bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adrenergic Mechanisms in the Pupillary Light‐Reflex Path
Authors: Dahlström Annica , Fuxe Kjell , Hillarp Nils‐Åke , Malmfors Torbjörn 
Published: December 2008

AbstractOn the basis of the known effects of reserpine on the eye, the presence of monoaminergic mechanisms in the light‐reflex path of the rat was studied with the use of a fluorescence method for the localization of catecholamines and 5‐hydroxytryptamine at the cellular level. The nucleus of Edinger‐Westphal — but not the large‐celled nuclei of the oculomotor complex — was found to receive abundant nerve fibres which show a massive accumulation of a primary cateholamine, in all probability nor‐adrenaline. There is little doubt that the nerves are adrenergic synaptic terminals. This adrenergic system is so richly developed that is must be assumed to play an important role in the regulation of the activity of the visceromotor outflow to the eye. Except this system and the adrenergic neurons recently discovered (Malmfon 1963) in the retina, no other monoaminergic mechanisms have so far been detected with certainty in the light‐reflex path. Abundant fibres of both the adrenergic and 5‐hydroxytryptaminergic type terminate in other parasympathetic (e. g. the dorsal motor nucleus of the vagus) and also sympathetic nuclei (c. g. the sympathetic lateral column of the spinal cord). 5‐hydroxytryptamine and noradrenaline in the central nervous system are thus not confined to action upon the parasympathetic and sympathetic systems respectively. — Current views on the central action of reserpine are discussed on the basis of the findings.
Dynamic Response of Chest Wall and Lung Injuries in Rabbits Exposed to Air Shock Waves of Short Duration
Authors: CLEMEDSON CARL‐JOHAN , JUNSSON ARNE 
Published: December 2008

AbstractThe movements of the chest walls of rabbits exposed to steep‐fronted air shock waves of short duration produced by 50 g spherical charges of TNT were recorded by means of a mechano‐electric motion transducer originally developed for this investigation. The main purpose has been to study the correlation between the deformations of the chest and the damage inflicted to the underlying organs, especially the lungs. The motion parameters, amplitude, velocity and acceleration of the chest wall, were correlated to the physical characteristics of the shock wave as well as to the lung injury produced. The lung injuries were found to be highly correlated to the impulse of the incident shock wave, and also, although to a lesser degree, to the maximum overpressure of the shock wave, and to the velocity and acceleration acquired by the chest wall. The correlation of the lung injuries to the maximum amplitude of the inward displacement of the chest wall, on the other hand, was found to be much lower or even uncertain. The following critical values of the motion parameters were established. If the chest wall receives an impulse load of such a strength and duration that an inward relative movement results with a velocity of more than 15 m se& attained within a period of time of 150–200 ps, i. e. involving accelerations of the order of 104 g, there is a high probability that a severe lung injury will result. Corresponding maxi mum amplitudes of the displacement of the chest wall were 5 to 7 mm. The lower limit of effective reflection pressures and impulses causing severe lung injuries were 10 bar and 1.5 gf sec cm‐2, respectively. The biomechanical events occurring in the exposed chest are discussed in some detail.
Spermidine and Spermine in Rat Tissues at Different Ages
Authors: Jänne J. , Raina A. , Siimes M. 
Published: December 2008

AbstractConcentrations of spermidine and spermine in fifteen different tissues of male and female rats aged three months were determined, using amido black as the quantitative reagent, after paper electrophoretic separation of the amines. The changes in the concentrations of these polyamines in relation to age were followed by determinations from six tissues of newborn rats and of male rats aged 1, 3 and 9 months. At the age of three months the largest amounts of the polyamines were found in the liver and the thymus, 900 to 1600 mμmoles of spermidine and 700 to 900 mμmoles of spermine per g wet weight. No great sex differences were observed. In most tissues the molar concentration of spermidine was higher than that of spermine. The spermidine content in every tissue studied decreased with increasing age, the fall being most marked during the first month of life. The spermine content as a rule increased somewhat during the first month and then remained nearly constant or decreased slightly. Consequently, the molar ratio spermidine/spermine was highest immediately after birth, decreasing in the liver, for instance, from 4.52 to 0.84 during 9 months. In the brain, in contrast to the other tissues investigated, it increased from 1.31 to 2.08 during the first 9 months.
On the Silent Period and Golgi Tendon Organs of the Soleus Muscle of the Cat
Authors: Jansen J. K. S. , Rudjord T. 
Published: December 2008

AbstractThe silent period in the soleus during twitch contractions has been studied in intercollicularly decerebrated cats. The duration of the silent period was independent of the initial tension in the muscle and remained constant in spite of large variations in the twitch tension with springs of varying compliances inserted in series with the muscle. The responses of 42 tendon organs of the soleus to twitch contractions, passive stretch and fused tetanic contractions have been determined in Nembutal anaesthetized cats. The majority of the tendon organs had appreciably lower thresholds to active contraction than to passive stretch of the muscle. They were all excited by isometric twitches developing less than 160 g tension. There was an approximately linear relationship between the discharge frequency of the tendon organs and the tension in the muscle during isometric, graded, fused tetanic contractions of the muscle. The slope of this relationship varied between 2 and 18 imp/sec/100 g. It is concluded that the duration of the silent period in the decerebrate cat is primarily determined by the pause in the discharge of the primary endings of the muscle spindle during the twitch.
The Disappearance of Acetic Acid and Acetate from the Cat's Stomach and its Influence on the Permeability for Hydrochloric Acid
Authors: Flemström G. , Frenning B. , ÖBrink K. J. 
Published: December 2008

AbstractExperiments were performed on anæstethized cats to study the diffusion of acetic acid out of a nonsecreting stomach and its effect on the gastric permeability for hydrochloric acid. Acetic acid diffuses more rapidly than hydrochloric acid out of the stomach. The diffusion of hydrochloric acid is increased by an instillationofacetic acid. The acidityofthe instilled hydrochloric acid decreases more rapidly and reaches lower end‐values. There is also a larger initial dip in chloride concentration. A mixture of sodium acetate and hydrochloric acid was found to have a similar effect on the permeability for hydrochloric acid.
Accommodation in Myelinated Nerve Fibres of Xenopus Laevis as Computed on the Basis of Voltage Clamp Data
Authors: Frankenhaeuser B. , Vallbo Å. B. 
Published: December 2008

AbstractThe equation system earlier derived from the voltage clamp analysis on myelinated nerve fibres from Xeonpus laevis was programmed for a digital computer. The response of the nerve model to linearly rising currents was computed for a number of quantitative modifications of the nerve model. The agreement between the computations and the earlier experimental results was qualitatively satisfactory. The quantitative agreement was not perfect but the discrepancies were not greater than what is expected from the known errors in the voltage clamp technique. The computations indicated that changes of any of the constants of the nerve model have effects on the rate of accommodation. The greatest effects were obtained by changing the inactivation of the sodium permeability. It was concluded, on the basis of the results obtained in the present and in the earlier investigation, that the slow excitability changes of the nerve fibres are well predicted by the equation system describing the ionic currents. Further, it was concluded that the normal variation in accommodation among myelinated nerve fibres from Xenopus laevis is accounted for mainly by variations in the rate constants ah although this may not be the only variable of importance. A variation in the turning on of the potassium permeability might also be significant.
The Utilization of a Presumably Low‐Cariogenic Carbohydrate Derivative
Authors: Dahlqvist Arne , Telenius Ulf 
Published: December 2008

AbstractThe digestion and absorption of a presumably low‐cariogenic carbohydrate derivative, a hydrogenated partial hydrolyzate of starch, has been studied. This contains free sorbitol, plus disaccharides, oligosaccharides and dextrins in which the glucose molecule which had a free aldehyde group prior to hydrogenation has been reduced to sorbitol. The dextrins present are rapidly hydrolyzed by α‐amylase under the formation of di‐and oligosaccharides. Those disaccharides which are composed only of glucose, are completely hydrolyzed by the intestinal disaccharidases and rapidly utilized in the body. The disaccharides containing one molecule of glucose and one of sorbitol, either initially present as disaccharide or formed on the enzymatic cleavage of the dextrins and oligosaccharides, are very slowly hydrolyzed. The glucose bound in this way largely escapes absorption. The sorbitol, whether free or bound, is very slowly absorbed.
Enzyme Activities in Various Organs of Hypophysectomized Rats and Rabbits
Authors: Jacobsohn Dora , Larsson S. , Norgren A. 
Published: December 2008

AbstractThe activities of nine different enzymes (glucose‐6‐phosphatase, combined activities of glucose‐6‐phosphate dehydrogenase and 6‐phosphogluconate dehydrogenase, phosphohexose isomerase, aldolase, iso‐citric dehydrogenase, lactic dehydrogenase, glutamic‐oxalacetic transaminase, glutamic‐pyruvic transaminase and glutamic acid dehydrogenase) were measured in liver, skeletal muscle, cerebral cortex, hypothalamus, adrenal cortex and thyroid gland of hypophysectomized rats and rabbits. The water and fat contents were determined in liver and muscle. DNA and protein were measured in all tissues. After hypophysectomy the activities of the Embden‐Meyerhof enzymes were unaffected when the values were expressed per unit wet weight or per unit protein. When calculated on unit DNA the activities of almost all enzymes were in most tissues significantly decreased after hypophysectomy. This finding is due to the fact that except for cerebral cortex and hypothalamus in rabbits the DNA content of all tissues studied is significantly increased after hypophysectomy. The observed changes in enzyme activities and DNA content in the tissues are discussed in relation to hormonal and dietary influences on enzyme activities.
The Pattern of Muscular Activity During the Arm Swing of Natural Walking
Authors: Ballesteros Maria L. Fernandez , Buchthal Fritz , Rosenfalck Poul 
Published: December 2008

AbstractA telemetering device is described to record action potentials from muscles of the upper arm and the shoulder during the arm swing of natural walking. The forward swing is caused by activity in some inward rotators, the flexors remaining inactive. The posterior part of the deltoid and some outward rotators are responsible for the backward swing. During walk‐turning electrical activity occurred in flexors inactive during straight walking accounting for the increased excursion of the forward swing which counteracts the torsional movement of the trunk. Step‐related muscular activity persisted even when the arm was prevented from swinging.
Decrease in Cardiac Activity by Carotid Sinus Baroceptor Reflex
Authors: Lindgren Percy , Manning John 
Published: December 2008

AbstractElectrical stimulation of the sinus nerve or excitation of the carotid baroceptors by increasing the intrasinus pressure significantly decreased the right ventricular contractile force, heart rate, and blood pressure in 19 anesthetized cats. The decreases in force and rate, but not blood pressure, were abolished by stellate ganglionectomy and by 3–6 mg/kg of dichloroisoproterenol (DCI). The decreases in cardiac contractility and rate were not secondary to the hypotension for they were still obtained when aortic pressure was kept constant. The reductions in contractile force and heart rate are the results of an inhibition of sympathetic control of the heart activity. The data indicates that 40 per cent of contractile force measured in the anesthetixed vagotomized preparation is dependent upon tonic sympathetic impulses. In experiments in which the stellate ganglia were decentralized, the force and rate were increased to predenervation levels by stimulating the isolated right stellate ganglion at a frequency of 1/sec. Seventy‐five per cent of the maximum response in force and rate were obtained at stimulus frequencies of 3/sec. The sinus baroceptor reflex exercises its major effects on the heart and blood vessels within a relatively limited range of 40 mm Hg on either side of normal blood pressure for the cat.
Uptake of Catecholamines by the Hearts of Rabbits Treated with Segontin
Authors: Mackenna B. R. 
Published: December 2008

AbstractA single i.v. injection of 8 mg/kg of Segontin caused a fall in the NA content of rabbit hearts to less than 10 per cent of their normal value in about 2 hrs. After 4 hrs the tissue content of NA started to rise again and after 24 hrs it had recovered to about one third of its normal value. An i.m. injection of 0.75 mg/kg NA 2 hrs after Segontin treatment, caused a temporary rise in the NA content of the heart to the normal value. NA was increased in the coarse particle fraction, the high speed sediment and in the particle free supernatant fraction of the heart after homogenization, indicating that the exogenous NA is temporarily filling the available storage sites. An i.v. infusion of NA (10 μg/kg/min for 20 min) caused an uptake of NA into the heart previously depleted by Segontin, followed by a rapid and then slower release of the NA. The uptake of 1‐NA and d‐NA and also of 1‐A and d‐A showed stereochemical specificity in favour of the 1‐isomers. Phenoxybenzamine blocked the uptake of NA into the heart of rabbits depleted by Segontin, whereas DCI had only a small blocking effect. Phenoxybenzamine by itself reduced the NA content of all fractions of the heart.
The Potassium Ion as a Vasodilator during Muscular Exercise
Authors: Kjellmer Ingemar 
Published: December 2008

AbstractCalf muscles of cats were perfused with blood at constant flow rates. Tissue volume, blood flow, arterial and venous pressures were measured. Exercise was imitated by intermittent contractions of the muscles. During contractions the potassium concentration of the venous plasma from the calf increased by up to 100 per cent. Potassium salts infused intra‐arterially at low rates dilated the vessels. It was calculated that the potassium released during exercise directly explains 25 to 65 per cent of the dilatation during exercise, the percentage being smallest when dilatation was slightest. There is presumably a diffusion gradient for potassium between tissue and blood with consequent underestimation of the role of the potassium ions, particularly when the dilatations are only weak. Therefore, 65 per cent probably comes closest to the true value of the proportion of the dilatation due to the potassium ions.Potassium infusions produced the same vascular response as exercise: a decrease of flow resistance was accompanied by a proportionate increase of the capillary filtration coefficient without signs of any increase in capillary permeability or dilatation of the capacitance vessels. Potassium is the only dilative substance hitherto found to produce exactly the same response as exercise.
In Vitro Glucose Metabolism, in Different Tissues of Hypophysectomized Rabbits
Authors: Jacobsohn Dora , Larsson S. , Norgren A. 
Published: December 2008

AbstractThe effect of hypophysectomy on the fate of uniformly labelled14C glucose was studied in cerebral cortex, anterior and posterior hypothalamus, adrenal cortex and thyroid gland of rabbits. Determinations were also made of DNA content and oxygen consumption of the tissues. The findings after hypophysectomy were as follows: Oxygen uptake of all brain parts increased. The14COSproduction of the posterior hypothalamus was increased. Oxygen consumption and14CO2production decreased in adrenal cortex and thyroid gland. The formation of free14C alanine in the cerebral cortex decreased. The formation of14C aspartic acid in the posterior hypothalamus increased. In the adrenal cortex and thyroid gland a decreased conversion of14C glucose into all metabolites studied was found. The rate of formation of radioactive protein bound amino acids in the brain parts remained unchanged. In the proteins of adrenal cortex and thyroid gland hardly any radioactivity could be detected. The changes appeared to be closely correlated with the activities in various enzyme systems observed previously.
A Comparison of Neural and Psychophysical Responses to Taste Stimuli in Man
Authors: DIAMANT HERMAN , OAKLEY BRUCE , STRÖM LENNART , WELLS CAROLYN , ZOTTERMAN YNGVE 
Published: December 2008

AbstractDiamant, H. B. Oakley, L. Ström, C. Wells and Y. Zotterman. A comparison of neural and psychophysical responses to taste stimuli in man. Acta physiol. scand. 1965 64. 67–74. – Electrophysiological records of taste activity have been obtained from the chorda tympani nerve of otosclerotic patients. When possible, preoperative psychophysical responses to taste stimuli were also obtained. The summated chorda tympani discharge to 0.2 M NaCl adapts completely and the time required agrees with psychophysical reports. Psychophysical estimates of the sweetness of different sugars correspond closely with nerve response magnitudes. Gymnema extract abolishes both the sweet sensation and the nerve response to sweet tasting chemicals. The total sum of taste activity in the entire chorda tympani nerve appears to be an important determinant of the psychophysical responses. There are large individual differences in the relative size of the neural response to different taste stimuli. Responses to ethyl alcohol are described.
The Urinary Excretion and the Tissue Uptake of Noradrenaline after Severe Tissue Depletion of Noradrenaline by α‐Methyl‐Meta‐Tyrosine and Metaraminol
Authors: ANDÉN NILS‐ERIK 
Published: December 2008

AbstractAndén, N. ‐E. The urinary excretion and the tissue uptake of noradrenaline after severe tissue depletion of noradrenaline by α‐methyl‐meta‐tyrosine and metaraminol. Acta physiol. scand. 1965. 64. 136–143. Four to eleven hours after an i. v. injection of metaraminol (0.2 mg/kg) to rats pretreated with α‐methyl‐m‐tyrosine (400 mg/kg intraperitoneally on each of the two preceding days) there was a severe reduction of the noradrenaline levels in the sympathetically innervated organs but no significant change in urinary noradrenaline excretion. This finding may indicate that the release of noradrenaline from the sympathetic nerves is unaffected in spite of severe transmitter depletion. The uptake of tritiated noradrenaline from the blood by the sympathetically innervated organs was about 40 per cent of normal after this treatment. Metaraminol (and its precursor α‐methyl‐m‐tyrosine) is almost as efficient as reserpine in causing depletion of the adrenergic transmitter but this effect appears to be due to simple displacement rather than interference with transmitter storage and release.
The Luminal Occlusion Time of Proximal Tubules in Kidneys of Young Rats
Authors: LEYSSAC PAUL P. 
Published: December 2008

AbstractLeyssac, P. P. The luminal occlusion time of proximal tubules in kidneys of young rats. Acta physiol. scand. 1965. 64. 176–181. – The purpose of this investigation was to test the validity of the luminal occlusion time as a method for estimation of the rate of proximal reabsorption. The occlusion time denotes the time required from interruption of the renal circulation until the proximal tubules have completed reabsorption of the luminal fluid. The results demonstrate that the close correspondance between the rate of reabsorption as evaluated from the occlusion time and the immediately preceding clearance of inulin holds also in experiments with young rats of a body weight of 100 g, in which the volume of luminal fluid per unit tubular length is far less than in kidneys of adult rats.
5‐Hydroxyindoleacetic Acid of Rabbit Spinal Cord Normally and after Transection
Authors: ANDÉN NILS‐ERIK , MAGNUSSON TOR , ROOS BJÖRN‐ERIK , WERDINIUS BENGT 
Published: December 2008

AbstractAndén, N. ‐E., T. Magnusson, B. ‐E. Roos and B. Werdinius. 5‐Hydroxyindoleacetic acid of rabbit spinal cord normally and after transection. Acta physiol. scand. 1965. 64. 193–196. – The normal spinal cord of rabbits was found to contain 0.20 μg/g 5‐hydroxyindolcacetic acid in the part cranially to Th4–Th6. Caudally the concentration was 71 per cent of that cranially. After transection at this level there was no significant change in the cranial part, when analyzed as a whole. Caudally to the lesion the 5‐hydroxyindoleacetic acid showed a substantial drop during the first 2 days and thereafter a gradual fall. It had disappeared almost completely after 10 days. The 5‐hydroxytryptamine, determined in the same rabbits, was unchanged after 2 days, was considerably reduced after 5 days, and had almost completely disappeared after 10 days. It is concluded that the level of 5‐hydroxyindoleacetic acid better than that of 5‐hydroxytryptamine mirrors the metabolic rate of 5‐hydroxytryptamine.
Direct Studies on the Disappearance of the Transmitter and Changes in the Uptake‐Storage Mechanisms of Degenerating Adrenergic Nerves
Authors: MALMFORS TORBJÖRN , SACHS CHARLOTTE 
Published: December 2008

AbstractMalmfors, T. and Ch. Sachs.Direct studies on the disappearance of the transmitter and changes in the uptake‐storage mechanisms of degenerating adrenergic nerves. Acta physiol. scand. 1965.64. 211–223. – The histochemical fluorescence method of Falck and Hillarp has been applied to a study of the disappearance of the endogenous noradrenaline (NA) and the uptake‐storage mechanisms of the adrenergic nerves in the rat iris during the course of degeneration following axotomy. It was found that the transmitter stored in the terminals does not disappear gradually but quite suddenly and with various times of onset for the different systems of terminals. The uptake and accumulation of NA and α‐methyl‐NA were examined in untreated and reserpinized animals. These experiments show that the uptake‐storage mechanisms in any given system of terminals operate up to a certain time without any obvious changes, but then deteriorate rapidly, at about the same time as the transmitter stores disappear. The axon membrane reabsorption mechanism seems to be lost somewhat prior to the storage mechanism of the transmitter granules, at the same time as degenerative changes seem to occur in the axon membrane, making possible a passive leakage of NA. – The results add further weight to the view that the cocaine‐like component in the denervation supersensitivity is due to the loss of the uptake mechanisms. – Following the administration of bretylium the degenerative processes were delayed for about 8 hrs.