bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional development of the visual system in normal and protein deprived rats II. Morphometric and biochemical studies on adult optic nerve
Authors: CONRADI NILS G. , SJÖSTRÖM ANDERS , KARLSSON BÖRJE , SOURANDER PATRICK
Published: December 2008

The optic nerve of normal (C) and protein deprived (PD) adult rats was examined by morphometry and biochemistry. The mean cross‐sectional area of the optic nerve was reduced by 15% and the number of axons per unit area increased by 17% in the PD rats. Calibre spectrum analysis of axons revealed a reduction in median diameter from 0.49 μm in controls to 0.45 μm in PD rats. The number of axons with a diameter larger than r μm was reduced by 35% in PD rats. These reductions were probably due to a general reduction in size, since the calculated total number of axons in the optic nerve was almost identical in C and PD rats (126 times 103 and 124 times 103, respectively). The increased packing density of axons in the nerve was not only due to thinner axons. The biochemical measurements showed a marked reduction in myelin basic protein in the optic nerves of PD rats, without an alteration in the composition of the total protein. This confirms the persistant hypomyelination which has been reported previously in other malnutrition models. The possible relations between the structural and biochemical changes affecting optic nerve fibres and physiological findings on cortical visual evoked response and on optic nerve in vitro in PD rats are discussed.
Motor control of voluntary trunk movements in standing
Authors: THORSTENSSON ALF , ODDSSON LARS , CARLSON HANS
Published: December 2008

The pattern of activity in different trunk muscles during voluntary trunk movements was studied in the standing position in man. The electromyographic activity from ventral and dorsal trunk muscles on the left and right sides were recorded together with the movements in the sagittal and frontal planes (Selspot optoelectronic system). Movement direction, amplitude, velocity and initial posture were varied. In all movements there was a basic pattern of alternation between antagonist muscle groups. Fast movements were initiated by a sharp burst of activity, whereas slow flexions and side bendings resulted from a decrease in antigravity muscle activity. Movement amplitude was related to the magnitude of the initiating burst, and also to the time of onset of antagonist muscle activity with a braking effect. The contribution of passive internal forces in the braking of a movement was indicated by the myoelectrical pattern of activity, particularly in slow large side bendings, where ipsilateral activity was present at the end of the movement. Sagittal movements starting at different initial trunk inclinations resulted in shifts in onset time and duration between antagonist muscles. The observed modifications are specific adaptations of the motor program to balance changes in mechanical conditions, such as angular acceleration, moment arm for the gravitational force, and intrinsic forces of active and passive structures surrounding the spine and pelvis. In conclusion, the present results demonstrate that trunk movements are generated and controlled by specific patterns of muscle coordination.
ATP‐induced cation influx in myotubes is additive to cholinergic agonist action
Authors: HÄGGBLAD JOHAN , ERIKSSON HÅKAN , HEILBRONN EDITH
Published: December 2008

HÄGGBLAD, J., ERIKSSON, H. & HEILBRONN, E. 1985. ATP‐induced cation influx in myotubes is additive to cholinergic agonist action. Acta Physiol Scand125, 389–393. Received 20 March 1985, accepted 1 May 1985. ISSN 0001–6772. Unit of Neurochemistry and Neurotoxicology, University of Stockholm, S‐172–46 Sundbyberg, Sweden.

Using biochemical methods, ATP was shown to induce an inward flux of 86Rb into cultured chick myotubes. A biphasic dose‐response curve was observed, the first part of which was saturable and had an EC50 value of approximately 10 μM. β,γ‐imido ATP inhibited the ATP‐induced uptake. ADP, AMP and adenosine were less potent than ATP in producing influx. ATP‐induced influx of 86Rb was found to be additive to carbachol‐induced influx and, in contrast to the latter, not blocked by the nicotinic acetylcholine receptor antagonist α‐bungarotoxin. The results suggest the presence of an ATP recognition‐site on myotubes, triggering ion‐permeation.
Evidence for substance P‐immunoreactive spinal afferents that mediate bronchoconstriction
Authors: SARIA ALOIS , MARTLING CLAES‐ROLAND , DALSGAARD CARL‐JOHAN , LUNDBERG JAN M.
Published: December 2008

SARM, A., MARTLING, C.‐R., DALSGAARD, C.‐J. & LUNDBERG, J.M. 1985. Evidence for substance P‐immunoreactive spinal afferents that mediate bronchoconstriction. Acta Physiol Scand 125, 407–414. Received 7 March 1985, accepted 30 April 1985. ISSN 0001–6772. Department of Experimental and Clinical Pharmacology, University of Graz, Austria, and Departments of Pharmacology and Anatomy, Karolinska Institutet, and Department of Anaesthesiology, Karolinska Sjukhuset, Stockholm, Sweden

The origin and functional role of capsaicin‐sensitive substance P‐(SP‐) immunoreactive (IR) nerve fibres in the lower airways were studied in the guinea‐pig. Stellatectomy caused a significant reduction of SP‐IR in the lung and pulmonary artery. Immuno‐histochemical analysis, however, did not reveal any clear‐cut change in the number and distribution of SP‐IR fibres in the lung of these animals. After combined stellatectomy plus local capsaicin treatment of the vagal nerves, most SP‐IR nerves disappeared in the lower airways. The bronchoconstriction induced by capsaicin was significantly reduced after stellatectomy and abolished after stellatectomy plus capsaicin pretreatment of the vagal nerves. Ether inhalation caused bronchoconstriction, which was not influenced by stellatectomy but markedly reduced by combined capsaicin treatment of vagal nerves and stellatectomy. Stellate ganglion stimulation in animals that had been chemically sympathectomized by 6‐OH‐dopamine caused bronchoconstriction, which was resistant to cholinergic or adrenergic receptor blockade. This response was absent after systemic capsaicin pretreatment, suggesting that it was due to antidromic stimulation of afferent fibres traversing the stellate ganglion. In conclusion, the present data suggest that the lower airways receive SP‐IR capsaicin‐sensitive C‐fibre afferents of both vagal and spinal origin. These sensory fibres seem to have branches both within the bronchial smooth muscle and around blood vessels.
Effects of calcium and limited proteolysis on membrane‐bound and releasable dopamine β‐hydroxylase in adrenomedullary catecholamine granules
Authors: HELLE K. B. , PIHL K. E. , SERCK‐HANSSEN G.
Published: December 2008

HELLE, K.B., PIHL, K.E. & SERCK‐HANSSEN, G. 1985. Effects of calcium and limited proteolysis of membrane‐bound and releasable dopamine β‐hydroxylase in adrenomedullary catecholamine granules. Acta Physiol Scand125, 423–427. Received 9 January, accepted 6 May 1985. ISSN 0001–6772. Department of Physiology, University of Bergen, Norway.

Bovine chromaffin granules were shown to contain two potent proteolytic systems resulting in limited proteolysis of granule proteins at pH 6.0 in the cold in the presence of inhibitors of serine and thiol proteases. Calcium, whether added during lysis or remaining bound to the lysate protein during dialysis in non‐chelating solutions, enhanced recoveries of total immunoreactive dopamine β‐hydroxylase (14% of total protein) and soluble enzyme (9% of lysate protein) due to degradation of chromogranins. A pepstatin A‐blockable, catepsin D‐like proteolytic system converting membrane‐bound enzyme to its soluble counterpart at pH 6.0 was detected in the granule membrane fraction.
Mecamylamine pretreatment counteracts cigarette smoke induced changes in hypothalamic catecholamine neuron systems and in anterior pituitary function
Authors: ANDERSSON KURT
Published: December 2008

ANDERSSON, K. 1985. Mecamylamine pretreatment counteracts cigarette smoke induced changes in hypothalamic catecholamine neuron systems and in anterior pituitary hormone function. Acta Physiol Scand125, 445–452. Received 8 January 1985, accepted 7 May 1985. ISSN 0001–6772. Department of Histology, Karolinska Institute, Stockholm, Sweden.

We have studied the eifects of acute, intermittent exposure to tobacco smoke on discrete hypothalamic CA nerve terminal networks and on neuroendocrine function by means of quantitative histofluorimetrical determinations of catecholamine (CA) fluorescence in sections of rat brain and by radioimmunoassay procedures for hormones. Acute intermittent exposure to cigarette smoke induced a lowering of NA levels and increased NA turnover in discrete hypothalamic nerve terminal regions. This exposure also induced increases in DA turnover in the median eminence. The cigarette smoke lowered TSH, prolactin, LH and FSH serum levels, but induced an increase in serum corticosterone concentrations. To determine if the above mentioned changes in neuroendocrine function were nicotine mediated, a cholinergic nicotine‐like blocking agent, mecamylamine, was administered prior to exposure to cigarette smoke. Pretreatment with mecamylamine (1.0 mgkg‐1) counteracted the cigarette smoke induced changes in CA levels and turnover in all hypothalamic CA nerve terminal regions as well as the changes in serum levels of the pituitary hormones and corticosterone. It is suggested that acute intermittent exposure to cigarette smoke, via its nicotine component, lowers TSH, prolactin, LH and FSH secretion at least in part through activation of the tubero‐infundibular DA neurons. Furthermore, the nicotine component of the cigarette smoke is suggested to induce the increase in corticosterone serum levels via increasing NA turnover in the paraventricular hypothalamic nucleus.
Evaluation of the ‘stretched pore phenomenon’ in isolated rat hindquarters
Authors: RIPPE BENGT , HARALDSSON BÖRJE , FOLKOW BJÖRN
Published: December 2008

RIPPE, B., HARALDSSON, B., FOLKOW, B. 1985. Evaluation of the ‘stretched pore phenomenon’ in isolated rat hindquarters. Acta Physiol Scand125, 453–459. Received 5 March 1985, accepted 7 May 1985. ISSN 0001–6772. Department of Physiology, University of Göteborg, Sweden.

In order to study the changes in capillary permeability occurring upon marked elevations in microvascular pressure, capillary filtration coefficient (CFC) and diffusion capacity (PS) for Cr‐EDTA were repeatedly measured ‘on‐line’ before and after brief periods (3 min) of large venous pressure (Pv) elevations in maximally vasodilated perfused rat hindquarters. First at Pv's ≥ 55 mmHg, increases in CFC and Ps‐Cr‐EDTA were observed immediately after the pressure elevations. While the CFC increases were then always pronounced (up to 4‐ to 5‐fold), the concomitant increases in PS‐Cr‐EDTA were small (at most 30–40%). For Pv≥ 55 mmHg there was a rough proportionality between Pv and CFC. While PS for Cr‐EDTA showed little reversibility with time upon Pv normalization, CFC was usually almost completely reversed after 10–20 min. The mentioned CFC and PS increases at Pv's ≥ 55 mmHg were quantitatively similar to those induced by histamine‐type mediators in the same preparation. It is concluded that capillary hydraulic conductivity can increase markedly but reversibly upon large Pv elevations, and that this is mainly due to forceful opening of ordinarily closed ‘large pores’ in the microvascular membrane, rather than being caused by lesional rifts in the endothelium,
Inhibition of the cholinergic neurotransmission in human airways via prejunctional alpha‐2‐adrenoceptors
Authors: GRUNDSTRÖM N. , ANDERSSON R. G. G.
Published: December 2008

GRUNDSTRÖM, N. & ANDERSSON, R.G.G. 1985. Inhibition of the cholinergic neurotransmission in human airways via prejunctional alpha‐2‐adrenoceptors. Acta Physiol Scand 125, 513–517‐ Received 1 February 1985, accepted 29 May 1985. ISSN 0001–6772. Department of Pharmacology, Linköping University, Sweden.

Previous investigations on guinea‐pig airways indicate that the excitatory, cholinergic neurotransmission can be inhibited via prejunctional alpha‐2‐adrenoceptors. The aim of this study was to investigate whether a similar inhibition of the cholinergic neurotransmission is present in human airways. Ring preparations of human bronchi were mounted for recording of isometric tension and immersed in oxygenated Krebs solution. Electrical field stimulation of the preparations elicited atropine‐sensitive twitch contractions. Exogenous noradrenaline (in the presence of cocaine and propranolol) inhibited the electrically evoked contractions. The noradrenaline‐induced inhibition could be antagonized by yohimbine whereas prazosin was ineffective, indicating that the inhibition was mediated by alpha‐2‐adrenoceptors. Contractions evoked by exogenous acetylcholine (in the presence of cocaine and propranolol) was unaffected by the addition of noradrenaline, which suggests that the alpha‐2‐adrenoceptors have a prejunctional localization. In conclusion, this report gives evidence that the human bronchial, cholinergic neurotransmission can be inhibited by stimulation of prejunctional alpha‐2‐adrenoceptors.
The influence of extrasegmental mechanical vibratory stimulation and transcutaneous electrical nerve stimulation on histamine‐induced itch
Authors: EKBLOM A. , HANSSON P. , FJELLNER B.
Published: December 2008

EKBLOM, A., HANSSON, P. & FJELLNER, B. 1985. The influence of extrasegmental mechanical vibratory stimulation and transcutaneous electrical nerve stimulation on histamine‐induced itch. Acta Physiol Scand125, 541–545. Received 16 April 1985, accepted 13 June 1985. ISSN 0001–6772. Department of Physiology II, Karolinska Institutet, and Department of Dermatology, Karolinska Sjukhuset, Stockholm, Sweden.

The effect of peripheral conditioning stimulation on experimentally induced pruritus was studied in 12 healthy volunteers. Itch was induced by intradermal injections of histamine on the upper arms. Vibration at 100 Hz and transcutaneous electrical nerve stimulation (TENS) at 2 and 100 Hz were applied extrasegmentally (dorsal aspect of the lower part of the leg, ipsilateral to the injected arm) for a period of 5 min following induction of itch. The effect of a 5 and 30 min stimulation period before itch elicitation was also studied as well as the influence of placebo stimulation. No significant effects were obtained with 100 Hz vibration and 100 Hz TENS, and none with placebo stimulation, whereas significant itch reduction was seen using 2 Hz TENS. The local skin flare response following histamine injections was not altered following conditioning stimulation of any type.
On the hormonal regulation of lipolysis in isolated reindeer adipocytes
Authors: LARSEN TERJE S. , NILSSEN KJELL J.
Published: December 2008

LARSEN, T.S. & NILSSEN, K.J. 1985. On the hormonal regulation of lipolysis in isolated reindeer adipocytes. Acta Physiol Scand125, 547–552. Received 19 December 1984ac cepted 12 June 1985. ISSN 0001–6772. Department of Arctic Biology and Department of Physiology, Institute of Medical Biology, University of Tromsø, Norway.

The effects of insulin and bovine growth hormone (bGH) on lipolysis (basal and/or adrenaline‐stimulated) were investigated in isolated adipocytes from the Norwegian reindeer. Addition of 100 nmol 1‐1 adrenaline to the cells increased lipolysis 20‐fold above basal lipolytic rate. Insulin (0.1 and 1 nmol l‐1) depressed lipolysis significantly at submaximal adrenaline stimulation but had no effect when lipolysis was stimulated maximally. Bovine GH (25 and 100 ng ml‐1) inhibited basal lipolysis during the first 2 h of incubation, whereas refractoriness to this action was induced during the third and fourth hour of incubation. These effects were not influenced by inclusion of a small amount of glucocorticoid (dexamethasone, 25 ng ml‐1). Addition of 0.1 and 1 nmol 1‐1 insulin together with bGH (100 ng ml‐1) prevented the initial antilipolytic effect of the latter and resulted in the expression of normal basal lipolytic rates. Preincubation with bGH (100 ng ml‐1) for 2 h did not alter the lipolytic response of the adipocytes to adrenaline. These findings lend support to the conclusion that insulin exerts a major control of lipolysis in reindeer adipose tissue. The significance of the antilipolytic effect of bGH is difficult to evaluate since this effect was transient and was abolished during the third and fourth hour of incubation.
Changes in isometric force‐ and relaxation‐time, electromyographic and muscle fibre characteristics of human skeletal muscle during strength training and detraining
Authors: HÄKKINEN K. , ALÉN M. , KOMI P. V.
Published: December 2008

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 Scand 125, 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, especially in highly trained subjects.
Dissociation between renal prostaglandin E2and renin release. Effects of glucagon, dopamine and cyclic AMP in dogs
Authors: VIKSE ARILD , BUGGE JAN , DAHL ELLEN , KIIL FREDRIK
Published: December 2008

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‐adrenergic stimulation.
Cyclic AMP potentiates glucose‐induced insulin release from mouse pancreatic islets without increasing cytosolic free Ca2
Authors: RORSMAN PATRIK , ABRAHAMSSON HÅKAN
Published: December 2008

RORSMAN P. & ABRAHAMSSON, H. 1985. Cyclic AMP potentiates glucose‐induced insulin release from mouse pancreatic islets without increasing cytosolic free Ca2+. Acta Physiol Scand 125, 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 from ob/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+]i was 158 ± 7 nM. After increasing glucose to 20 mM there was a lag‐period of 1–2 min before [Ca2+]i gradually 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+]i after depolarization evoked by high extracellular K+. Also dibutyryl cyclic AMP and theophylline lacked the ability to raise [Ca2+]i beyond that obtained by glucose. The results suggest that cyclic AMP potentiates glucose‐induced insulin release by sensitizing the secretory machinery to changes of [Ca2+]i rather than by increasing the cytosolic concentration of the ion.
Effects of shape and size on red blood cell deformability: a static bending analysis
Authors: ENGSTRÖM GUNNAR , TÄLJEDAL INGE‐BERT
Published: December 2008

ENGSTRÖM, G. & TÄLJEDAL, I.‐B. 1985. Effects of shape and size on red blood cell deformability: a static bending analysis. Acta Physiol Scand 125, 669–679. Received 16 April 1985, accepted 19 June 1985. ISSN 0001–6772. Department of Histology and Cell Biology, University of Umea, Sweden.

When flowing down a tapered tube, such as a narrow capillary, red blood cells (RBCs) are subject to deformation, the first event of which is folding in a pancake manner. The RBC deformability is reduced during cell ageing, a phenomenon that may reflect alterations in intracellular viscosity, membrane rigidity or RBC shape. Age related shape changes and their importance for increased RBC rigidity were theoretically analysed. The average empirically observed RBC profile is shown to offer little resistance to bending as compared to other, theoretically possible profiles of the same membrane area and RBC volume. Because of a decrease in projected area (diameter size), and therefore in pressure load, the pressure needed to initiate folding of an old RBC is between 20 and 55% higher than that required to fold a young one if, during RBC ageing, membrane area to cell volume ratio is constant as empirically observed. This difference exists whether the RBC is mathematically treated as a solid body or as a membrane shell.
Pre‐ and postjunctional modulation of cholinergic neuroeffector transmission by adenine nucleotides. Experiments with agonist and antagonist
Authors: WIKLUND N. PETER , GUSTAFSSON LARS E. , LUNDIN JAN
Published: December 2008

WIKLUND, N.P., GUSTAFSSON, L.E.&LUNDIN, J. 1985. Pre‐and postjunctional modulation of cholinergic neuroeffector transmission by adenine nucleotides. Experiments with agonist and antagonist.Acta Physiol Scand125, 681–691. Received 27 May 1985, accepted 26 June 1985. ISSN 0001–6772. Departments of Physiology and Toxicology, Karolinska Institute, and The Swedish National Laboratory of Environmental Medicine, Stockholm, Sweden.

Adenosine, 2‐chloroadenosine, AMP, AMPNH2, ADP, ATP, AMPPNP and β, γmeATP dose‐dependently and reversibly inhibited contractile responses to nerve stimulation in longitudinal plexus‐containing muscle preparations of guinea pig ileum. All the purines, except for 2‐chloroadenosine, were virtually equipotent and elicited maximal inhibition within 2 min after application. Adenosine deaminase abolished inhibition by adenosine but did not block the effect of 2‐chloroadenosine or the adenine nucleotides. During transmural nerve stimulation, the nucleotidase‐resistant analogues α, βmeADP and AMPPNP significantly depressed acetylcholine release measured by gas chromatography‐mass spectrometry. The inhibitory effect of all the purines was competitively, reversibly and at comparable pA2values antagonized by 8‐φ‐sulphophenyltheophylline. The results indicate that nucleotidesper secan inhibit neurotransmission via a prejunctional receptor common to nucleosides and nucleotides. An excitatory effect by all the di‐ and triphosphate nucleotides was also observed. The excitation was unaltered by atropine, tetrodotoxin and 8‐φ‐sulphophenyltheophylline, thus suggesting an action at postjunctional ADP‐ and ATP‐like receptive sites.
Transcapillary extravasation rate of albumin in rat skeletal muscle. Effect of motor activity
Authors: REED ROLF K.
Published: December 2008

REED, R.K. 1985. Transcapillary extravasation rate of albumin in rat skeletal muscle. Effect of motor activity. Acta Physiol Scand 125, 719–725. Received 6 December 1984, accepted 19 July 1985. ISSN 0001–6772. Department of Physiology, University of Bergen, Bergen, Norway.

Transcapillary extravasation of albumin in hindlimb and neck skeletal muscle of rats was determined as extra vascular plasma equivAlént volumes (I‐HSAev), 1–168 h after a single intravenous injection of radiolabelled human serum albumin (I‐HSA). One experimental group was immobilized in pentobarbital anaesthesia for the first 8 h after injection of I‐HSA. With longer extravasation periods, the rats then woke up and moved freely. In the other experimental group, injections were made in ether anaesthesia allowing the rats to move freely within 10 min after injection. One hour after injection, I‐HSAev in the immobilized group averaged 1.5 10‐3 ml g‐1 in neck and hindlimb muscle. In the mobile group, I‐HSAev was two to three times higher than in the immobilized rats up to 12 h in both muscle groups (P < 0.05). At 24 h and later I‐HSAev was similar in mobile and immobile rats (P > 0.05). The I‐HSAev increased up to 48 h, levelling off at about 0.06 and 0.08 ml g_I in hindlimb and neck skeletal muscle, respectively. Corresponding interstitial albumin concentration, calculated from steady‐state I‐HSAev and interstitial fluid volume (51Cr‐EDTA space), averaged 48% and 34 % of plasma albumin concentration, respectively.
GABA antagonists increase the release of [3H]acetylcholine from the chick retina
Authors: AGARDH ELISABET
Published: December 2008

The release of [3H]acetylcholine from the chick retina was studied. A 5 mM increase in K+‐concentration caused an increased release, which was Ca2+‐dependent. The effect of 5 mM K+ was neither potentiated by bicuculline nor inhibited by isoguvacine or muscimol. This indicates that the K+‐induced release is not controlled by GABA. However, bicuculline and picrotoxin increased the spontaneous efflux of radioactivity, whereas GABA had no significant effect. The results suggest that cholinergic neurons are tonically inhibited by a continuous release of endogenous GABA. Neither glycine or strychnine, nor dopamine or haloperidol had any effect on the spontaneous release.
Arginine vasopressin excretion in response to volume expansion in the healthy human, and in patients with glomerulonephritis
Authors: LINNÉ TOMMY , RUNDGREN MATS
Published: December 2008

The urinary excretion of arginine vasopressin (AVP) was studied during volume expansion (VE) in nine healthy normotensive individuals and 14 patients with active IgA glomerulonephritis (GN). The studies were started after 17–18 h of food and fluid deprivation (hydropenia, HP) and VE was induced by a continuous infusion of Ringer solution up to an amount corresponding to 3% of the body weight. The clearance of inulin and PAH, urine osmolality and urinary excretion of sodium and AVP were determined. The AVP excretion decreased in response to VE in the healthy individuals, both when related to GFR (from 129+ 17 pg min ‘ 100 ml ’ GFR during HP to 65 ± 9 after 3% VE, P < 0.01)andtobody surface area (BSA) (from 134 ± 22 pg min“1 1.73 m‐2 BSA to 75 ±11, P < 0.05). In the patients with IgA GN, who had normal blood pressure and normal GFR, the AVP excretion tended to decrease, but the change was not significant (0.05 < P < 0. 1). The patients with hypertension but essentially normal GFR, and those with hypertension and markedly decreased GFR did not change their renal excretion of AVP in response to VE. If related to the GFR, the latter patients had a markedly increased AVP excretion.
The effect of reserpine treatment on choline acetyltransferase activity in rat submaxillary glands
Authors: EKSTRÖM JÖRGEN
Published: December 2008

Rats were treated daily with a low dose of reserpine (0. 1 mg kg‐1) injected subcutaneously for 3 weeks. In the submaxillary glands the noradrenaline content was reduced by about 95%. The total activity of the acetylcholine‐synthesizing enzyme choline acetyltransferase remained unchanged. However, the activity of this enzyme was found to be increased when the reserpine treatment was followed by surgical sympathetic denervation and the glands were analysed 3 weeks post‐operatively. The enzyme activity also increased in the glands when the surgical sympathetic denervation was performed on the day of the start of the reserpine treatment. The lack of effect of reserpine on choline acetyltransferase activity in the glands seems to exclude the possibility that it is the depletion of neuronal noradrenaline stores that initiates the events giving rise to increases in choline acetyltransferase activity after sympathetic denervation.
Functional, morphological and metabolic characteristics of isolated hearts from normotensive and spontaneously hypertensive rats before, during and after renal hypertension
Authors: FRIBERG PETER , NORDBORG CLAES
Published: December 2008

It has been much discussed whether left ventricular hypertrophy (LVH) in hypertension implies improved or impaired cardiac performance, mainly because experiments in various hypertensive models have given controversial results. It has, for example, been suggested that increased collagen content may depress LV function both in renal and spontaneous hypertension (SHR) in rats. For such reasons cardiac performance was studied both in SHR and in normotensive control rats (NCR) before and during superimposed two‐kidney, one clip Goldblatt hypertension, and also 1 week after reversal of hypertension by unclipping. The LV function of the isolated hearts was determined in an antegrade working heart perfusion system. Further, myocardial morphology, with regard to fibrous tissue infiltration and energy metabolic status, were evaluated in the renal hypertensive rats before and after unclipping. Compared with NCR, maximal cardiac performance was elevated in the hypertrophied SHR hearts, but depressed when renal hypertension was superimposed, even though this led to further LVH. However, one week after reversal of renal hypertension, when LVH was still considerable, cardiac function was increased well above the control level, even though the stores of high energy compounds and the content of myocardial fibrous tissue was almost the same as during renal hypertension. It is concluded that LVH generally enhances cardiac performance, but that concomitant renal hypertension exerts a cardio‐depressive influence which can neither be ascribed to an increased fibrous tissue content nor to a reduced energy charge potential. It is therefore suggested that some negative inotropic agent of renal or extrarenal origin is released during two‐kidney, one clip renal hypertension, which offsets the enhanced performance induced by the left ventricular hypertrophy.
The effects of varying sodium diets on haemodynamics and fluid balance in the spontaneously hypertensive rat
Authors: ELY D. L. , NORLANDER M. , FRIBERG P. , FOLKOW B.
Published: December 2008

Spontaneously hypertensive rats (SHR) were given either ‘low’ (LNa; 0.5 mmol Na 100 g˜˜ food), ‘contro’ (CNa; 12 mmol) or ‘very high’ (vHNa; 120 mmol) sodium diets from 5 to 13–14 weeks of age, to explore how these 240‐fold variations in Na intake affected body weight, cardiac, renal and adrenal weights, overall water‐electrolyte equilibrium and haemodynamic balance during rest, mental stress and blood loss. Body growth was retarded both in vHNa and LNa SHR presumably reflecting disturbed appetite due to the greatly altered dietary Na contents. Compared with CNa SHR, both cardiac and renal weights 100 g_1 body wt were slightly increased in vHNa and decreased in LNa SHR, with opposite changes of adrenal weights. Total body water, haematocrit and plasma Na‐K levels were largely equal in the three groups. Furthermore, cardiac output (CO), stroke volume (SV) and central blood volume (CBV) did not differ significantly between groups; if anything, CO and SV were higher and CBV lower in vHNa and LNa SHR than in CNa SHR. However, while mean arterial pressure (MAP) was only marginally elevated in vHNa compared with CNa SHR, both MAP and total peripheral resistance (TPR) were lowered about 15% in LNa SHR with signs of increased sympathetic activity to the heart also during rest. Despite an apparently normal volume and cardiac output balance in LNa SHR, the latter changes suggest a disturbed neuro‐hormonal cardiovascular control. This was also evident from the attenuated pressor responses to mental stress in LNa SHR and from their clearly reduced ability to compensate for blood loss, earlier observed in normotensive LNa rats as well. These results agree with our earlier findings that alterations of Na intake his functionally important effects on sympathetic neurons, reducing the transmitter release/impulse in LNa rats with reverse changes in vHNA rats.
Fetal cerebral, cardiovascular and metabolic reactions to intermittent occlusion of ovine maternal placental blood flow
Authors: ROSÉN K. G. , HRBEK A. , KARLSSON K. , KJELLMER I.
Published: December 2008

In 10 mature, acutely exteriorized fetal sheep cardiovascular, cerebral and metabolic reactions were followed during intermittent occlusions of maternal placenta blood flow. The response was analysed from blood pressure, heart rate, myocardial contractility, combined cardiac output, ST waveform analysis of the fetal ECG, and from the evoked EEG response. The metabolic response was judged from blood gases, pH, lactate and circulating catecholamines. Basal values were within the range seen in the ‘chronic’ fetal lamb preparation. During moderate asphyxia, achieved by 10 1 min occlusions separated by 2 min periods of free maternal aorta blood flow, cardiovascular performance was increased with a substantial catecholamine surge but minor effects on cerebral and metabolic functions. During the marked asphyxia, achieved by five 2 min occlusions, marked metabolic changes occurred together with abolition of cerebral function. Forty‐five minutes after asphyxia, 9/10 of the fetuses had regained cerebral, metabolic and cardiovascular functions.
Influence on plasma levels of somatostatin, gastrin, glucagon, insulin and VIP‐like immunoreactivity in peripheral venous blood of anaesthetized cats induced by low intensity afferent stimulation of the sciatic nerve
Authors: UVNÄS‐MOBERG KERSTIN , POSLONCEC BRANKA , ÅHLBERG LOUISE
Published: December 2008

The objective of the present study was to investigate whether gastrointestinal hormones can be released in response to low intensity afferent activation of the sciatic nerve. Experiments were performed on anaesthetized cats in which the sciatic nerve was stimulated electrically at 3 Hz, 10 V and 0.2 ms. Blood samples were collected in a peripheral vein and the plasma levels of somatostatin, gastrin, glucagon, insulin and VIP‐like immunoreactivity (below referred to as somatostatin, gastrin, glucagon, insulin and VIP) were recorded by radioimmunoassay. Afferent stimulation of the sciatic nerve caused immediate (∽ 15 min long) changes of the levels of all the above mentioned peptides. Somatostatin, gastrin and glucagon levels rose significantly, whereas in the case of insulin and VIP a significant relationship between the effect of sciatic nerve stimulation and basal levels was established. Thus, insulin and VIP levels decreased when basal levels were high and increased when basal levels were low. The secretion of gastrointestinal and pancreatic hormones is in part regulated by the autonomic nervous system. It is suggested that afferent stimulation of the sciatic nerve causes a reflex activation of the vagal and/or the splanchnic nerves, which in turn affects the release rate of the above‐mentioned hormones. In conclusion, these data show that the release of gastrointestinal hormones can be influenced by low intensity stimulation of the sciatic nerve. The physiological trigger of these responses may be touching of the skin.
An improved algorithm and a computer program for the analysis of capillary gas exchange
Authors: GRØNLUND J. , GARBY L. , LORENZEN A. G. , CARTER A. M.
Published: December 2008

In most models of capillary gas exchange, the binding curves for O2 and CO2 are represented by simple analytical expressions, and the interactions among the haemoglobin ligands are either neglected or are assigned fixed values independent of PO2, PCO2, pH and red cell DPG. We here present algorithms and a computer program in which the binding curves are described in a near‐rigorous manner. This enables solution of a set of typical equations for a unit of blood which undergoes gaseous and proton exchange. We have applied the algorithms to the problem of calculating pulmonary blood flow from the gaseous exchange in the lung by the single‐breath method of Kim et al. (1966), where the CO2 binding curves of arterial and mixed venous blood are approximated by straight lines. The application of the algorithms shows that this approximation introduces significant errors in the calculated pulmonary blood flow.
Immunoextracted calcitonin from human seminal plasma constitutes different forms
Authors: BUCHT ELISABET , ARVER STEFAN , SJÖBERG HANS‐ERIK
Published: December 2008

Levels of immunoreactive calcitonin (iCT) in human seminal plasma were studied after extraction with immobilized antibodies. Immunoextraction of semen was necessary to abolish the high concentrations of proteolytic enzymes that can interfere in radioimmunoassay (RIA). Since proteolysis occurs already during semen liquefaction, iCT levels and chromatographic properties were compared in extracts from liquefied ejaculates, and samples where the proteolysis was suppressed by immediate dilution of the ejaculates with buffer. The levels in the two groups were 81±43 pg‐equivalents ml‐1 seminal plasma (mean ± SD, n = 6) in liquefied samples and 120 ± 42 pg‐equivalents ml‐1 (n = 7) in diluted samples, which is about ten times the iCT levels in extracted blood plasma from healthy males. Extracted liquefied seminal plasma from two vasectomized men contained 93 and 107 pg‐equivalents of iCT ml‐1 seminal plasma, respectively. Gel chromatography of undiluted semen samples disclosed that iCT was composed of forms larger than monomeric CT, the major part with an approximate molecular weight (MW) of 10,000. Two of the six subjects had a smaller amount of iCT eluting with a MW of about 40,000. In diluted samples, iCT seemed to be more heterogenous with approximate molecular weights ranging from 40,000 to fragments smaller than monomeric CT. In some ejaculates, monomeric CT seemed to be present. Undiluted samples from vasectomized men contained iCT with the same chromatographic pattern as in normal men.
Myogenic and neurogenic control of electrical and mechanical activity in human oviductal smooth muscle
Authors: SAMUELSON ULF E. , SJÖSTRAND NILS O.
Published: December 2008

Isolated strips from isthmic and ampullary muscle layers of the human fallopian tube were investigated with the sucrose‐gap technique and in organ baths. Generally good correlation existed between electrical and mechanical activity, but dissociation was also noted. The isthmic external longitudinal layer (IEL) was characterized by slow waves of depolarization and broad ‘spikes’. Tonic contraction followed depolarization, and phasic waves followed the spikes. In the other layers, regular spikes and phasic contractions dominated. Late in the menstrual cycle, more irregular patterns and slow waves, which could synchronize spike activity, were found. Automaticity tended to be highest in the late proliferative phase. Active response to stretch was best demonstrated in IEL. Excitatory α‐adrenergic responses (hypopolarization, firing and contraction) to noradrenaline and nerve stimulation dominated in the IEL. In the other layers, β‐adrenergic inhibition prevailed. Non‐adrenergic, non‐cholinergic neurogenic inhibition was demonstrated. Decrease in spike frequency and hyperpolarization seemed to be as prominent as during β‐adrenergic inhibition. Muscarinic stimulation by acetylcholine was recorded as depolarization, spikes and contraction. However, a role for cholinergic nerves could not be defined. Thus, the human oviductal smooth muscle belongs to the single unit category; its activity can be modified during the menstrual cycle, by stretch and by excitatory and inhibitory nerves.
Transient supersensitivity in the hypertrophied rat urinary bladder
Authors: EKSTRÖM JÖRGEN , MALMBERG LARS , WALLIN ÅSA
Published: December 2008

The presence of a paraffin bolus intravesically for 1 or 4 weeks was accompanied by an approximate three‐fold increase in bladder weight. A supersensitivity to methacholine was demonstrated in these hypertrophied bladders at 1 week but not at 4 weeks. At the earlier time of observation, the contractile responsesin vitroto nerve stimulation were reduced, while at the later time of observation the responses were the same as those of controls; the atropine‐sensitive fraction of the response was entirely responsible for the recovery. The concentration of choline acetyltransferase, indicating cholinergic nerve density and initially reduced by about 50%, rose in course of time. It is suggested that in the beginning of the experimental period, the muscle cells of the hypertrophied bladdersin situare exposed to ‘subnormal’ transmitter concentration. An extension of the field of innervation of the cholinergic nerves may explain the disappearance of the supersensitivity.
Electrophysiological effects of substance P and VIP in the denervated rat parotid gland
Authors: THESLEFF PETER
Published: December 2008

The effects of SP and VIP were studied in vitro in normal and denervated parotid glands of the rat using electrophysiological techniques. After sympathetic, and especially after parasympathetic, denervation the number of cells responding to peptides increased significantly. Furthermore, sub‐threshold doses for control glands induced membrane potential changes after denervation. It seems reasonable to correlate these findings to the development of supersensitivity. The underlying mechanisms, however, require further investiGátion.
The influence of maternal protein deprivation on the developmental pattern of serum immunoreactive insulin‐like growth factor 1 (IGF‐1) levels
Authors: SARA VICKI R. , HALL KERSTIN , MENOLASCINO SHELLY , SJÖGREN BARBRO , WETTERBERG LENNART , MÜNTZING KRISTINA , OLDFORS ANDERS , SOURANDER PATRICK
Published: December 2008

The influence of maternal protein deprivation on body and brain growth and on serum immunoreactive insulin‐like growth factor 1 (IGF‐1) levels was examined in rats during development. The offspring of protein‐deprived mothers were significantly growth‐retarded postnatally and showed an altered developmental pattern of serum immunoreactive IGF‐1 levels. In contrast to control animals, between days 5 and 20 postnatally, a significant elevation in serum immunoreactive IGF‐1 levels which peaked at day 15 was found. However, in adult growth‐retarded rats a significant reduction in serum immunoreactive IGF‐1 levels was found. These findings suggested the preweaning period to be critical for the development of the mature somatomedin system.
Studies on cardiac distribution and function of neuropeptide Y
Authors: ALLEN JANET M. , GJÖRSTRUP P. , BJÖRKMAN J.‐A. , EK L. , ABRAHAMSSON T. , BLOOM S. R.
Published: December 2008

High concentrations of a novel peptide, neuropeptide Y, have been demonstrated in the guinea‐pig and canine heart and in the latter, a particularly high concentration was found in the region of the coronary vasculature (126 ± 31 pmol g‐1). Intra‐arterial infusion of neuropeptide Y for 30 s into the coronary artery of the intact, innervated dog heart resulted in a rapid and short‐lasting reduction of blood flow from 38 ± 4 to 31 ± 3 ml min‐1(P< 0.05) to resume control level, 39 ± 5 ml min‐1, within 5 min. These injections were unaccompanied by changes in heart rate and aortic pressure, while there was an associated small reduction in dP/dt, used as a measure for changes in contractility.In vitrostudies using the isolated, paced papillary muscle from cat, guinea‐pig and rat, and spontaneously beating right atria from the guinea‐pig, demonstrated no effect of NPY on active tension or beating frequency. The results indicate that NPY has vasoconstrictor properties, but under the test circumstances to lack both positive and neGátive inotropic and chronotropic effects.
Some observations made by intracellular recordings in a primary astrocyte culture and a glioblastoma ‘138 MG’
Authors: NILSSON ÅKE , LIDÉN EVA , SELLSTRÖM ÅKE
Published: December 2008

Intracellular recordings were performed in a primary astrocyte culture from rat brain and in a human glioblastoma cell line, 138 MG. The technique proved insufficient to verify the heterogenous composition of the primary astrocyte culture, since this study shows most cells present in the culture to have similar resting membrane potential, membrane impedance, membrane potential/impedance relationship and K+‐sensitivity. With the exception of macrophages, identified by their response to externally applied yeast particles, the results do not allow the identification of different cells that are known to be present. The membrane potential of the primary astrocyte was ‐ 68 ± 14 mV, and the membrane potential of the 138 MG cells ‐ 37 ± 15 mV. The membrane potential of cells in the primary culture have a K+‐sensitivity resembling that of astrocytes in situ, whereas the K+‐sensitivity of 138 MG more resemble that of a dedifferentiated cell. A reduction of 0.95 mm Ca2+ to o mM depolarises the astrocyte with 9.6 mV and hyperpolarises the glioma cell 2.6 mV.
Immunological characterization of plasminogen activators in human mixed saliva
Authors: KJAELDGAARD A. , KJAELDGAARD M.
Published: December 2008

In mixed saliva obtained from six healthy volunteers, the plasminogen activators were characterized immunologically using antibodies specific for human tissue plasminogen activator and urokinase, which were raised in goats immunized with low molecular weight urokinase and tissue‐type activator from melanoma cells. The fibrinolytic activity in mixed saliva upon stimulation was assayed on fibrin plates containing plasminogen after preincubation with immunoglobulins with and without specific antibodies. In both centrifuged and uncentrifuged saliva, antibodies against tissue plasminogen activator completely quenched the fibrinolytic activity. By contrast, antibodies against urokinase had no suppressive effect, neither did non‐immunized goat serum influence the fibrinolytic activity in mixed saliva. In conclusion, during physiological conditions tissue plasminogen activator appears to regulate fibrinolytic activity in mixed saliva, in which no activity of urokinase‐like plasminogen activators could be demonstrated.