bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical and Metabolic Effects of β‐Receptor Stimulators, the C‐Terminal Octapeptide of Cholecystokinin, and Prostaglandin E2on the Isolated, Depolarized Sphincter of Odd
Authors: Andersson K.‐E. , Andersson R. , Hedner P. , Persson C. G. A. 
Published: December 2008

AbstractSimilar to their actions on normally polarized, isolated sphincter of Oddi, the β‐receptor stimulators isoprenaline and terbutaline, and prostaglandin E2produced relaxation of the depolarized preparation. The relaxation was accompanied by an increase in the intracellular content of cyclic AMP. In contrast to its relaxing effect on normally polarized sphincter preparations, the C‐terminal octapeptide of cholecystokinin (C8‐CCK) contracted or had no effect on the depolarized sphincter. There was no change or a small decrease in the content of cyclic AMP in the muscle. It is suggested that the relaxing effects of β‐receptor stimulators and prostaglandin E2on isolated sphincter of Oddi, and the simultaneous increase in cyclic AMP‐content are mediated by processes independent of the electrical activity of the membrane. However, C8‐CCK mediated relaxation and increase in cyclic AMP is dependent on the membrane potential.
Effects of Gonadotrophins on the Cumulus Oophorus of Isolated Rat Graafian Follicles
Authors: Hillensjö Torbjörn , Dekel Nava , Ahrén Kurt 
Published: December 2008

AbstractGraafian follicles were extirpated before the endogenous LH surge on the day prior to ovulation from PMS‐injected immature rats. They were incubated in chemically defined medium in presence or absence of gonadotrophins for 4–10 h. After incubation the oocyte‐cumulus complexes were recovered from the follicles and one group inspected by Nomarski interference contrast microscopy and one group was placed in saline containing hyaluronidase. In hormone‐free medium both the oocyte and the cumulus cells remained morphologically unchanged: a dictyate oocyte surrounded by a compact mass of cumulus cells. Hyaluronidase did not detach cells from the cumulus structure. However, in presence of LH or FSH morphological changes developed in both cell types: the oocyte resumed meiosis as revealed by germinal vesicle breakdown and polar body formation; the cumulus structure became dispersed and embedded in a viscous matrix. The individual cumulus cells displayed pseudopodia‐like processes of the cell surface. Treatment with hyaluronidase resulted in detachment of cells from the cumulus. The effects of LH described on the oocyte and cumulus cells were unimpaired in presence of cyanoketone or aminoglutethimide although these agents blocked the follicular relase of progesterone, estradiol and androstenedione as revealed by RIA. The results indicate that a close functional relationship exists between the two cell types of the cumulus oophorus, the oocyte and the cumulus granulosa cells. Both cell types are affected directly or indirectly by gonadotrophins and characteristical morphological changes develop synchronously in both cell types.
Pathways for Chloride and Sodium Transport across Toad Skin
Authors: Bruus K. , Kristensen P. , Larsen E. Hviid 
Published: December 2008

AbstractThe voltage dependencies of Na and CI fluxes were investigated in the isolated toad skin. With Cl‐Ringer's on both sides Cl outflux varied very little with clamping voltage. The same was true for the influx of Cl at depolarizing voltages (ψi ‐ ψo < 0 mV). whereas hyperpolarization led to a marked increase in this flux. A net chloride influx under short circuit conditions indicated active transport of chloride. The outflux of Cl was a saturable function of outside Cl concentration. The outflux of urea was hardly affected by raising outside Cl concentration, and the effect of varying outside nitrate concentration on Cl outflux was likewise small. Both influx and outflux could be inhibited partially by acetazolamide. The outflux of Na varied with the clamping voltage as would be expected for an ion transported by electrodiffusion, and it was shown that amiloride had no effect on Na outflux, so it was concluded that the Na outflux route is paracellular. In the absence of Cl in the outside solution a small outflux of Cl persists. Also this flux varied with the clamping voltage according to laws for electrodiffusion. The variation of the ratio of sodium outflux to chloride outflux with clamping voltage indicated free passive diffusion of both these ions under the conditions mentioned. A comparison of the outfluxes of Na and Cl in skins bathed with gluconate Ringer's outside showed that the outflux route of these two ions was cation selective (PNa/Pcl= 1.88). When the paracellular leak pathway of the skins was opened by exposing the outside to hyperosmolar urea solutions, the ratio of the transport numbers was found to be TNa/Tcl= 1.71. The roles of the two ions in determining the steady state current‐voltage relationships were compared. At hyperpolarizing voltages most or all of the clamping current was carried by an inward Cl flux. By depolarization sodium influx plays an increasing role with increasing depolarization. Under short circuit conditions active chloride transport was found to contribute to the short circuit current.
Prostaglandin‐mediated Inhibition of Noradrenaline Release: Its Resistance to Variations in Rate of Prostaglandin Synthesis
Authors: Wennmalm ÅKe , Junstad Marianne 
Published: December 2008

AbstractIsolated rabbit hearts were perfused according to Langendorff. The bilateral sympathetic nerve supply to the organ was stimulated at intervals, and the overflow of noradrenaline and of prostaglandins of the E series in the effluent was assayed, using fluorimetric and bioassay methods, respectively. The synthesis of prostaglandins in the organ was stimulated, either by perfusing the heart at a low pO2, or by infusing nicotinic acid. Hypoxia increased the coronary flow, provided the prostaglandin synthesis was not inhibited, probably as a consequence of hypoxia stimulation of the endogenous formation of prostaglandins. The release of NA in response to nerve stimulation was, however, unaffected by hypoxia. Nicotinic acid also stimulated prostaglandin formation, doubling the overflow of the lipid in response to nerve stimulation. In this series, too, the release of NA induced by nerve stimulation was unaffected by stimulation of prostaglandin synthesis. It is concluded that local variations in the rate of prostaglandin synthesis are unable to change the degree to which the release of sympathetic neurotransmitter is inhibited. Furthermore, it is suggested that the prostaglandin synthesis in rabbit heart takes place in compartments, separated functionally or morphologically.
Identification of the Mucopolysaccharides in Catecholamine‐Containing Subcellular Particle Fractions from Various Rat, Cat and Ox Tissues
Authors: Blaschke E. , Bergqvist U. , Uvnäs B. 
Published: December 2008

AbstractSubcellular fractions containing adrenergic vesicles were obtained from bovine adrenal medulla and splenic nerve, rat and cat heart, and rat spleen. The fractions were washed free from lipids, digested with papain and the mucopolysaccharides (MPSs) then precipitated from the supernatant with ethanolic potassium acetate. The MPSs were identified by several different methods—microelectrophoresis on cellulose acetate in various media, cellulose column chromatography using elution solvents of increasing ionic strength, and treatment with specific enzymes followed by electrophoresis or column chromatography. The MPS precipitate from all the sources investigated contained dermatan sulphate or a dermatan sulphate‐chon‐droitin sulphate hybrid. In addition, the precipitate from rat spleen was found to contain chondroitin sulphate. Heparan sulphate was found in the precipitates from rat heart and spleen and hyaluronic acid in that from bovine splenic nerve. The finding of sulphomucopolysaccharides in the adrenergic vesicles, probably in a complex with protein, raises the question of the functional significance of such complexes. They might, by analogy with the ion‐exchange function of the heparin‐protein complex in mast cell granules, play a role in the storage and release of the amines.
Effect of Physical Training on LDH Activity and LDH Isozyme Pattern in Human Skeletal Muscle
Authors: Sjödin B. , Thorstensson A. , Frith K. , Karlsson J. 
Published: December 2008

AbstractTotal lactate dehydrogenase (LDH) activity and LDH isozyme pattern were studied in muscle biopsies obtained from m. vastus lateralis after 1) “aerobic” training performed as interval and extreme distance running, respectively (3 subjects); and 2) “anaerobic” training for two months, carried out as repeated maximal bursts of approximately 1 min running (6 subjects). After the “anaerobic training” no changes in LDH properties could be detected, although running performance improved. The extreme distance running resulted in a decrease in total LDH activity and an increase in relative activity of the heart specific isozymes. A relationship was also shown between the relative activity of these isozymes and the training distance covered. The relatively more aerobic conditions prevailing during distance running as compared to “anaerobic training” were proposed to decrease muscle specific subunits and/or increase synthesis of heart specific subunits in both muscle fibre types. This suggestion was supported by isozyme analysis of lyophilized and dissected single muscle fibres.
Hemodynamic Consequences of Resistance Vessel Rarification and of Changes in Smooth Muscle Sensitivity
Authors: Hallbäck M. , Göthberg G. , Lundin S. , Ricksten S.‐E. , Folkow B. 
Published: December 2008

AbstractAlterations in resistance vessel design in form of an increased wall/lumen ratio appears to markedly influence the resistance control in primary hypertension (Folkow et al. 1973). The raised resistance has also been suggested to be a consequence of a rarification of resistance vessels or/and to an increased vascular smooth muscle sensitivity. Thus two series of paired experiments were performed on matched normotensive rats, utilizing the responses of their hindquarter vascular beds during constant flow perfusion. In the first series, the precapillary resistance vessels section was first “rarified” by graded microplugging, thereby raising resistance at maximal dilatation about 50 per cent. Then the vascular responses to noradrenaline were studied to characterize the dose‐response or “resistance curves”. In the second series the vascular smooth muscle sensitivity to noradrenaline of one of the hindquarters was changed by infusion of phentolamine. The resistance responses were then recorded and the ensuing “resistance curves” compared. These changes of resistance vascular architecture and vascular smooth muscle sensitivity, respectively, led to mutually different characters of the “resistance curves”. Both of these differ, however, in virtually all important respects from those curves characterizing vascular beds of spontaneously or renal hypertensive rats.
Renal Cortical Blood Redistribution after Bumetanide Related to Heterogenicity of Cortical Prostaglandin Metabolism in Dogs
Authors: Olsen Uffe Bang , Ahnfelt‐Rønne Ian 
Published: December 2008

AbstractBumetanide is shown to increase renal blood flow and to augment the proportion of the cortical blood flow to middle cortex. This redistribution still takes place even when renal blood flow is maintained constant by renal artery clamping. Indomethacin pretreatment inhibits the increase of renal blood flow as well as the cortical blood redistribution. In vitro examinations of canine kidney tissue slices suggest that outer cortex and papilla are sites of prostaglandin synthesis. No differences in prostaglandin E degradation are observed within the cortex. This suggests a relative autonomy for prostaglandins in the outer cortex, whilst inner cortical areas are dependent on medullary/papillary prostaglandin E supply. The renal hemodynamic effect of bumetanide is therefore thought to be a result of a stimulation of mainly medullary/papillary prostaglandin synthesis.
Effects of Secretagogues on Oxygen Consumption, Aminopyrine Accumulation and Morphology in Isolated Gastric Glands
Authors: BERGLINDH Thomas , Helander Herbert F. , ÖBrink Karl Johan 
Published: December 2008

AbstractA recently developed method to isolate gastric glands from the rabbit gastric mucosa (Berglindh and Öbrink 1976) was used to study the effects of some common gastric secretagogues. Three parameters were investigated: 1) Respiratory activity; 2) Intraglandular accumulation of the weak base aminopyrine; 3) Quantitative morphology of the parietal cells. The following substances were tested: Histamine, cAMP, db‐cAMP, aminophylline, carbachol and pentagastrin. The strongest effect was obtained with db‐cAMP which dose‐dependently stimulated the respiration up to 200%, increased the aminopyrine accumulation 80% and altered the parietal cell morphology from a typically resting to a typically stimulated state. cAMP also stimulated the respiration but was about 10 times less effective on a molar basis than the dibutyryl form. Histamine, like db‐cAMP, stimulated the respiration in a dose‐dependent manner and strongly increased the aminopyrine accumulation. The morphological changes Were, however, not of the same magnitude as after db‐cAMP. Aminophylline, tested only for respiratory activity, stimulated the oxygen consumption moderately. Carbachol induced a transient increase in both the oxygen consumption and in the aminopyrine accumulation with a peak value after approximately 15 minutes for both, but gave no significant morphological alterations. Pentagastrin, finally, was incapable of inducing changes in any of the three parameters. Aminopyrine was also found to accumulate approx. 50 times in unstimulated, morphologically resting glands. This seems to indicate that there might be acid sites already in resting glands.
Glycerol Transport in Human Red Cells
Authors: Carlsen Anders , Wieth Jens Otto 
Published: December 2008

AbstractThe kinetics of 14C‐glycerol exchange was studied in human red cells. Glycerol appeared to be transported by two mechanisms: (i) by facilitated diffusion with permeability depending on glycerol concentration, and (ii) by an unspecific pathway, presumably representing the diffusion of individual glycerol molecules through the membrane with permeability independent of glycerol concentration. The latter permeability was 8 times 10‐8 cm/s at 20°C, it was independent of pH, and had an activation energy of 25 kcal/mol. The facilitated transport of glycerol was completely inhibited by Cu++, and the activation energy was low, about 10 kcal/mol. The transport system was competitively inhibited by H+, reacting with at least three hydrogen ions. The chemical specificity of the transport system was remarkably low: 1,3 propandiol, a structural analogue, as well as dimethylsulfoxide (a hydrogen bonding molecule with no structural resemblance to glycerol), inhibited glycerol transport competitively. Steins “dimerizer hypothesis” was revised according to our findings. A kinetic scheme describing the reactions of a transport controlling site with glycerol is presented in the Appendix. It is demonstrated in the article that the scheme accounts for our experimental results.
A Study of the Relationship between the Electrocardiogram and Hemodynamics in the Fetal Lamb during Asphyxia
Authors: Rosén K. G. , Hökegård K. H. , Kjellmer I. 
Published: December 2008

AbstractProgressive changes in the S‐T interval of the fetal ECG were studied in 22 lamb fetuses, acutely exteriorized and submitted to graded hypoxia. The ECG changes were studied in order to correlate them with cardiovascular function, as measured by heart rate, mean arterial pressure, end diastolic pressure and combined cardiac output, estimated by the thermodilution method, as well as with blood gases and acid‐base status. Close correlations were obtained between Pao., pH and base deficit and the severity of ECG changes, graded according to a scoring system. Alterations in the ECG pattern consistently preceeded signs of failing cardiovascular function. Our previous findings indicated that the hypoxic ECG changes could be regarded as a sign of myocardial glycolysis. Accordingly, similar progressive ECG changes could be induced by isoprenaline injections. It is concluded that progressive changes of the S‐T interval of the fetal ECG contains information about fetal hypoxic stress before signs of failing cardiovascular function are seen.
Influence of Age, Growth, Castration and Testosterone Treatment on the Noradrenaline Levels of the Ductus Deferens and the Auxiliary Male Reproductive Glands of the Rat
Authors: Sjöstrand Nils O. , Swedin Göran 
Published: December 2008

AbstractThe total amount of noradrenaline (NA) in the male accessories increases with normal growth of the organs and also with the age of the rat. The ductus deferens of the old rat has about twice as high NA concentration as that of the young rat. Castration of the prepuberal rat or the puberal rat leads to retardation or cessation, respectively, of the increase in NA amount of the male genital tract. Only in the old rat does castration produce a definite decrease in NA amount of the tract. Castration always raises the NA concentration of the sex accessories. Testosterone treatment of the puberal rat or the old rat produces minor or no increase, respectively, in total amount of NA of the male sex accessories. Testosterone treatment of old prepuberally castrated rats produces a marked increase in NA content of the male organs. It is concluded that androgens have no substancial direct effect on the adrenergic innervation per se, but affects the transmitter levels of the male organs indirectly through changes in number, size and relative proportion of the target cells of the adrenergic nervesi.e. the smooth muscle cells.
A Perfluorochemical Oxygen Carrier (Fluosol‐43) in a Synthetic Medium Used for Perfusion of Isolated Rat Liver
Authors: Nováková Vera , Birke G. , Plantin L.‐O. , Wretlind A. 
Published: December 2008

AbstractAn emulsion of perfluorotributylamine (Fluosol‐43) was used as substitute for the gas‐carrying function of erythrocytes in a synthetic medium for perfusion of isolated rat liver. The efficiency and effect of this synthetic gas‐carrier were evaluated from measurements of the concentrations of rat albumin, the unsaturated vitamin B.,‐binding capacity of small‐molecular‐size vitamin B12‐binding proteins (UBBC of SBP), urea nitrogen, glucose, sodium, potassium, alanine amino transferase (ALAT) in the medium, and the incorporation of 14C‐lysine into the circulating proteins. Secretion of bile, portal pressure, PO2, PCO2 and pH in the affluent and the effluent mediums were also measured. The results demonstrate that the oxygen‐carrying capacity of the medium and the metabolic functions of the liver were higher, and the liver damage less, when the medium included Fluosol‐43 than without it. The albumin synthesis and the secretion of bile were as high as has been reported for perfusions with erythrocytes. This indicates that the oxygen carried by the Fluosol‐43 was utilised by the liver, and that the metabolic functions were not adversely affected during 4 h of perfusion by the medium containing Fluosol‐43.
A Possible Vagal Adrenergic Release of Serotonin from Enterochromaffin Cells in the Cat
Authors: Ahlman H. , Lundberg J. , Dahlstrom A. , Kewenter J. 
Published: December 2008

AbstractThe intracellular concentrations of serotonin (5‐HT) in enterochromaffin cells (EC) in the cat small intestine have been studied by a cytofluorimetric method before and after long‐lasting efferent vagal nerve stimulation in the neck. Such stimulation induces a decrease of 5‐HT in EC of the gut as observed previously. Pretreatment with atropine could not block this decrease, suggesting a noncholinergic mechanism. Pre‐treatment with a β‐blocking agent, propranolol, or bilateral removal of the superior cervical ganglia could, however, block this 5‐HT decrease. Pretreatment with an α‐blocking agent, phenoxybenzamine, caused an increase in the 5‐HT content of EC both with and without nerve stimulation; the reason for this is obscure. The results indicate, that vagal nerve stimulation induces a neurogenic 5‐HT release from EC in the gut, and that adrenergic fibres, originating in the superior cervical ganglia, mediate this release probably via a β‐receptor mechanism. Whether or not an α‐receptor mechanism is also involved cannot be judged at present.
Intracerebroventsicular Glycerol: A Potent Inhibitor of ADH‐release and Thirst
Authors: Olsson K. , Larsson B. , Liljekvist E. 
Published: December 2008

AbstractOlsson, K., B. Larsson and E. Liljekvist. Intracerebroventricular glycerol: A potent inhibitor of ADH‐release and thirst. Acta physiol. scand. 1976. 98. 470477.Infusions of isotonic or hypertonic (0.3 or 0.5 M) glycerol into the lateral cerebral ventricle (60 min, 0.02 ml/min) of non‐hydrated goats invariably induced a conspicuous and sustained water diuresis. Corresponding infusions of 0.3 M glycero 1/0. 16 M NaCl were almost equally efficient in this respect. A more short‐lasting and less pronounced water diuresis was obtained in response to equivalent infusions of pure d‐glucose, and the response to 0.3 M glucose/0.16 M NaCl was variable. Intravenous injections of vaso‐pressin blocked the glucose‐induced diuresis, but only postponed the glycerol‐induced diuresis. Intracerebroventricular (IVT) infusions of 0.5 M glycerol caused a sustained, complete inhibition of the urge to drink in the 48 h dehydrated goat, whereas IVT glucose only attenuated dehydrative drinking. Twenty min after the infusions of glycerol the CSF [Na+] in the lateral ventricle was about 15% below normal. About 1056 reduction of CSF [Na+] was obtained 20 min after the IVT infusion of glycerol/NaCI. The corresponding infusion of pure d‐glucose reduced the CSF [Na+] by <5%. The glycerol and glycerol/ NaCl infusions caused a moderate reduction of renal Na+ + K+ excretion. The possibility is discussed that the observed effects of IVT glycerol is a manifestation of its efficiency to inhibit choroidal and/or juxtaventricular (Na+‐K+)‐ATPase activity.
Capillary Permeability in Cutaneous Tissue
Authors: Paaske William P. 
Published: December 2008

AbstractPaaske, W. P.Capillary permeability in cutaneous tissue. Acta physiol. scand. 1976.98. 492–499.Capillary permeability in cutaneous tissue was determined by the single injection, external counting method. A rabbit abdominal skin preparation was developed. After local vasodilatation, 5 μ1 (400 μCi)51Cr‐EDTA was administered intraarterially by a special bolus injection technique, and the response curve was recorded by external registration. The capillary diffusion capacity (the permeability‐surface area product) for51Cr‐EDTA amounted to 3.7 m1/100 g·min at a capillary extraction of 0.59 and a plasma flow of 4.8 m1/100 gemin. The permeability coefficient for51Cr‐EDTA in cutaneous tissue was calculated to 0.9.10‐5cm/s assuming a capillary surface area of 70 cm2/g.