bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exclusive Thalamic Location of Subcortical Spontaneous Barbiturate Spindles
Authors: Junge K. , Sveen O. 
Published: December 2008

AbstractSpontaneous discharges of neurones in the thalamus, the mesencephalic and pontine reticular formation, the caudate nucleus and the hypothalamus were recorded in cats anesthetized with barbiturates.Only thalamic cells showed the spindle pattern of discharges, consisting of high frequency bursts separated by silent intervals, corresponding to a repetition frequency of 7–14/sec.All neurones outside the thalamus discharged randomly, with no correlation to the simultaneously occurring thalamic spindle activity.It is concluded that subcortical neutrones participating in spontaneous barbiturate spindle activity have an exclusive thalamic location.Consequently, the processes of synchronization and desynchronization both most likely take place at a thalamic level.
Changes in Alveolar‐Arterial Oxygen Tension Difference (A‐aDo2) during Variations in Alveolar Ventilation
Authors: Kim Byong M. , Refsum Harald E. 
Published: December 2008

AbstractThe alveolar‐arterial PO2 difference (A—aDO2) was determined at various levels of alveolar ventilation in anesthetized, tracheotomized dogs, ventilated with room air by means of a volume cycled respirator; the ventilation being changed by varying the tidal volume, keeping the respiratory rate constant.—A decrease in ventilation was accompanied by a marked decrese in A—aDO2, and vice versa: At PaCO2≤30 mm Hg (mean 25.5 mm Hg) A—aDO2 was 28.3 mm Hg (range 18—42 mm Hg), at PaCO2 31–50 mm Hg (mean 41.5 mm Hg) A—aDO2 was 19.3 mm Hg (range 13—30 mm Hg); at PaCO2≥51 mm Hg (mean 60.5 mm Hg).A—aDO2 was 9.7 mm Hg (range 5—14 mm Hg).—Assuming an arterio‐venous difference in hemoglobin O2 saturation of 20% and 40%, respectively, the A—aDO2 for the 3 PCO2 intervals were calculated as venous admixture, being 7.1, 10.4 and 23.0%, and 3.7, 5.5 and 13.0%, respectively.—This indicates that reduction of the alveolar ventilation is accompanied by increasing disturbances of the alveolar‐arterial gas exchange,—of the nature uneven distribution of ventilation and perfusion, and/or venous admixture.The inverse relationship between the extent of the disturbances of alveolar‐arterial gas exchange and A—aDO2 in these studies show that A—aDO2 should only be used for the evaluation of changes in the alveolar‐arterial gas exchange when the alveolar ventilation remains unchanged.
The Relation between the Action Potential and the Active State in Human Fetal Myocardium and its Dependence on Muscle Length and Contraction Frequency
Authors: Gennser G. , Nilsson E. 
Published: December 2008

AbstractActive state and action potential measurements were performed on papillary muscles from human foetuses.Changes in these two parameters induced by alterations in muscle length and contraction frequency were studied.Shortening of the muscle not only reduced the intensity of the active state, but also shortened its time course without any concomitant alteration in action potential duration.A decrease in stimulation frequency caused a reduction in the intensity of the active state and an increase in the durations of the active state and the action potential.The change in the action potential duration was considerably greater than that of the active state.The results are discussed in the relation to the activator hypothesis for excitation‐contraction coupling in the myocardium.
The Effect of Prostaglandin E1 on the Response of the Rabbit Oviduct to Hypogastric Nerve Stimulation
Authors: Brundin Jan 
Published: December 2008

AbstractThe effect of sympathetic nerve stimulation was studied on the response of rabbit oviducts under the influence of prostaglandin E1 (PGE1).PGE1 inhibited the constrictory response to nerve stimulation and i.v.injection of noradrenaline (NA).A possible physiological role of PGE1 is discussed.
Potentiation of Tyramine Effect on the Isolated Iris Muscle by Cocaine
Authors: Lagercrantz H. 
Published: December 2008

AbstractEffects of noradrenaline, tyramine and cocaine have been studied on the sphincter of the isolated bovine iris muscle preparation.After administration of cocaine in low concentrations (0.5X10‐5‐2X10‐5M) applied for 2–10 min the tyramine response was incresed in 5 cases out of 12.Various explanations for this effect of cocaine are discussed.
Studies on Uptake and Decarboxylation of Histidine by Isolated Rat Mast Cells
Authors: Cabut Martha , Haegermark ÖSten 
Published: December 2008

AbstractIsolated rat mast cells, when incubated in a medium containing histidine‐H3, took up and decarboxylated histidine, thus forming histamine.Uptake and decarboxylation were measured as a function of incubation time and extracellular histidine concentration.The influence of amino acids, amines, inhibitors of cell metabolism, and inhibitors of histidine decarboxylase was studied on these two processes.It was concluded that at least part of the histidine transport into the cell was mediated by a carrier mechanism.In the presence of the histidine decarboxylase inhibitor NSD‐1055, the amount of histidine accumulated by the cells reached a certain level within 10 min and was not increased significantly by prolonging the incubation time.Histamine‐H3formed by the mast cellsin vitrofrom histidine‐H3was bound to granules of sonically disintegrated cells, but to a lesser extent than that originally present in the cells.Only a very small proportion of the histidine taken up in the presence of a decarboxylase inhibitor was recovered in the granular fraction.Treatment of mast cells with compound 48/80 released the same relative amounts of the histamine formedin vitroand of that originally present in the cells.
Effect of Directly and Indirectly Acting Sympathomimetic Amines on Adrenergic Transmitter Granules
Authors: Euler U.S.von , Lishajko F. 
Published: December 2008

AbstractThe actions of various sympathomimetic amines on release and reuptake of noradrenaline (NA)1in splenic nerve granules during incubation in phosphate buffer have been studied.The effect on the basic release rate was studied in the absence of NA in the medium.The degree of reuptake was determined with the aid of dl‐3H‐NA.Tyramine (TA) 10‐7–10‐4M causes a moderate direct releasing effect of NA from nerve granules which reaches a constant level within 10 min at 20d̀.In 10‐5–10‐3M concentration TA inhibits the reuptake of NA in granules.After previous loading of granules with radioactive NA, addition of TA to the incubation medium releases NA with apporoximately the same specific activity as that in the total store.Tritiated TA is taken up in nerve granules to a small extent, approximately corresponding to the direct release of NA.The releasing action of TA is blocked by reserpine 10‐5M.phenoxybenzamine 3 X 10‐4M and desmethylimipramine 3 X 10‐4M.Phenethylamine and amphetamine have a strong direct releasing effect and a moderate effect on reuptake of NA in granules.Ephedrine and mephentermine slightly retard NA release and inhibit NA reuptake at 3 X 10‐4M.Dopamine competitively inhibits reuptake of NA in granules.The effects of amines on release and reuptake in granules differ markedly from those exerted on the overall uptake of NA in perfused organs.
Effects of Temperature Changes on the Pressor Response to Acute Alveolar Hypoxia in Isolated Rat Lungs
Authors: Nilsen K.Haavik , Hauge A. 
Published: December 2008

AbstractThe effects of perfusate cooling upon the pressor response to 3 min periods of ventilation hypoxia was tested in an isolated blood‐perfused rat lung preparation.The response was found to be markedly and reversibly thermosensitive.Lowering the perfusate temperature from 38d̀ C to 27.5d̀ C abolished the pressor response to the subsequent test of ventilation hypoxia.When, however, perfusion was continued at 27.5d̀ C moderate pressor responses to ventilation hypoxia developed.The number of pressor responses which could be obtained to 3 min tests of hypoxia was limited in this preparations.In perfusions carried out at 27.5d̀ C the responses were smaller, but 1 1/2 to 2 1/2 times as many, as in perfusions at 38d̀ C.The thermosensitivity of the pressor response could not be correlated with pH changes in the perfusate.The findings seem to support the theory of a vasoconstrictor agent being released or activated by alveolar hypoxia.
Distribution and Intensity of Monoamine Oxidase Activity in the Mammalian Duodenum
Authors: Penttilä A. 
Published: December 2008

AbstractThe quantity and localization of monoamine oxidase (MAO) activity was studied in the duodenum of eight mammalian species.There were great differences in the enzyme activity between various species.In the guinea pig, the rabbit and the mouse MAO activity was 6–9 times as high as that in the rat, the cow, the pig and the horse.The sheep differed significantly (P<0.001) from all other species.In the pig, the activity of the muscular layers was about a third of that observed in the united mucous and submucous layers.Histochemically the epithelium adjacent to the intestinal lumen showed a strong enzyme activity in all the species but the cow, the sheep and the rat.The Brunner glands and the muscular coats exhibited a moderate or weak reaction.The serosa and mucous muscular layer were negative.The results are compared with those made by the present author on the distribution of 5‐HT and the enterochromaffin cells in the same species.There is no correlation between chemically estimated MAO activity and 5‐HT content in the duodenum.The histochemical distributions of the enzyme activity and 5‐HT are also different.
Uptake of Noradrenaline in the Isolated Perfused Rat Heart after Depletion with Decaborane
Authors: Bhattacharya I.C. 
Published: December 2008

AbstractAfter depletion of noradrenaline (NA)in vivowith decaborane, isolated perfused rat hearts rapidly take up NA to approximately the normal content from a perfusion medium containing NA 10‐7–10‐6M.The NA uptake is inhibited to varying degrees by cocaine, desmethyl‐imipramine, phenoxybenzamine, reserpine, iso‐methyl nicotinium bromide, prenylamine and by certain sympathomimetic and other autonomic drugs.The decaborane‐depleted heart appears to be a useful preparation for the study of the bulk uptake of NA.
The Effect of Protriptyline on the Metabolism of Dopamine and Noradrenaline in Rabbit Brain in vitro
Authors: Jonason Jan , Rutledge Charles O. 
Published: December 2008

AbstractSlices of rabbit brain cortex were incubated with labeled dopamine or noradrenaline.Dopamine was deaminated twice as fast as noradrenaline.Pretreatment of rabbits with protriptyline reduced the catabolism of dopamine and noradrenaline to values of 58 and 35 per cent of normal, respectively, using the same substrate concentration.Furthermore, protriptyline‐pretreatment inhibited the retention of each amine correspondingly, whereas the monoamine oxidase activity of brain cortex homogenates was unchanged.These observations suggest that protriptyline inhibits the metabolism of catecholamines by inhibiting the amine uptake by the cell membrane.Protriptyline (10 mg/kg) caused a marked reduction of dihydroxyphenylacetic acid, a slight reduction of homovanillic acid and an increase in methoxytyramine using dopamine as substrate, whereas a marked reduction of dihydroxyphenylglycol and dihydroxymandelic acid, a smaller reduction of both vanilmandelic acid and 3‐methoxy‐4‐hydroxy‐phenylglycol with no effect on normetanephrine was seen using noradrenaline as substrate.These observations indicate that monoamine oxidase is localized at least partially intraneuronally whereas catechol‐O‐methyltransferase is localized at almost exclusively extraneuronally.Protriptyline‐pretreatment inhibited the total synthesis of noradrenaline from dopamine an effect antagonized by increasing the substrate concentration supporting the view that dopamine‐β‐hydroxylase is localized within the monoamine neurons in the cerebral cortex.
Excitability of the Frog's Muscle Spindle to Transient Stretches Following Spontaneous and Evoked Afferent Action Potentials1
Authors: Jahn Samia Al Azharia 
Published: December 2008

AbstractIn isolated muscle spindles of the frog the recovery of excitability, tested by threshold stretches, lasted for 30 msec (17–20d̀ C), whether the conditioning afferent action potential occurred spontaneously or was evoked by stretch.Suprathreshold stretches were responded to earlier, depending on the size and the rise time of the stretch.The minimum interval between a spontaneous afferent action potential and the onset of a suprathreshold stretch responded to decreased with increasing rise time whereas the irresponsive period was shortest for fast stretches.When the afferent action potential was evoked by a conditioning stretch the minimum interval between the response and the onset of test stretches responded to was longer than after a spontaneous action potential, and increased with the size of the conditioning deformation.There was evidence for a period of supernormal excitability occurring about 8 msec (17–20d̀ C) after a spontaneous and an evoked afferent action potential.
Capillary Permeability to and Extravascular Dynamics of Myoglobin, Albumin and Gammaglobulin in the Uvea
Authors: Bill Anders 
Published: December 2008

AbstractThe dynamics of myoglobin, albumin and gammaglobulin in the tissue fluids of the rabbit eye were studied in two‐isotope experiments to elucidate the mechanisms for transcapillary movement of protein and protein drainage from the eye, the nature of the blood‐aqueous barrier and the way in which extravascular protein may influence the formation of aqueous humor.The permeability of the blood vessels of the choroid and the ciliary processes to myoglobin was 10 to 15 times higher than that to albumin which was about twice that to gammaglobulin.In the tissue fluid of the ciliary processes the turnover rate constant for myoglobin was 25 per cent/min, for albumin it was 3.9 per cent/min and for gammaglobulin 1.6 per cent/min.The extravascular albumin spaces in the ciliary processes and the choroid were 158 μl/g and 165 μ/g respectively.The extravascular albumin spaces were 68 and 57 per cent of the myoglobin spaces in the ciliary processes and the choroid, respectively.The extravascular gammaglobulin spaces were 87, 98 and 117 per cent of the extravascular albumin spaces in the choroid, the ciliary processes and the rest of the anterior uvea, respectively.The methods employed will give new information about the dynamics of the tissue fluids also in tissues with lymph vessels.
Relationship between Drug‐Induced Changes in Blood Pressure and Cerebral Oxygen Availability
Authors: Aquilonius S.‐M. , Sundwall A. , Winbladh B. 
Published: December 2008

AbstractUnder certain conditions it proved possible to obtain reproducible measueres of changes in cerebral oxygen availability, aO2, when using open‐ended polarographic electrodes.In anaesthetized cats and rabbits a relationship was found to exist between the blood pressure changes produced by noradrenaline, acetylcholine and hexamethonium, and their effect on cerebral aO2.However, the decrease in cerebral aO2produced by acetylcholine and bexamethonium was normalized long before the blood pressure was normal.In addition, the increase in aO2produced by adrenaline was always smaller than that produced by an equihypertensive dose of noradrenaline.This difference may be due to the fact that adrenaline also increases the cerebral oxygen consumption.Potassium cyanide increased cerebral aO2without significantly affecting the blood pressure.
Histochemical and Biochemical Observations on Cholinesterases of Cat's Tapeworm Taenia Taeniaformis
Authors: Eránkö Olavi , Kouvalainen Kauko , Mattila Mauri , Takki Seppo 
Published: December 2008

AbstractCholinesterase activity of the tapeworm was studied histochemically with the Koelle method, using acetylthiocholine and butyrylthiocholine as substrates, and biochemically with the Warburg technique, using acetylcholine, acetyl‐β‐methylcholine and butyrylcholine as substrates.Eserine.tetra‐isopropylpyrophosphoramide (iso‐OMPA), 1,5‐bis (4‐trimethylammonium‐phenyl‐phntan‐3‐one diiodide (BW 62 C 47) and 1,5‐bis(4‐allylmethyl‐ammonium‐phenyl) pentan‐3‐one diiodide (BW 284 C 51) were used as inhibitors.Both the histochemically and the biochemically demonstrable tapeworm cholinesterase activity was readily inhibited by low concentrations of eserine but resistant to the other inhibitors employed, whatever substrate was used.In this respect the tapeworm cholinesterase activity markedly differed from that in the human serum, the rat brain homogenate or the duodenum of the cat, which were used as reference sources of cholinesterase.The histochemical cholinesterase reactions obtained with acetylthiocholine and butyrylthiocholine, with or without iso‐OMPA or BW 62 C 47, showed identical distributions, selectively limited to nervous ganglia, nerve trunks and nerve fibres of the worm, including those innervating the suckers.It is concluded that the tapeworm cholinesterase is distinct from mammalian acetylcholinesterase and non‐specific cholinesterase, even if it is, like acetylcholinesterase, a selectively neuronal enzyme and inhibited by excess substrate.
Effect of Maternal and Fetal Hypophysectomy or Adrenalectomy on the Fatal Extra‐Adrenal Chromaffin Tissue of the Rat.
Authors: Lempinen Matti , Ojala Kari 
Published: December 2008

AbstractThe present work was undertaken to study hormonal relationship between developing extraadrenal chromaffin tissue and both fetal and maternal adrenal cortex.Maternal adrenalectomy performed during early or mid‐pregnancy caused a slight increase in the intensity of the chromaffin reaction of the full‐term para‐aortic body.Hydrocortisone substitution seemed to depress this effect.Maternal hypophysectomy performed in the late pregnancy caused complete disappearance of the chromaffin reaction of the extra‐adrenal chromaffin cells of the full‐term fetus.while fetal hypophysectomy failed to produce any significant changes.It is suggested that maternal adrenocorticotropic hormone affects the chromaffin cells of the fetus during its late developmental stage.
Adrenergic Innervation of the Male Reproductive Ducts of Some Mammals. III. Distributions of Noradrenaline and Adrenaline
Authors: Eliasson Rune , Risley Paul L. 
Published: December 2008

AbstractDistributions of noradrenaline (NA) and adrenaline (A) in testes, epididymides, and vasa deferntia were determined by fluorespectrophotometric quantitative analyses of organs from rats, guinea‐pigs, rabbits, and cats. Cat testes and caput epididymides have larger NA concentrations than those of other species. Increasing NA concentratiosn appear in cauda epididymides and the largest ones occur in vasea deferentia. Conventrations of A were low in all organs examined. The data correlates closely with previous histochemical observations on the distributions of the adrenergic innervatiosn of these organs
The Purity of Two Commercial p‐aminohippurate Preparations
Authors: Frederiksen S. , Nissen O. I. 
Published: December 2008

AbstractP‐aminohippuric acid (PAH) preparations made by “Koch‐Light” and “Fluka” were analyzed by a column chromatographic technique using columns of Dowex‐1‐Cl‐, 200—400 mesh, X2 and Dowex‐50‐H+, 200—400 mesh, X12. A commonly used procedure for determination of PAH in plasma and urine was applied to the effluents. The preparations contained impurities giving positive PAH reaction in concentrations of 1.3 % (Koch‐Light) and 0.3 % (Fluka) expressed as PAH. The major parts of the contaminants are probably p‐aminobenzoic acid, 1.2 % and 0.2 %, respectively
Similarities between the Vascular Smooth Muscle Responses to Sudden Changes in External Potassium, Soldium and Chloride Ion Concentrations
Authors: JOHANSSON BORJE , JONSSON OLOF 
Published: December 2008

AbstractThe effects of graded reductions in extracellular potassium, sodium and chloride concentrations on the spontaneous electrical and mechanical activity of the isolated rat portal vein have been studied. The immediate responses obtained on marked reduction in these ion concentrations and on readministration of normal solution were common to the three ion concentrations and on readministration of normal solution were common to the three ion species and differed from the long‐term effect of the ionic environment. Thus abrupt large reductions in the concentration of any of the three ions resulted in a transient excitation whereas return to normal Krebs solution led to a temporary complete inhibition of muscle activity. These initial, transient responses could in many cases not be predicted on the basis of the “constant field equation” by merely inserting the actual ion concentration values. However, if the concentrations of chloride and potassium ions (or chloride and sodium ions) were changed in a reciprocal manner no such transient responses occurred. Some possible explanations for this difference between the immediate and long‐term effects of a changed ionic environment are discussed
Position and Velocity Sensitivity of Muscle Spindles in the Cat. III. Static Fusimotor Single‐Fibre Activation of Primary and Secondary Endings
Authors: Lennerstrand Gunnar , Thoden Uwe 
Published: December 2008

AbstractDuring the tetanic stimulation of single static fusimotor fibres, primary and secondary endings in ankle extensor and flexor muscles of the cat have been subjected to ‘triangular’ length changes. Position and velocity sensitivities were determined and compared with those obtained in non‐activated endings. Two types of action of static fibre stimulation on the position sensitivity have been observed both in primary and secondary endings: it was either unchanged, or it decreased with increasing rate of stimulation (type I effect); it increased with increasing rate of stimulation (type II effect). The distribution of the two types was different to primary and secondary endings and to extensor and flexor endings. During stimulation of most static fibres, irrespective of their type, the velocity responses of both primary and secondary endings resembled those of non‐activated secondary endings. The ‘quick’ component of the velocity response was usually larger in primary than in secondary endings, while the ‘slow’ components were about the same. Comparisons made in secondary endings between the velocity responses during static activation and in the non‐activated state showed that the ‘quick’ component was reduced and the ‘slow’ component increased by the stimulation. ‘Exceptional’ velocity responses were observed in type I activation of some primary endings.
Effect of Angiotensin on Sympathetic Nerve Activity
Authors: Aars H. , Akre S. 
Published: December 2008

AbstractThe nervously mediated effect of angiotensin was studied in 13 rabbits by recording of renal and cervical sympathetic nerve activities, and was compared to results obtained with infusion of noradrenalin. I.v. infusion of angiotensin (0.5–3 μg/kg. min) raised the blood pressure, and initially reduced the normal rhythmical sympathetic activity. Whereas with noradrenalin the reduction of sympathetic nerve activity persisted, being determined by the blood pressure level, angiotensin shortly after the start of infusion was found to induce a non‐rhythmical activity in the renal nerve. This activity was associated with a further rise of blood pressure. The non‐rhythmical activity and the concomitant pressure rise were transient, and disappeared after a few minutes, in spite of continued infusion of angiotensin. This suggests that the nervously mediated effect, although capable of causing considerable transient increase of arterial blood pressure, is of minor importance for the blood pressure response to prolonged infusion of angiotensin in rabbits. The non‐rhythmical sympathetic activity was not related to changes in baroreceptor activity, and was probably not caused by stimulation of chemoreceptors or sympathetic ganglions. Most likely, this effect of angiotensin was brought about by interartion with central sympathetic neurons.