bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adrenergic Nerve Function, Noradrenaline Level and Noradrenaline Uptake in Gat Nictitating Membrane after Reserpine Treatment
Authors: Andén Nils‐Erik , Henning Matts 
Published: December 2008

AbstractAfter reserpine injection to cats (0.1 mg/kg subcutaneously) there was a severe impairment of the adrenergic transmission in the nictitating membranes with recovery after 48 to 72 hrs. The noradrenaline of the nictitating membrane was virtually completely lost at the time of the disturbed nerve function and showed no significant restoration at the time of functional recovery. The uptake of tritiated noradrenaline by the nictitating membranes was blocked by reserpine but was partially restored after 48 to 72 hrs, thus coinciding with functional recovery. It is suggested that an intact adrenergic transmission is dependent on the ability of the amine storage granules to incorporate noradrenaline in a small fraction immediately important for the function.
Effect of the Supply of Oxygen on the Tensile Strength of Healing Skin Wound and Granulation Tissue
Authors: Kulonen E. , Niinikoski J. , Penttinen R. 
Published: December 2008

AbstractExperimental granulomas were induced in rats with subcutaneously implanted viscose cellulose‐sponges. The rats were kept for 10 days in normobaric atmospheres containing 21, 35 or 70 °., (V/V) oxygen. After killing, the tensile strengths of the granulomas and skin wounds were measured. In granulomas the tensile strengths were: in 21 % O2 107.2±9.7 g (23 determinations), in 3.5 °., O2 190.2 ± 18.5 g (41), in 70 % O2 221.0±24.6 g (26) and in skin wounds 431.3±32.8 g (29). 534.0 ± 22.8 g (40) and 574.1 ±32.9 g (24), respectively. The analysis of variances confirmed that the variation between the groups is larger than within the groups (for the granulomas P<0.001 and for the skin wounds P<0.005).
The Effect of DOPA on the Spinal Cord 6. Half‐centre organization of interneurones transmitting effects from the flexor reflex afferents
Authors: Jankowska E. , Jukes M. G. M. , Lund S. , Lundberg A. 
Published: December 2008

AbstractIn unanaesthetized spinal cats a systematic microelectrode exploration has been made in the lumbosacral spinal cord in order to find interneurones that may transmit the late longlasting reflex effects that volleys in the FRA (flexor reflex afferents) evoke after an intravenous injection of DOPA. Interneurones that may transmit these late effects are found in the lateral part of Rexed's layer VII and three main types are identified: A) cells activated from the ipsilateral FRA and inhibited from the contralateral FRA, B) cells activated from the contralateral FRA and inhibited from the ipsilateral FRA, C) cells activated from both the ipsilateral and contralateral FRA. The receptive fields and other criteria employed suggest that type A and B transmit excitatory action to flexor and extensor motoneurones respectively, and type C depolatization to Ia afferent terminals. The functional organization of these pathways is discussed mainly in relation to the mechanisms responsible for the long latency and duration of the discharge.
Blood Flow, Oxygen Uptake and Lactate Production in the Forearm during Exercise Induced by Median Nerve Stimulation
Authors: Landin Sven , Wahren John 
Published: December 2008

AbstractA technique is described for percutaneous stimulation of the median nerve and the induction of a standardized involuntary forearm exercise. The electrically induced exercise is compared with voluntary forearm exercise in 14 healthy subjects at work intensities of 4, 6 and 8 kpm/ min. Blood flow, oxygen uptake and lactate production were found to be higher for electrically induced exercise than for voluntary, especially when the duration of the stimulus was increased from 0.1 sec to 0.3 sec. The increases in these parameters in relation to work intensity were steeper for electrically induced exercise than for voluntary. The differences are partly attributed to the exercise induced by electrical stimulation having a larger component of energy expenditure in static work from the activation of muscles that do not participate in finger flexion.
Studies of Blood‐pressure Regulation
Authors: ÖBerg P. Å. , Sjöstrand U. 
Published: December 2008

AbstractA method has been worked out by which one of the closed control circuits in the blood‐pressure‐regulating system in the dog can be reversibly interrupted for varying periods of time. Careful studies of the chemistry of the carotid‐sinus blood, using this method, as well as of other conditions described in the literature, make it probable that the chemoreceptor mechanism in the carotid‐sinus region and the C.N.S. remain unaffected in this connection. The method provides the pre‐requisite conditions for on‐line simulation of the regulatory properties of the carotid‐sinus reflex, as regards the baroreceptor function.
Effects of Increased Intracranial Pressure on Cerebral Blood Flow and on Cerebrospinal Fluid HCO3, pH, Lactate and Pyruvate in Dogs
Authors: Kjällouist Å. , Siesjö B. K. , Zwetnow N. 
Published: December 2008

AbstractThe cerebral perfusion pressure was reduced in dogs by infusing an artificial cerebrospinal fluid (CSF) into the cisterna magna, or by reducing the mean arterial pressure by means of arterial bleeding, and the effects of the reduced perfusion pressure on the CSF concentrations of lactate, pyruvate and bicarbonate were studied. Even relatively small reductions (25–40 mm Hg) of the cerebral perfusion pressure were found to be accompanied by an increased CSF lactate concentration and an increased lactate / pyruvate ratio, and by a decreased bicarbonate concentration, suggesting the appearance of a slight hypoxic lactacidosis in spite of a normal, or near‐normal flow in the autoregulation range. When the cerebral perfusion pressure was markedly, or repeatedly, reduced a longlasting and often very marked lactacidosis was seen in the CSF. With a moderate lactacidosis in the CSF there was a good agreement between the increase in the lactate, and the decrease in the bicarbonate concentration, but with a marked and longlasting lactacidosis the decrease in the bicarbonate concentration could exceed the lactate accumulated. The possible coupling between the lactacidosis and the decrease in the cerebrovascular resistance is discussed.
The Acetylcholine Content and Cholinesterase Activity of the Bull Retractor Penis Muscle
Authors: Klinge Erik 
Published: December 2008

AbstractThe acetylcholine content of the bull retractor penis muscle, duodenum and urinary bladder was assayed By super fusion of the eserinized frog rectos muscle. The capacity of retractor homogenates to split acetyl‐β‐methylcholine, butyrylcholine and acetylcholine was estimated with the manometric technique. The acetylcholine content of the retractor was of the same order of magnitude as that of the duodenum, but it was twice as high as the amount found in the urinary bladder. A moderate activity of acetylcholinesterase and non‐specific cholin esterase was observed. The role of acetylcholine in the function of the efferent nerve fibres running in the bull retractor is discussed. So far as the classical definitions are applied it is regarded as unlikely that it serves as a neurohumoral transmitter substance either at ganglionic synapses or at neuro effector junctions. There is as yet no conclusive explanation for the mode of action of acetylcholine in these nerve fibres.
Catechol‐O‐Methyl Transferase and Monoamine Oxidase Activity in Some Tissues of the Bull
Authors: Klinge Erik 
Published: December 2008

AbstractThe catechol‐O‐methyl transferase activity in the retractor penis muscle, liver, and kidney of the bull was determined by measuring the amount of metanephrine formed from adrenaline when S‐adenosylmethionine was used as methyl donor. The monoamine oxidase activity in the same tissues was estimated By measuring the rate of disappearance of 5‐hydroxytryptamine added to the incubation mixture. There was a very low, if any, catechol‐O‐methyl transferase activity in the retractor muscle, a slight but distinct activity in the kidney, and a high one in the liver. The monoamine oxidase activity exhibited By the retractor muscle was moderate. In the liver the activity of this enzyme was high but it was still clearly exceeded by that in the kidney. The role of both enzymes in the function of the retractor muscle is briefly discussed.
Transient Dynamics of Ventilation and Heart Rate with Step Changes in Work Load from Different Load Levels
Authors: Broman Svetlana , Wigertz O. 
Published: December 2008

AbstractBroman, Svetlana and O. Wigertz, Transient dynamics of ventilation and heart rate with step changes in work load from different load levels. Acta physiol. scand. 1971. 81. 54–74.Transient dynamics of ventilation (V̇) and heart rate (HR) in response to 650 kpm/min step changes in work load were analyzed in six male athletes performing submaximal cycling exercise in the supine position, with the steps initiated at different levels of stable‐state exercise, including “loadless” pedaling (0 kpm/min). By applying mathematical parameter identification, the responses of V̇ to both positive and negative step changes in work load could be accurately described by first‐order exponential models. With the positive steps initiated at 0, 300, and 650 kpm/min, the means of the time constant estimates for V̇ ranged from 67 to 101 sec, and seemed to be independent of the initial work level. Shifting from rest to pedaling at zero load and back to rest caused abrupt changes in V̇, whereas this was rarely the case after step changes from one work load to another with the subjects already pedaling. The responses of HR required second‐order models, with the two time constants ranging from 9.0 to 11.7 sec and from 1.8 to 3.7 min, and with the share of the slower component increasing with the initial work level. Pure time delays were negligible, indicating that the early readjustments in both V and HR are under neurogenic influence. The results support the notion that in exercise the respiratory and circulatory control systems exhibit dissociated dynamic properties.
Intracellular Distribution of Phospholipases in the Rat Pancreas
Authors: Arnesjö Bo 
Published: December 2008

AbstractThe intracellular distribution of free and potential phospholipases (EC 3.1.1.4) has been studied using isopycnic gradient centrifugation 06 rat pancreatic homogenates. 30 % of the free phopsholipase A2 activity was found in the zymogen granules while only 15 % of the total phospholipase A activity was present there. Tryptic digestion increased the phospholipase A activity 20 fold‐an increase only in phospholipase A2 activity. The zymogen granules accounted for 30 % of the prophospholipase and revealed a specific activity (activity per mg protein) 3 to 5 times higher than those of the other cell components. The intracellular distribution of prophospholipase is similar to lipase.
Characterization of Neuronal and Glial Fractions Separated in Sucrose and Ficoll Media
Authors: Hemminki K. , Holmila E. 
Published: December 2008

AbstractRat brain cerebral cortices were dispersed by a collagenase‐hyaluronidase treatment and the suspensions obtained were fractionated in sucrose and Ficoll systems by centrifugation. For sucrose a short sedimentation run was followed by a density gradient; for Ficoll only a density gradient was used. Isolated cell populations were examined by light microscopy and differential cell counts were taken. Separation in sucrose yielded more homogenous but smaller fractions. In Ficoll up to 37 million neuronal and glial cells could be collected from 5 cortices. Cells isolated in sucrose and Ficoll contained 70 and some 50 pg protein, respectively.Neuronal and glial cells separated in sucrose and Ficoll systems accumulated potassium, and were metabolically active. Both respiration and incorporation of radioactive leucine into protein were clearly more active in neuronal fractions. In Krebs‐Ringer phosphate buffer containing 10 mM glucose, neurons respired 946 and 875, and glia 706 and 396 nmoles oxygen/mg protlhr after sucrose and Ficoll separation respectively. Incorporation of radioactive leucine into protein was 5370 and 4980 dpm/mg prot for neurons, and 3110 and 4480 dpm/mg prot for glia. On the other hand, no clear difference was found in TCA‐soluble radioactivities be tween neuronal and glial fractions.
Lipids of the Sympathetic Nerve Trunk Vesicles. Comparison with Adrenomedullary Vesicles
Authors: Lagercrantz Hugo 
Published: December 2008

AbstractThe phospholipid and cholesterol contents of isolated nerve trunk vesicles were analyzed in a preparation obtained from bovine splenic nerves, made up to about 40 % of noradrenaline storage particles. The cholesterol/phosholipid ratio and the relative phospholipid composition of this preparation were about the same as in adrenal medullary vesicle preparations. How ever, lysolecithin, which is a characteristic constituent of the chrornaffin cell vesicles, was found only in trace amounts in the nerve vesicle preparation. The results support earlier findings of biochemical similarities between the water insoluble phase of the two types of amine storage vesicles.
Diameter and Elasticity of the Ascending Aorta during Infusion of Noradrenaline
Authors: Aars H. 
Published: December 2008

AbstractThe effect of smooth muscle contraction on diameter and elasticity of the ascending aorta was examined in 18 anesthetized rabbits. Aortic diameter was measured with ultrasonic technique inside the intact thorax, and blood pressure was recorded from a catheter in the right common carotid artery. Control observations were obtained at various blood pressure levels by producing stepwise changes of the blood volume. At diastolic pressures from 40–90 mm Hg, i.v. infusion of noradrenaline (4–6 μg/kg · min) caused a 6.6% average reduction in diastolic aortic diameter. Noradrenaline at low pressures increased the aortic pressure‐strain elastic modulus (Ep) and theoretical pulse‐wave velocity (PWV) by 30–67%. Control values of Ep and PWV were slightly higher for rabbits than those usually found in dogs. It is concluded that at comparable pressures, contraction of aortic smooth muscle tissue, induced by infusion of noradrenaline, produces a small but significant constriction of the ascending aorta, and, at low pressures only, increases dynamic stiffness of the vessel.
Increased Nerve Stimulation Induced Release of Noradrenaline from the Rabbit Heart after Inhibition of Prostaglandin Synthesis
Authors: Samuelsson Bengt , Wennmalm ÅKe 
Published: December 2008

AbstractThe effect of inhibition of prostaglandin synthesis on the release of noradrenaline induced by sympathetic nerve stimulation was studied in the isolated perfused rabbit heart. It was found that 5,8,11,14‐eicosatetraynoic acid, a compound known to block prostaglandin synthesis in vitro, decreased the outflow of prostaglandins normally induced by nerve stimulation. Simultaneously the outflow of noradrenaline in response to nerve stimulation increased. Since the acetylenic acid did not affect the uptake of exogenous noradrenaline, the increased outflow probably reflects an augmented release of transmitter from the neurons. It has earlier been shown that exogenous prostaglandins inhibit the release of noradrenaline from adrenergic neurons, and that endogenous prostaglandin‐like substances are released in response to sympathetic nerve stimulation in amounts sufficient to exert this inhibitory action. Thus a prosta‐glandin‐mediated negative feed‐back control of the release of adrenergic transmitter is known to be feasible. The present observation that inhibition of prostaglandin synthesis enhances the release of noradrenaline, provides the first conclusive evidence for the occurrence of such an endogenous control mechanism.
The Influence of Physical Training and Other Factors on the Subjective Rating of Perceived Exertion
Authors: Ekblom Björn , Golobarg Alberto N. 
Published: December 2008

AbstractThe relationship between the subjective rating of perceived exertion (RPE) and different physiological variables during work were investigated in 19 healthy subjects under the following conditions: 1) after heart rate (HR) has been experimentally changed during work by the use of autonomic nervous system blocking agents. 2) during different types of physical work and 3) before and after an 8 week period of physical training, respectively. In most work situations, HR mirrors the physical strain subjectively experienced. However, this good correlation between HR and RPE was altered during the experiments with blocking agents. Therefore, a tachycardia as such is not the primary factor in the setting of HR during exercise — RPE was higher for a given level of oxygen uptake during arm work than during leg work, as well as during bicycling compared to running or swimming. A better correlation was found in these experiments between RPE and blood lactate concentration. After training, and in parallel to the decrease in HR at submaximal work loads, RPE was lower for a given level of oxygen uptake, but was the same when related to the “relative” (per cent of maximum) oxygen uptake.
General Characteristics of Sympathetic Activity in Human Muscle Nerves
Authors: Delius W. , Hagbarth K.‐E , Hongell A. , Wallin B. G. 
Published: December 2008

AbstractMultiunit sympathetic activity was recorded from muscle nerve fascicles in the median or peroneal nerve of resting, relaxed human subjects. The impulses, which were reversibly abolished by a Sympathetic ganglion blocking agent, were grouped in the pulse rhythm, and series of such pulse rhythmic bursts of impulses regularly appeared during spontaneously occurring blood pressure reductions, whereas temporary blood pressure elevations were associated with neural silence. The findings agree with the notion that the sympathetic muscle nerve activity recorded consists of vasoconstrictor impulses, the outflow of which is modulated by a strong phasic and tonic inhibitory baroreflex influence. The reflex delay from an arterial pulse wave to the corresponding inhibition of efferent sympathetic activity was 0.9–1.4 seconds, depending on the recording site. Several stimuli, such as sudden chest compression, a rapid deep breath or an electrical shock against the skin, caused a transient inhibition of the sympathetic discharges lasting a few seconds.
Uptake of Atropine and Methylatropine by Immature Choroid Plexus in vitro*
Authors: Winbladh B. 
Published: December 2008

AbstractChoroid plexa from newborn rabbits accumulate atropine and methylatropine in vitro by a mechanism which fulfils the requirements for activie transport. Tissue medium ratios at a fixed concentration increase from 3 days before term until 2 weeks of age, when adult levels are reached. Uptake maximal velocity per unit tissue wet weight (Vmax) increases with age, while apparent Km remains constant. The conclusion is drawn that the same carrier mechanism is involved in the newborn and adult tissues. The change in Vmax is discussed in relation to developmental changes in tissue composition and morphology. Further, possible in vivo significance of the in vitro findings is discussed.
Measurement of Blood Flow in Adipose Tissue from the Washout of Xenon‐133 after Atraumatic Labelling
Authors: Nielsen S. Levin 
Published: December 2008

AbstractThe experiments were performed on isolated, autoperfused subcutaneous tissue in urethane‐anesthetized female rabbits. Directly recorded blood from adipose tissue averaged 6.6 ml/100 g‐min (S. D. 4.2, 11 expts.). The blood flow calculated from the washout of Xenon‐133 with an average partition coefficient on 11.8 (ml/g) was 7.4 ml/100 g‐min (S. D. 5.3, 11 expts.). A direct proportionality was found between blood flow in adipose tissue calculated from the washout of Xenon‐133 and directly recorded blood flow. The coefficient of correlation was 0.995 (p < 0.001). When blood flow was constant during the experiments, the washout curves were monoexponential. In the preparation used, the adipose tissue appears to have homogeneous distribution of blood flow and it is likely that diffusion equilibrium of the highly diffusible, inert gases exists between adipose tissue and blood during the washout. The discussion contains a survey of the recently found values of blood flow in adipose tissue obtained with different techniques.
Chloride Transport across Isolated Frog Skin
Authors: Kristensen Poul 
Published: December 2008

AbstractKristensen, P. Chloride transport across isolated frog skin. Acta physiol. scand. 1972. 84. 338–346.A net inward transport of chloride was found to occur in isolated skins of Rana temporia. This transport was not dependent on sodium transport and was inhibited by diamox, thio‐cyanate and bromide. The active chloride transport was not affected by changes in the transepithelial potential difference. On the other hand, the curve describing efflux as a function of potential difference was found to have a shape resembling the shape of the Goldman equation.Graphical determination of apparent pools showed the influx pool to be about six times greater than the efflux pool. Diamox had no effect on efflux pool size but reduces the apparent influx pool so that it becomes about equal to the efflux pool. This means that at least part of the paths for active and passive chloride movements are different.A working hypothesis is put forward, according to which chloride is actively transported across the outward facing membrane of the outermost living cell layer of the frog skin epithelium, and the main part of the passive flux occurs across the tight seals and via the interspace system.
Excitability of the Acoustic m. Stapedius and m. Tensor Tympani Reflexes in the Nonanesthetized Rabbit
Authors: Borg Erik 
Published: December 2008

AbstractMiddle ear muscle responses to tone bursts (0.5 to 12.0 kHz) were studied in nonanesthetized, unrestrained rabbits. The combined (total reflex) and the separate activity of the two muscles were recorded as changes of acoustic impedance in both ears simultaneously. The mean threshold of the ipsilateral total reflex, defined as the stimulus intensity eliciting 10 % of maximal response, was 98 dB SPL at 0.5 kHz and fell 12 dB/octave up to 2.0 kHz. Above 4.0 kHz it was about 70 dB SPL. The m. stapedius reflex was not found to differ from the total reflex, whereas the threshold of the m. tensor sympani reflex was about 10 dB higher at all frequencies. The crossed reflexes were significantly less sensitive than the ipsilateral reflexes. The stimulus‐response curves of the m. tensor tympani were less steep than those of the m. stapedius and reached their maxima at a higher sound level. The time course of the responses was interpreted to show nonlinear properties of the reflex system. The sensitivty to acoustic stimulation in the rabbit was found to be significantly higher than in man. The relationship between the activities of the two muscles as well as differences between species are discussed.
Muscle Metabolites with Exhaustive Static Exercise of Different Duration
Authors: Karlsson Jan , Ollander Bo 
Published: December 2008

AbstractConcentrations of ATP, CP, glycogen and lactate were determined in the lateral portions of the thigh at rest and at different percents (75, 50, 25 and 10 %) of the individual maximal voluntary isometric contraction (MVC). Endurance times were 0.5, 1.6, 5.8 and 38.7 min respectively. A phosphagen depletion of 15 mmol x kg‐1 wet muscle and a lactate accumulation of 20 mmol x kg‐1 was obtained only with the 50 % MVC which is similar to what is observed with short time exhaustive bicycle exercise. At both higher and lower intensities phosphagen depletion and lactate accumulation were less.