultaneous recordings were made of the pressure pulses produced in the fluid near the parietal site of loading of the brain and at several places within the contents of the skull cavity and spinal canal. By adjusting the fluid input to the skull cavity it was possible to produce intracranial pressure pulses predictable with respect to peak amplitude and duration within a range between 0.1 and 4.0 atm. and one and several hundred msec, respectively. The pressure pulses produced extracranially and in the major part of the skull contents were similar. Simultaneous recordings of the pressure course in the vicinity of the cranio‐spinal junction and in the spinal canal revealed however, that peak amplitude and duration of the pressure pulse then decreased continuously at increasing distance from the site of application of the load. No pressvire changes were found to occur caudally to the level of the fifth cervical vertebra. This method seems suitable for studying the effects of controlled and varied sudden mechanical loading of the brain in animals and the relations between subsequent brief intracranial pressure changes and pathological alterations, similar to those occurring in skull traum

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04477.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractAn extradural fluid volume (0.04–1.0 ml) was suddenly applied to the parietal brain surface in rabbits by means of a plunger system, attached to a hole in the skull. The immediate changes in arterial blood pressure, pulse rate and respiration were recorded and used as criteria of a “concussive response”. These pathophysiological effects were related to peak amplitude (0.1–3.0 atm.) and duration (5–300 msec) of the recorded intracranial pressure pulse. Similar pathophysiological effects could be reproduced by application of the same single load to the brain through a series of experiments. The “severity” of the concussive response varied with the peak amplitude and duration of the intracranial pressure pulse. At pressure pulses of 5–15 msec duration no pathophysiological effects occurred with a pressure pulse not exceeding about 0.7 atm. peak amplitude, but at 2.5 atm. peak pressure irreversible apnea was produced. Decrease in blood pressure occurred at induction of pressure pulses of comparatively low magnitude while a sudden increase in blood pressure was produced at pressure pulses of higher magnitude. Duration of apnea increased with increasing peak amplitude of the pressure pulse and seems to be a useful measure of the “severity” of the concussive response in the present t

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04478.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY