bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cerebral Energy State and Cerebral Venous Po2 in Experimental Hypotension Caused by Bleeding
Authors: Eklöf Bo , Macmillan Vernon , Siesjö Bo K. 
Published: December 2008

AbstractArterial hypotension was induced by bleeding lightly anesthetized rats to mean arterial blood pressures of 60 and 45 mm Hg, respectively, with subsequent measurements of arterial and cerebral venous gas tensions, of extra‐ and intracellular acid‐base parameters, as well as of parameters necessary for an evaluation of the energy state of the brain tissue. In none of the groups were there significant changes in extra‐ or intracellular pH, indicating that a non‐chemical mechanism was responsible for the autoregulation of flow. Most of the animals in the 60 mm Hg group, and about half of those with a blood pressure of 45 mm Hg, showed a normal metabolic pattern in the brain. In the remaining animals, there were moderate in‐creases in lactate and, simultaneously, slight decreases in the charge potential of the adenine nucleotides of the tissue due to moderate increases in ADP and AMP. Such changes occurred at a venous Po, of about 25 mm Hg. Since other results indicate that the cerebral energy state fails at higher mean arterial blood pressures, and at higher Pvo, values, provided that the tissue is acidotic, it is concluded that the efficient energy homeostasis observed in the present experiments may have been due to the fact that no tissue acidosis developed.
The Effect of Bilateral Carotid Artery Ligation upon Acid‐Base Parameters and Substrate Levels in the Rat Brain
Authors: Eklöf Bo , Siesjö Bo K. 
Published: December 2008

AbstractThe effect of bilateral carotid artery ligation upon acid‐base parameters and substrate levels in the brain were studied in lightly anesthetized rats, either at normal blood pressure or after a reduction in blood pressure to 100 and 70 mm Hg, respectively. As evaluated arteriovenous differences the tissue CO2 tension was consistently higher than the Pco2 in cisternal CSF. At low blood pressures most animals showed a marked to excessive elevation of the tissue lactate content but since the CSF lactate content was only moderately increased it is concluded that a larger reduction in blood flow occurred in the supratentorial than in the infratentorial parts of the brain. At low perfusion pressures the tissue contents of glucose, α‐ketoglutarate and glutamate were considerably reduced. The results suggest that the experimental model used gave rise to an inhomogenous decrease in flow in the tissue, and a correlation between the increase in the lactate and the decrease in the bicarbonate contents suggests that a mixture of perfused and non‐perfused tissue areas may have existed.
Motoneurone Models Based on ‘Voltage Clamp Equations' for Peripheral Nerve
Authors: Kernell Daniel , Sjöholm Hans 
Published: December 2008

AbstractMotoneurone models were developed by modifications of the Frankenhaeuser‐Huxley equations (1964) for voltage clamp data amphibian nerve fibre. The major modifications were: (i) that the subthreshold sodium inactivation was decreased, and (ii) that the Frankenhaeuser‐Huxley model was provided with a long‐lasting after‐hyperpolarization due to potassium permeability changes. Besides, model versions were developed that also had passive membrane properties (e. g. a resting membrane time constant) similar to those of spinal motoneurones. For various model versions, single spikes and the associated afterpotentials were shown in the present paper. The main aim was to use the motoneurone models for studies of repetitive impulse firing. This will be done in a subsequent paper (Kernell and Sjoholm 1972).
Glyoxylic Acid Condensation: A New Fluorescence Method for the Histochemical Demonstration of Biogenic Monoamines
Authors: Axelsson Sture , Björklund Anders , Falck Bengt , Lindvall Olle , Svensson Leif‐Åke 
Published: December 2008

AbstractA new methodological approach to the fluorescence microscopical visualization of biogenic monoamines, based on condensation with gaseous glyoxylic acid, is presented. Glyoxylic acid treatment seems both to be more sensitive for the well‐known biogenic catecholamines and indolamines, and to allow the detection of other biogenic amines—such as melatonin—which are not demonstrable with available techniques.
Cerebral Blood Flow in Ischemia Caused by Carotid Artery Ligation in the Rat
Authors: Eklöf Bo , Siesjö Bo K. 
Published: December 2008

AbstractIn order to study if bilateral ligation of the carotid arteries, either alone or combined with moderate arterial hypotension is accompanied by a macroscopically uneven brain perfusion, the regional cerebral blood flow (rCBF) was measured using the antipyrine‐14C method with direct counting of the radioactivity in the tissue. Ligation of the carotid arteries at normal blood pressure decreased blood flow in the frontal‐parietal regions by about 50 % in both hemispheres. At a mean blood pressure of 100 mm Hg, the ligation caused a further reduction in flow but the results were variable and gross differences often occurred between the hemispheres. At 70 mm Hg in blood pressure carotid occlusion drastically reduced the frontal‐parietal rCBF but flow in the occipital and basal temporal regions was usually better upheld. It is concluded that in the rat, combined carotid artery ligation and moderate hypotension gives rise to a macroscopically inhomogenous reduction in rCBF, and that regions of nonperfusion may coexist with adequately perfused areas.
Increased N‐Acetylserotonin and Melatonin Formation Induced by d‐Amphetamine in Rat Pineal Gland Organ Culture via a β‐Adrenergic Receptor Mechanism
Authors: Bäckström Maria , Wetterberg Lennart 
Published: December 2008

AbstractDextro‐amphetamine (10–5M) added to the medium of rat pineal glands in organ culture produces an eightfold increase of radiolabeled N‐acetylserotonin and melatonin when tryptophan or serotonin are used as labeled precursors. In concentration of 10–4M d‐amphetamine causes a decreased formation of 5‐hydroxyindoleacetic acid from tryptophan and serotonin. Addition of d‐amphetamine to pineal glands also resulted in an increase of N‐acetyltransferase activity as compared with untreated glands. The effect of d‐amphetamine and noradrenaline was blocked by propranolol, a β‐adrenergic blocking agent but not by the α‐adrenergic blocking agent phentolamine. In cervical ganglionectomized rats the addition of d‐amphetamine to the culture medium did not produce an increase in N‐acetylserotonin production. Conversely noradrenaline added to the medium gave a high formation of N‐acetylserotonin. This indicates that the major effects of d‐amphetamine on pineal N‐acetyl‐transferase activity are mediated by noradrenaline.
The Linguo‐Chorda Tympani Reflex—an Electrophysiologically Undescribed Reflex
Authors: Hellekant Göran , Kasahara Yasuo 
Published: December 2008

AbstractThe impulse activity in the central part of the chorda tympani nerve of the rat was recorded during mechanical stimulation of the oral region. The results obtained at a stimulation rate of 1 Hz show that a) a reflex discharge could be recorded about 6–10 ms after stimulation of the ipsilateral side of the tongue, b) stimulation of the contralateral side increased the latency by about 1–1.5 ms, c) the reflex could be evoked in animals which showed no spontaneous efferent activity in the chorda tympani nerve, d) recordings from nerve filaments showed that a filament could display spontaneous activity without being involved in the reflex, e) the lingual nerve serves as the main sensory link on the reflex to mechanical stimulation of the anterior part of the tongue, and f) the reflex evoked by stimulation of other parts of the oral region had a longer latency and less intense discharge. The results obtained at higher stimulation rate show that a) individual bursts of reflex discharge could be traced at stimulation frequencies up to 60 Hz, b) except for a moderate decrease the discharge did not disappear when stimulus frequencies of 5, 30 and 50 Hz were used.
Metabolism of Fracture Callus of Rat in vitro: II. Incorporation of 35S‐Sulphate, 3H‐Proline and 32P‐Phosphate
Authors: Penttinen R. 
Published: December 2008

AbstractThe incorporation rate of 35S‐sulphate into the glycosaminoglycans of callus in vitro was at the highest on the 7th day after the fracture corresponding with the proliferation of cartilage. Protein synthesis per callus occurred at the maximal rate 4 days later (during the transition of cartilaginous to ossifying callus) as judged from the radioactivities of 3H‐hydroxyproline and 3H‐proline in collagen and other proteins.Radioactive phosphate accumulated maximally into the cartilaginous matrix on the 7th day and into the osseous matrix on the 21st day after the fracture. No differences in activities were detected between heated and intact slices indicating non‐enzymatic uptake of phosphate ions from the medium.
Storage Properties of Rat Mast Cell Granules In vitro
Authors: Bergendorff Anders , Uvnäs Börje 
Published: December 2008

AbstractBasophil granules were isolated from rat peritoneal and thoracic mast cells. The granules were depleted of their endogenous Hi and 5‐HT. The uptake of Hi, 5‐HT, TrpA, PhEA, TA, DA, NA, ACh, Na and Ca (for abbreviations see page 215) by the depleted granules, the release of Hi from Hi‐recharged granules by Ca, Na and K and the competition between NA and Hi, ACh and NA, ACh and Hi for the granule storage sites were studied. The results support the hypothesis that these granule stores have the properties of a weak cation exchange resin. Furthermore it was found that amphetamine and ephedrine competed with NA for the storage sites The results indicate an unspecific granule storage of cations—organic and inorganic—differing only in their affinities for the binding sites.
Increased Synthesis of Prostaglandins in the Guinea Pig Following Scalding Injury
Authors: Hamberg Mats , Jonsson Carl‐Evert 
Published: December 2008

AbstractThe urinary excretion in guinea pigs of the major urinary metabolite of prostaglandins E1 and E2, viz 5β,7α‐dihydroxy‐11‐ketotetranor‐prostanoic acid, was increased 5–9 fold following scalding injury. Lipid extracts of homogenates of scalded guinea pig skin contained 20–40 times more smooth muscle stimulating activity than did extracts of non‐scalded skin. Prostaglandins (mainly PGE2 and PGF2α) were responsible for about 80% of this activity.
Intestinal Vasodilatation in Response to Transmural Electrical Field Stimulation
Authors: Biber Björn , Fara John , Lundgren Ove 
Published: December 2008

AbstractElectrical field stimulation of the small intestine in vivo in cats induces a 60–150% increase in total intestinal blood flow. The vasodilatory response to field stimulation is blocked by tetrodotoxin and lidocaine, but is unaffected by extrinsic denervation of the intestine, by cholinergic and adrenergic pharmacological blocking agents, and also by cross perfusion of the stimulated intestine from a donor animal. The participation of a local nervous structure in the control of intestinal blood flow is suggested.
The Effect of Noradrenaline and Adrenaline on Hepatosplanchnic Hemodynamics, Functional Capacity of the Liver and Hepatic Metabolism
Authors: Krarup Niels 
Published: December 2008

AbstractCats in the postabsorptive state and anesthetized with chloralose were used for the experiments. Following a control period noradrenaline and adrenaline at doses of 0.5, 1.0, 2.0, and 5.0 μg/kg/min were infused continuously for about an hour into a femoral vein. Noradrenaline caused a pronounced constriction of the hepatic artery and a slight increase in the mesenteric vascular resistance. Small doses of adrenaline had a slight dilatory effect on the hepatic artery and mesenteric vessels whereas the largest dose caused a slight constriction in both these vascular beds. Neither of the drugs changed the portal venous resistance. The catecholamine infusions resulted in hepatic glycogenosis and glycolysis, but neither the splanchnic elimination of ethanol, the secretion and composition of bile, excretion of Indocyanine Green nor the splanchnic oxygen consumption were affected, indicating that the number of sinusoids perfused was not changed. A slight effect on the hepatic clearance and extraction ratio of Indocyanine Green was, however, observed. The results indicate that although the infusion of catecholamines in the present doses is accompanied by marked changes in hepato‐splanchnic hemodynamics and liver metabolism, the intrahepatic distribution of blood flow is not subject to gross alterations. The existance of catecholamine dependent sphincter activity in the hepatic sinusoids observed in transillumination studies have not been confirmed by the present experiments.
An Investigation of the Action of Ouabain on the Sodium Efflux in Barnacle Muscle Fibres
Authors: Bittar E. Edward , Chen Stephen S. , Danielson Bo G. , Tong Edmund Y. 
Published: December 2008

AbstractMeasurements of radiosodium efflux were carried out on single fibres from the barnacleBalanus nubilusorB. aquila, using the micro‐injection technique. 10‐4M ouabain caused an average fall of 68% of the Na efflux, the minimal effective concentration beingca.10‐7M. Internal application of 4 × 10‐3M ouabain was without effect. Abolition of the ouabain‐sensitive component with ouabain, followed by raising the external K concentration to 30 mM, resulted in a marked rise in the residual Na efflux. Stimulation of the ouabain‐insensitive Na efflux was also seen after reducing the external pH, as well as after microinjecting CaCl2but not MgCl2. Uncoupling of the active transport system by K removal, followed by external application of ouabain, and subsequent acidification of the bathing medium, led to stimulation which was considerably greater than that taking place when the Na efflux was uncoupled by K removal and then stimulated by external acidification.
Nervous and Humoral Control of Vascular Resistance during Acute Hemorrhagic Hypotension in Rabbits
Authors: Aars H. , Akre S. 
Published: December 2008

AbstractPeripheral vascular resistance in anesthetized rabbits quickly increased during hemorrhagic hypotension, despite almost unchanged sympathetic nerve activity. Simultaneous measurement of blood flow to denervated and innervated kidneys showed that the acute rise of renal vascular resistance during hypotension was independent of innervation. In other animals, the left, innervated kidney was perfused with blood from either the host or a donor rabbit, by means of a pump. Renal vascular resistance invariably rose during systemic hypotension when the kidney was perfused with blood from the rabbit subjected to hemorrhage, but not when perfused with blood from a normovolemic animal. The results support the view that increased peripheral vascular resistance during the first minutes of hemorrhagic hypotension is caused by humoral agents, rather than by increased sympathetic activity.
Oxygen Uptake during Maximal Work at Lowered and Raised Ambient Air Pressures
Authors: Fagraeus L. , Karlsson J. , Linnarsson D. , Saltin B. 
Published: December 2008

AbstractThe maximal aerobic power (Vo2max) was measured in 12 subjects exercising on a bicycle ergometer breathing air at 0.68, 1.0 and 1.40 ATA ambient pressures. Seven of the subjects were also investigated at 2.0 and 3.0 ATA. Vo2max averaged 3.67 1·min‐1 STPD at 1.0 ATA and was reduced by 14 per cent at 0.68 ATA (p < 0.001), while at 1.40 ATA Vo2max was increased by 9 per cent (p < 0.001). The increased PIO2 at the two highest pressures did not result in any further improvement of vo2max compared to 1.40 ATA. At all pressures changes in endurance time parallelled those of Vo2max. Ventilation decreased markedly as ambient pressure increased with a concomitant rise of PACO2 up to a mean value of 43 mm Hg at 3.0 ATA as compared to 32 mm Hg at 1.0 ATA. It is concluded that moderate hyperoxia produced by increased ambient air pressure enhances circulatory transport of oxygen in maximal exercise, and that the working muscles have an aerobic potential exceeding what the circulation normally can offer.
An Indicator‐Dilution Method for Studying Intestinal Hemodynamics in the Cat
Authors: Blber Björn , Lundgren Ove , Stage Lars , Svanvik Joar 
Published: December 2008

AbstractAn indicator‐dilution technique is described for studying intestinal mucosal red cell and plasma flow and volume quantitatively and muscularis red cell and plasma flow and volume qualitatively. The technique involves a close intra‐arterial injection of an intravascular β‐radiating tracer and its detection with sensoring devices placed in the gut lumen and outside the intestine at the antimesenteric border. Knowing the amount of tracer injected and total venous outflow, it is possible to estimate regional flow from the height of the registered curve and regional blood volume from its area. Since the volume of the region monitored by the detector depends on the energy level of the β‐radiation, 32P‐labelled red cells and plasma colloids, used in this study, were monitored from the whole mucosa, while 108Au‐labelled plasma particles were registered only from the villi. This paper presents the theoretical background of the technique and some model experiments.
Effect of Hemorrhagic Hypotension on the Distribution of Renal Cortical Blood Flow in Anesthetized Dogs
Authors: Aukland K. , Kirkebö A. , Löyning E. , Tyssebotn I. 
Published: December 2008

AbstractThe distribution of renal cortical blood flow was studied in seven Nembutal anesthetized dogs in control periods, during hemorrhagic hypotension and after retransfusion. Local cortical blood flow was measured as hydrogen clearance recorded simultaneously from 3 to 6 platinum electrodes inserted into inner and outer half of the cortex. Total renal blood flow (RBF) was measured by electromagnetic flowmeter. In control periods flow averaged 3.47 ± 0.83 ml/min×g in outer cortex and 3.61 ± 0.86 ml/min × g in inner cortex. Bleeding to mean arterial pressure of 50 mm Hg in the course of 5–36 min in 5 expts. caused a proportional reduction of RBF and average flow in outer and inner cortex to 40–60 % of control, with further reduction to 10–30 % with maintenance of hypotension for 2 h. Bleeding to 70 mm Hg in 2 expts. gave princpially the same response. All electrodes showed a similar response and the percentual deviation between electrodes did not increase during hypotension. Thus no evidence was obtained for patchy or segmental ischemia or for regional redistribution of cortical blood flow. Retransfusion gave only incomplete restoration of flow.
Two Types of Lateral Line Afferents in the Eel (Anguilla anguilla)
Authors: Alnæs Egil 
Published: December 2008

AbstractThe spontaneous and evoked discharges of eel lateral line sensory organs have been investigated. Each afferent nerve fibre has a well defined punctate receptive field, corresponding to a single canal organ. No axons were found to innervate more than one of these. All afferents pass through the Rarnus lat. dors. N.X. to the medulla oblongata. No peripheral unidirectional synapses exist in the nerve. Afferent axons are myelinated and belong to a large calibre (mode 12 μm) and a small calibre (mode 3 μm) axonal population in the nerve. The nerve contains about 800 myelinated axons at the level of its medullary entry, subserving approximately 100 sensory organs. In both groups rates of spontaneous discharge range from 0 c/s‐50 c/s. Both groups include extremely mechano‐sensitive units, and less sensitive units. The main difference between the slowly and rapidly conducting units is the more regular spontaneous firing pattern of the former group.
Effect of Spinal Transection on the Metabolism of 5‐Hydroxyindoles Formed in vivo from3H‐Tryptophan in the Rat Spinal Cord
Authors: Schubert Johan 
Published: December 2008

AbstractThe nerve impulse flow in 5‐hydroxytryptamine (5‐HT) neurons descending to the caudal part of the spinal cord of rats was interrupted by a spinal transection. At various time intervals after the operation3H‐tryptophan was administered i.v. and the accumulations of labelled 5‐HT and 5‐hydroxyindoleacetic acid (5‐HIAA) in the cord were determined. 6–8 days after the section the cord caudal to the lesion was almost depleted of 5‐HT and very little3H‐5‐HT was formed from the labelled precursor. Between 8 and 24 h post‐lesion the level of 5‐HT was increased by 20 % below the lesion, whereas the accumulation of3H‐5‐HT was markedly reduced. Immediately after the transection the endogenous 5‐HT level as well as the3H‐5‐HT accumulation were unchanged in the caudal cord. The accumulation of3H‐5‐HIAA below the section was reduced at all time intervals after the operation. The specific activity of tryptophan seemed to be increased following nerve section. The results indicate that 5‐HIAA synthesis is controlled by nerve impulse activity. The synthesis of 5‐HT was not directly dependent on neuronal activity or tryptophan levels but seemed to be inversely correlated to the endogenous 5‐HT level.
Peripheral Inhibition of Eel Lateral Line Receptors as Caused by Antidromic Sensory Terminal Invasion
Authors: Alnæs Egil 
Published: December 2008

AbstractNo evidence of efferent inhibitory activity on eel lateral line sensory cells has been found in a number of different types of experiments. Proximal transection of the lateral line nerve induces no changes in the ongoing activity from the sensory cells, even in the uncurarized, un‐anesthetized animal. Stimulation of peripheral nerve filaments induces no inhibition of afferent spontaneous and/or evoked activity, either ipsilaterally or contralaterally. No spontaneous or evoked efferent activtiy could be recorded from proximal nerve filaments. Antidromic invasion of sensory terminals resets the ongoing spontaneous activity. In the intervening interval the mechanical and electrical thresholds of these sensory units are similarly elevated. Antidromic invasion is suggested to be the phenomenon reported as peripheral inhibition by Hashimoto et al. (1970).
On the Relative Importance of Extra‐Neuronal Uptake of Noradrenaline Released by Nerve Stimulation in the Rabbit Heart
Authors: Junstad Marianne , Stjärne Lennart , Wennmalm ÅKe 
Published: December 2008

AbstractDrugs known to inhibit the extra‐neuronal uptake of noradrenaline were given to the sympathetically stimulated, perfused rabbit heart, and the subsequent change in the overflow of transmitter was studied. Normethanephrine (10‐5M) increased the outflow of noradrenaline on nerve stimulation by about 25%, while lower doses were ineffectual. However, in the dose mentioned, the drug did not potentiate the earlier reported increase in overflow caused by desmethylimipramine (5.5 × 10‐7M). On nerve stimulation, intact noradrenaline made up 83% of the increase in radioactivity in the perfusate before, and 94% after, inhibition of the extra‐neuronal uptake of noradrenaline. It is concluded that extraneuronal uptake of noradrenaline, released by sympathetic nerve stimulation, plays a small but significant role in the inactivation of the transmitter from the neuro‐effector junctions. The findings are discussed with regard to earlier observations where phenoxybenzamine, another potent inhibitor of extra‐neuronal uptake, was found to increase the overflow of transmitter on nerve stimulation more than could he expected from its uptake‐inhibiting properties alone.