bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some Characteristics of Lipolysis in Dog Adipose Tissue. Effects of Noradrenaline, Prostaglandin E1and Nicotinic Acid
Authors: Carlson Lars A. , Micheli Horace 
Published: December 2008

AbstractOmental adipose tissue from twelwe fasted dogs of both sexes was incubated in vitro and the glycerol release determined as a measure of lipolysis. The effect of addition of noradrenaline, prostaglandin E1(PGE1) and nicotinic acid into the medium was studied. On basal lipolysis the following effects were obtained with PGE.,0.1 μgPGE Inhibition 4 dogs, no effect 6 dogs. 1 μg PGE1:Inhibition 1 dog, no effect 5 dogs, stimulation 6 dogs,10 pg PGE1: Inhibition 1 dog, no effect 3 dogs, stimulation 8 dogs. A dualistic action of PGE1was seen in some of the dogs. PGE1, 1 μg, inhibited lipolysis stimulated by noradrenaline only in those dogs where the same amount of PGE1either inhibited or did not modify basal lipolysis. In those dogs where 1 μg of PGE1stimulated basal lipolysis, this dose did not inhibit the stimulation caused by noradrenaline. The β‐adrenergic blocker Kö 592 inhibited the stimulation of lipolysis caused by PGE, only slightly while Kö 592 completely inhibited the stimulation elicited by noradrenaline.Nicotinic acid inhibited the basal lipolysis in five of ten dogs and the stimulation induced by noradrenaline in three of ten. In those dogs where nicotinic acid inhibited lipolysis PGE1was in general also inhibitory.
Parasympathetic Neuro‐Effector Transmission and Functional Vasodilatation in the Submandibular Salivary Gland of Cats
Authors: Gautvik Kaare 
Published: December 2008

AbstractThe present study deals with the effect of different pharmacological agents on the secretory and vasodilator responses caused by stimulation of the chordo‐lingual nerve in cat submandibular salivary glands perfused under conditions of constant volume inflow.When the gland was perfused with red cellsiuspended in normal cat plasma or in kininogen‐free solutions, the vasodilator and secretory responses raused by stimulation of the chordo‐lingual nerve were mimicked by close arterial injections of acetylcholine. Atropine injected intravenously in doses of 0.5–1 mg/kg did not affect the chorda‐induced vasodilatation while salivary secretion was blocked. Increasing doses of atropine caused a successive reduction in the chorda‐mediated vasodilatation.Close arterial injections of isoprenaline caused vasodilatation, but no secretion of saliva. Propranolol in doses of 10–200 μg infused into the gland, abolished the effect of injected isoprenaline, but caused a small reduction of the chorda‐mediated vasodilatation. The combined action of propranolol and atropine depressed the long‐lasting vasodilator phase of chorda stimulation while the initial decrease in perfusion pressure was not affected.The findings suggest that the chordo‐lingual fibres to this gland all are cholinergic and that the nerve‐effector transmissions vary in their atropine sensitivity. The neuroglandular synapse responsible for secretion of watery saliva is easily blocked by atropine. The neuro‐vascular transmission and the neuro‐glandular connection responsible for release of kallikrein, are both relatively atropine‐resistant.
The Mucopolysaccharides in the Myocardium of Growing Rats
Authors: von Knorring Johan 
Published: December 2008

AbstractNo change in the myocardial mucopolysaccharide (MPS) content, measured as uronic acid of alkali‐extracted tissue or hexosamine in papain‐digests of fresh tissue, was observed in rats from the age of 7 days to 18 months. When MPS from papain‐digested myocardial and aortic tissue was separated by electrophoresis on cellulose acetate, three Akian blue‐positive fractions were demonstrated. Identification of the fractions was attempted on the basis of their electrophoretic mobility, their response to testicular hyaluronidase and autoradiography of 35S‐containing fractions. The slowest fraction (fraction 1) was designated hyaluronic acid (HA), fraction 2 was thought to be identical with heparitin sulphate (HS) and fraction 3 with chondroitin sulphate A/C (CS‐A/C). Fractions 1 and 2 in myocardium and aorta had the same electrophoretic properties, while fraction 3 from the two tissues differed in this respect. As calculated from photoscanned strips, HA was predominant in the myocardium and the HS‐like fraction in the aorta. The HA‐peak showed a slight proportional increase in the myocardium with increasing age, corresponding to a decrease in CS‐A/C. The results suggested that the MPS pattern of the myocardium is definitely formed at an early foetal stage and postnatally undergoes only slight age changes.
Concentration of Trypsin Inhibitors of Different Molecular Size and of Albumin and Haptoglobin in Blood and in Lymph of Various Organs in the Dog
Authors: Ganrot P. O. , Laurell C.‐B. , Ohlsson K. 
Published: December 2008

AbstractThe concentration and homogeneity of some plasma proteins in lymph from various tissues in dog was studied immunochemically. Special interest was focused on the enzyme inhibitors, at‐antitrypsin, and α2–macroglobulin. The ratio between the concentrations in lymph and plasma was the same for albumin and α1 antitrypsin, but decreased significantly with increasing molecular size in the order α1–antitrypin, haptoglobin and α2–macroglobulin. The ratio α1–antitrypsin/α2–macroglobulin was, on the average, twice as high in the intercellular fluid as in plasma. The protein content of the lymph varied considerably between the organs with the highest values for lung and liver. These organs also showed the lowest selectivity, expressed as the quotient between the α1–antitrypsin lymph/plasma ratio and the az‐macroglobulin lymph/ plasma ratio. The influence of different rates of lymph flow in different organs on these values is discussed. No enzyme‐inhibitor complexes were demonstrated.
Excitation and Impulse Conduction in the Human Fetal Heart
Authors: Gennser Gerhard , Nilsson Erik 
Published: December 2008

AbstractIntracellular and bipolar surface electrodes were used to record electrical activity from isolated hearts of human fetuses at midgestation (17–24 weeks). Action potential characteristics for cells in the sinus node, the atrium, the AV‐node, and the ventricle are described. Diastolic depolarizations and subthreshold oscillations indicating latent pacemaker activity were found in arrial cells but not in ventricle cells. Resting membrane potential in ventricle cells was – 81.4 mV at 37°C and an external potassium concentration of 4 mM. With increasing external potassium concentrations, the resting membrane potential increased, within the range 8–64 mM the change was 51.2 mV per tenfold increase in potassium concentration. In 0.5 mM potassium solution, the amplitude of the resting membrane potential declined in ventricle cells and spontaneous action potentials appeared. Within the temperature range 37–19°C, a decrease in temperature increased the resting membrane potential 0.9 mV per°C. Conduction velocity in both atrium and ventricle was 0.4–0.7 mlsec. In ventricle, the conduction velocity decreased with increasing stimulation frequency within the range studied (12–240 stim./min). In atrium, the conduction velocity decreased both at frequencies above 100/min and at very low frequencies. The conduction velocity through the AV‐node was approximately 0.01 m/sec and decreased with increasing stimulation frequency above 100 stim./min.
Relation between Tension and Sensory Response of the Isolated Frog Muscle Spindle during Stretch
Authors: Husmark I. , Ottoson D. 
Published: December 2008

AbstractThe tension developed in the isolated frog muscle spindle during stretch has been studied and related to the impulse response and the isolated receptor potential of the spindle. With a steplike stretch tension rose to an initial peak and then declined towards a steady level. The decay consisted of an initial phase of rapid fall and a later phase of slow decline when stretch was prolonged. The magnitude of the peak and the static level of tension were exponential functions of the amount of stretch. The response of the spindle in terms of the impulse discharge and the isolated receptor potential closely followed the tension changes during various phases of stretch. Adaptation of the spindle to maintained stretch, in terms of the fall of the receptor potential, followed the same general time course as the decay in tension. The results suggest that tension during stretch reflects structural changes within the spindle and that these changes may bear a more direct relation to the sensory response than lengthening. Neither the gross tension nor the elongation ran, however, be regarded as a dirert representation of the actual stimulus to the endings.
Properties of Muscle and Liver Lysosomes in Adrenalectomized Rats
Authors: Berg Trond , Bird John W. C. 
Published: December 2008

AbstractThe stability of lysosomes from liver and muscle of adrenalectomized, young rats has been tested by measuring the release of acid hydrolases (RNase, cathepsin D, β‐glucuronidase and aryl sulphatase) from lysosomes under various conditions. Adrenalectomy increased the proportion of enzyme released from the lysosomal particles, as measured in tissue homogenates or fractions. The release, which may have occurred in vivo or during homogenization, probably reflects an increased lysosomal fragility. In muscle (but not in liver) an increase in the total activtiy of acid hydrolases could also be observed after adrenalectomy. The effects of adrenalectomy could not be corrected by saline treatment, and were not due to reduced food intake. All parameters were restored to normal by administration of 300 μg of corticosterone daily for 5 days, and higher doses (3 mg per day) led to further reduction in enzyme release. The stability of muscle and liver lysosomes in vitro was tested by exposing particles to osmotic stress, vitamin A alcohol and acid medium (pH 5). Liver and muscle lysosomes from adrenalectomized rats were less stable when exposed to osmotic stress or vitamin A, but hepatic lysosome were more stable towards acid incubation than particles prepared from normal rats. Differential centrifugation of liver homogenates indicated that more acid hydrolases were associated with the heavier fractions in homogenates from operated animals. An increased particle size in tissues from the adrenalectomized animals may possibly account for the observed changes in lysosomal stability.
Structurally Based Increase of Flow Resistance in Spontaneously Hypertensive Rats
Authors: Folkow Björn , Hallbäck Margareta , Lundgren Yen , Weiss Lilian 
Published: December 2008

AbstractThe resistance to flow in the maximally dilated systemic vascular bed (except the coronaries) was compared in spontaneously hypertensive rats (SHR) and normotensive controls. – The aortic root was cannulated for perfusion with an oxygenated plasma substitute, both the aortic inflow and the venous effluent via the right heart being recorded continuously. Temperature and viscosity of the perfusate were kept constant and it was checked with supramaximal doses of vasodilator drugs that complete vascular relaxation was at hand. Pressure‐flow curves were plotted and flow resistances at equal pressure heads and transmural pressures were compared. — Flow resistance in the maximally dilated systemic vessels was increased in the spontaneously hypertensive rats to an extent that largely equalled their raised blood pressure during “resting” conditions, the difference to the control animals being highly significant. – The results suggest the presence of a morphological adaptation of the resistance vessels of the entire systemic circuit which raises the structurally set “baseline” for functional vascular adjustments, and which therefore may largely account for the increased flow resistance during rest. These findings are in agreement with earlier studies concerning the regional flow resistance in hypertensive man (Folkow 1956, Sivertsson and Olander 1968).
Bretylium and the Degeneration Contraction of the Sympathetically Innervated Periorbital Smooth Muscle in the Rat
Authors: Lundberg Dag 
Published: December 2008

AbstractThe ability of bretylium to delay the start of the degeneration contraction of the sympathetically innervated periorbital muscle has been studied in conscious rats. The sympathomimetic and neuron blocking action of bretylium at the doses most frequently used were also tested. A low dose, 0.5 mg/kg, that induced no measurable neuron block still delayed. The delay caused by local injection into the muscle exceeded the duiation of the neuron block. These findings indicate that the bretylium‐induced delay is not caused by neuron block and that the delaying action mainly is exerted on the terminal parts of the neurons. Bretylium given repeatedly postponed the onset of the degeneration contraction at least 6 to 10 hrs. Later the processes responsible for the degeneration contraction appeared to develope despite the treatment. Within 4 hrs preceding or just including the start of the degeneration contraction the time of injection was very critical for the effect of bretylium on the time course of the contraction. An injection of bretylium during an ongoing degeneration contraction interrupted the contraction and displaced the latter part for several hrs. Before the interruption the drug seemed to enhance the transmitter release. It appeared that early during the degeneration contraction there are nerve endings at different stages of degeneration on which bretylium acts differently.
Morphogenesis of Myoneural Junctions Induced Postnatally in the Tibialis Anterior Muscle of the Rat
Authors: Juntunen Juhani , Terävänen Heikki 
Published: December 2008

AbstractThe structure of myoneural junctions induced during nerve regeneration outside the zone of previously existing, degenerating myoneural junctions was studied with the light microscope after histochemical demonstration of acetylcholinesterase (AChE) activity in the tibialis anterior muscle of the postnatal rat. The escape of regenerating nerves from their original glial sheaths was produced by severe crushing of the sciatic nerve at different stages of development of the rat, from newborn animals to adults. New myoneural junctions were induced in the previously undifferentiated part of the muscle plasma membrane in animals of all age groups, although not in every individual animal, if the old myoneural junctions did not regenerate. New myoneural junctions were observed in about 70 % of the rats operated on before the age of 10 days and in less than 20 % in the older groups. The older the animal, the fewer new myoneural junctions were seen among the re‐innervated old ones, and in the adult animals a new myoneural junction was only sporadically foundMyoneural junctions were first seen outside the zone of previously existing junctions 14–16 days after the operation. Irrespective of the age of the animal at operation, the postnatally induced myoneural junction was plate‐like in structure during the early stages of morphogenesis. Postsynaptic infoldings appeared between the 16th and 25th days after the operation, the infoldings had become deeper between the 25th and 35th days, and the ramification of the AChE distribution typical of the mature myoneural junctions was observed between the 35th and 45th postoperative days.
Temperature Regulation during Exercise Dehydration in Man
Authors: Ekblom Björn , Greenleaf Carol J. , Greenleaf John E. , Hermansen Lars 
Published: December 2008

AbstractThe effects of mild exercise dehydration (1 % of the body weight) on temperature regulation were investigated in 3 men during continuous and intermittent exercise of 1 hr duration on a Krogh bicycle ergometer with the same average heat production at a relative O2 uptake of 62 % in the environment‐independent zone (22° C Ta and 38 % rh). In both hydration and dehydration, during intermittent work, equilibrium levels of rectal temperature (Tre) were 0.3° C higher than during continuous work. Progressive dehydration elevated equilibrium levels of Tre and mean body temperatures 0.3 to 0.4° C above hydration control values while mean skin temperatures (Ts) were essentially constant at 30±0.2° C. The elevation of Tre with dehydration was due, predominantly, to reduced sweating. It is suggested the sweat depression was due to reduced stimuli from the central nervous system to the glands. These results emphasize the sensitivity of the thermoregulatory system to dehydration and point up the need to control water intake during such experiments.
Uptake of 5‐Hydroxytryptamine by Rat Peritoneal Mast Cells in vitro
Authors: Jansson S.‐E. 
Published: December 2008

AbstractThe mechanism of 5‐hydroxytryptamine (5‐HT) uptake by rat peritoneal mast cells in vitro was studied under different incubation conditions. The uptake reached a saturation level even at low concentration of exogenous 5‐HT resulting in a concentration ratio of more than one thousand times. The uptake during the first hour was more rapid when compared with the slow uptake during succeeding hours. The uptake was dependent on temperature and calcium and magnesium ions. Addition of glucose to the medium did not accelerate the uptake which also was unaffected by pH alteration from 6.0 to 7.4. The proposed active uptake mechanism Tor 5‐HT was supported by the results obtained with metabolic inhibitors; those belonging to the group of uncouplers of oxidative phosphorylation effectively inhibited the uptake while sodium cyanide and sodium azide were without significant effect. Results obtained further indicated that 5‐HT at high exogenous concentrations may passively diffuse into the mast cells.
Estimation of Ionic Concentrations and Intracellular pH in Slices from Different Areas of Rat Brain
Authors: Hertz L. , Schousboe A. , Weiss George B. 
Published: December 2008

AbstractTissue spaces occupied by14C‐sucrose and3H‐inulin were measured at different incubation time intervals (15–120 min) in rat brain slices prepared from cortex, cerebellum, caudate, diencephalon and midbrain. Total water content, total Na+and K contents and14C‐DMO (5,5‐dimethyl‐2,4‐oxaolidinedione) spaces were obtained from the same tissues. At all time intervals,14C‐sucrose spaces were larger than corresponding3H‐inulin spaces. After 60 min incubation, the mean values for14C‐sucrose spaces in preparations from different brain areas ranged from 31.5 to 38.1 m1/100 g, whereas the3H‐inulin space mean values were 19.3–26.1 m1/100 g. Average intracellular pH was calculated from14C‐DMO spares in the presence and absence of 3.67 mM procaine. The pH1values obtained using inulin‐derived extracellular spares were 6.91–6.99, and those calculated from sucrose spaces were 6.77–6.89. The contents of K+and Na+showed no distinct regional differences, but a potassium uptake with time could only be observed in preparations from cerebral and cerebellar cortex.
Incorporation and Disappearance of Sulfate in Different Regions of Mouse and Rat Costal Cartilage in vivo and in vitro
Authors: Herbai Georg 
Published: December 2008

AbstractA rapid and simple method for liquid scintillation counting of 33S‐sulfate in biological tissues is described. Sulfate incorporation per mg dry weight into selected lateral, medial and intermediate regions of ribs was studied using costal cartilage from rats and mice. In vitro, cartilage pieces embracing the osteochondral junction had 2–4 times larger incorporation rate than the remaining homogeneous parts of the ribs, both if entire rib cages or stripped and diced cartilage were incubated. After in vivo injection to rats and mice the incorporation rates of sulfate into the region of the osteochondral junction was 2.6 times that found in “resting” cartilage in rats and 4.4 times in mice. The 35S‐sulfate uptake in the ribs per mg dry cartilage diminished in the caudal direction. Growth of the chest cage was mainly a longitudinal growth of the bony segments. Marked differences in the disappearance rates of previously incorporated sulfate were found in different regions along the rib. Rapid sulfate disappearance was found in the bony segment which, however, had incorporated only one seventh of the amount per mg taken up by “resting” cartilage. The “resting” cartilage segments exhibited a steady slow disappearance rate for sulfate and the osteochondral junction region consisting of several differently active tissues showed a rapid sulfate disappearance in the beginning followed by a slow clearance after 2 weeks similar to that of “resting” cartilage. The necessity of careful selection of costal cartilage samples with respect to regional differences is emphasized.
Dilatation of a Medium‐Sized Artery Immediately after Local Changes of Blood Pressure and Flow as Measured by Ultrasonic Technique
Authors: Ingebrigtsen R. , Leraand S. 
Published: December 2008

AbstractThe effect of changes in blood pressure and flow on the calibre of the medium‐sized artery has been studied in model experiments with an a‐v fistula on the femoral vessels in dogs, On opening of the fistula a large local fall of blood pressure proximal to the fistula and an increase in flow up to 1000 % has been found. With the use of an ultrasonic technique for measurement of arterial diameter—by which it was possible to measure changes in the diameter in the order of 0.001 mm—we found an immediate increase, in the order of 10 %, in the diameter of the femoral artery on the opening of the a‐v fistula. This increase remained as long as the fistula was patent. The results were identical in 5 dogs.The effect on the diameter of clamping the artery for some time, with consequent removal of the clamp, was examined in 5 dogs. Removal of the clamp itself resulted in only a small and temporary increase in the diameter of the artery. It is concluded that the dilatation of the artery on opening of the fistula must be connected to the sudden increase in flow.
Effects of Secretin on Fat Mobilizing Lipolysis and Cyclic AMP Levels in Rat Adipose Tissue
Authors: Butcher R. W. , Carlson L. A. 
Published: December 2008

AbstractSecretin, 0.0025 μg/ml, stimulated fat mobilizing lipolysis in rat adipose tissue in vitro, while cholecystokinin was without effect. Various fragments of the secretin peptide (amino acids 1–14, 15–27, 1–23 and 1–6) were inactive in roughly equirnol amounts. Secretin raised the concentration of cyclic AMP in isolated fat cells with a half maximal concentration of 2 × 10‐8M. Secretin also increased the formation of cyclic AMP from ATP in homogenates of isolated fat cells. Nicotinic acid and PGE1 inhibited the effects of secretin in rat fat with regard to lipolytic rate and accuniulation of cyclic AMP.
Releasing Effect of Calcium and Phosphate on Catechol‐amines, ATP, and Protein from Chromaffin Cell Granules
Authors: Lishajko F. 
Published: December 2008

AbstractAddition of Ca2+3 mM to isolated bovine adrenal niedullary granules incubated in 130 mM K‐phosphate buffer pH 6.8–7.2 causes a rapid initial release of noradrenaline (NA), adrenaline (A), ATP and soluble protein. The effect is increased by addition of 1–6 mg/ml of RNA and inhibited by 1–6 mM Mg2+. The effect of Ca2+is dependent on the presence of phosphate ions in the incubation medium and does not occur in sucrose, RCI or NaCl. Addition of freshly precipitated calcium phosphate is also effective in inducing release, but addition of CaHPO4 or Ca2P2O7 had no effect. CaCl2 0.3–1 mM did not increase the release but was effective together with 1–6 mg/ml of RNA. In the absence of phosphate ions Ca2+and Mg2+as well as the divalent ions Ba2+and Sr2+inhibited the release. The catecholamine releasing effect of Ca2+in the presence of phosphate is reduced by 2 mM ATP and almost completely prevented by ATP‐Mg2+. It is suggested that the increased outflow of granular contents is due to membrane alterations induced by Ca‐phosphate.