摘要:

AbstractThe effect of stimulation of the sensorimotor cortex on spinal reflex arcs was investigated in cats with intracellular recording from motoneurones and with conditioning of monosynaptic reflexes. Stimulation of cortex enhances the following synaptic actions in motoneurones: Ia inhibitory, Ib reciprocal, FRA reciprocal, FRA inhibitory to flexor and cutaneous excitatory to extensor motoneurones. The effects are mediated by the pyramidal tract which presumably exerts an excitatory action on interneurones of reflex arcs. Stronger stimulation of cortex evokes synaptic actions in motoneurones with excitatory action dominating in flexor and inhibitory in extensor motoneurones. There was frequently evidence of mixed excitatory and inhibitory effects in extensor motoneurones and inhibitory action in flexor motoneurones was also found. It is suggested that these actions on motoneurones are due mainly to activation of interneurones of spinal reflex arcs.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1962.tb02497.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractIntracellular recording was made from 23 interneurones in the dorsal horn and intermediate region. Stimulation of the sensorimotor cortex evoked excitatory postsynaptic potentials in interneurones receiving excitatory action from: 1) group I muscle afferents, 2) flexor reflex afferents, 3) cutaneous afferents. In a few of the interneurones the latency was so brief as to suggest a monosynaptic connexion from the pyramidal tract. Stimulation of the sensorimotor cortex evoked inhibitory action only in one interneurone, which received inhibitory action from the periphery as well. The findings are discussed mainly in relation to facilitatory actions evoked by volleys in the pyramidal tract on paths from primary afferents to motoneurones.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1962.tb02498.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractFive isoflavones, biochanin A, genistein, formononetin, daidzein and 5–7‐dihydroxyisoflavone have been synthesized. Their estrogenic activity was assayed by the mouse uterine weight method under different administration routes. Daidzein, in contrast to the four other isoflavones, was not absorbed, when injected subcutaneously and its estrogenic activity was in consequence of this negligible by subcutaneous injection. By oral or intraperitoneal administration the estrogenic activity of daidzein and genistein was approximately 10‐5times that of diethylstilbestrol. Biochanin A and 5–7‐dihydroxy isoflavone were about half as active estrogens as daidzein and genistein. Formononetin was inactive. A free para‐hydroxy group in the phenylnucleus of the molecule is present in daidzein and genistein but is lacking in biochanin A, formononetin and 5–7‐di‐hydroxy isoflavone. The presence of a free para‐hydroxy groups therefore seems to be of importance for the

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1962.tb02499.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractThe purpose with the investigation was to compare the removal of three different artificial intravenous fat emulsions from the blood of nonfasted rats with the removal from blood of washed chylomicrons collected from rats fed cottonseed oil. The injected dose of glycerides varied between 300 and 1,000 mg/kg body weight. The elimination pattern of the injected particulate fat was determined turbidimetrically. The chylomicrons as well as the different emulsions showed an exponential type of disappearance during the major part of the elimination process. Two of the tested emulsions contained vegetable oil stabilized with phospholipids. These emulsions showed an elimination rate very similar to that of chylomicrons. The third emulsion (“SR”), lacking phospholipids and containing vegetable oil stabilized with synthetic agents, disappeared from blood significantly faster than chylomicrons. With all the injected substrates the elimination rate decreased with increasing fat lo

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1962.tb02500.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractUptake of palmitic acid‐1‐C14in albumin plus α1lipoprotein fraction, in α2lipoprotein, SbT lipoprotein and chylomicron fractions separated by paper electrophoresis was followed from 3 to 76 hours after oral administration of palmitic acid‐1‐C14. Except the initial high activity in the chylomicrons, the highest activity was found in the albumin plus α1lipoprotein fraction. Apparent turnover time of this fraction between 3 and 18 hours after ingestion of the label was about 12 hours. Activity of the α2lipoprotein fraction was not much altered up to 28 hours. Activity of the β lipoprotein fraction seemed to follow the activity of the chylomicron fraction to a gr

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1962.tb02501.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractWhole body autoradio‐grams of mice injected intravenously with (‐)‐nicotine‐methyl‐C14show an initial accumulation of radioactivity in the CNS. This high concentration of nicotine and/or its metabolites in the brain disappears within 30 min to 1 hour. Autoradio‐grams of cat brain show a similar accumulation of radioactivity following i. v. injection of C14‐nicotine. The distribution picture changes with time after injection. Only one metabolite, viz. cotinine, has been found to occur in the brains of mice and cats. The possible existence of nicotine receptors in the brain

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1962.tb02502.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractA method for the determination of small amounts of metanephrine and normetanephrine in tissues and body fluids is described. The disturbing effect of adrenaline and noradrenaline is eliminated in two alternative ways: 1. By differential oxidation and subsequent ion exchange chromatography, 2. by separation on an ion exchange column. Metanephrine and normetanephrine are determined in the eluate from the ion exchange column according to the principles of the trihydroxyindole method for the fluorimetric determination of adrenaline and noradrenaline. Applications of the method on urine and brain tissue extracts are described.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1962.tb02503.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractThe work was performed with a hand ergometer, the intensity of work being varied with respect to frequency and load. Blood samples were obtained through catheters inserted in the brachial artery and in deep and superficial forearm veins. The deep veins of the forearm contain fairly pure muscular blood during and immediately after work, whereas at rest there is an admixture of blood from the hand. At rest, a significant difference was present between the arterial and deep venous blood with respect to oxygen saturation, lactate and pyruvate concentration and pH. During work of about 4 min duration, a significant rise occurred in both arterial and venous lactate and pyruvate. The highest venous lactate concentration was usually noted at the end of work, while pyruvate did not reach its maximum until 5 min after work. The resting levels were regained about 45 min later. The oxygen saturation of the venous blood fell from a mean 56.6 to 23.9 per cent. In connection with work of high intensity but very short duration (5–30 sec) a marked increase was observed in venous lactate and pyruvate, while very small changes were seen in arterial bloo

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1962.tb02504.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractBy local irradiation of the pigeon's brain with high energy protons, lesions were produced in the cerebral peduncles and the septal region at a level in front of the anterior commissure, without apparent damage to diencephalic structures. The behaviour of the animals following the procedure was observed. Spontaneous eating, drinking and flying, escape responses and all social behaviour disappeared during the first four days after irradiation, with a dose of 30 krad, in a group of pigeons in which all connections from the cerebral hemispheres were destroyed. On the contrary, swallowing, blinking and pupillary reflexes as well as the muscular and visual control of standing, walking and flying remained. In another group of pigeons with small, caudal parts of the peduncles intact, similar behaviour changes were observed, but no pattern of behaviour disappeared until after five days or more. In a third group of pigeons in which only more anterior parts of the peduncles were transsected no behavioural changes were observed. The experiments demonstrate that delayed, circumscribed destruction of cerebral structures by means of ionizing radiation may be used to particular advantage in the study of the anatomical foundation of animal behavior.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1962.tb02505.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractFor studies of the rate of change of alveolar gas composition in transitional states, a breath‐by‐breath end‐tidal gas sampler is proposed which combines great simplicity in design with a much reduced mixing of successive samples. The validity of the method is discussed and illustrated by breath‐by‐breath comparisons of end‐tidal and arterial Pco2, the latter being followed by continuous recording of the arterial pH. It is shown that, in or near the resting conditions, the two parameters closely follow each other, even when exhibiting rapid and great fluctuations, and that the Pco2of the samples approximates the functional mean al

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1962.tb02506.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY