bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uptake of3H‐cortisol by Rabbit Polymorphonuclear Leukocytes in vitro
Authors: Simonsson Bengt 
Published: December 2008

AbstractRabbit pseudoeosinophilic polymorphonuclear leukocytesin vitrohave an uptake of3H‐cortisol, which is partly saturable and partly non‐saturable. The saturable component was much more dependent on temperature during accumulation and washout than the non‐saturable component. The metabolic inhibitors N‐ethyl maleimide, p‐chloro‐mercuribenzene sulfonic acid, iodoacetic acid and 2,4‐dinitro‐phenol and preheating at 67° C significantly decreased the saturable uptake while the non‐saturable uptake, if anything, was increased in some experiments. Dinitro‐phenol slightly accelerated the washout of the saturable component.The characteristics of the saturable3H‐cortisol uptake strengthens the evidence that it corresponds to a specific interaction with a receptor in the rabbit pseudoeosinophilic polymorphonuclear leukocytes, since it behaves like the specific hormone uptake in other tissues under similar conditions. The non‐saturable uptake behaves like a non‐specific uptake.
Concentration of Noradrenaline in Pial Vessels, Choroid Plexus, and Iris during Two Weeks after Sympathetic Ganglionectomy or Decentralization
Authors: Edvinsson L. , Owman Ch. , Rosengren E. , West K. A. 
Published: December 2008

AbstractChanges in the noradrenaline concentration of the sympathetically innervated pial vessels, choroid plexuses, and irides of the rabbit were measured fluorometrically at various periods during the first 2 weeks after pre‐ or postganglionic denemation (decentralization or excision of the superior cervical ganglia). The noradrenaline values fell to negligible amounts within 2 days after ganglionectomy in all organs, probably somewhat slower in choroid plexuses. After decentralization the noradrenaline level increased in the pial vessels, whereas in the choroid plexuses and iris it initially decreased followed by normalization. The fall occurred somewhat later in the iris. It is suggested that the results of the denervation experiments reflects the presence of functionally different types of sympathetic neurons in one and the same ganglion.
Characteristics of Monosaccharide Permeability in Arterial Tissue and Intestinal Smooth Muscle; Effect of Insulin
Authors: Arnqvist Hans J. 
Published: December 2008

AbstractMonosaccharide permeability was studied in bovine mesenteric arteries and rabbit intestinal smooth muscle. 14C‐labelled 3–0‐methylglucose was used to study counter‐transport and saturation kinetics. L‐glucose‐1–14C and D‐glucose‐1–14C were used to study substrate stereospecificity. 14C and 3H‐labelled sorbitol were used to estimate the extracellular space. In both bovine mesenteric arteries and smooth muscle from rabbit colon the membrane permeability of mono‐saccharides was characterized by substrate stereospecifici, ty, counter‐transport and saturation kinetics. Monosaccharides were transported down a concentration gradient. These results suggest that monosaccharides penetrate vascular and intestinal smooth muscle cell membranes by facilitated diffusion, In the concentration range 5.6–44.4 mM the distribution of unlabelled glucose in bovine mesenteric arteries corresponded to the distribu, tion of sorbitol‐14C, indicating that the membrane transport of glucose was rate limiting for the glucose metabolism. Insulin (0.1 U/ml) increased to a small degree the membrane transport of 3–0‐methylglucose in bovine mesenteric arteries. Compared with the effect of insulin on monosaccharide transport in skeletal muscle the effects on monosaccharide transport in bovine mesenteric arteries and rabbit colon smooth muscle were very small.
Effective Transmitter Concentrations in the Rat Portal Vein as Reflected by Neurogenic Potentiation of Responses to Exogenous Noradrenaline
Authors: Ljung Bengt , Wennergren Göran 
Published: December 2008

AbstractIn the rat portal vein exogenous noradrenaline (NA) and the transmitter released during nerve activity seem to react with the same set of α‐receptors, located on muscle cells close to the nerve terminals. Very shortlasting, high transmitter concentration peaks have been calculated to occur at the receptors for each nerve impulse. In the present study an indirect approach was utilized to evaluate to what extent these peak concentrations, in view of their short duration, are effective in activating the smooth muscle. Electrical field stimulation of the adrenergic nerve supply of the rat portal vein was applied during fully developed responses to graded concentrations of exogenous NA. Transmural stimulation at 2–32 imp/s was found to increase the established responses to exogenous NA in concentrations up to 10‐5M. These effects were abolished by tetrodotoxin. The findings imply that the high, shortlasting NA concentrations, which occur at the α‐receptors for each nerve impulse, lead to high transient degrees of receptor occupancy during nerve activity. The effective transmitter concentrations, over a wide range of impulse frequencies, thus seem to approach the levels of NA which produce maximum responses when applied exogenously.
Role of Cyclic AMP and Ca++in the Metabolic and Relaxing Effects of Catecholamines in Intestinal Smooth Muscle
Authors: Andersson Rolf 
Published: December 2008

AbstractIn rabbit colon muscle there was a quantitative correlation and a co‐ordination in time between relaxation and an increase in cyclic AMP on stimulation of adrenergic β‐receptors. The cyclic AMP content had increased before the muscle had started to relax. There was an increase in the phosphorylaseaactivity and reduction of the ATP content. The adrenergic β‐receptor blocking agent sotalol inhibited the relaxation and the increase in cyclic AMP content. Reduction of the Ca++content of the muscle decreased the cyclic AMP content and the phosphorylaseaactivity. These effects were restored on addition of Ca++ions. In a Ca‐poor muscle adrenergic β‐receptor stimulation still produced an increase in cyclic AMP content and phosphorylaseaactivity but there was an increase in the ATP content instead. The reduction of cyclic AMP which followed an adrenergic a‐receptor stimulation was eliminated in the Ca‐poor muscle. The existence of a Ca++‐accumulating ATP‐utilizing mechanism, stimulated by cyclic AMP, might explain the relation between relaxation, cyclic AMP and Ca++and adrenergic β‐receptor stimulation.
Effects of Sympathetic Stimulation on Mechanoreceptors of Cat Vibrissae
Authors: Nilsson Bengt Y. 
Published: December 2008

AbstractIn a previous investigation adrenergic nerve terminals were demonstrated in the hair follicles of cat vibrissae. The present study shows that electrical stimulation of the cervical sympathetic trunk produces small but repeatable changes in the dynamic responses of the slowly adapting mechanoreceptors of the vibrissae in that the number of impulses in each discharge is reduced and their latency increased. Changes in the static responses are very small. These effects were abolished by phentolamine. The receptor responses as well as effects of sympathetic stimulation remain unaffected by a brief carotid occlusion. It is concluded that the sympathetic modulation observed is a direct effect of locally released noradrenaline and is not attributable to circulatory changes or to pilomotor activity.
The Effect of Bilateral Carotid Artery Ligation upon the Blood Flow and the Energy State of the Rat Brain
Authors: Eklöf Bo , Siesjö Bo K. 
Published: December 2008

AbstractThe cerebral effects of bilateral carotid artery ligation were studied in ligthly anesthetized rats, either alone or combined with moderate reductions in the mean arterial blood pressure. The relative decreases in cerebral blood flow were estimated from the a‐v differences for O2 and CO2 on the assumption of an unchanged cerebral metabolic rate. Ligation of the carotid arteries alone was found to decrease cerebral blood flow to about 50 % of normal, but to give no significant changes in the energy state of the tissue, as judged from the tissue contents of the ATP, ADP and AMP. When the cerebral blood flow was reduced further by means of an induced decrease in blood pressure, the energy state of the tissue was severely affected. At this point the cerebral venous Po2 was reduced from about 50 to about 30 mm Hg. Since pure hypoxemia with a reduction of venous Po2 to about 10 mm Hg can be tolerated without changes in the energy state of the tissue, it is concluded that ischemia may lead to a grossly inhomogenous reduction in the tissue perfusion.
Microvascular Dimensions and Blood Flow in Skeletal Muscle
Authors: Eriksson Elof , Myrhage Rhagnar 
Published: December 2008

AbstractIn cats anesthetized with chloralose the lengths and diameters of the different vascular segments in the tenuissimus muscle were measured in the vital microscope. The flow characteristics, including red cell velocity, were registered. Fixed and stained muscle specimens were analyzed histologically as well as Indian ink‐perfused muscles treated according to the method of Spalteholz. The average muscle fibre diameter was 44 μm. 62% of the muscle fibres were red (48% B‐fibres, diameter 41 μm and 14% C‐fibres, diameter 26 μm) and the remaining 38% were white (A‐fibres, diameter 55 μm). The average muscle fibre was surrounded by 3.6 capillaries. The capillaries were 1015 ± 16.3 (S.E.) μm long and 5.3 ± 0.0(3) (S.E.) μm in internal diameter. The calculated capillary surface area was 0.9 m2/100 cm3of muscle tissue. Average red cell velocity in the capillaries was found to be 0.5 mm/s, but there was a wide variation with time and between different capillaries. Neither “spontaneous” changes in internal diameters of the microvessels nor a distinct precapillary sphincter activity could be observed. Arterio‐venous anastomoses within the muscle tissue were rare exceptions.
The Action of Physostigmine, Morphine, Cyclopentolate and Homatropine on the Secretion and Outflow of Aqueous Humour in the Rabbit Eye
Authors: Uusitalo Risto 
Published: December 2008

AbstractThe influence on the intraocular fluid dynamics (intraocular pressure, inflow and outflow) of one i.v. injection or a 3 day topical application of physostigmine, morphine, cyclopentolate or homatropine was investigated. Special attention was paid to the inflow of aqueous humour and ATPase activity in the ciliary body‐iris after administration of these drugs. Systemic injection of physostigmine caused a marked decrease in intraocular pressure, which seemed to be due to the decrease in inflow of aqueous humour. On the contrary, three day topical applications of this drug had no effect on the IOP or intraocular fluid dynamics. Intravenous injection of morphine increased both the inflow rate and the outflow facility of the eye. Cyclopentolate and homatropine did not decrease the outflow facility. However, cyclopentolate applied intravenously or topically increased both the inflow rate and the outflow facility slightly. Homatropine intravenously injected had no effect on the intraocular fluid dynamics but applied topically slightly increased the IOP, possibly due to the increased inflow of aqueous humour. None of these drugs caused any significant change in the NaK‐ATPase activity in the ciliary body‐iris. Physostigmine and morphine markedly reduced Mg‐ATPase activity. Physostigmine did not decrease Mg‐ATPase activity when the eye had been sympathectomized 7 days before administrations of the drug. It was concluded that the effect of physostigmine on Mg‐ATPase was possibly mediated by way of the sympathetic nervous system.
Catecholamines and Cholinesterases in the Paracervical (Frankenhauser) Ganglion of Normal and Pregnant Rats
Authors: Kanerva Lasse , Lietzen Ralf , Terävaïnen Heikki 
Published: December 2008

AbstractChatecholamines and cholinesterases were studied histochemically in the uterine paracervical ganglion of normal and pregnant rats and after both sympathectomy and sacral parasympathectomy. About one fifth of the ganglion cells revealed intense acetylcholinesterase (AChE) activity. The cells were large and devoid of catecholamines and received AChE‐containing nerves. — About one third of the ganglion cells contained weak to moderate yellow‐green catecholamine fluorescence. They were presumed to be adrenergic although they also exhibited moderate to weak AChE activity. These postganglionic neurons represent “short” adrenergic neurons. The rest of the ganglion cells with moderate to weak AChE activity were presumed to be cholinergic. Increased ganglion cell fluorescence was observed after 2 weeks of pregnancy. There was no change in the cholinesterase activity of the neurons. — Division of the sympathetic or the sacral parasympathetic nerves did not cause changes in the intensity of the histochemical reactions. The small, intensely fluorescent cells (SIF‐cells) did not show AChE activity. Other cholinesterases, although present in the cytoplasm of the ganglion cells and SIF‐cells, were mainly localized in the glial cells.
Effect of Sympathetic and Parasympathetic Stimulation on the Secretion and Outflow of Aqueous Humour in the Rabbit Eye
Authors: Uusitalo Risto 
Published: December 2008

AbstractThe influence of electrical stimulation of the superior cervical sympathetic ganglion or parasympathetic (oculomotor) preganglionic nerves on the IOP and intraocular fluid dynamics of rabbits was investigated. Special attention was paid to the inflow of aqueous humour and the NaK‐ATPase activity in the ciliary body‐iris after these stimulations. Sustained sympathetic stimulation was found to cause a significant decrease in the equilibrium pressure of the eye. This stimulation was found to decrease the rate of secretion of aqueous humour but not to influence significantly the rate of drainage of aqueous humour. Parasympathetic stimulation caused a significant increase in IOP, which was due to an increased inflow of aqueous humour. The NaK‐ATPase activity measured after these stimulations in the ciliary body‐iris was unaffected.
Effect of Physical Training on Hemodynamic Response during Submaximal and Maximal Exercise in 11–13‐Year Old Boys
Authors: Eriksson Bengt O. , Koch Günter 
Published: December 2008

AbstractNine healthy boys, mean age 11.7 years (11.0–13.0), height 150.4 cm and weight 45.1 kg, were examined with determinations of maximal oxygen uptake (1.85 1×min‐1), heart volume (499 ml) and total hemoglobin (391 g). Cardiac output was determined at rest and during exercise, including maximal exercise, using the dye‐dilution technique and i.a. pressures were recorded. Cardiac output was approximately 2 1×min‐1 lower and the systemic a‐v oxygen difference (AVD) was correspondingly higher than for young adult men at the same sub‐maximal oxygen uptake. At maximal exercise cardiac output was 12.5 1×min‐1, stroke volume 67 ml, AVD 14.2 ml × 100 ml‐1, systolic, diastolic and mean blood pressure 160, 71 and 105 mm Hg respectively and total peripheral resistance 8.6 mm Hg×1–1×min. After a training period of 4 months a normal increase in height was found in all boys, but body weight was unchanged. Maximal oxygen uptake increased to 2.21 1×min‐1 (p < 0.01), almost entirely due to increased stroke volume (80 ml), resulting in a maximal cardiac output of 14.6 1×min‐1. No significant increase in AVD was found. Mean blood pressure at maximal exercise increased significantly, total peripheral resistance was unchanged. Both heart volume and total hemoglobin showed minor increases, but the changes found were not significantly larger than expected from body growth. The hemoglobin concentration was normal (13 g%) for the age and unaffected by training.
Circulatory Responses to Stimulation of Medullated and Non‐medullated Afferents in the Cardiac Nerve in the Cat
Authors: ÖBerg Bengt , Thorén Peter 
Published: December 2008

AbstractRecordings of the evoked compound potentials in the right main cardiac nerve in the cat demonstrated the presence of both medullated and non‐medullated fibres. The circulatory responses to afferent stimulation of these two fibre populations were followed in terms of changes in blood pressure, heart rate and skeletal muscle and renal flow resistances. A selective stimulation of the medullated afferents, which probably arise mainly from atrial receptors, induced a moderate reflex rise of blood pressure, an increased heart rate and a vasoconstriction in the skeletal muscle and kidney. Clearcut effects were observed first with high stimulation frequencies, and then only in case the buffering influences from other receptor sites were minimized. Stimulation of the non‐medullated fibres, which probably emanate from ventricular receptors, caused a very marked reflex blood pressure fall, slowing of the heart and vasodilatation in the muscle and the kidney, already with very low stimulation rates. These results suggest that the powerful reflex influence from cardiac receptors on the cardiovascular system is exerted by receptors with non‐medullated afferents, while endings firing in medullated pathways as e.g. atrial receptors, have very small direct effects on the cardiovascular system and then rather of an excitatory nature.
Interaction of Adenosine 5‘‐Triphosphate (ATP) with Histamine Release Induced by Compound 48/80
Authors: Dahlquist Rune , Diamant Bertil , Elwin Kerstin 
Published: December 2008

AbstractThe histamine releasing action of compound 48/80 disappeared after pretreatment of rat mast cells with ATP in the absence of divalent cations. The inhibitory action was evident already with 2 μM of ATP, provided the cells were preincubated with ATP for short periods of time prior to the addition of 48/80. When mast cells were exposed to 48/80 combined with ATP more than 10 μM of ATP was needed to induce inhibition of histamine release. This inhibitory effect was found to be specific for ATP compared with various organic phosphorous compounds tested and was not mimicked by EDTA. With concentrations of ATP less than 10 μM the sensitivity to the action of 48/80 was spontaneously restored after prolonged preincubation of the cells with ATP. The experimental findings suggest that ATP, in the absence of divalent cations, induced configurational changes of the plasma membrane of the mast cells so that 48/80 could no longer exert its degranulating and histamine releasing action.
Effect of Divalent Cations on the Interaction of Adenosine 5‘‐Triphosphate (ATP) with Histamine Release Induced by Compound 48/80
Authors: Dahlquist Rune , Diamant Bertil , Elwin Kerstin 
Published: December 2008

AbstractThe inhibition exerted by ATP on histamine release caused by compound 48/80 from isolated rat mast cells was counteracted by Ca++, Mg++, Ba++, and Sr++, but not by Be++. In addition, after the inhibitory effect had been obtained by pretreatment of mast cells with ATP, addition of Mg++restored the sensitivity of the cells towards 48/80. The spontaneous restoration of the sensitivity of the mast cells towards 48/80 observed after prolonged pretreatment of the cells with ATP (< 10 μM.) was enhanced by the presence of glucose. Glucose did not effect the inhibitionper se.EDTA blocked 1) the protecting effect of divalent cations on the action of ATP on mast cells in regard to their sensitivity towards 48/80, 2) the action of Mg++to restore the sensitivity of mast cells towards 48/80 after rendered insensitive by treatment with ATP, 3) the spontaneous restoration of the sensitivity of ATP‐treated mast cells towards 48/80 observed after prolonged incubation alone, as well as the enhanced restoration observed in the presence of glucose. The results suggest an interaction between divalent cations and ATP on the plasma membrane.
Circulatory Control via Vagal Afferents V. Impairment of the circulatory adjustment to hemorrhage by vagal deafferentation and prolonged hypotension
Authors: Sjöstrand Torgny 
Published: December 2008

AbstractIn order to study the effect of vagal deafferentation on the resistance to bleeding, Sprague‐Dawley rats were subjected to repeated blood loss to an arterial pressure of 40–50 nim Hg. The time to the critical point, when blood had to be reinfused to maintain the pressure, as also the total drawn blood volume, was estimated after partial or complete vagal deafferentation. The time was reduced to, respectively, 64 and 40% compared with controls, and the blood loss to 86%. The bradycardia provoked on the first blood drawing decreased gradually to the critical point. A direct correlation was found between the time to the critical point and the duration of the heart rate depression in controls and partially deafferentated animals. On reinfusion at the critical Foint a phase of increased resistance to bleeding, falling off exponentially, was demonstrated. Subsequently the resistance was lowered in the controls and some animals died in circulatory insufficiency. During the phase of decreased resistance, the animals reacted on a renewed blood loss as after vagotomy. It is concluded that the resistance to bleeding is significantly influenced by vagal afferents, probably mediating impulses from the low pressure side, and that the effect of these receptors is abolished on prolonged hypotension.
Afferent Discharges via the Laryngeal Communicans Related to Respiration in the Rat
Authors: Castenfors Jan , Knutsson Evert , Sjöstrand Torgny 
Published: December 2008

AbstractImpulse discharges in vagal afferents via the laryngeal communicans and related to respiration have been recorded in Sprague‐Dawley rats. Particular interest has been devoted to 2 types of discharges, one appearing on deflation of the lungs and the other on active inspiration. The former is occasionally seen during ordinary expiration, but especially on application of pressure on the thorax, suction of air through trachea, insufflation of air into the pleural cavity, and on collapse of the lungs by exclusion of artificial breathing with open thorax. On suction of air and light compression of the thorax impulses may appear, after an initial burst, on each expiration.The discharges during the inspiratory phase appear independently of inflation of the lungs. They are very evident during gasps and auxiliary breathing. Discharges on inflation of the lungs have only occasionally been recorded.
Comparative Studies of Capillary Permeability in Brain and Muscle
Authors: Crone Christian , Thompson Alan M. 
Published: December 2008

AbstractThe permeability of the capillary wall in the brain was compared with that in muscle by means of the ratio between outflow concentrations (relative to inflow concentrations) after single i.a. injections of various combinations of two radioactive tracers. A ratio above 1 means that the solute in the denominator left the capillaries faster than the other tracer, vice versa. The following outflow ratios were obtained: Hind limb: Glucose/K+ and 3‐O‐methyl‐glucose/K+: above 1. Brain: Glucose/K+ and 3‐O‐methyl‐glucose/K+: below 1. The hind limb results show a faster transcapillary transport of potassium than of the sugars—in agreement with the predictions of the Pappenheimer pore model for muscle capillaries. In brain the sugars are transported faster across the capillary wall than tracer potassium. This finding cannot be explained by diffusion through a common interendothelial diffusion pathway (pore). but signify that the sugars are transported through the capillary endothelial cells in brain—a route not available to potassium. The Pappenheimer pore model only applies to the brain capillaries as a limiting case with a pore permeability close to zero, even for small solutes. Thus, the permeability characteristics of the brain capillaries are in closer agreement with those of mono‐layered epithelia than with the Pappenheimer pore model. It is concluded that important blood‐brain barrier functions are carried out in the cerebral capillary walls.