摘要:

HARALDSSON, B. 1985. Effects of noradrenaline on the transcapillary passage of albumin, fluid and CrEDTA in the perfused rat hindlimb.Acta Physiol Scand125, 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‐1mmHg‐1100g‐1and PS for CrEDTA was 8.2 ± 0.4 ml min‐1100 g‐1Noradrenaline 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‐1100 g‐1, CFC was 0.0141 ml min‐1mmHg‐1100 g‐1and PS for CrEDTA was 2.4 ml min‐1100 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 i

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1985.tb07758.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

HÄKKINEN, K., ALÉN, M.&KOMI, P.V. 1985. Changes in isometric force‐ and relaxation‐time, electromyographic and muscle fibre characteristics of human skeletal muscle during strength training and detraining.Acta Physiol Scand125, 573–585. Received 26 January 1985, accepted 9 May 1985. ISSN 0001–6772. Department of Biology of Physical Activity and Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland.Eleven male subjects (20–32 years) accustomed to strength training went through progressive, high‐load strength training for 24 weeks with intensities ranging variably between 70 and 120% during each month. This training was also followed by a 12‐week detraining period. An increase of 26.8% (P<0.001) in maximal isometric strength took place during the training. The increase in strength correlated (P<0.05) with significant (P<0.05–0.01) increases in the neural activation (IEMG) of the leg extensor muscles during the most intensive training months. During the lower‐intensity training, maximum IEMG decreased (P<0.05). Enlargements of muscle‐fibre areas, especially of fast‐twitch type (P<0.001), took place during the first 12 weeks of training. No hypertrophic changes were noted during the latter half of training. After initial improvements (P<0.05) no changes or even slight worsening were noted in selected force‐time parameters during later strength training. During detraining a great (P<0.01) decrease in maximal strength was correlated (P<0.05) with the decrease (P<0.05) in the maximum IEMGs of the leg extensors. This period resulted also in decreases (P<0.05) of the mean muscle‐fibre areas of both fibre types. It was concluded that improvement in strength may be accounted for by neural factors during the course of very intensive strength training. Selective training‐induced hypertrophy also contributed to strength development but muscle hypertrophy may have some limitations during long‐lasting strength training, es

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1985.tb07759.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

.HÄKKUKINEN, K., KOMI, P.V.&ALÉN, M. 1985. Effect of explosive type strength training on isometric force‐ and relaxation‐time, electromyographic and muscle fibre characteristics of leg extensor muscles.Acta Physiol Scand125, 587–600. Received 26 January 1985, accepted 9 May 1985. ISSN 0001–6772. Department of Biology of Physical Activity and Department of Health Sciences, University of Jyväskylä, Finland.To investigate the influence of explosive type strength training on isometric force‐ and relaxation‐time and on electromyographic and muscle fibre characteristics of human skeletal muscle, 10 male subjects went through progressive training which included primarily jumping exercises without extra load and with light extra weights three times a week for 24 weeks. Specific training‐induced changes in force‐time curve were observed and demonstrated by great (P<0.05–0.001) improvements in parameters of fast force production and by a minor (P<0.05) increase in maximal force. The continuous increases in fast force production during the entire training were accompanied by and correlated with the increases (P<0.05) in average IEMG‐time curve and with the increase (P<0.05) in the FT:ST muscle fibre area ratio. The percentage of FT fibres of the muscle correlated (P<0.05) with the improvement of average force‐time curve during the training. The increase in maximal force was accompanied by significant (P<0.05) increases in maximum IEMGs of the trained muscles. However, the hypertrophic changes, as judged from the anthropometric and muscle fibre area data, were only slight during the training. It can be concluded that in training for fast force production considerable neural and selective muscular adaptations may occur to explain the improvement in performance, but that genetic factors may determine the ultimate potential of the trainability of this aspect of the

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1985.tb07760.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

WIIG, H., OPDAHL, H., NICOLAYSEN, A.&NICOLAYSEN, G. 1985. Interstitial fluid pressure in the isolated perfused rabbit lung.Acta Physiol Scand125, 601–607. Received 10 March 1985, accepted 9 May 1985. ISSN 0001–6772. Department of Physiology, University of Bergen and Institute of Physiology, University of Oslo, Norway.Interstitial fluid pressure was measured in nine isolated perfused rabbit lungs with the servonull micropipette method. Bevelled glass micropipettes, with tip diameter 2–6 μm (o.d.) were inserted 2–6 mm into the left lung. At alveolar pressures of 3 to 5 cm H2O we found mean interstitial fluid pressures of 1.0 (SD 1.0) and 1.6 (SD 1.0) cm H2O relative to pleural pressure in the upper (n =19) and lower (n= 21) lobes respectively. The vertical distance between the measuring sites in the upper and lower lobes was about 3 cm. Net filtration caused by elevated left atrial pressure caused practically no change in interstitial fluid pressure. Increased alveolar pressure either increased or decreased interstitial fluid pressure. The measured pressures probably represent interstitial fluid pressure in alveolar junctions or in the interstitium around small pulmonary arteries or veins. We conclude that interstitial fluid pressure in these sites is between alveolar and pleural pressure, and that it is only moderately affected by changes in alveolar pressure. The interstitial compliance appears to be high and there seem to be little or no vertical gradients in interstitial fluid pressure within

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1985.tb07761.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

HAUG, A., HØSTMARK, A.T.&SPYDEVOLD, Ø. 1985, Plasma lipoprotein distribution, faecal cholesterol excretion, and activities of lipoprotein lipase, hepatic lipase, and lecithin: cholesterol acyltransferase in rats fed diets rich in sucrose or sunflower oil.Acta Physiol Scand125, 609–617. Received 10 January 1985, accepted 10 May 1985. ISSN 0001–6772. Department of Preventive Medicine and Institute for Medical Biochemistry, University of Oslo, Norway.Plasma HDL2has been suggested to carry cholesterol to the liver for subsequent excretion in the bile and faeces. The enzymes lipoprotein lipase (LPL), hepatic lipase (HL) and lecithin: cholesterol acyltransferase (LCAT) have been implicated in the centripetal cholesterol transport. Activities of these enzymes, the amount of faecal cholesterol excretion and the level of plasma lipoproteins were determined in male rats fed for 4 weeks on purified diets in which the sunflower oil: sucrose ratio was either 0.03 (group a) or 1.01 (group b). Whole plasma triacylglycerols (TG), unesterified cholesterol (UC) and phospholipids (PL) were highest in group (a). The concentration of cholesteryl esters (CE) was similar in the two groups. Protein, TG and UC of VLDL, and TG, UC, CE and PL of HDL2were higher in group (a) than in group (b). The HDL3‐protein and TG were lowest in group (a). Thus, total weight of VLDL and HDL2were increased, and HDL3reduced in group (a), which had also increased activities of HL and adipose tissue LPL. Activity of LCAT was lower, and faecal excretion of cholesterol was reduced by about 50% in group (a) compared to group (b). Accordingly, in the rat increased plasma levels of HDL2are not necessarily indicative of increased faecal cholesterol ex

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1985.tb07762.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

VIKSE, A., BUGGE, J., DAHL, E.&KIIL, F. 1985. Dissociation between renal prostaglandin E2and renin release. Effects of glucagon, dopamine and cyclic AMP in dogs.Acta Physiol Scand125, 619–626. Received 14 March 1985, accepted 10 May 1985. ISSN 0001–6772. University of Oslo, Institute for Experimental Medical Research, Ullevaal Hospital, Norway.To examine the relationship between prostaglandin E2(PGE2) and renin release, glucagon, dopamine and dibutyryl cyclic AMP (DB‐cAMP) were infused into dog kidneys during autoregulatory dilation of preglomerular vessels. Autoregulatory vasodilation, which enhances PGE2and renin release, was induced by renal arterial constriction or ureteral occlusion. Glucagon infusion increased both PGE2and renin release during autoregulatory vasodilation, and renin release was almost abolished after inhibiting PGE2release by indomethacin. In contrast, dopamine and DB‐cAMP infused during autoregulatory vasodilation increased renin release without significantly changing PGE2release. Stimulation of renin release was not dependent on vasodilatory effects, which for all drugs were greatly diminished during autoregulatory vasodilation. Hence, glucagon stimulates both PGE2and renin release. Most of the increase in renin release during glucagon infusion is prostaglandin‐dependent since indomethacin greatly reduced the stimulatory effect. In contrast, dopamine and DB‐cAMP stimulate renin release without increasing PGE2release as previously found for β‐adrenerg

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1985.tb07763.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

LINDVALL‐AXELSSON, M., HEDNER, P., OWMAN, CH.,&WINBLADH, B. 1985. Influence of thyroid hormones on transport function and Na+‐K+‐ATPase activity in the rat choroid plexus.Acta Physiol Scand125, 627–632. Received 11 February 1985, accepted 28 May 1985. Departments of Histology and Internal Medicine, University of Lund, Lund, and Department of Pediatrics, Sachs' Children Hospital, Karolinska Institute, Stockholm, Sweden.The sympathomimetic stimulation of choroid plexus transport and secretion in rat seems to be mediated by β‐adrenergic receptors. In the present report the effect of induced changes in thyroid function on transport mechanisms in the rat choroid plexus was studied. Following induction of hyperthyroidism (treatment with T3for 10 days) the tissue/medium ratio (T/M) for choline uptake in choroid plexusin vitrodecreased significantly by 68%. The Na+‐K+‐ATPase activity showed a statistically significant increase of about 16%. Also following cervical sympathectomy, T3caused a reduction of the T/M for choline, to the same level as in the non‐sympathectomized animals, while the effect of T3on the Na+‐K+‐ATPase activity was changed into a 22% decrease. Hypothyroidism (administration of PTU in the drinking water) had little or no effect on the uptake and accumulation of choline in the choroid plexus. The Na+‐K+‐ATPase activity was reduced by 40%, in contrast to the stimulating effect of T3. There is, hence, reason to believe that the transport of choline in the choroid plexus is only partly regulated by adrenergic mechanisms acting via Na+‐K+‐ATPase. The major effect of T3on the choline uptake may be exerted by a mechanism different from the ATPase activity and not in

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1985.tb07764.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

MEKJAVIC, I. B.&EIKEN, O. 1985. Inhibition of shivering in man by thermal stimulation of the facial area.Acta Physiol Scand125, 633–637. Received 26 April 1985, accepted 28 May 1985. ISSN 0001–6772. Department of Kinesiology, Simon Fraser University, Burnaby, Canada, and Department of Environmental Medicine, Karolinska Institutet, Stockholm, SwedenThe contribution of the facial thermoreceptors to thermoregulatory shivering was studied. Seven subjects were exposed to – 3 °C ambient air for 1 h. Radiant heat was applied to the facial area during 30 s periods at 10 min intervals and the effects on the integrated electromyographic activity (IEMG) in the brachial biceps, trapezius and femoral rectus muscles, and on the heart rate (HR) were studied. During cold‐air exposure mean skin temperature as measured at four sites decreased by 15.5±0.6 °C (mean ± SE) while rectal temperature remained virtually unchanged. During the radiant heat exposures IEMG activity decreased by 18.9 ± 2.3%; HR decreased by 11± 1 beats min‐1. The changes in IEMG occurred within or slightly below the range of maximum cold receptor sensitivity (20–30 °C) and coincided with the maximum rate of change in chin temperature. The observed inhibition of shivering IEMG during locally applied facial heat stimulation suggest that the trigeminal region contributes an important input to the overall thermore

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1985.tb07765.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

RORSMAN P.&ABRAHAMSSON, H. 1985. Cyclic AMP potentiates glucose‐induced insulin release from mouse pancreatic islets without increasing cytosolic free Ca2+.Acta Physiol Scand125, 639–647. Received 18 March 1985, accepted 28 May 1985. ISSN 0001–6772. Department of Medical Cell Biology, Biomedicum, University of Uppsala, Sweden.The effects of various stimulants of insulin release on cytosolic free Ca2+, [Ca2+]i, in dispersed and cultured pancreatic β‐cells fromob/ob‐mice were studied using the indicator quin‐2, which in itself has only slight effects on the glucose‐induced insulin release and the metabolism of the sugar. The resting [Ca2+]iwas 158 ± 7 nM. After increasing glucose to 20 mM there was a lag‐period of 1–2 min before [Ca2+]igradually rose, reaching a new plateau 60% higher after 5–6 min. Increasing intracellular cyclic AMP by adding forskolin did not further increase [Ca2+]i; on the contrary there was a slight temporary reduction despite a doubling of insulin secretion. The maintenance of the β‐cell function was evident from a marked increase of cytosolic [Ca2+]iafter depolarization evoked by high extracellular K+. Also dibutyryl cyclic AMP and theophylline lacked the ability to raise [Ca2+]ibeyond that obtained by glucose. The results suggest that cyclic AMP potentiates glucose‐induced insulin release by sensitizing the secretory machinery to changes of [Ca2+]irather than by increasing the cytosoli

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1985.tb07766.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

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 Scand125, 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 fr

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1985.tb07767.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY