bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermoregulation during Work in Carbon Monoxide Poisoning
Authors: Nielsen Bodil 
Published: December 2008

AbstractA mild to moderate CO poisoning, blocking 25 to 33 % of the oxygen binding capacity of the blood, was used to produce a change in maximal oxygen intake (max VO2). Subjects working at the same work load (Vo2= 1.5 1/min) for 1 hour under normal conditions and during CO poisoning showed an increase in plateau level of deep body temperature (Te8) of 0.3–0.5° C. The plateau levels correlated with the relative loads (percentage of max Vo2) of the subjects but not with absolute work load and oxygen uptake. The CO‐poisoning may act 1) directly on the hypothalamic temperature center, the low tissue O2 tensions changing the activity of its neurons, 2) through the low venous O2 tensions on peripheral chemoreceptors in the working muscles or the venous side of the circulation, or 3) the changes in temperature may be a passive reaction to a shift in blood towards the periphery in the CO poisoned state.
The Effect of Deuterium on the Release and Uptake of Noradrenaline in Isolated Nerve Granules
Authors: Euler U. S. von , Lishajko F. 
Published: December 2008

AbstractThe release of noradrenaline (NA) from isolated bovine splenic granules in phosphate buffer is decreased by 10–25 per cent by addition of 50–90 % D2O to the medium. The ac companying uptake of 14C(‐)NA is unchanged in 50–70 % D2O and slgihtly decreased in 95 % D2O. After previous partial NA depletion of the granules the net uptake of NA in the presence of ATP‐Mg2+ is lowered by D2O in concentrations above 25 % in the medium and has fallen to 63 per cent of normal with 87.5 % D2O.
The Effect of Changes in the Blood Flow to the Tongue on the Chorda Tympani Response in Rat
Authors: Hellekant Göran 
Published: December 2008

AbstractThe summated chorda tympani response to taste stimuli was recorded in rats during repeated occlusion of the blood flow to the tongue. It was then observed that the response diminished and disappeared within a few minutes after bilateral or ipsilateral occlusion of the blood supply. Intravital staining through the lingual artery showed that each half of the tongue was chiefly supplied with blood from its ipsilateral lingual artery. A close relation between the simultaneous variation of the systemic blood pressure and the taste response was also observed and is discussed here.This study was supported by grants from Swedish Medical Research Council grant No B71–14X‐2467.04 and Svenska Maltdrycksforskningsinstitutet.
Studies on the Intestinal Vasodilatation Observed after Mechanical Stimulation of the Mucosa of the Gut
Authors: Lungren Björn Biber Ove , Svanvik Joar 
Published: December 2008

AbstractMechanical stimulation of the jejune mucosa of the cat induces a transient increase of total intestinal blood flow amounting to 30–140 per cent of control. The vasodilatation is at least partly localized to the intestinal villi. The observed blood flow augmentation cannot be abolished by autonomic denervation or blockade by atropine, α‐ or β‐blocking agents or by a cholinergic ganglionic blocking agent. However, the intestinal blood flow augmentation was completely abolished by tetrodotoxin, a nerve conductivity blocking agent, by lidocaine, a local anesthetic, and by 2‐bromo‐LSD, a 5‐hydroxytryptamine (5‐HT) receptor blocker. These results seem to suggest that the studied intestinal vasodilatation is evokedviaan intramural nervous reflex in some way dependent on the release of 5‐HT.‐The observation that bile administered into the intestinal lumen causes a prolonged intestinal vasodilatation is briefly discussed.
Dopa‐decarboxylase in Autonomic and Sensory Ganglia of the Cat
Authors: Giacobini Ezio , Noré Barbro 
Published: December 2008

AbstractAs far as dopadecarboxylase (DDC) activity is concerned sympathetic ganglia can be collected into 3 groups: celiac and superior mesenteric show the highest activity, superior cervical and stellate are intermediate, lumbar and sacral ganglia show the lowest activity. Ciliary and nodose ganglia show significantly lower DDC activity than sympathetic ganglia and spinal ganglia show no measurable activity. There is a good correlation between DDC activities, monoamineoxidase (MAO) activities and the catecholamine contents of autonomic ganglia. Preganglionic de‐nervation did not significantly change DDC, MAO or catechol‐O‐methyltransferase (COMT) activity of L.r ganglia. It is concluded that although MIAO and DDC are not exclusively as sociated with adrenergic neurons, a high level of DDC or MAO activity in the cell body is a specific attribute of adrenergic neurons.
Dynamics of Arterial Oxygen Tension in Response to Sinusoidal Work Load in Man
Authors: Bjurstdt Hilding , Wigertz Ove 
Published: December 2008

AbstractDynamic characteristics of the response of arterial O2 tension (Pao2) to supine submaximal leg exercise were studied in 7 physically active young men. Pao2 was recorded continuously in the radial artery at the wrist; work load was varied sinusoidally between the extremes of 250 and 1050 kpm/rnin with periods of 0.75, 1.5, 3.0, and 7.0 min. Time‐averaging harmonic analysis showed a clear dominance of the fundamental component over the second and third harmonics in the Pao2 response, indicating approximately linear properties of the underlying system within the work‐load region studied. The transfer function for PaO2, exhibiting the characteristics of a variable regulated within narrow limits in the steady‐state condition, indicated that the basic response of PaO2 to a change in work load is a transient change in the opposite direction preceded by a pure time delay. Resonance occurred for work‐load periods near 3.0 min (peak‐to‐peak deviations approaching 14 mm Hg). Referring Pao2 changes to blood entering the left heart, the estimated time delay before a change in work load resulted in a change in Pao2 amounted to 15 sec. The existence of a resonance is interpreted in terms of an unbalance between factors determining O2 uptake from, and supply to, the alveolar space.
Dynamics of Arterial Blood Pressure Responses to Sinusoidal Work Load in Man
Authors: Rosenhamer Gunnar , Wigertz Ove 
Published: December 2008

AbstractSystolic, diastolic, mean and pulse pressures in the radial artery, and heart rate in 7 physically active young men were subjected to frequency analysis by using sinusoidal work load as a forcing function. Subjects exercised in the supine position on a cycle ergometer. With the pedalling rate constant, the work load was varied sinusoidally over a range of drive frequencies between the two fixed extremes of 250 and 1050 kpm/min. Predicted step responses obtained by applying the trans fer functions estimated for radial systolic and pulse pressures showed close similarity to observed step responses, indicating linear properties of the underlying systems. Using known characteristics of the peripheral distortion of the pressure pulse, the responses of both the radial and central systolic and pulse pressures to work load could be described by second‐order transfer functions. Resonance occurred for periods near 7 min, indicating overshoots for both variables in the time domain. This behaviour suggests baroreflex inhibition as an explanation of an overdamped response of the heart rate. The changes in radial diastolic pressure were small and not clearly related to the drive frequency. The response of the radial mean pressure could not be described accurately by either first‐or second‐order functions, but exhibited phase lead features, suggesting sensitivity to rate of change in work load.
Synaptic Connections of the Paracervical (Frankenhauser) Ganglion of the Rat Uterus Examined with the Electron Microscope after Division of the Sympathetic and Sacral Parasympathetic Nerves
Authors: Mustonen T. , Teäväinen H. 
Published: December 2008

AbstractThe fine structure of the synapses in the paracervical (Frankenhauser) ganglion of the rat uterus was studied after sympathectomy and sacral parasympathectomy. Degenerative nerve endings to the ganglion cells were observed after division of both the sympathetic and parasympathetic nerves. No degeneration of the synapses to the chromaffin cells were seen. The results are interpreted as evidence of both sympathetic and parasympathetic innervation of the ganglion cells, which send their axons to the uterus, whereas the “chromaffin cells” are innervated by intraganglionic nerves.
Cyclic Variation of Body Temperature in Female Rabbits before and after Ovariectomy
Authors: Kihlström J. E. , Lundberg C. 
Published: December 2008

AbstractThe body temperature of 18 female rabbits was recorded once a day for about 3 months. Three of these rabbits demonstrated a statistically significant cyclic variation in temperature, the mean length of the cycles varying from 6 to 11 days.The observed cyclic variations persisted after ovariectomy with cyclicity appearing in two additional animals. In 6 out of 8 rabbits the mean body temperature decreased significantly upon removal of the ovaries.
Long‐Term Changes in the ERG Following Transection of the Optic Nerve in the Rabbit
Authors: Borg Erik , Knave Bengt 
Published: December 2008

AbstractThe changes in ERG were studied in the: rabbit for 22 months after transection of the optic nerve. Immediately after the transection a small amplitude increase was found. This increase was constant for the next 8 months. Twenty‐two months after the section, however, the amplitudes decreased. The initial increase is interpreted as a functional sign of the existence of Centrifugal activity in the optic nerve that decreases retinal excitability. The final decrease in the ERG amplitudes is interpreted as a sign of retrograde degeneration in the retina.
Endotoxin‐induced Suppression of Rabbit Kidney DOPA Decarboxylase Activity
Authors: Fritz Hans , Håkanson Rolf 
Published: December 2008

AbstractThe kinetic properties of the histamine‐forming enzyme in the cortex of the rabbit kidney were found to be identical with those of DOPA decarboxylase. There was no evidence of “specific” histidine decarboxylase in the rabbit kidney cortex. Following i.v. injection of endotoxin, reduced DOPA decarboxylase activities were demonstrated after 3 and 6 hrs; after 24 hrs low as well as conspicuously high enzyme activities were observed.
Catecholamines, Monoamine Oxidase and Cholinesterase Activity in the Human Sympathetic Ganglion
Authors: Härkönen Matti , Penttilä Antti 
Published: December 2008

AbstractCholinesterase (ChE) and monoaniine oxidase (MAO) activities were measured in 17 surgically removed human lumbar sympathetic ganglia. Four further ganglia were obtained from accidentally killed men, autopsied at the Department of Forensic Medicine. ChEs were determined by automatic titration using acetylcholine, propionylcholine and butyrylcholine as substrates and specific ChE inhibitors (iso‐OMPA and 284C51). Of the total ChE activity (61.4 × 10‐‐3μmol/mg protein/min) 85%was found to be due to acetylcholinesterase (AChE, 53.6 × 10‐‐3μmol/mg protein/min) when acetylcholine was used as substrate. Propionylcholine (38.1 × 10‐‐3μmol/mg protein/min) was also mainly hydrolyzed by AChE (75%) and butyrylcholine (14.5 × 10‐‐3μmol/mg protein/min) by non‐specific cholinesterase (ns. ChE, 71 %). Histochemically, all the nerve cells showed AChE activity, most of them being moderately positive. Ns. ChE was chiefly present in the satellite cells and only a few weakly reactive nerve cells could be seen. MAO activity was measured fluorometrically with kynur‐amine as substrate (0.57 × 10‐‐3μmol/mg protein/min). Histochemically, all the nerve cells showed strong activity. Catecholamine fluorescence was weak in most of the ganglion cells. There were no significant differences in ChE or MAO activity between the different disease groups.
The Effects of K+ ‐free Solution on Tension Development in the Smooth Muscle Taenia Coli from the Guinea Pig
Authors: Axelosson Jóhann , Holmberg Bo 
Published: December 2008

AbstractIn the smooth muscle taenia coli from guinea pig changes in the pattern of electrical and mechanical activity and their relationship occur in K+‐free solutions. The ability to develop tension falls parallel with changes in intracellular concentrations of K' and Na'. The changes in mechanical properties are probably not according to interference with metabolic energy supply or more direct effects on the contractile components or passive mechanial properties. An interference with the normal functions of Ca2+ in the excitation‐contraction coupling is suggested.
The Effects of Changes in the Ionic Environment on Venous Smooth Muscle Distribution of Sodium and Potassium
Authors: Wahlström Bo 
Published: December 2008

AbstractThe sodium, potassium, calcium and magnesium content in the portal vein of the rat was determined by atomic absorption spectrophotometry in different environmental conditions. It was found that minute changes in the ionic environment caused considerable variations in the Na+, K+ and Ca2+ content, and Na/K ratio. Phosphate in the solution increased the sodium and calcium content. In sodiumfree solution all muscle sodium was rapidly lost. No bound sodium was detected. The ionic content of portal vein was also dependent on dissection and blotting technique. A standard procedure and a standard solution was therefore chosen. In this solution the following values were obtained: Na+: 88, K+: 52, Ca2+: 5.7 and Mg2+: 3.7 mmolelkg freshweight respectively.The extracellular space, determined with 14C‐sorbitol was 490 ml/kg freshweight. The calculated intracellular concentrations and equilibrium potentials for Na+ and K+ were 62 and 157 mM and +21 and ‐86 mV respectively. The uptake of 42K showed that about 20 % of the total muscle potassium did not exchange within 5 hrs. The efflux of 42K+ showed that for the linear exchange of muscle potassium the rate constant was 0.85–0.90/hr.K‐low solution decreased the efflux of 42K+ in spite of increased electrical activity. This suggests that the permeabilty to potassium is lowered. Noradrenaline had no effect on the 42K efflux in normal solution.
Aspects of the Cardiovascular Nervous Control in a Mammalian Diver (Myocastor Coypus)
Authors: Folkow B. , Lisander B. , ÖBerg B. 
Published: December 2008

AbstractExperiments were performed to analyse to what extent diving mammals, represented by the coypu (nutria), exhibit similar characteristics with regard to cardiovascular nervous control as earlier found in diving birds such as the duck. As in this latter species, submersion of the un‐anesthetized coypu led to a profound and prompt bradycardia and reduction of cardiac output at a largely unchanged arterial pressure. ‐ Graded stimulations of the vasoconstrictor fibres to skeletal muscle, kidney and intestine in anesthetized animals produced far stronger responses at given stimulation rates than in non‐diving mammals (cats), and virtual flow obstruction could be achieved by rates as low as 6 imp/sec. The coypu thus possesses a vascular neuro effect or system, so organized as to shut off almost completely the blood supply to the mentioned tissues during a dive and hence distribute available oxygen reserves by means of a greatly reduced cardiac output preferentially to the brain and myocardium. Further, the vagal nerves exert on the heart ventricles a negative inotropic effect besides the profound negative chronotropic effect, helping to keep cardiac output very low during submersion. ‐ The cardiovascular nervous control in the coypu is therefore in important respects more related to that in diving birds than to that in non‐diving mammals, which probably is a prerequisite for the endurance of prolonged submersion.
Red Blood Cell and Plasma Volumes, Total Body Water and Sulfate Space in Obese‐Hyperglycemic Mice and Lean Litter Mates
Authors: Bill Anders , Herbai Georg , Westman‐Naeser Sighild 
Published: December 2008

AbstractA comparative study was performed on different body compartments of mice with the hereditary obese‐hyperglycemic syndrome and their lean litter mates. In 5–months‐old obese mice the body weight was increased by 79 %, the red cell volume by 70 % and the plasma volume by 50 % as compared to lean controls. The blood volume per unit b. w. was probably lower and the orbital vein and body hematocrits were probably higher in the obese animals than in the non‐obese litter mates. The sulfate space of adult obese mice exceeded that of the controls by 27 %. The total amount of water in obese mice was not significantly different from that in lean mice. The erythrocyte: plasma sulfate ratio was approximately 0.3.
Efflux of Slow Reacting Substance (SRS) and Prostaglandins from Cat Paws Perfused with d‐Tubocurarine and n‐Octylamine
Authors: Strandberg Kjell 
Published: December 2008

AbstractRelease of histamine and formation of lipid‐soluble smooth muscle stimulating principles oc curred when cat paws were perfused with d‐tubocurarine or n‐octylamine. Regardless of re‐leaser the lipid‐soluble spasmogenic material was found to consist of two components, one of which chromatographically behaved as prostaglandin E2. Incubation of this principle with 15–hydroxy prostaglandin dehydrogenase in the presence of NAD' resulted in complete loss of the biological activity. The more polar component elicited slow, sustained contractions of the guinea‐pig ileum; effects associated with SRS. The chromatographic behaviour and chemical properties of this principle were the same as those of compound 48/80 induced SRS. The dose‐response relations and the time courses for the appearance of histamine and SRS induced by d‐tubocurarine and n‐octylamine were studied. The release processes were inhibited by N‐ethylmaleimide, potassium cyanide, dinitrophenol and disodium ethylene diamine tetraacetate (EDTA). The results indicate that in the cat paw d‐tubocurarine and n‐octylamine release histamine and induce the formation of identical or very similar lipid‐soluble spasmogenic principles by activating a common Ca++‐dependent energy‐requiring mechanism.
Alterations in Intracranial Pressure, Blood‐Brain Barrier, and Brain Edema after Sub‐chronic Implantation of a Cannula into the Brain of Conscious Animals
Authors: Edvinsson L. , Nielsen K. C. , Owman Ch. , West K. A. 
Published: December 2008

AbstractChanges related to the intracranial pressure measured as the ventricular fluid pressure (VFP) accompanying implantation of a small cannula into the brain was studied in conscious rabbits. The cannula (7 mm‐long and 1.3 mm in diameter) was inserted into the left lateral ventricle, the intracerebral part of the cannula occupying 0.0093 cm3 volume. The ventricular fluid pres sure was continuously recorded on a Grass Polygraph via a cannula and a pressure transducer. Already within 1 hr after insertion of the cannula, VFP started to increase, and within 4–6 hrs it had reached a maximum about 5 times higher than the initial pressure. A slow progressive decrease did not supervene until 30–35 hrs after implantation; at 50 hrs the VFP was only twice the original value. This VFP was maintained during the following 25 hrs after which recording was discontinued. With trypan blue infusion, only an initial, transient, and local damage to the blood‐brain barrier could be demonstrated. Microscopy of stained sections revealed a varying degree of brain edema, anoxic cell damage, and damage to the capillary net work in the region of the track. The variation in extent of these changes corresponded well to the alterations in VFP and hence they see in to be an important reason for these alterations. The findings are discussed in terms of the important error introduced by these pressure alterations when recording various functional parameters from electrodes, needles, cannulas and other small instruments implanted into the brain parenchyma.
Quantitative Evaluation of Release and Reuptake of Adrenergic Transmitter in the Rabbit Heart
Authors: Wennmalm ÅKe 
Published: December 2008

AbstractDrugs known to block the reuptake of noradrenaline into sympathetic nerves were compared with respect to their potency to increase the outflow of noradrenaline from the isolated rabbit heart in response to nerve stimulation. At a dose level where the drugs tested strongly and equally blocked the uptake of exogenous noradrenaline, they appeared to form two distinct groups differing in potentiation of the noradrenaline outflow. Thus, at optimal concentrations cocaine and desipramine were about equally efficient and increased the outflow of nor adrenaline by about 100%, while protriptyline, phenoxybenzamine and LU 3–010 raised the outflow by about 200 %. The effect of cocaine and desipramine on nerve stimulation‐induced outflow of noradrenaline was further increased by addition of the a‐blocking drug Hydergin. It is concluded that while all the drugs used increase the outflow of noradrenaline in response to nerve stirnulation by strongly depressing reuptake of the transmitter into the neurons, PBA, protriptyline and LU 3–010 apparently in addition augment the amount of noradrenaline re leased from the nerves, possibly by counteracting some braking mechanism normally restricting the release of noradrenaline in response to nerve stimulation.
The Effect of Protriptyline on the Disappearance and Nerve Impulse Induced Release of Labelled Metaraminol in the Rat
Authors: Almgren Olle 
Published: December 2008

AbstractThe uptake and disappearance of3H‐metaraminol (3H‐MA) after an i. v. injection of 40mUg / kgwas studied in intact hearts and in intact, atrophied (by duct ligation), decentralized and atrophied plus decentralized salivary glands of rats. The uptake of3H‐MA in the atrophied glands was reduced to 35 per cent of normal when calculated per gland. The disappearance rate of the amine from these glands did not differ from normal glands. Ten mg/kg of pro triptyline (PTP) 30 min after the3H‐MA injection greatly accelerated the disappearance of the amine from all types of glands also from the heart. The effect was weakest in the intact glands and most pronounced in the glands both atrophied and decentralized. The data argue in favor of a rapid leakage of MA through the neuronal cell membrane, normally balanced by the membrane pump, but unmasked if this pump is blocked. Extraneuronal binding appeals to influence the results obtained after PTP treatment.
Transducer Characteristics of the Muscle Spindle as Revealed by its Receptor Potential
Authors: Ottoson D. , Shepherd G. M. 
Published: December 2008

AbstractThe transducer properties of the sensory endings of the muscle spindle have been studied in isolated spindles of the frog's toe muscle. The depolarization of the sensory endings during dynamic stretch at constant velocity is a rectilinear function of the amount of lengthening of the spindle, for stretches up to about 30 % of its resting length. This suggests that the dynamic phase of the stimulus is transmitted to the endings with little distortion. When the spindle is stretched by more than 30 % of its resting length a saturation phase of constant depolarization is formed. The development of this phase may be explained by the assumption that parallel elastic elements take up the load or that the sensory membrane saturates beyond a given amount of distortion.After release of stretch the depolarization of the endings decreases exponentially with time. The time course of repolarization is considerably slower than the return of the spindle to resting length and relatively independent of the rate of release of stretch. This suggests that the repolarization is governed by the transduction process and related to the electrical proper ties of the sensory membrane.