bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Location of the Line of Gravity in Relation to L5 in Standing
Authors: Klausen Klaus , Rasmussen Birger
Published: December 2008

Klausen, K. and B. Rasmussen. On the location of the line of gravity in relation to L5 in standing. Acta physiol. scand. 1968. 72. 45–52.

The determination of the location of the horizontal axis in the frontal plane for movements in the sagittal plane between L4 and L5 is based on the observation that the erectores spinae muscles and the rectus abdominis muscles in the upright standing position are acting as antagonists and antigravity muscles. X‐ray pictures were taken in the sagittal plane with the subjects standing a) with slight activity in the erector spinae muscles and b) with slight activity in the rectus abdominis muscles. The location of the line of gravity for the parts of the body above the level of L5 was then determined with the subjects standing in the same positions. These determinations revealed that the activity in the erector spinae muscles ceases and is replaced by activity in the rectus abdominis muscles, when thv line of gravity passes a point about 3 cm dorsally to the center of the inter‐vertebrate disc between L4 and L5. Similarly the location of the line of gravity in the frontal plane was determined in relation to L5. The results are discussed in view of previous findings.
Function of Cholinergic Nerve Fibres in the Cat Iris Dilator
Authors: Ehinger B. , Falck B. , Persson H.
Published: December 2008

Ehinger, B., B. Falckand H. Persson.Function of cholinergic nerve fibres in the cat iris dilator. Acta physiol. scand. 1968.72. 139–147.

The effect of electrical stimulation, noradrenaline, acetylcholine, isoprenaline, tyramine, phenoxybenzamine, dibenamine, atropine, and INPEA was investigated in normal, sympathetically and parasympathetically denervated dilator muscles. High‐frequency stimulation caused the muscle to contract and low‐frequency stimulation caused it to relax. The response to high‐frequency stimulation was blocked by phenoxybenzamine, dibenamine and sympa‐thectomy, while the response to low‐frequency stimulation was blocked by atropine and para‐sympathectomy. Acetylcholine gave an initial relaxation followed by a slow contraction. The latter was blocked by phenoxybenzamine. After sympathetic denervation, acetylcholine in moderate doses elicited relaxations only. Atropine in moderate concentrations depressed the response to noradrenaline and to high‐frequency stimulation. At lower doses, the effect was reversed: atropine potentiated the response to noradrenaline and high‐frequency stimulation. This potentiation was abolished by parasympathectomy. It is concluded that the dilator pupillae is innervated by both adrenergic and cholinergic fibres, and an interaction between the two fibre types is not excluded.
Nervous Control of Urinary Bladder in Cats: I. The collecting phase
Authors: Edvardsen Per
Published: December 2008

Edvardsen, P. Nervous control of urinary bladder in cats. I. The collecting phase. Acta physiol. scand. 1968. 72. 157–171.

Intravesical pressure under isometric conditions was studied in anesthetized cats after operative canalization of the bladder. Records were obtained after selective transection at the peripheral and at the intraspinal level of the sympathetic and parasympathetic nerves supplying the bladder, after rhizotomy of the thoraco‐lumbar and sacral nerves to the bladder, and after transection of the spinal cord at various levels. With small bladder volumes no change in pressure was observed after the various lesions, but as the volume increased, the concomitant rise in bladder pressure was progressively inhibited by sympathetic nervous impulses. In particular was this inhibition marked during the last one‐third of the cystometrogram. The sympathetic influefice is maintained by a spinal ieflex with the afferent path through the posterior sacral roots, its stimulus being stretching of the bladder wall. The effect of this spinal adaptation reflex is thus to permit increasing bladder volumes with only moderate increases in bladder pressure. ‘Nonspecific’ bladder responses consisted in an increase in motility caused by the laparotomy, and an inhibition of motility caused by any intraspinal procedure. This inhibitory effect was found to be due to discharge through the sympathetic nerves on manipulation of spinal structures, regardless of their relation to the segments supplying the bladder.
Nervous Control of Urinary Bladder in Cats: III. Effects of autonomic blocking agents in the intact animal
Authors: Edvardsen Per
Published: December 2008

Edvardsen, P.Nervous control of urinary bladder in cats. III. Effects of autonomic blocking agents in the intact animal. Acta physiol. scand. 1968.72. 183–193.

Bladder motility in anesthetized or decerehrated cats was recorded under isometric conditions before and after the administration of graded doses of various agents with peripheral or ganglionic blocking effects on the autonomic nervous system. Direct or indirect cystometry was employed when the effects on the collecting or on the expulsion phase, respectively, were studied.Atropine, which blocks at cholinergic receptor sites, made the micturition contraction inefficient as the ability of the bladder to sustain the initial contraction was abolished.Hexamethonium, which blocks ganglionic transmission, impaired the spontaneous micturition contraction as well:by also preventing, the initial pressure rise from occurring. The drug blocked the sympathetic ganglia at doses smaller than those which blocked the parasympathetic ones. The effects ofpropranololanddibenzyline, which block adrenergic inhibitory and excitatory receptors respectively, suggest that both these receptors are present in the bladder. The former drug increased bladder tone, the latter had an atropine‐like effect on the micturition contraction and an excitatory influence on the micturition reflex. Finally,guanethidine, which blocks the adrenergic neuro‐muscular junction, had an excitatory effect on the bladder and a facilitatory effect on the micturition reflex in addition to its presynaptic blocking effect. These results support previous hypotheses of a sympathetic inhibition and absence of parasympathetic activity during the collecting phase, and of bladder pressure as the determinant of the micturition threshold.
The Mechanical Parameters of Myocardial Contraction Studied zit a Constant Length of the Contractile Element
Authors: Edman K. A. P. , Nilsson E.
Published: December 2008

Edman, K. A. P. and E. Nilsson.The mechanical parameters of myocardial contraction studied at a constant length of the contractile element. Acta physiol. scand. 1968.72. 205–219.

The time course of the active state, the force‐velocity relation and the series compliance were investigated in isolated papillary muscles of the rabbit.—The force‐velocity curve defined at a precise length state of the contractile element and at a given time after the stimulus could be fitted by Hill's equation. The shape of the curve remained constant during the activity period, indicating that the ability to produce motion and the ability to produce tension undergo parallel changes during a myocardial contraction cycle.—The active state, at a given length of the contractile unit, had a slow onset (1/3–1/2 of the entire activity period being needed for attainment of the maximum) and did not form a distinct plateau. The time course of the active state was critically dependent on the degree of extension of the contractile unit. Evidence is presented that the duration of the active state is not definitely programmed at the start of the contraction; its final outcome is determined by the amount of shortening of the contractile element during the activity period.—The stiffness of the series elastic element, at a given tension, was independent of the intensity of the active state. This fact supports the view that the active. force‐producing structures in the cell do not contribute substantially to the series compliance of the cardiac muscle.
Blood Flow and Flow Distribution in the Small Intestine of the Cat as Analysed by the Kr85Wash‐Out Technique
Authors: Kampp Mogens , Lundgren Ove
Published: December 2008

The blood flow and flow distribution of the small intestine of cat were studied at various levels of vascular smooth muscle tone by means of the Kr85wash‐out technique. At “resting” total intestinal blood flow about 80 per cent of flow was distributed to the mucosa‐submucosa, where the flow rate amounted to 40–80 ml/min × 100 g. Blood flow of the muscularis was then 10–20 ml/min × 100 g. As total intestinal blood flow was increased by constant, intra‐arterial infusions of isopropylnoradrenaline a larger and larger part of intestinal blood flow was distributed to a highly vascularized part of the intestine probably located in the submucosa and adjacent parts of the mucosa. At intense vasodilatation (venous outflow 225 ml/min × 100 g) about 60 per cent of total flow passed through these intestinal structures, the blood flow of which amounted to 800–1000 ml/min × 100 g. The blood flow of the rest of the mucosa‐submucosa increased concomitantly to 150–200 ml/min × 100 g and that of the muscularis to 35–40 ml/min × 100 g.
The Effect of Calcium on the Skeletal Muscle Membrane after Treatment with Phospholipase C
Authors: Albuquerque E. X. , Thesleff S.
Published: December 2008

The effects of phospholipase C on the muscle membrane were studied by the recording of the resting membrane potential, the input resistance and the action potential generation in single fibres of the isolated extensor digitorum longus and soleus muscles of the rat. Incubation with phospholipase C abolished spike generation, depolarized the fibres by 15–20 mV and increased the ionic permeability of the membrane as shown by a fall of about 40 per cent of the “input” resistance. Removal of the enzyme by washing the preparation with Krebs‐Ringer solution did not restore membrane exitability. the resting membrane potential nor the input resistance of the fibres. When the external calcium concentration was raised from the normal 2 mM to 15 mM the muscle fibres repolarized and action potentials with a reduced rate of rise and amplitude were recorded. No recovery of the input resistance occurred. When the calcium concentration was brought back to 2 mM the fibres again depolarized and became inexcitable. Potassium (10 or 15 mM), caesium (10 mM) or rubidium (6 mM) antagonized the aforementioned effects of 15 mM calcium. It was concluded that phospholipase C irreversibly affected the muscle membrane and that an increase in the external calcium ion concentration only functionally restored some of the membrane properties, i.e., spike generation and the resting membrane potential. The results support the view that the hydrophilic head of certain membrane phospholipids is connected with passive ion transport in the electrogenic membrane.
Response of Isolated Muscle Spindles to Single Transient Stretches*
Authors: Jahn Samia Al Azharia
Published: December 2008

The smallest stretch of isolated frog muscle spindles which regularly evoked an afferent discharge was 8 ± 2 μ measured as the displacement of a graphite granule placed above the equatorial region 5–8 mm from the distal tendop of the muscle. The threshold deformation (T) was independent of an increase in the rate of deformation from 0.016 xT/msec to 1.0 × T/msec and of an increase in the initial elongation from 10 to 25 per cent above equilibrium length. The rate below which the spindle did not respond to stretch was 0.01 × T/msec. With low rates of stretch (0.016–0.03 × T/msec) the afferent response occurred before the deformation was completed and with higher rates (0.1–1.0 × T/msec) after it was completed.

A second afferent response was elicited when the deformation exceeded 2 times threshold (rate of stretch: 0.1–0.3 × T/msec) or 3–4 times threshold (rate of stretch: 0.6–2.7 × T/msec). The shortest interval between two afferent responses was 2 msec.

Depending on the timing of the spontaneous afferent activity and the spontaneous intrafusal contractions the afferent response evoked by a stretch was abolished or its latency was shortened or increased.
Effect of Adrenaline, Noradrenaline, Angiotensin and Renal Nerve Stimulation on Intrarenal Distribution of Blood Flow in Dogs
Authors: Aukland Knut
Published: December 2008

The acute effect of adrenaline, noradrenaline. angiotensin and renal nerve stimulation on intrarenal blood flow was studied in 15 dogs. Local clearance of hydrogen gas measured polarographically with 2–4. needle‐shaped platinum rlectrodes in the outer medulla served as indicator for medullary blood flow. Total renal blood flow was measured simultaneously with electromagnetic flowmeter. Adrenaline, noradrenaline and angiotensin infused i.v. or into the renal artery over a period of 5–15 min reduced outer medullary hydrogen clearance and total renal blood flow to 25–90 per cent of control, and on an average to the same extent. Renal nene stimulation produced the same pattern with flow reduction to 50–75 per cent of control. Since changes in total renal blood flow mainly reflect changes in cortical per‐fusion. it is concluded that resistance to flow was increased proportionately in the cortical and juxtamedullary circulation. Considerable local xrariations in response of outer medullary hydrogen clearance observed with all stimuli suggested local differences in vasoconstrictor response, but no consistent difference between cortex and medulla.
Exclusive Thalamic Location of Subcortical Spontaneous Barbiturate Spindles
Authors: Junge K. , Sveen O.
Published: December 2008

Spontaneous 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

The 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

Active 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

The 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

Effects 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

Isolated 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

The 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

The 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

The 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

After 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

Slices 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

In 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

The 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

Under 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

Cholinesterase 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

The 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

Distributions 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

P‐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

The 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

During 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

The 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.
Post‐Tetanic Decurarization in Developing Cat Leg Muscles
Authors: Nyström Bo
Published: December 2008

The effect of a conditioning tetanization on the twitch tension and size of compound muscle action potentials of subsequent twitches has been studied in partly curarized gastrocnemius and soleus muscles of kittens, ranging in age from 3–140 days, and adult cats. Nembutal® anesthesia was used. Comparisons were made with results obtained in non‐curarized animals.

At all ages, a post‐tetanic increase in twitch tension in both muscles, when partly curarized. was accompanied by a similar increase in size of the muscle action potentials.

In adult cats, high‐frequency tetanizations (250–450 d/sec) were more effective than low (45 c/sec) in eliciting the decurarizing effect. In young kittens, both were about equally effective.

The effect of tetanization on the half relaxation time of post‐tetanic twitches was found to differ in normal and in partly curarized gastrocnemius muscles, whereas this did not apply to the soleus of young kittens.

In both muscles, the post‐tetanic effects seen in non‐curarized and in partly curarized muscles differed with respect to the muscle action potential changes, as well as to the time course and frequency‐dependence of twitch potentiation. This indicates that the PTP of twitch tension found in normal muscles is, most probably, brought about mainly by a mechanism other than recruitment of muscle fibres.
The Relative Role of Recapture and of de novo Synthesis for the Maintenance of Neurotransmitter Homeostasis in Noradrenergic Nerves
Authors: Hedqvist P. , Stjärne L.
Published: December 2008

Experiments were carried out in the isolated, perfused cat spleen to assess the capacity of the mechanisms of synthesis of noradrenaline to keep pace with the loss of noradrenaline by overflow from the organ, during prolonged periods of electrical nerve stimulation. The organ was pretrcated with the monoamine oxidase inhibiting drug nialamide to block deamination of noradrenaline. Phenoxybenzamine or cocaine+ Hydergin were added to the perfusion fluid in order to inhibit reuptake of noradrenaline liberated from the nerves, and to facilitate washout of noradrenaline in the extracellular fluid by preventing the vasoconstriction response.De novosynthesis of noradrenaline was found to proceed at a rate comparable to the highest values described in the literature. However, the discharge of noradrenaline from the neurons in response to nerve stimulation, as reflected by the peak overflow of noradrenaline from the organ, occurred at an approximately ten times higher rate. The results imply that the major mechanism for the maintenance of a constant noradrenaline level in the neuron from one moment to the next, during periods of increased nerve activity, is notde novosynthesis, but rather an almost quantitative reuptake of the noradrenaline liberated from the neurons.
Studies on the Histamine Releasing Effect of Bee Venom Fractions and Compound 48/80 on Skin and Lung Tissue of the Rat
Authors: Fredholm Bo , Haegermark ÖSten
Published: December 2008

Two bee venom fractions, F I and F II, obtained by gel filtration, and compound 48/80, were shown to release histamine from skin and lung tissue of the rat. F I is the phosphatidase A containing fraction, and F II contains a basic polypeptide. Dose‐response relationships, the time course of the histamine release, and the influence of enzyme inhibitors were studied. The results with F II and compound 48/80 were similar, suggesting that the two substances activate the same kind of release mechanism. It is concluded that F II is not related to the earlier described bee venom polypeptides melittin and aparnin. The mode of action of phosphatidase A was distinctly different from that of F II or compound 48/80. The results are consistent with the assumption that it acts in a “non‐specific.” way by hydrolysing tissue phosphatides to lyso compounds, which in turn damage the tissue.
Enzyme Activities at the Surface of Intact Human Erythrocytes
Authors: Ronouist Gunnar
Published: December 2008

The activity of glyceradehyde‐3‐phosphate dehydrogenase, phosphoglycerate kinase and adenylate kinase was determined at the surface of intact red cells, suspended in isotonic sodium chloride or isotonic sodium chloride containing 6 % Dextran. The surface‐bound phosphoglycerate kinase activity was found to be 4.5 %of the total phosphoglycerate kinase activity of the cell. The corresponding figures for glyceraldehyde‐3‐phosphate dehydrogenase and adenylate kinase were 3.1 % and 2.0 %, respectively. The extent of hemoglobin leakage into the assay medium did not exceed 1 % in any case. The suspending medium, after the cells had been removed, contained no glyceraldehyde‐3‐phosphate dehydrogenase or phosphoglycerate kinase activity, whereas part of the adenylate kinase activity had been eluted from the cells.
The Mechanism of Histamine Release from Isolated Rat Peritoneal Mast Cells Induced by d‐Tubocurarine
Authors: Frisk‐Holmberg Marianne , Uvnäs Börje
Published: December 2008

Isolated rat peritoneal mast cells were exposed to d‐tubocurarine, and the release of histamine was studied under various conditions. The proposal is made that d‐tubocurarine although a monomer induces histamine release by a mechanism similar to that one triggered by the polymer synthetic amine compound 48/80.
The Effect of Menthol on Taste Receptors
Authors: Hellekant Göran
Published: December 2008

The response to menthol and its effect on the excitability of the gustatory receptors were studied by recording the impulse activity in the chorda tympani nerve of the cat. It was observed that menthol elicited a slowly increasing activity in all gustatory fibres. Adding menthol changed the gustatory response of the sapid solutions in two respects: a) It slightly suppressed the initial burst of activity, b) It enhanced the sustained response. Rinsing with menthol left the gustatory receptors with a changed sensitivity to stimulation with other sapid solutions. This effect on the receptors was related to concentration and length of the preceding menthol rinse. It showed also variations with regard to stimulus, concentration and subject.
The Evolution of Vascular Smooth Muscle Responses to Histamine and 5‐Hydroxytryptamine: II. Appearance of inhibitory actions of 5‐hydroxytryptamine in amphibians1
Authors: Reite Ola Bodvar
Published: December 2008

Systematic studies on the vascular smooth muscle responses to histamine and 5‐hydroxytryptamine, similar to those previously accomplished in jawless vertebrates and fish, were performed in amphibians (frogs, toads and salamanders). Both intact animals and artificially perfused preparations were studied. The effects were recorded as changes in systemic arterial blood pressure after intravascular administration of drugs or as changes in vascular resistance after introduction of drugs into the perfusion fluid during perfusion at constant flow rate. Responses to adrenaline, noradrenaline and acetylcholine were studied for comparison. The direct or indirect nature of actions produced by the different drugs were evaluated by means of pharmacological blocking agents. The outcome of the studies may be summarized as follows: Marked and specific inhibitory actions of 5‐hydroxytryptamine on vascular smooth muscle, manifest as vasodilatation, are present in all studied species, displaying a feature which has not been demonstrated in jawless vertebrates and fish. In addition, the blood vessels of some amphibians occasionally show a constrictor response to 5‐hydroxytryptamine. The nature of the latter response remains uncertain. Histamine apparently has but negligible influence on amphibian vascular smooth muscle. The inhibitory and stimulatory actions of adrenaline and noradrenaline and the stimulatory action of acetylcholine, pharmacological characteristics of vascular smooth muscle also in more primitive vertebrates, are retained in the amphibians, while the inhibitory action of acetylcholine, like the inhibitory action of 5‐hydroxytryptamine, appears as a new feature.
Hemodynamics in the Bone Marrow of Anemic Rabbits with Increased Hematopoiesis
Authors: Michelsen Kåre
Published: December 2008

In fifteen rabbits heniatopoiesis was stimulated by a grave phenylhydrazine anemia. When the hematopoietic activity was maximal as judged from the reticulocyte counts, 6 or 7 days after the first injection of phenylhydrazine, the left femur was perfused in situ through the nutrient artery by blood led through an extracorporal perfusion arrangement from the left carotid artery of the anesthetized animal. The blood flow, the nutrient artery perfusion pressure and the intramedullary venous pressure were recorded. The bone marrow blood flow was greater and varied less than in non‐anemic animals. The arterial vessels exhibited a weak ability to auto‐regulate flow and acetylcholine caused arterial dilatation showing that neither the grave anemia nor the great hematopoietic activity had brought about a maximal dilatation of the arterial vessels. The venous resistance to bone marrow blood flow was constantly small whereas it has previously been shown to vary greatly in non‐anemic animals.
The Firing Pattern of Dorsal Spinocerebellar Tract Neurones during Inhibition
Authors: Jansen J. K. S. , Nicolaysen K. , Walløe L.
Published: December 2008

Dorsal spinocerebellar tract neurones adequately activated by Ia afferents from the tibialias anterior (TA), extensor digitorum longus (EDL) or flexor digitorum longus (FDL) muscles are regularly inhibited by group I afferents from the gastrocnemius‐soleus (GS) nerve. The inhibition is maintained throughout the duration of GS nerve stimulation. During inhibition the irregularity of firing may be unchanged or moderately reduced. Correspondingly the serial dependency between neighbouring intervals may be unchanged or reduced. The inhibitory input usually caused a constant reduction in firing frequency at various levels of excitatory drive or occasionally a greater reduction at higher levels of excitatory drive. The latter effect was associated with increased regularity of firing and reduced serial dependency. Comparable inhibitory effects were obtained by repetitive stimulation of the contralateral somato sensory‐cortex. It is suggested that the inhibitory effects can be accounted for by post‐synaptic inhibitory mechanisms.