bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclic AMP as a Mediator of Hormonal Metabolic Effects in Brown Adipose Tissue
Authors: Beviz Andras , Lundholm Lennart , Mohme‐Lundholm Ella 
Published: December 2008

AbstractThe role of cyclic AMP for the calorigenic and some other metabolic effects of noradrenaline, 5‐hydroxytryptamine and ACTH has been studied in brown adipose tissue from the rat. Noradrenaline (5×10‐‐6g/ml) increased significantly the cyclic AMP level in brown adipose tissue. All hormones stimulated the O2‐consumption, the lactate and glycerol productions, the FFA release and reduced the ATP content of the tissue. Noradrenaline and 5‐hydroxytryptamine also reduced the glucose‐6‐phosphate content. Noradrenaline increased both the total and the phosphorylase a activity. Addition of cyclic AMP (4.5 × 10‐‐6moles/ml) to the suspension solution increased the O2consumption, the glycerol and lactate productions and the FFA release; the actions were equivalent to those of a noradrenaline concentration of 5×10‐‐8g/ml. In contrast to noradrenaline, cyclic AMP increased the ATP content. Dibutyryl‐cyclic AMP in a ten times lower concentration (5× 10‐‐7mo les/ml) had the same potency in stimulating the O2consumption and FFA‐release as cyclic AMP. Theophylline (4.5×10‐‐3g/ml) stimulated the O2consumption, the glycerol and lactate productions and the FFA release of brown adipose tissue. Theophylline potentiated the effect of cyclic AMP on the O2consumption; and in combination the drugs reduced the ATP and glucose‐6‐phosphate content of the tissue and increased the phosphorylase activity. The magnitude of the metabolic effects was equivalent to the maximal effect of noradrenaline. The increase of AMP produced by cyclic AMP was blocked by theophylline. It is suggested that the studied metabolic effects of noradrenaline is mediated by an increased formation of cyclic AMP in brown adipose tissue.
Blood Flow in the Calf Muscle of Man during Heavy Rhythmic Exercise
Authors: Folkow Björn , Haglund Ulf , Jodal Mats , Lundgren Ove 
Published: December 2008

Abstract 133Xenon clearance was recorded during maximal vasodilatation in the calf muscles of trained subjects during rest and during heavy rhythmic exercise (contraction about 0.3 sec, relaxation about 0.7 sec) when the subject was tilted from a supine to a “leg down” position. The k‐value for the wash‐out curve, divided by the mean arterial blood pressure at heart level (MABP), was considered to reflect the relative levels of maximal flow in the two experimental situations. While a shift to “leg down” position during post‐exercise hyperemia did not significantly increase flow through the fully dilated muscle vessels, indicating that they were already maximally distended, the same shift during rhythmic exercise raised the average value of k/MABP approximately 60 per cent above control. This observation is in all probability explained by a marked lowering of mean venous pressure by the “muscle pump” in the dependent legs, despite the huge flow during the heavy rhythmic exercise. This would result in a considerable gain in local perfusion pressure and hence in maximal flow capacity.
Electrolytes in Leg and Neck Muscles of Rats during Ontogeny
Authors: Beroström J. , Boëthius J. , Hultman E. 
Published: December 2008

AbstractThe contents of sodium, potassium, magnesium, chloride, phosphorus and water were determined in the leg and neck muscle of 3– and 14‐day old rats. There were marked differences in electrolyte content between the two age groups and also between the leg and neck muscle of the 3‐day old rat.The results indicate that there is a decrease in the amount of extracellular fluid during maturation. The composition of the intracellular fluid also changes during development insofar as there is a marked decrease in its sodium content.The results indicated that the decrease in intracellular sodium roughly paralleled the rise in membrane potential. It was therefore suggested that the developmental change in the intracellular sodium concentration was secondary to a decrease in the sodium permeability of the muscle cell membrane or to a change in the active transport of sodium across the membrane.
Reactivity to Noradrenaline of Aortic Strips and Portal Veins from Spontaneously Hypertensive and Normotensive Rats
Authors: Hallbäck Margareta , Lundgren Yen , Weiss Lilian 
Published: December 2008

AbstractTo investigate whether vascular smooth muscle of spontaneously hypertensive rats, SHR, (Oka‐moto 1963) displays any hypersensitivity to noradrenaline (NA) as compared to that of normotensive control rats, NCR, helical aortic strips, alternatively portal vein segments, from a SHR and a NCR were mounted in the same organ bath, to which graded NA doses were added. In neither case did the dose‐response curves, expressed as per cent of the maximal responses, reveal any significant difference between SHR and NCR. These in vitro studies are therefore in agreement with the view that the enhanced flow resistance responses, caused by NA (and other vasoconstrictor agents) in SHR as compared with NCR are not the result of any increased sensitivity to NA of the vascular effector cells proper but may rather, as suggested by Folkow et al. (1970), be due to an increased wall/lumen ratio of the SHR resistance vessels.
The Effect of Cooling on Liver Function in Cats
Authors: Larsen Jens Anker 
Published: December 2008

AbstractLiver function was followed by the elimination rate of glyceorol and ethanol and the hepatic uptake of Indocyanine Green. It was demonstrated that a 1° to 2° C reduction of the body temperature or cooling of the portal vein reduced the elimination rate of glycerol and ethanol, as well as the hepatic uptake of Indocyanine Green, about 40 per cent. The experimental findings may be explained by restricted distribution of blood flow in the liver and a corresponding reduction of the functional capacity.
The Effect of Iso‐Carbic Metabolic Acidosis in Blood on [H+] and [HCO3‐] in CSF with Deductions about the Regulation of an Active Transport of H+/HCO3 ‐ between Blood and CSF
Authors: Mines A. H. , Morril C. G. , Sørensen S. C. 
Published: December 2008

AbstractThe changes in pH and [HCO3] in csf of anesthetized, paralyzed dogs during metabolic acidosis were compared with those changes when the blood acid‐base parameters were tept at a normal level. Arterial and csf Pco2 were kept constant at the same level during both kinds of experiments. Arterial [HCO3‐‐] was kept cmstant at about 25 meq/l during normal acid‐base experiments and at about 19 meq/l during acidosis experiments. Arterial and csf samples were simultaneously withdrawn after 1 hr, 3 hrs, and 6 hrs. The changes in csf pH and [HCO3‐‐] were expressed as the changes in the electrochemical potential differences (csf‐blood) for H+‘ and HCO3‐ During metabolic acidosis the electrochemical potential differences for H+ and HCO3‐ decreased which could be explained by a decrease in the rate of an active transport of H+/HCO3‐‐ between blood and csf during metabolic acidosis at a constant Pco2. The findings are compared with previous findings and we conclude that the rate of active transport of H+/HCO3‐ between blood and csf if affected by changes in plasma [HCO3‐]. This mechanism provides pH stability in the brain environment during metabolic blood acid‐base changes, whereas the effect is opposite during respiratory acid‐base changes. The mechanism is however “useful” during respiratory acidosis because it provides a negative feed‐back mechanism for the increase in Pco2 during respiratory acidosis.
Vascular and Lipolytic Responses in Canine Subcutaneous Adipose Tissue Following Infusion of Catecholamines
Authors: Ballard Kathryn , Cobb Cully A. , Rosell Sune 
Published: December 2008

AbstractThe aim of the present study was to evaluate the vascular and lipolytic effects of circulating catecholamines in canine subcutaneous adipose tissue. Adrenaline, noradrenaline or isoprena‐line were added at constant rate to the arterial blood supplying subcutaneous adipose tissuein situ. Concentrations of added catecholamine ranged from 10‐‐3to 10‐‐1μg/ml plasma. Blooc/ flow and the net release of glycerol were determined. Adrenaline and noradrenaline were both vasoconstrictor at concentrations above 1 × 10‐‐2μg/ml plasma but differed in the character of the response. Occasionally vasodilatation was observed during infusion of both noradrenaline and adrenaline. Isoprenaline caused vasodilatation at 1 × 10‐‐2μg/ml. Glycerol output was enhanced concomitantly with the vascular responses. The concentration of added noradrenaline (5 × 10‐‐2μg/ml) required to elicit a significant increase in the net release of glycerol exceeded plasma levels reported to be present in resting dogs. It appeared that blood‐borne catecholamines were not as effective for lipolysis as activity in sympathetic nerves to subcutaneous adipose tissue. However, during bleeding or other extreme forms of stress the plasma catecholamine levels may be high enough to induce vasomotor as well as lipolytic responses in subcutaneous adipose tissue.
Metabolism of14C‐Histamine in Domestic Animals
Authors: Eliassen K. A. 
Published: December 2008

AbstractThe metabolism of14C‐histamine injected i.v. in goats has been studied previously. The present study was undertaken to examine whether the metabolic pattern of14C‐histamine found in goats is characteristic for ruminating species. The urinary14C‐metabolites of i.v. injected14C‐his‐tamine to cows and sheep were quantitated by means of isotope dilution technique and paper chromatography. During the first week after injection 74–84 % and 93–99 % of the injected radioactivity was found in sheep and cow urine, respectively. Only 1 % of the radioactivity could be accounted for in the feces and less than 0.03 % in the cow milk. Known metabolites accounted for 84–91 % and 97 % of the urinary radioactivity for sheep and cow, respectively. The metabolic pattern for14C‐histamine degradation in sheep and cow did not differ much. As in goats, the oxidative deamination of histamine to imidazoleacetic acid and imidazoleacetic acid riboside seemed to be the only pathway of quantitative importance. Both in sheep and cows histaminol was found to be a metabolite of i.v. injected14C‐histamine accounting for about 2 % of the urinary radioactivity. In cows the specific radioactivity of histamine was found to be up to 24 times larger than that for 1.4 methylimidazoleacetic acid.
Failure of High Pco2 in the Duodenal Bulb to Inhibit Gastric Acid Secretion
Authors: Nilsson Göran , Rune Simon J. 
Published: December 2008

AbstractGastric acid secretion was stimulated by intravenous infusion of pentagastrin (ICI 50 123) in dogs with Pavlov pouches and isolated pouches of the duodenal bulb. Elevation of the Pco2 to 150 or 700 mm Hg in the bulbar pouches did not reduce the gastric acid output. It is suggested that the high CO2 tension which normally exists in the canine duodenum during periods of stimulated gastric acid secretion is not involved in the activation of the bulbar mechanism inhibiting the gastric acid secretion.
Histamine Release from Rat Peritoneal Mast Cells and Cat Paws Induced by Some Neuromuscular Blocking Agents
Authors: Frisk‐Holmberg M. , Strandberg K. 
Published: December 2008

AbstractThe capacity of some neuromuscular blocking agents to release histamine from rat peritoneal mast cells and cat paws has been investigated. Only nondepolarizing agents were effective in the concentration ranges used. The order of potency was tubocurarine, dimethyltubocurarine, toxiferine‐C, alcuronium, in contrast to published data on their corresponding order of neuromuscular blocking activity. In addition to histamine release, tubocurarine and dimethyltubocurarine induced the efflux of slow reacting substance (SRS) from perfused cat paws. The release evoked by tubocurarine or dimethyltubocurarine was reduced by potassium cyanide and lack of Ca++. It is concluded that the interonium distance in neuromuscular blocking agents may be critical for histamine releasing capacity.
The Distribution of 15‐Hydroxy Prosta‐glandin Dehydrogenase and Prostaglandin‐Δ13‐Reductase in Tissues of the Swine
Authors: ÄNggård Erik , Larsson Carin , Samuelsson Bengt 
Published: December 2008

AbstractProstaglandin dehydrogenase (15‐hydroxy prostanoate oxidoreductase, EC 1.1.1 (PGDH) and prostaglandin‐Δ13‐reductase (prostanoate Δ13‐oxidoreductase) were assayed in homogenates of 15 different tissues of the swine. Both enzymes were located mainly in the particle free fraction. The highest activities for PGDH were found in the lung, spleen and kidney, which ranged from 50–82 mU/g of tissue or from 482 to 808 m/g of protein. Lower activities of PGDH were observed in the stomach, testicle, liver and small intestine. The renal cortex contained about three times more PGDH than the medulla. The reductase was most abundant in spleen, kidney, liver, adrenal and small intestine, which ranged between 27–38 mU/g of tissue or 232–390 mU/g of protein. The highest specific activity was however found in adipose tissue which contained 3383 mU/g of protein. The wide distribution of these enzymes as well as other evidence support the concept that they catalyze the initial reactions in the metbolism of the prostaglandins.
Histochemical Demonstration of Carbonic Anhydrase Activity in the Rat Kidney
Authors: Lönnerholm Gudmar 
Published: December 2008

AbstractLönnerholm, G. Histochemical demonstration of carbonic anhydrase activity in the rat kidney. Acta physiol. scand. 1971. 81. 433–439.The carbonic anhydrase activity in the kidney of male Sprague‐Dawley rats was studied by a histochemical technique. Enzyme activity was found not only in the proximal and distal tubules, but also in the thin segment of Henle's loop and in the collecting tubules. The arched collecting tubules in the outer cortical zone of the kidney are known to consist of two kinds of cells, the so called light and dark cells. When stained for carbonic anhydrase activity, the arched collecting tubules showed a very distinct staining pattern, with some cells heavily stained and other cells weakly stained. This is of special interest in view of the fact, that other investigators have found an increase in the number of the so called dark cells after administration of sodium or potassium bicarbonate to rats.
Inhibitory Control of the Abdominal Stretch Receptors of the Crayfish
Authors: Jansen J. K. S. , Njå A. , Ormstad K. , Walløe L. 
Published: December 2008

AbstractJansen, J. K. S., A. Njå, K. Ormstad and L. Walløe, Inhibitory control of the abdominal stretch receptors of the crayfish. III. The accessory reflex as a recurrent inhibitory feed‐back. Acta physiol. scand. 1971. 81. 472–483.The autogenetic activation of the thick accessory fibre of the stretch recepton has been examined by intracellular recording and excitation of reflexly intact recepton. The steady‐state effect of this recurrent inhibitory feed‐back is to decrease the sensitivity of the receptor over its entire working range. The closed loop effect can be predicted from the mechanism of the inhibitory action and. the central coupling of the reflex. The effect of the feed‐back can be reversed by increased internal chloride concentration in the receptor. Some time‐dependent properties of the responses of the feed‐back loop are described.
Inhibitory Control of the Abdominal Stretch Receptors of the Crayfish
Authors: Jansen J. K. S. , Njå A. , Ormstad K. , Walløe L. 
Published: December 2008

AbstractJansen, J. K. S., A. Njå, K. Ormstad and L. Walløe, Inhibitory control of the abdominal stretch receptors of the crayfish. IV Qbantitative description of the central coupling of the accessory reflex. Acta physiol. scand. 1971. 81. 484–491.The two accessory neurones have been reflexly activated from neighbouring ipsilateral stretch receptors. The firing frequencies of both increase with increasing input frequencies up to a saturation level which was higher for the thick accessory neurone. Inputs from different segments are summated. The frequency response of the reflex activation of the large accessory neurone has a maximal gain between 2 and 5 Hz. This is within the frequency range of normal movements.
Increase in Capillary Filtration Rate Resulting from Reduction in the Intravascular Calcium Ion‐Concentration
Authors: Nicolaysen G. 
Published: December 2008

AbstractNicolaysen, G. Increase in capillary filtration rate resulting from reduction in the intravascular calcium ion‐concentration. Acta physiol. scand. 1971. 81. 517–527.Marked reductions in intravascular concentrations of Ca++ and Mg++ has previously been shown to cause edema development. The effect of moderate reductions in the intra‐vascular concentration of Ca++ on the net rate of filtration from a vascular bed during increased capillary pressure has been analyzed. Isolated, ventilated rabbit lungs were perfused with plasma at 2° C. In each preparation repeated filtration tests were performed by standardized increases in the outflow pressure lasting for 6 or 10 min. The rate of weight increase for the preparation when 4 min of a test had elapsed was taken as the net rate of filtration. This net rate of filtration was shown to be increased when the [Ca++] was reduced to about 0.1 mM. This increase in filtration rate could be reversed by Ca++‐addition, but not by Mg++‐addition. Evidence is presented that this increase in filtration rate was due to changes in the “hydraulic conductivity” of the capillary wall.
Effects of Variations in the Extracellular Osmolality on the Permeability to Nonelectrolytes of Vascular Smooth Muscle
Authors: Jonsson Olof 
Published: December 2008

AbstractJonsson, O., Effects of variations in the extracellular osmolality on the permeability to non‐electrolytes of vascular smooth muscle. Acta physiol. scand. 1971. 81. 528–539.The effects of variations in the osmolality on the general permeability properties of the smooth muscle cell membranes have been studied by measuring the effluxes of 14C urea and 14C erythritol from rat portal veins at different extracellular tonicities. Permeability coefficients were calculated by introducing the rate constants for the cellular component of the washout curve as well as the estimated cell volume – cell surface ratios into a modified Fick's law of diffusion. The values obtained at normal tonicity of the washout medium were 8.78 10‐8 cm/sec for urea and 3.70 10‐8 cm/sec for erythritol. No definite alteration in the rate‐limiting properties of the cell membranes could be registered on exposure to hyperosmotic or moderately hypo‐osmotic (–54 mOsm/kg) media. However, when the tonicity of the washout medium was more markedly reduced (–109 mOsm/kg) a clearcut increase in the permeability coefficients for both substances was obtained. Possible explanations to this alteration in the permeability characteristics of the cell membranes on swelling of the smooth muscle cells are discussed.
Unit Responses in the Rat Cochlear Nucleus to Tones of Rapidly Varying Frequency and Amplitude
Authors: Møller Aage R. 
Published: December 2008

AbstractMøller, A. R. Unit responses in the rat cochlear nucleus to tones of rapidly varying frequency and amplitude. Acta physiol. scand. 1971. 81. 540–556.The response of single units in the cochlear nucleus of the rat to sweep tones (FM sounds) and short tone‐bunts (AM sounds) has been investigated. It was found that the response pattern to Fhl sounds became more restricted with regard to tone frequency at a certain rate of tone‐frequency change. The probability of firing within a narrow frequency range surrounding the unit's CF became frequently more than ten times greater than that at low sweep‐speeds.For a certain range of higher sweep‐rate, cycle histograms become narrower and higher than at low sweep‐rates. The range of frequency change where the peaks had maximal height was found to lie in the region between 1 and 15 MHz/sec for units with CF from 5 to 30 kHz. This effect was found to persist over a sound‐intensity range of more than 60 dB, but was less marked at very low intensity levels. The threshold of the units investigated did not become lowered at any rate of frequency change.The cycle histograms of the response to sounds of constant frequency and variable duration (AM sounds) differed significantly from that to FM sounds. Only occasionally was an increase in height of the cycle histograms seen when the duration of the sounds was narrowed and the repetition rate increased.
Intracellular Accumulation and Permeability Effects of Some Weak Acids in the Isolated Frog Gastric Mucosa
Authors: Flemström Gunnatr 
Published: December 2008

AbstractAcetate, propionate and L‐lactate (10 meq/l) stimulated hydrogen ion secretion in the isolated frog (Rana temporaria) gastric mucosa. By use of this stimulatory effect it was shown that these acids accumulate in the gastric mucosal cells when present in the undissociated form on the mucosal (secretory) side. From determinations of the impedance locus diagram and the resistance of the mucosa it was shown that undissociated propionic acid (100 meq/l) increased the ionic permeability of the frog gastric mucosa. A similar effect was obtained with acetic acid. It is probable that intracellular accumulation of undissociated weak acids is the mechanism underlying their permeability increasing effects on the gastric mucosa.
Effect of Some Drugs on the Uptake of Monoamines and Their Precursors in the Mouse Paneth Cells
Authors: Ahonen A. , Penttilä A. 
Published: December 2008

AbstractThe accumulation of some biogenic substances in the Paneth cell cytoplasmic granules of the mouse jejunum, ileum and colon and the effect of some drugs on this accumulation were studied, using the histochemical formaldehyde‐induced fluorescence method. The biogenic substances were injected i.v. and the specific catecholamine fluorescence appeared in the cytoplasmic secretory granules of the mouse Paneth cells about 10 min after I‐DOPA, dopamine, a‐methyl‐DOPA, noradrenaline, a‐methylnoradrenaline and adrenaline administration. Nia‐lamide and pargyline markedly intensified the fluorescence intensity in the Paneth cell granules after administration of the biogenic substance.Imipramine and cocaine inhibited specifically the I‐DOPA and dopamine accumulation, whereas amphetamine, amitriptyline, nortriptyline, chlorpromazin, promazine and guanethidine had no effect. After nialamide pretreatment amphetamine, nortriptyline and amitriptyline were also capable of inhibiting slightly the accumulation of these biogenic substances. 5‐Hydroxytryptamine or 5‐hydroxytryptophan were not taken up by the Peneth cell granules even after nialamide pretreatment. The apparent mechanism of the accumulation of biogenic substances by the Paneth cell secretory granules was discussed.
Action Potential Generation in Denervated Rat Skeletal Muscle
Authors: Redfern Paul , Thesleff Stephen 
Published: December 2008

AbstractAction potential generation was studied in the presence of tetrodotoxin (TTX) up to one week after denervation in individual muscle fibres of the extensor digitorurn longus and diaphragm muscles of the rat. TTX 10‐6M completely blocked spike generation in innervated inuscle and in niuscle denervated for one day. On the second and subsequent days after denervation, action potentials resistant to TTX were recorded in the muscle fibres. In the extensor digitorum longus muscle denervated for 5 days, action potentials recorded in the presence of TTX 10‐6M had a mean rate of rise 250 V/sec, and they exceeded the zero membrane potential by an average of 28 mV. This TTX resistant action potential generation was impaired by reducing the external sodium concentration, and abolished in the absence of that cation. A correlation was obsrrved between the presence of TTX resistant action potentials and the acetylcholine sensitivity of the muscle membrane.