bluuebunny/crossref_metadata_2025 huggingface dataset:
Unit Responses in the Cochlear Nucleus of the Rat to Pure Tones
Authors: Moller Aage R.
Published: December 2008

In a study of the response of single units in the cochlear nucleus of the white rat it was found that all the units which responded to pure tones showed a selectivity with regard to tone frequency. Responses were obtained in the tone frequency range from 200 to 34,000 Hz. Most of the units responded to pure tones with a sustained train of discharges. The threshold in these units was found to rise abruptly when the tone frequency was increased above that of the unit's characteristic frequency (CF). A much more gradual increase in threshold was noted when the tone frequency was decreased below the unit's CF. The slope of the high frequency part of the tuning curves varied between 0 and 50 Hz per dB increase in threshold, when measured 20—30 dB above the unit's threshold at its characteristic frequency. The slope measured in that way showed no apparent dependence of on the CF of the units. Many units with a high CF had tuning curves with a second peak located at a lower frequency. A few units had almost symmetrical tuning curves with a slope of the same order of magnitude as that recorded for the low frequency part of the common type units. The maximal obtainable firing rate of common type units was found to decrease rapidly when the frequency of the stimulus tone was increased above the unit's CF. Conversely the maximal discharge rate was almost constant for tones below the unit's CF. Iso‐rate functions based on stimulus response curves, were found to be similar to tuning curves when a discharge rate of about 20 per cent about the unit's spontaneous rate was used as a criterion of response.
The Secretion of Adrenaline and Noradrenaline in 20° C and 3° C Acclimated Rats Injured by Limb Ischemia
Authors: Stoner H. B. , Westerholm Barbro
Published: December 2008

The effects of hind‐limb ischemia on the concentrations of adrenaline and noradrenaline in the adrenals, heart and spleen, on the excretion of these compounds and their 3‐0‐methylated metabolites in the urine and on the uptake of (°)‐noradrenaline‐7‐3H by the adrenals, kidneys. spleen and heart have been studied in 20° C and 3° C acclimated rats at an environmental temperature of 20° C. The adrenals of uninjured 3° C acclimated rats contained more adrenaline and noradrenaline than those from 20° C acclimated rats. In a 20° C environment both types of rat excreted the same amounts of these compounds. Hind‐limb ischemia increased the rate of secretion of adrenaline and noradrenaline since the adrenal contents of these compounds were reduced, their excretion and that of two of their metabolites was increased and tissue uptake was not reduced. The response was the same in 20° C and 3° C acclimated rats after a 4 hr period of bilateral hind‐limb ischemia. According to the assay methods used adrenaline secretion preceded that of noradrenaline and the secretion of both continued for up to 26 hrs after the injury. The possible factors in the injury leading to the increase in catecholamine secretion are discussed and also the relation between these changes and some of the biochemical sequelae of limb ischemia.
Effect of Reserpine on Accommodation and Pupil Diameter in Monkeys (Macaca irus)
Authors: Töurnqvist Göuran
Published: December 2008

Pupil diameter and refractive state were measured in cynomolgus monkeys under pentobarbital before and after i.m. administration of reserpine, 2 and 5 mg/kg. Reserpine was found to cause only a small miotic response and no accommodation at all.
Intercostal‐to‐Phrenic Reflexes in the Spinal Cat
Authors: Decima Emilio E. , Euler Curt von , Thoden Uwe
Published: December 2008

The diaphragm, which previously has been shown to contain relatively few proprioceptors and to lack autogenetic facilitation, was found to be under reflex control from intercostal afferents. Electrical stimulation of the intercostal nerves of the lowest thoracic segments elicited a polysynaptic reflex excitation of phrenic motoneurones followed by a depression of ‘spontaneous’ phrenic motor activity. No phrenic responses were elicited from the upper thoracic segments. Increased phrenic activity was also elicited by mechanical stimulation of the trunk wall; the receptive area of these effects was similarly limited to the region of the insertion of the diphragm. Alike reflex effects were obtained from both the internal and the external intercostal nerves. In the internal nerve both group Ib and II afferents were found to contribute to the reflex whereas in the external nerve it was mainly the secondary muscle spindle endings which gave rise to the response. In contrast to the intercostal‐to‐intercostal reflexes cutaneous afferents proved to be without effect in the intercostal‐to‐phrenic reflex.
Excitability of Phrenic Motoneurones to Afferent Input from Lower Intercostal Nerves in the Spinal Cat
Authors: Decima Emilio E. , Euler Curt von
Published: December 2008

The reflex connections between the lower intercostal segments and the phrenic motor pool, described in a preceding paper, has been studied further. It was found that the diaphragm on contraction could exert enough mechanical force on the lower part of the rib cage to provoke a reflex discharge in the phrenic motoneurones. The intercostal‐to‐phrenic reflex arch thus constitutes a link in a loop for self‐excitation of the phrenic nucleus which may make up for its lack of autogenetic facilitation. Up to five synchronized reverberating phrenic volleys could be recorded in response to a single diaphragmatic jerk. These were abolished by paralyzing doses of gallamine. Conduction times and excitability cycles for the loop have been studied. Examination of reflex firing probality for phrenic motoneurones has revealed considerable individual differencies in their responsiveness to each of the three afferent input parameters: a) nerve stimulated, b) strength and c) frequency of stimulation. The order of reflex recruitment of phrenic motoneurones followed the same order as found for their respiratory engagement: small spikes always appeared earlier than bigger spikes.
Possible Relation between the Degree of Cardiac Adrenergic Innervation and the Resistance to Hypothermic Ventricular Fibrillation in Young Cats
Authors: Nielsen Kai C.
Published: December 2008

Kittens weighing 0.5 to 1 kg, corresponding to an age of 5 to 10 weeks, were subjected to immersion hypothermia to 17.4–16.2oC rectal temperature. Blood pressure, ECG, respiration, and rectal temperature were continuously recorded. Metaraminol was administered intermittently to maintain an adequate blood pressure at lower temperatures, and the animals were respirated mechanically when necessary. Only 1 out of 12 kittens developed ventricular fibrillation; the remaining animals could be re‐warmed without major complications. Under similar conditions, adult animals have previously been found to develop ventricular fibrillation constantly. Fluorescence microscopy revealed a low degree of development of cardiac adrenergic nerves compared with adult animals, in agreement with a lower concentration of cardiac noradrenaline. The possibility is discussed that the not yet fully developed adrenergic innervation of the heart in young animals may account for the higher resistance to reduction of the body temperature as compared with adult animals.
Control of Spontaneous Ventricular Fibrillation during Induced Hypothermia in Cats by Acute Cardiac Sympathectomy
Authors: Nielsen Kai C. , Owman Christer
Published: December 2008

17 adult cats were subjected to cardiac sympathectomy under nembutal anesthesia by bilateral excision of the cervical sympathetic chains between and including the superior cervical and stellate ganglia. Immediately after operation, the anesthetized animals were cooled by submersion in an ice‐water bath. Blood pressure, ECG, rectal temperature and respiration were continuously observed. Angiotensin was administered intermittently to maintain the blood pressure at an adequate level at the lower body temperatures. Artificial respiration was applied when indicated. Under these conditions, only 2 out of 17 denervated animals died in ventricular fibrillation, at 23 and 18.4oC rectal temperature. The remaining animals were cooled to 17.7–15oC and subsequently re‐warmed to normothermia without complications. All of 17 unoperated control animals subjected to hypothermia in the same way developed ventricular fibrillation. Cardiac noradrenaline determined fluorimetrically at the end of the experiments did not differ significantly between the two experimental groups. The results of the present and earlier investigations indicate that hypothermia activates the sympathetic system through a central mechanism and that the cardiac sympathetic nerves represent an important factor for the spontaneous development of ventricular fibrillation, a characteristic complication of induced deep hypothermia in homeothermic mammals.
Effects of Epsilon Aminocaproic Acid (EACA) and Trasylol on Thromboplastin‐Induced Intravascular Coagulation, Studied in Dogs with Iodine‐Labelled Fibrinogen
Authors: Nordström Sam , Zetterqvist Eric
Published: December 2008

The elimination of iodine‐labelled fibrinogen was followed in 3 groups of dogs after: 1. thromboplastin infusion, 2. simultaneous infusions of thromboplastin and epsilon aminocaproic acid (EACA), and 3. simultaneous infusions of thromboplastin and Trasylol. Platelet count, fibrinogen concentration, radioactivity in plasma and in fibrinogen as well as hematocrit were determined. Thromboplastin caused changes of the same type as those previously obtained with thrombin, indicating the development of a fibrinolytic process, secondary to intravascular coagulation. The secondary changes were effectively blocked by pretreatment with EACA and Trasylol. The incidence of and mortality in thromboembolism suggest some anticoagulant effect of Trasylol. The antifibrinolytic activity of Trasylol is much stronger than the anticoagulant one. EACA too, seems to give some protection against thromboplastin‐induced coagulation.
Hypoxia and Pulmonary Vascular Resistance. The Relative Effects of Pulmonary Arterial and Alveolar PO2
Authors: Hauge Anton
Published: December 2008

The relative effects of pulmonary arterial and alveolar P02 on pulmonary vascular resistance (PVR) have been studied in isolated and ventilated rat lung preparations. The experimental arrangement included two such preparations perfused in series with homologuous blood. Pulmonary arterial hypoxemia (Po2 28–44 mm Hg) without alveolar hypoxia did not elicit vasoconstrictor response. High pulmonary arterial P02 (120–320 mm Hg) reduced the pressor response to alveolar hypoxia. This effect of arterial Po2 could be counteracted by a rise in ventilation frequency. Pulmonary arterial hypoxemia during periods with arrest of ventilation caused brisk vasoconstrictor responses. It was apparent that the combined effect of alveolar and arterial Po2 on PVR depends on the relative intensities of ventilation and perfusion, the alveolar Po, being the main denominator for the vasoconstriction effect. The results have been discussed in relation to the possible shape of the Po2 gradient from alveolar gas to lumen of small resistance vessels.
Release, Reuptake and Net Uptake of Dopamine, Noradrenaline and Adrenaline in Isolated Sheep Adrenal Medullary Granules
Authors: Lishajko F.
Published: December 2008

Isolated storage granules from sheep adrenal medullary cells incubated in isotonic K‐phosphate at 37° C give off dopamine (DA) and adrenaline (A) at characteristically different rates following an exponential course. The average half time for the DA release in granules during the prevailing conditions was 22 min and for A 49 min. Noradrenaline (NA) was released more rapidly during the initial stage and thereafter exponentially at a slow rate. DA in concentrations of 3 × 10‐5 M in the incubation fluid increased the half time for DA to 34 min, owing to reuptake, and decreased it for A to 43 min.

Addition of ATP‐Mg, 3 mM, considerably decreased the release rate of DA as well as that of NA and A, presumably owing to inhibition of release and increased reuptake. In the presence of ATP‐Mg the addition of 3 × 10‐5 M DA further retarded the net release of DA from the storage granules.

After partial depletion, the granules take up DA in the presence of ATP‐Mg. This effect is inhibited by reserpine. No net uptake of NA or A was observed in partially depleted granules in the presence of added ATP‐Mg. Addition of ATP‐Mg retards the release of soluble proteins concomitantly with catecholamines. The rapidly released NA has been localized in the heavy granule fractions.
Metabolism of14C‐Histamine in Domestic Animals: Goat
Authors: Eliassen K. A.
Published: December 2008

It has been suggested that increasedin vivoformation of histamine might he of importance in the pathogenesis of some diseases in ruminants. However, little is known about the degradation of i.v. injected histamine in these species. In the present study isotope dilution technique and paper chromatography were used to examine urinary14C‐metabolites subsequent to i.v. injection of14C‐histamine to the goat. During the first week after administration, 80–90 per cent of the activity was found in urine, and about 1 per cent in feces. Known metabolites accounted for 91 –108 per cent of the urinary radioactivity. Oxidative deamination of histamine to imidazoleacetic acid and its riboside seemed to be the only pathway of quantitative importance for histamine degradation in the goat. Paper chromatography revealed that histaminol (4(5)‐imidazolyl‐ethane‐2‐ol) is a metabolite of histamine in the goat accounting for about 2%of the urinary radioactivity.14C‐histaminol is formed when liver or kidney homogenates are incubated with14C‐histamine.
pH‐Dependence of the Mechanism in the Duodenal Bulb Inhibiting Gastric Acid Responses to Exogenous Gastrin
Authors: Andersson Sven. , Nilsson Göran
Published: December 2008

Gastric secretion was stimulated by intravenous infusion of gastrin n Pavlov and Heidenhain pouch dogs provided with isolated pouches of the duodenal bulb. Lowering the intrabulbar pH to pH 1.1 –1.3 almost abolished the acid response to a low dose of gastrin, whereas the inhibition of secretory responses to higher doses was less pronounced. Inhibition of secretory responses to a fixed submaximal dose of gastrin did not occur until the bulbar pH was reduced to 2.0–2.5. Secretory responses to threshold doses of gastrin, on the other hand, were significantly inhibited already at pH 3–4. The results question the concept that very low intra‐duodenal pH is required to activate the mechanism by which acid in the duodenum inhibits gastric acid secretion.
Kininogen in Plasma from Cat, Hamster and Guinea‐pig
Authors: Gautvik Kaare
Published: December 2008

The kininase activity and the level of the two kininogens, substrate 1 and 2, have been determined in plasmas from cats, hamsters and guinea‐pigs. Kininase activity was found to be far more pronounced in the latter type of plasma than in the former ones. The efficiency of di‐sodium edetate and phenanthroline as kininase inhibitor was also evaluated in the three plasma types. In plasma from cat and hamster, human plasma kallikrein was found to release kinins from the socalled substrate 1 only, whereas in guinea‐pig plasma the same agent released kinin from both types of kininogens. The animal's own saliva acted only upon substrate 2 in plasma from cat and guinea‐pig, whereas it induced kinin formation from both substrates in plasma from hamster. Ellagic acid and glass contact released kinins from substrate 1 only in all three plasma types. Intravenous injection in hamsters and guinea‐pigs of a buffered solution of ellagic acid, caused pronounced effects on blood pressure and respiration. On repeated injections these effects subsided. After four such injections the concentration of substrate 1 in arterial blood samples from hamsters was found to be very low (varying from 0 to 20 %). The level of substrate 2 was, however, unchanged. The level of substrate 1 reached 83 % of the initial value after 24 hrs.
Relations of Polyuria and Polydipsia in Experimental Diabetes Insipidus
Authors: Olsson Kerstin
Published: December 2008

Hypothalamic radio‐frequency lesions were produced in unanesthetized goats with the use of thermo‐couple electrodes permanently implanted into the median eminence region. Lesions restricted to the median eminence induced the triphasic response typical of experimental diabetes insipidus (DI). The polyuria of the temporary phase of DI developed before the polydipsia commenced. The increased water intake was apparently secondary to the excessive renal water loss. When the median eminence lesions were extended into the midhypothalamic region no clear distinction could be made between the onset of polyuria and polydipsia. Similar lesions encroaching upon the anterior hypothalamus and affecting the paraventricular nuclei, caused temporary hyperdipsia but no transient polyuria, or a much delayed temporary increase in urine flow. All three types of lesions induced the permanent phase of DI after a latent period of 6 to 11 days. The polydipsia of the permanent phase occurred after the commencement of the polyuria (observations in 2 animals), and was evidently due to a physiological stimulation of the thirst mechanism.
Effect of Salicylate Treatment on Fetal and Maternal Prothrombin Time in the Mouse
Authors: Eriksson Margareta
Published: December 2008

In order to investigate earlier observed salicylate‐induced fetal hemorrhage, sodium salicylate or dicumarol was given i.m. to A/Jax mice on the 17th gestation day. Prothrombin time was measured in the fetuses and the mother at autopsy at different times after injection. A decrease in the prothromth concentration was found in fetuses with salicylate‐induced hemorrhage after 4, 8 and 12 hrs, but not after 24 hrs. Fetuses wihout hemorrhages and the mothers in the salicylate group had the same prothrombin time as those in the control groups. Dicumarol lowered the prothrombin concentration in both the mother and fetuses, but did not cause visible hemorrhage. The possible correlation between salicylate‐induced hemorrhage and hypo‐prothrombinemia is briefly discussed.
The CSF/Blood Potential in Sustained Acid‐Base Changes in the Rat. With Calculations of Electrochemical Potential Differences for H+and HCO‐3
Authors: Kaällquist Å.
Published: December 2008

The electrical D.C. potential difference between cisternal cerebrospinal fluid and external jugular blood was measured in rats during sustained acid‐base changes. One group, serving as a control series, was given an artificial extracellular fluid i.p., while two other groups were made acidotic or alkalotic by means of i.p. injections of NH4Cl or NaHCO3 solutions. In the last two groups NH4Cl or NaHCO3 was given, but Con was simultaneously administered so as to keep either the plasma bicarbonate or the plasma pH constant. In all groups the CSF/ plasma potential was permanently changed in relation to the arterial plasma pH, but there was a larger potential change in alkalosis (about 50 mV/pH unit) than in acidosis (about 30 mV/pH unit). Calculations of electrochemical potential differences for H+and HCO3‐between CSF and plasma showed no significant differences in nonrespiratory acidosis and alkalosis but significant increases in hypercapnia. The results do not support the theory that an active H+transport regulates the CSF pH to constancy.
Neurotransmitter Releasing Effects of Two Quaternary Nicotine Analogues
Authors: von Euler U. S. , Haclid F. , Hedqvist P. , Motelica I.
Published: December 2008

Two nicotine analogues, im‐monomethylnicotinium bromide (IMN) and 1–methyl‐3–(pyrro‐lidinomethyl)‐pyridinium bromide (MPP) have been studied with regard to their catechol‐amine releasing effects in the guinea pig and the rat. In doses of 10–30 mg/kg intraperitoneally IMN decreased the noradrenaline (NA) content of the guinea pig heart. In larger doses, up to 300 mg/kg, both substances caused 80–90 per cent NA depletion of the heart but not in the brain. Maximal effect was reached in 6–12 hn. In the decentralized sub‐maxillary gland the NA content decreased more slowly after IMN than in the normal gland. 6 hrs after sympathetic denervation of the gland the NA content was unchanged in the controls but fell to about one third of the normal after IMN, indicating a peripheral effect. Cold exposure (+2°) for 1 1/2 to 30 hrs did not increase the NA depleting effect of IMN in the rat heart. Catecholamine and vanilmandelic acid excretion in urine of the rat were not significantly increased after IMN and MPP even in doses of 300 mg/kg.

It is concluded that the compounds release NA from the nerve terminals and that the release is enhanced by the normal nerve activity. Some reasons for the slow action are discussed.
Uptake of Some Catecholamines and Their Precursors into Neurons of the Rat Ciliary Ganglion
Authors: Ehinger B. , Falck B.
Published: December 2008

No adrenergic perikarya and only vascular adrenergic terminals were found in ciliary ganglia of normal rats, cats, guinea‐pigs, goats and monkeys, but adrenergic neurons occurred in animals that died under severe stress. Small, intensely fluorescent cells were irregularly observed in rats and cats, and in a cebus monkey. In rats, Nialamide and L‐DOPA (but not D‐DOPA) induced specific fluorescence in certain neurons, which was prevented by dopa decarboxylase inhibition. a‐Methyldopamine and α‐methyldopa also induced fluorescence, but less effectively. The increase in fluorescence in the ciliary ganglion was always less than in the superior cervical ganglion. Cervical sympathectomy did not influence the appearance of fluorescence in the ciliary ganglion. The results were interpreted to indicate that the ciliary ganglion contains a system of neurons which are presumably intraganglionic, do not normally contain catecholamines in sufficient concentration to make them readily demonstrable, presumably contain dopa decarboxylase and monoamine oxidase, and can take up certain amines. These neurons are perhaps ordinary adrenergic nerves operating with an unusually low concentration of noradrenaline, but it cannot be excluded that they have a transmitter substance that is not noradrenaline.
Left Ventricular Pressure and Maximum Rate of Pressure Rise as Determinants of Myocardial Oxygen Consumption during Hemorrhagic Hypotension in Dogs
Authors: Bugge‐Asperheim B. , Kjekshus J.
Published: December 2008

The influence of systolic left ventricular pressure (SLVP) and maxjmum rate of rise of left ventri cular pressure (dP/dt) on left myocardial oxygen consumption (MVO2) has been studied in intact, anesthetized dogs. Noradrenaline and angiotensin were infused in animals which had been bled to a mean aortic blood pressure of 50–60 mm Hg. End‐diastolic volume was reduced by bleecling, but remained fairly constant during the pressure changes caused by the noradrenaline and angio tensin infusions. Wall tension could therefore be regarded as proportional to SLVP.

During noradrenaline infusions, which were adjusted so as to increase mean aortic blood pressure to 130 mm Hg, SLVP, dP/dt and MVO2 increased. An unchanged relationship remained between dP/dt and MVO2 after a‐adrenergic receptor blockade when SLVP did not rise. During infusion of angiotensin there was a marked elevation of SLVP, but only small increases in MVO2 and dP/dt.

On the basis of the changes in MVO2, SLVP and dP/dt, it was shown that the contribution to an increase in MVO, of a rise in SLVP is accounted for By the concomitant increase in dP/dt.
Effects of Hemorrhagic Shock and Treatment with Hypothermia on the Potassium Content and Transport of Single Mammalian Skeletal Muscle Cells
Authors: Haljamäe Hengo
Published: December 2008

The effect of in vivo hemorrhagic shock and its treatment with hypothermia was studied by following the temporal pattern of intracellular potassium content in single skeletal muscle fibres during in vitro incubation. For the control cells isolated before the different experi mental procedures were instituted, reproducible changes in potassium content were observed during the period of incubation. The potassium content of cells isolated shortly after the taking of the biopsy was somewhat lower than of cells isolated after 10 min of incubation. After 10 to 15 min of incubation a marked loss of cellular potassium was seen, followed by a period of active reaccumulation. After hemorrhagic shock under normothermal conditions the potassium content of the cells was markedly lower and no active cellular potassium reaccumulation was obtained during prolonged incubation. Hemorrhagic shock treated with hypothermia lowered the initial pptassium content somewhat but both the periods of cellular potassium loss and active reaceumulation were seen. Hypothermia alone only slightly modified potassium transport during the first 10 to 15 min of in vitro incubation.

The results are discussed from the standpoint of cellular metabolism and high‐energy phosphate production with special reference to the exchange of substances between body com partments under the diffrent experimental conditions.
Effect of the C‐Terminal Octapeptide of Cholecystokinin on Guinea Pig Ileum and Gall‐Bladder in vitro
Authors: Hedner Pavo
Published: December 2008

The C‐terminal octapeptide of cholecystokinin shares the pharmacological properties of the original molecule. Both seem to act directly on the smooth muscle cell of the gall‐bladder but indirectly via a nervous pathway in the ileum. Both reduce the resistance of the choledocho‐duodenal junction. This pharmacological profile is characteristic for a group of substances which besides cholecystokinin and its C‐terminal octapeptide also includes gastrin, pentagastrin and caerulein. There is a close chemical relationship between these substances, e.g. they all have the same C‐terminal tetrapeptide.

Effective doses for the octapeptide were 0.1–0.5 ng/ml in vitro. Its molar activity in the gall‐bladder and ileum is comparable to that of caerulein and about 3 times that of cholecysto kinin and 1000 times that of pentagastrin.

Besides the heterologous caerulein the C‐terminal octapeptide of cholecystokinin appears as the most active gall‐bladder contracting agent known at present, with a molar activity about 100 times that of acetylcholine, histamine or bradykinin.
Effects of Noradrenaline upon Cerebrocortical Activity in Asphyxiated Newborn Rabbits
Authors: Boëthius Jörgen , Brunclin Tomas , Persson Nils‐Åke
Published: December 2008

The asphyxia resistance of the direct cortical response (DCR) and the electrocorticogram (ECG) was determined in noradrenaline treated and untreated newborn rabbits. The resistance of the untreated animals was similar to what has previously been found for the adult, the DCR being blocked within 3 1/2 min and the ECG within 2 min of asphyxia. After the ad ministration of noradrenaline the DCR became more resistant to asphyxia and could be evoked for 8–17 min. The ECG was not sustained by noradrenaline, and was blocked within 2 min of asphyxia as it was in the untreated animals.

An increased ability of the DCR to withstand asphyxia has been described for the fetus. In view of the above mentioned effect of noradrenaline, it was proposed that this resistance of the fetal DCR to asphyxia is due to the fact that in the fetus asphyxia stimulates the release of noradrenaline from the preaortal paraganglia and the adrenal medulla. Possible mechanisms whereby the increased resistance of the DCR could be effected by noradrenaline were discussed.
Disappearance of Serum Insulin in Obese‐Hyperglycemic Mice
Authors: Coore Haldane G. , Westman Sighild
Published: December 2008

The disappearance from serum of i.v. injected insulin has been studied in obese‐hyperglycemic and lean mice. Groups of mice were given either a high dose, 600 U bovine insulin/kg b.w., or a tracer dose 125I‐labelled insulin. The serum content of immunoreactive insulin or anti body bound radioactive insulin was measured at intervals. No difference in disappearance rate was noted between the obese and lean mice after the high insulin dose. When studied under more physiological conditions with a tracer dose, it was found that the rate of insulin dis appearance from serum was greater in the obese animals. These finclings are discussed against the background of previous observations of increased resistance to insulin hypoglycemia in obese mice and an increased insulin degracling activity of adipose tissue homogenates from such mice.
Studies of the Damped Oscillatory Response of the Auditory Frequency Analyzer
Authors: Møller Aage R.
Published: December 2008

The temporal characteristics (system impulse response) of the peripheral, auditory spectrum analyzer, up to the level of the neural excitation, has been studied. This was accomplished by recording the average firing rate of single units in the rat cochlear nucleus in response to paired clicks in which the interval between clicks was varied over a large range. The results show that the system impulse response of all units studied was a damped oscillation. The frequency of the oscillation was equal to the characteristic frequency of the unit. On basis of these recorded responses the auto‐correlation of the system impulse response was computed. It was furthermore found that bandwidth values determined on the basis of the derived autocorrelation functions were smaller than those estimated from tuning curves and isorate curves. It is concluded that the auditory system of the rat has a higher spectral resolution in regards to double click stimulation than it has for stimulation with single pure tones. The study furthermore indicates that the sharpening of the spectral resolution of ‘the auditory system represented by unit responses in the rat cochlear nucleus is not accomplished by interactions between the time integrated output from a number of hair cells.
Dopamine‐Containing Cells in Sympathetic Ganglia
Authors: Björklund A. , Cegrell L. , Falck B. , Ritzén M. , Rosengren E.
Published: December 2008

In addition to noradrenaline (about 1.3–1.5 μg/g) dopamine (about 0.2 μ/g) is present in the sympathetic chains of the cat and pig. By means of a recently developed microspectro‐fluorimetric method, the cellular localization of these two catecholamines has been studied. Dopamine was found in a special type of small, intensely fluorescent cells (“SIF‐cells”) located among the adrenergic ganglion cell bodies. Most of the dopamine present in the sympathetic ganglia is probably stored in these cells.
The Transport of Halide Ions across the Membrane of Distal Rat Tubules
Authors: Danielson B. G. , Persson E. , Ulfendahl H. R.
Published: December 2008

The transport mechanism for chloride was studied in rat distal tubules with a free‐flow micro‐puncture technique. The tubular fluid to plasma concentration ratio (TF/P) was determined simultaneously for sodium, potassium, chloride and iodide. The experiments were designed to determine whether there is a common active carrier mechanism for halide transport out of the distal tubules with a higher affinity for iodide than for chloride. If such a transport system exists it should give rise to a lower TF/P value for iodide than for chloride. However, the TF/P value for iodide was 0.78 and was significantly higher than for chloride (0.39), a result which is interpreted to mean that no such active carrier transport mechanism for halides exists in the distal tubules. In our opinion the differences in TF/P values depended on a lower passive permeability for iodide than for chloride.
Water Permeability in Rat Proximal Tubules
Authors: Person E. , Ulfendahl H. R.
Published: December 2008

The diffusional water permeability in rat proximal tubules was studied in microperfusion experiments with triturated water. The perfusion solutions were chosen either to give no net flux or a net water flux in either direction. The diffusional water permeability at zero net water flux was 564. 10‐‐5 cm/sec. The significance of the permeability measurements made during a net flux is discussed. The osmotic water permeability was 15. 10‐‐8 cm3 cm‐2 sec‐1. (cm H2O)‐l The large differences between osmotic water permeability and diffusional water permeability in zero net flux conditions cannot be accounted for entirely by an unstirred layer effect and are interpreted to mean that water transport along osmotic gradients is mainly a bulk flow through aqueous pores and not a diffusional flow and that the proximal tubular wall is a highly porous membrane.
Differentiated Interaction between the Hypothalamic Defence Reaction and Baroreceptor Reflexes
Authors: Djojosugito A. M. , Folkow B. , Kylstra P. H. , Lisander B. , Tuttle R. S.
Published: December 2008

As the interrelationship of autonomic patterns involving cortico‐hypothalamic and bulbar levels is of general interest, the interaction between the hypothalamic defence reaction and the homeostatic baroreceptor reflexes was explored in cats with respect to cardiac as well as vascular effects. The results suggest, in conformity with Hilton's observations (1963), that defence area stimulation suppresses the baroreceptor reflex inhibition of the heart. On the other hand, the baroreceptor influence on vasoconstrictor fibre discharge was largely the same, whether defence area stimulations were performed or not. This had important haemodynamic consequences, especially for muscle blood flow, since the reflex inhibition of regional constrictor fibre tone could greatly enhance the cholinergic vasodilatation. Therefore such a differentiated interaction between oppositely directed central and reflex autonomic mechanisms has the consequence that the baroreceptor reflexes, rather than damping the defence reaction, act in synergism with it with respect to net haemodynamic effects; some further implications of this are dealt with in the subsequent paper (Kylstra and Lisander 1969).
Differentiated Interaction between the Hypothalamic Defence Area and Baroreceptor Reflexes
Authors: Kylstra P. H. , Lisander B.
Published: December 2008

In experiments on cats, the interaction between the oppositely directed hypothalamic defence reaction and the baroreceptor reflexes was analysed with particular regard to the effects on aortic blood flow, left ventricular work load and muscle blood flow. Because of their differentiated interaction — suppression of the baroreceptor reflex effect on the heart with preservation of the reflex modulation of the vascular bed (Djojosugito et al. 1969) — the baroreceptor reflex so modifies the primary defence reaction, with its intense neurogenic drive on the heart, that a greater cardiac output is gained for a given left ventricular work load. This particularly favours muscle blood supply. It follows that such a differentiated interaction between two basically opposite autonomic patterns causes them to act in synergism with respect to efficient cardiovascular performance in states of emergency.
Effect of Chlorpromazine, Mepyramine, Prenylamine and Reserpine on 5‐Hydroxytryptamine Content and Fine Structure of Rat Peritoneal Mast Cells Incubated in Vitro
Authors: Jansson Sten‐Erik
Published: December 2008

The mechanism of action of the drugs tested in releasing 5‐hydroxytryptamine from mast cells in vitro was studied under different incubation conditions and by observing the morphological changes associated with the amine release. It was proposed that chlorpromazine, mepyramine and prenylamine release 5‐hydroxytryptamine by a mechanism of action not requiring energy because neither did the drugs exert their maximal effect at physiological pH values nor was the release blocked by pre‐incubation with sodium cyanide. The suggestion is supported by the morphological observations revealing destructive changes of the mast cells. The reserpine induced release of 5‐hydroxytryptamine from mast cells was small upon incubation in a phosphate buffer and was completely inhibited upon incubation in a physiological medium containing divalent cations sand glucose. The release was not decreased by lowering the temperature of the incubation medium from 37°C to 23°C which indicate a mechanism of action not requiring energy. On the other hand, reserpine had a maximal releasing effect around neutral pH values and the release was totally blocked by pre‐incubation with sodium cyanide suggesting a necessity for metabolically active cells. An energy requiring mechanism of action of reserpine was further supported by the observed morphological alterations which were much of the same nature as those induced by compound 48/80.
Temperature Regulation during Continuous and Intermittent Exercise in Man
Authors: Ekblom Björn , Greenleaf Carol J. , Greenleaf John E. , Hermansen Lars
Published: December 2008

Ekblom, B. C. J. Greenleaf, J. E. Greenleaf and L. Hermansen, Temperature regulation during continuous and intermittent exercise in man. Acta physiol. scand. 1971. 81. 1–10.

Body temperature changes and heat dissipation responses were studied in three well‐trained men during moderately heavy (60 % of maximal aerobic power) continuous and intermittent exercise at the same average metabolic rate and heat production. The purpose was to determine if hypothetical “work factors” induced specifically by muscular activity influenced body temperature regulation. Compared with continuous work; a) the equilibrium level of rectal temperature (Tre) during intermittent work was elevated 0.35° C which accounted for 21 % of the total Tre increase from resting, and b) the decreased sweating of 32 g/(m2. hr) during intermittent work resulted in a decreased evaporative heat loss of 18.6 kcal/(m2. hr) that could account for the increased intermittent work Tre. These responses appear to be manifestations of reduced thermoregulatory efficiency due, perhaps, to non‐linearity in the relationship of body temperature to total work rate or to non‐linearity in the contribution of non‐thermal inputs at work rates above 100 % of max. V̇O2. It is also possible that other factors play a part, such as the frequency and duration of the work and rest cycles, rate of limb movement, or circulatory factors related to postural changes.
Uptake of Serotonin in Blood Platelets in vitro. I: The Effects of Chloride
Authors: Lingjærde O.
Published: December 2008

Lingjærde, O. Jr.Uptake of serotonin in blood platelets in vitro. I: The effects of chloride. Acta physiol. scand. 1971.81. 75–83.

The effects of chloride on the “active” uptake of14C‐serotonin in human blood platelets in vitro have been studied, using a phosphate buffered artificial medium. The uptake of serotonin requires the presence of chloride in the medium. The effect of chloride concentration on the rate of serotonin uptake is in agreement with Michaelis‐Menten type kinetics. The apparent Michaelis constant for chloride is about 35 mM at pH 7.2, and it is independent of the concentration of serotonin. Moreover, the apparent Michaelis constant for serotonin is independent of the concentration of chloride. Preincubation with low concentrations of chloride is accompanied by a decrease in the rate of uptake, whereas the converse is true when high concentrations of chloride are used. It is suggested that inward transport of serotonin is dependent on chloride in such a way that serotonin and chloride have to be attached to the same carrier. It is also suggested that the intracellular concentration of chloride is of importance for the rate of re‐trans‐location of the carrier from the inner to the outer surface of the membrane.
The Effect of Lactate in Canine Subcutaneous Adipose Tissue in Situ1
Authors: Fredholm Bertil B.
Published: December 2008

Fredholm, B. B.The effect of lactate in canine subcutaneous adipose tissue in situ. Acta physiol. scand. 1971.81. 110–123.

Na‐L(+)‐lactate and Na‐pyruvate were administered by intraarterial infusion in canine subcutaneous adipose tissue, perfused with the dogs own blood either at a constant rate from a reservoir or by autoperfusion. The glucose uptake was found to be dependent upon the arterial glucose concentration. Similarly the uptake of lactate and pyruvate increased with increasing arterial concentrations, the latter more rapidly than the former. Infusion of Na‐L(+)‐lactate below 5 mM and Na‐D(—)‐lactate (10–11 mM) had no effect on the release of FFA and glycerol upon nerve stimulation (4 cps for 5 to 10 min). On the other hand Na‐L(+)‐lactate above 10 mM caused a 70 per cent inhibition of the release of FFA without significantly affecting the glycerol release. Na‐pyruvate (5 mM) decreased the glycerol output significantly, but increased the FFA release. Neither of the anions had any significant effect on the glucose uptake. Na‐lactate was not vasoactive, whereas Na‐pyruvate was slightly vasodilator.

It is concluded that lactate in concentrations occurringa.g. during muscular exercise and shock is capable of significantly depressing the rate of FFA release upon nerve stimulation by increasing the rate of re‐esterification. The finding that lactate and pyruvate had opposite effects on esterification indicates a role of the cytoplasmatic NADH/NAD ratio in determining the rate of esterification.
Cyclic AMP as a Mediator of Hormonal Metabolic Effects in Brown Adipose Tissue
Authors: Beviz Andras , Lundholm Lennart , Mohme‐Lundholm Ella
Published: December 2008

The role of cyclic AMP for the calorigenic and some other metabolic effects of noradrenaline, 5‐hydroxytryptamine and ACTH has been studied in brown adipose tissue from the rat. Noradrenaline (5×10‐‐6g/ml) increased significantly the cyclic AMP level in brown adipose tissue. All hormones stimulated the O2‐consumption, the lactate and glycerol productions, the FFA release and reduced the ATP content of the tissue. Noradrenaline and 5‐hydroxytryptamine also reduced the glucose‐6‐phosphate content. Noradrenaline increased both the total and the phosphorylase a activity. Addition of cyclic AMP (4.5 × 10‐‐6moles/ml) to the suspension solution increased the O2consumption, the glycerol and lactate productions and the FFA release; the actions were equivalent to those of a noradrenaline concentration of 5×10‐‐8g/ml. In contrast to noradrenaline, cyclic AMP increased the ATP content. Dibutyryl‐cyclic AMP in a ten times lower concentration (5× 10‐‐7mo les/ml) had the same potency in stimulating the O2consumption and FFA‐release as cyclic AMP. Theophylline (4.5×10‐‐3g/ml) stimulated the O2consumption, the glycerol and lactate productions and the FFA release of brown adipose tissue. Theophylline potentiated the effect of cyclic AMP on the O2consumption; and in combination the drugs reduced the ATP and glucose‐6‐phosphate content of the tissue and increased the phosphorylase activity. The magnitude of the metabolic effects was equivalent to the maximal effect of noradrenaline. The increase of AMP produced by cyclic AMP was blocked by theophylline. It is suggested that the studied metabolic effects of noradrenaline is mediated by an increased formation of cyclic AMP in brown adipose tissue.
Blood Flow in the Calf Muscle of Man during Heavy Rhythmic Exercise
Authors: Folkow Björn , Haglund Ulf , Jodal Mats , Lundgren Ove
Published: December 2008

133Xenon clearance was recorded during maximal vasodilatation in the calf muscles of trained subjects during rest and during heavy rhythmic exercise (contraction about 0.3 sec, relaxation about 0.7 sec) when the subject was tilted from a supine to a “leg down” position. The k‐value for the wash‐out curve, divided by the mean arterial blood pressure at heart level (MABP), was considered to reflect the relative levels of maximal flow in the two experimental situations. While a shift to “leg down” position during post‐exercise hyperemia did not significantly increase flow through the fully dilated muscle vessels, indicating that they were already maximally distended, the same shift during rhythmic exercise raised the average value of k/MABP approximately 60 per cent above control. This observation is in all probability explained by a marked lowering of mean venous pressure by the “muscle pump” in the dependent legs, despite the huge flow during the heavy rhythmic exercise. This would result in a considerable gain in local perfusion pressure and hence in maximal flow capacity.
Electrolytes in Leg and Neck Muscles of Rats during Ontogeny
Authors: Beroström J. , Boëthius J. , Hultman E.
Published: December 2008

The contents of sodium, potassium, magnesium, chloride, phosphorus and water were determined in the leg and neck muscle of 3– and 14‐day old rats. There were marked differences in electrolyte content between the two age groups and also between the leg and neck muscle of the 3‐day old rat.

The results indicate that there is a decrease in the amount of extracellular fluid during maturation. The composition of the intracellular fluid also changes during development insofar as there is a marked decrease in its sodium content.

The results indicated that the decrease in intracellular sodium roughly paralleled the rise in membrane potential. It was therefore suggested that the developmental change in the intracellular sodium concentration was secondary to a decrease in the sodium permeability of the muscle cell membrane or to a change in the active transport of sodium across the membrane.
Reactivity to Noradrenaline of Aortic Strips and Portal Veins from Spontaneously Hypertensive and Normotensive Rats
Authors: Hallbäck Margareta , Lundgren Yen , Weiss Lilian
Published: December 2008

To investigate whether vascular smooth muscle of spontaneously hypertensive rats, SHR, (Oka‐moto 1963) displays any hypersensitivity to noradrenaline (NA) as compared to that of normotensive control rats, NCR, helical aortic strips, alternatively portal vein segments, from a SHR and a NCR were mounted in the same organ bath, to which graded NA doses were added. In neither case did the dose‐response curves, expressed as per cent of the maximal responses, reveal any significant difference between SHR and NCR. These in vitro studies are therefore in agreement with the view that the enhanced flow resistance responses, caused by NA (and other vasoconstrictor agents) in SHR as compared with NCR are not the result of any increased sensitivity to NA of the vascular effector cells proper but may rather, as suggested by Folkow et al. (1970), be due to an increased wall/lumen ratio of the SHR resistance vessels.
The Effect of Cooling on Liver Function in Cats
Authors: Larsen Jens Anker
Published: December 2008

Liver function was followed by the elimination rate of glyceorol and ethanol and the hepatic uptake of Indocyanine Green. It was demonstrated that a 1° to 2° C reduction of the body temperature or cooling of the portal vein reduced the elimination rate of glycerol and ethanol, as well as the hepatic uptake of Indocyanine Green, about 40 per cent. The experimental findings may be explained by restricted distribution of blood flow in the liver and a corresponding reduction of the functional capacity.