bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Method for Determining Blood Flow and Oxygen Consumption in the Rat Brain
Authors: Nilsson B. , Siesjö B. K. 
Published: December 2008

AbstractCerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRo2) were measured in rats under nitrous oxide anaesthesia, using a133Xenon modification of the Kety and Schmidt inert gas technique with sampling of cerebral venous blood from the retroglenoid vein. Extracerebral contamination of the venous blood sampled was studied by comparing the rates at which the activity of133Xenon decreased in blood and tissues. Contamination was avoided by gentle compression of the contralateral retroglenoid vein during sampling. CBF and CMRo2of the rat brain were 80±2 and 7.6 ± 0.2 ml·(100 g)‐1, min‐1, respectively. These values are about 25% lower than those previously obtained for cerebral cortical tissue under similar conditions. Induced hypercapnia (Paco2about 70 mm Hg) or hypocapnia (Paco215–20 mm Hg) gave rise to expected changes in CBF but did not alter CMRo2The CMRo2of the rat brain is at least twice that of the human brain. This species difference, which is similar to that previously reported for the oxygen uptake of cerebral tissuein vitro, probably reflects on inverse relationship between brain weight and neuronal packing density.
Mechano‐Elastic Properties of Human Muscles at Different Temperatures
Authors: Asmussen Erling , Bonde‐Petersen Flemming , Jørgensen Kurt 
Published: December 2008

AbstractThe effect of changes in the muscle temperature on their ability to store elastic energy was studied by having 5 trained subjects perform maximal vertical jumps on a force platform, with and without counter movement, at muscle temperatures between about 32°C and 37°C. The results showed that the heights of vertical jumps were considerably reduced at lowered temperature, but the gain in height after a counter movement in the form of a jump down from a height of 0.4 m over the force platform, was significantly higher in the cold condition. To test whether this was due to an increased stiffness of the muscles, experiments with imposed sinusoidal length variations at 14 Hz were performed. Δforce ×Δlength‐1 (i.e. stiffness) increased with isometric tension independent of muscle temperature. Experiments in which the rate of tension development and relaxation in voluntary maximal isometric contractions were measured at different muscle temperatures showed that maximal isometric tension changed by less than 1 % per degree but the rate of tension development and relaxation by 3–5 % and 5 % per degree, respectively, in the temperature range studied (30° to 40°). These data may be explained by the hypothesis that the series elastic components of the active muscle are located in the cross‐bridges between myosin and actin filaments. The storage of elastic energy would be enhanced if the rate of breaking of these bridges were decreased at lower temperatures.
The Effects of Estrogens on Regional Adipose Tissue Cellularity in the Rat
Authors: Krotkiewski Marcin 
Published: December 2008

AbstractThe effects of high and low dose estrogen administration on adipose tissue cellularity and metabolism were investigated and compared with the effect of total starvation in female rats. Total starvation in female rats resulted in local fat cell size decrease which was, in different adipose tissue regions, directly proportional to the primary fat cell size. Thus, the largest fat cell size decrease was observed in the parametrial depot of adipose tissue with primarily the largest adipocytes and the smallest decrease of fat cell size in the subcutaneous adipose tissue, with primarily the smallest adipocytes. High doses of estrogen (Estradurin®—120 μg/km/gonth) resulted in a body and adipose tissue weight decrease after 10 weeks treatment. Contrary to the starvation effect the greatest fat cell size decrease was observed in the subcutaneous depot with primarily the smallest adipocytes. Lower estrogen dose (60 μg/kg/month) resulted, after 4 weeks treatment, in weight increase of adipose tissue. Fat cell size increased most in the parametrial depot—an adipose tissue region with primarily the biggest adipocytes. This is in contrast to the situation after insulin treatment and overfeeding which produce the largest size increase in the region with the smallest fat cells, and can be interpreted as evidence for regional specificity of the estrogen effect on fat cells.
The vagal release of 5‐hydroxytryptamine from enterochromaffin cells in the cat
Authors: Ahlman H. , Bhargava H. N. , Donahue P. E. , Newson B. , Gupta T. K. Das , Nyhus L. M. 
Published: December 2008

AbstractEnterochromaffin cells (EC) from the cat duodenum were studied before and after electrical efferent stimulation of the cervical vagal by means of electron microscopy and fluorescence histochemistry according to the Hillarp‐Falck technique. From the same animals portal blood plasma was assayed for serotonin (5‐HT) at various stages of the nerve stimulation. Within 15 min after the onset of vagal nerve stimulation there was a more than twofold increase of the portal 5‐HT levels, which returned to normal after cessation of stimulation. There was also a pronounced reduction in the fluorescence intensity of EC demonstrating a lowered intracellular 5‐HT level. Ultrastructurally there was evidence for basal exocytosis as well as for a release of osmiophilic material from the EC directly into the gut lumen after nerve stimulation. Together, these observations strongly suggest a vagally induced 5‐HT release from EC in the cat.
Uptake and energy‐dependent extrusion of calcium in the rat uterus
Authors: BATRA SATISH 
Published: December 2008

BATRA, S.: Uptake and energy‐dependent extrusion of calcium in the rat uterus. Acta Physiol Scand 1982, 114: 447–452. Received 24 Aug. 1981. ISSN 0001–6772. Department of Obstetrics and Gynecology. University of Lund and Leo Research Laboratories, Helsingborg, Sweden.The ability of lanthanum (La) to displace extracellular calcium or/and block calcium efflux from smooth muscle cells of the rat uterus was examined. Presence of 10 mM La in the medium used for tissue wash following45Ta uptake (La method) increased45Ca efflux particularly in the early phase (60 min) indicating displacement of extracellular calcium. Lowering of temperature from 37°C to 2°C of the La wash resulted in about three‐fold increase in45Ca retention by the tissue. Depolarization of tissue induced by high KCI during La wash at 37°C had no effect on the retention of45Ca. However, depolarization during45Ca uptake significantly increased45Ca uptake by the tissue which was counteracted by the presence of Nifedipine in the medium. The inhibition of tissue metabolic activity by FCCP had different effects on45Ca retention depending on whether the tissues were washed at 37°C or TC. When active45Ca extrusion during tissue washing was blocked (2°C).45Ca content of the tissues exposed to FCCP was reduced by about 35%. When tissues were allowed to actively pump out45Ca (37°C).45Ca content of FCCP exposed tissues was increased by about 50%. It is concluded that about two thirds of the Ca extruded by the tissue is resistant to La blockage, and is dependent on the energy provided by tissue metabolic activity. During the use of the standard La method for measuring cellular calcium in the uterus, there is an underestimation due to unblocked45Ca loss.
Performance of the hypertrophied left ventricle in spontaneously hypertensive rats. Effects of adrenergic stimulation
Authors: NORESSON EDDY , THORÉN PETER , HALLBÄCK‐NORDLANDER MARGARETA 
Published: December 2008

NORESSON, E., THORÉN, P. & HALLBÄCK‐NORLANDER, M.: Performance of the hypertrophied left ventricle in spontaneously hypertensive rats. Effects of adrenergic stimulation. Acta Physiol Scand 1982, 114:497–504. Received 22 May 1981. ISSN 0001–6772. Department of Physiology. University of Goteborg. Sweden.The performance of isolated hearts from adult male spontaneously hypertensive rats (SHR) and matched normotensive controls (NCR) was investigated in an antegrade perfusion system, where preload and afterload could be varied independently. During electrical pacing of the heart to constant heart rate. increases in afterload, but not in preload, considerably raised cardiac contractility, measured as left ventricular max dP/dt. At after‐loads equalling their respective in vivo ones. max dP/dt was similar in SHR and NCR. This indicates that the SHR hearts by myocardial hypertrophy are so well adapted to their raised afterload that an increased inotropic state of the heart is not required. Upon adrenaline addition, SHR and NCR did not differ concerning either “chronotropic sensitivity”, i.e. per cent increase in heart rate of the spontaneously beating heart or in “inotropic sensitivity”, measured as increase in max dP/dt. However, in this in vitro situation adrenaline increased stroke volume only when the hearts worked at reduced inotropism, induced by lowered temperature (30°C). At maximal inotropic stimulation by adrenaline and occluded outflow, the SHR hearts produced higher systolic pressures than the NCR ones. This reveals an increased maximal contractile capacity of the hypertrophied SHR left ventricle, rather than a reduced one as sometimes suggested.
Occurrence of an insulin‐like peptide in extracts of peripheral nerves of the cat and in extracts of human vagal nerves
Authors: UVNÄS‐MOBERG KERSTIN , POSLONCEC BRANKA , HAGERMAN MAGNUS , CASTENSSON STAFFAN , RUBIO CARLOS , UVNÄS BÖRJE 
Published: December 2008

Biopsies from various peripheral nerves were collected from living cats. The biopsies were extracted with acid ethanol and the insulin‐like immunoreactivity (ILI) content of the extracts determined with radioimmunoassay. The vagal, sciatic and radial nerves contained on the average 90, 3 and 28 ng of ILI per gram nerve tissue (wet weight), respectively. In the sympathetic trunc no ILI was found. In order to partly purify and characterize the nerve ILI extracts these were run on an HPLC system. The ILI coeluted with standard bovine insulin. The same amounts of ILI were found in the nerve extracts whether run on the HPLC system or not. It can be concluded that all of the immunoreactive material of the nerve extracts corresponds to insulin or to a peptide very similar to insulin. In two cats the radial and sciatic nerves were ligated for 24 h. Two to ten times more ILI occurred in biopsies taken proximal to the site of ligation than in those from corresponding distal biopsies, indicating that the insulin‐like material is transported distally within the nerves. ILI was found in extracts from vagal nerves taken from 3 days old human autopsy material. Also this human ILI coeluted with the bovine insulin standard in the HPLC system.We propose that insulin or a very similar peptide is synthetized in peripheral nerves of cats and humans and we suggest that this neurogenic “insulin” might act as a neurotransmitter or neuromodulator.
Pancreatic polypeptide family (APP, BPP, NPY and PYY) in relation to sympathetic vasoconstriction resistant to α‐adrenoceptor blockade
Authors: LUNDBERG J. M. , TATEMOTO K. 
Published: December 2008

Electrical stimulation of the cat cervical sympathetic trunk caused submandibular salivary secretion and vasoconstriction simultaneously with a contraction of the nictitating membrane. Following α‐ and β‐adrenoceptor blockade by phentolamine or phenoxybenzamine combined with propranolol, the salivary response and the nictitating membrane contraction upon sympathetic stimulation were almost abolished. A considerable vasoconstrictor response (up to 40% of control) however still remained in the submandibular gland. This yasoconstriction, which persisted after α‐adrenoceptor blockade, was rather slow in onset and had a long duration without any poststimulatory hyperemia. Local intra‐arterial infusions of noradrenaline caused submandibular vasoconstriction, salivary secretion and nictitating membrane contraction. The blood flow response to exogenous noradrenaline did, however, not mimic the effects of sympathetic nerve stimulation with regard to vascular escape. Whereas the vascular escape after nerve stimulation was followed by a prolonged vasoconstriction with a gradual decline, the escape after noradrenaline infusions was accompanied by a normalization of blood flow. Local intra‐arterial infusions of pancreatic polypeptide (PP)‐related peptides caused a slowly developing vasoconstriction with a long duration in the submandibular gland, but no salivary secretion or contraction of the nictitating membrane. The relative molar potencies as vasoconstrictory agents were about PYY: 1, neuropeptide Y (NPY): 5, avian and bovine pancreatic polypeptid 100. The vasoconstrictor effects of PP‐related peptides were resistant to α‐adrenoceptor blockade and present also in sympathectomized animals, suggesting a direct action on vascular smooth muscle. Combined local infusions of noradrenaline and NPY caused a vascular response in the submandibular salivary gland which was similar to that seen upon sympathetic nerve stimulation. PYY and NPY caused increase in systemic arterial blood pressure upon systemic administration which indicates general vasoconstrictor actions. This effect was accompanied by a transient bradycardia which was due to inhibition of sympathetic tone, since it was absent in animals treated with propranolol.In conclusion, the present findings illustrate the differential sensitivity to α‐adrenoceptor antagonists of the submandibular vasoconstriction and salivation as well as smooth muscle contraction of the nictitating membrane induced by sympathetic nerve stimulation. This remaining vasoconstriction may be explained by release of a nonadrenergic, PP‐related transmitter such as NPY which may be present together with noradrenaline in the vascular nerves. Release of an additional vasoconstrictory factor may also account for the finding that infusions of noradrenaline do not mimic the vascular effects of sympathetic nerve stimulation in vivo.
Sympathetic stimulation of amylase secretion during a parasympathetic background activity in the rat parotid gland
Authors: ASKING BENGT 
Published: December 2008

The amylase secretion in vivo was examined in the rat parotid gland. A comparison was made between individual stimulation of sympathetic and parasympathetic nerves and simultaneous activation of both nerves. When sympathetic stimulation was superimposed on a parasympathetic background activity, amylase secretion was elicited at a frequency far below the threshold for secretion of fluid, and increased in a frequency‐dependent way. This augmented amylase secretion, seen when the two nerves were activated at the same time, gave an amylase output which far exceeded the sum obtained at individual nerve stimulation.The sympathetic amylase secretion obtained in a background of parasympathetic activity seemed to be dependent entirely on β1‐adrenoceptors. When high sympathetic stimulation frequency (3–10 Hz) was used a reduction in salivary flow was seen, which was accompanied by a reduced amylase output. This effect was counteracted by α‐adrenoceptor blockade. Isoprenaline, injected intravenously during an ongoing parasympathetic activity, was found to evoke an augmented amylase secretion in a similar way as sympathetic nerve stimulation.
Renal interstitial pressure measured in the subcapsular space using an in vivo oncometer
Authors: BOBERG ULF , MULLER‐SUUR CHARLOTTE , PERSSON A. ERIK G. 
Published: December 2008

BOBERG, U., MÜLLER‐SUUR, C. & PERSSON, A.E.G. 1985. Renal interstitial pressure measured in the subcapsular space using an in vivo oncometer. Acta Physiol Scand125, 377–381. Received 8 March 1985, accepted 1 May 1985, ISSN 0001–6772. Department of Physiology and Medical Biophysics, and Department of Urology, Uppsala University, Uppsala, Sweden.Continuous measurements of renal interstital pressure are of importance for several reasons. The present paper describes an in vivo oncometer developed for this purpose.A piece of dialysis tubing was filled with a 0.15 M NaCl solution containing 5 g albumin 100 ml‐1. For detecting the hydrostatic pressure inside the tubing, a thin catheter and a silver wire were inserted into it and both ends of the tubing were sealed with glue. The catheter and the silver wire were connected to a servo‐nulling pressure device. The oncometer was then placed under the renal capsule. The pressure inside the dialysis tubing was πonc+ Psc–πsc, and since πonc was known, the net interstitial pressure (Pnet, i.e. Psc–πsc) could be measured continuously in the subcapsular space.Measurements were made during (1) intravenous bolus injection of 2 ml of 0.9% NaCl, (2) saline expansion of 5% of body weight, and (3) elevation of renal venous pressure to 20 mmHg by clamping the renal vein.In the control situation, Pnei averaged –3.3 mmHg, a value in good accordance with findings in earlier studies in which the hydrostatic and oncotic pressure components have been measured separately. Following bolus injection of fluid, Pnet increased transiently by 2.6 mmHg, whereas volume expansion produced a permanent increase in Pnei of almost the same magnitude. During elevated renal venous pressure PDei was unaffected, except for a minor increase on clamping and a minor decrease on release of the clamp.The results show that reproducible and accurate measurements of Pnet in the renal subcapsular space can be made with an in vivo oncometer.
Distension‐dependent changes in noradrenaline sensitivity in small arteries from the rat
Authors: NILSSON HOLGER , SJÖBLOM NINA 
Published: December 2008

NILSSON, H. & SJÖBLOM, N. 1985. Distension‐dependent changes in noradrenaline sensitivity in small arteries from the rat.Acta Physiol Scand125, 429–435. Received 5 March 1985, accepted 6 May 1985. ISSN 0001–6772. Department of Physiology, University of Göteborg, Sweden.The effects of distension on the sensitivity to noradrenaline and potassium were assessed in ring preparations of 200 μM branches from the superior mesenteric artery of the rat. In response to noradrenaline, maximal tension development occurred at smaller luminal diameters than with potassium activation. The sensitivity to noradrenaline increased with increasing distension whereas potassium sensitivity remained largely unchanged. A distension‐dependent increase in noradrenaline sensitivity was observed also in vessels depolarized with high‐potassium solution. The role of the distension‐dependent sensitivity to noradrenaline for isotonic contractions was also studied. Upon activation with applied noradrenaline, submaximal isotonic responses were somewhat smaller than isometric responses at the same dose. This may be ascribed to a reduction in sensitivity during the isotonic contraction. Upon neurogenic activation, no difference between isotonic and isometric responses was found. The results show that distension increases noradrenaline sensitivity in resistance vesselsin vitro, but that the consequences for their function as neuroeffectors may be small.
Effects of noradrenaline on the transcapillary passage of albumin, fluid and CrEDTA in the perfused rat hindlimb
Authors: HARALDSSON BÖRJE 
Published: December 2008

HARALDSSON, B. 1985. Effects of noradrenaline on the transcapillary passage of albumin, fluid and CrEDTA in the perfused rat hindlimb. Acta Physiol Scand 125, 561–571. Received 30 January 1985, accepted 30 April 1985. ISSN 0001–6772. Department of Physiology, University of Göteborg, Sweden.Isolated rat hindlimbs were artificially perfused with serum solutions, either during maximal vasodilatation induced by papaverine or during infusions of noradrenaline (NA) at concentrations of 0.5–3.5 μM. Transcapillary exchange was followed with three independent techniques: (1) clearance of albumin, measured after tissue accumulation of radiolabeled tracer, (2) capillary filtration capacity (CFC), determined gravimetrically, and (3) the capillary diffusion capacity (PS) for CrEDTA, calculated from venous indicator dilution curves after single bolus injection of dyes. During maximal vasodilation, when resistance to flow was 2.3 ± 0.1 PRU100, albumin clearance was 0.0241 ±0.0012 ml min‐1100 g‐1, CFC was 0.0367 ± 0.0009 ml min‐1 mmHg‐1 100g‐1 and PS for CrEDTA was 8.2 ± 0.4 ml min‐1 100 g‐1 Noradrenaline given before radiolabelled albumin increased vascular tone and reduced all three capillary exchange parameters in parallel. Albumin clearance was reduced also when NA was given after the introduction of radiolabeled albumin. When NA raised vascular tone to a level largely corresponding to that in resting skeletal muscle (PRU100 = 14) albumin clearance was 0.0067 ml min‐1 100 g‐1, CFC was 0.0141 ml min‐1 mmHg‐1 100 g‐1 and PS for CrEDTA was 2.4 ml min‐1 100 g‐1. These findings suggest that albumin is transported by convective mechanisms and that the hydrostatic pressures fall in the exchange vessels as a consequence of functional precapillary ‘sphincter’ activity. Further, albumin clearance seems to be the same in the artificially perfused rat hindlimbs as in intact animals, at comparable vascular resistances, suggesting that capillary permeability is not influenced by the present surgical procedure.
Effects of calcitonin on elemental distribution and ultrastructure of rat submandibular gland acinar cells
Authors: SAGULIN GUN‐BRITT , WROBLEWSKI JOANNA , ARVER STEFAN , ROOMANS GODFRIED M. 
Published: December 2008

SAGULIN, G.‐B., WROBLEWSKI, J., ARVER, S., & ROOMANS, G.M. 1985. Effects of calcitonin on elemental distribution and ultrastructure of rat submandibular gland acinar cells. Acta Physiol Scand 125, 649–654. Received 22 February 1985, accepted 5 June 1985. ISSN 0001–6772. Departments of Prosthetics, Histology, and Physiology, Karolinska Institute, and Department of Ultrastructure Research, Wenner‐Gren Institute, University of Stockholm, Stockholm, Sweden.The effect of calcitonin on rat submandibular gland acinar cells was investigated by X‐ray microanalysis and electron microscopy. Calcitonin caused a transient increase of the cellular calcium and magnesium concentration, but did not affect the intracellular concentration of other electrolytes. The relative volume of intracellular mucus increased from 45% in control glands to 72% at 6 h after administration of calcitonin. Calcitonin caused an inhibition of the cellular response of the acinar cells to β‐adrenergic and cholinergic agonists. The changes in elemental composition and ultrastructure of the gland cells are probably due to inhibition of mucus release from the cells.