bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Prolonged Nerve Blockage on the Development of the Myoneural Junction
Authors: Juntunen J. , Teräväinen H.
Published: December 2008

The electrical conductivity of the sciatic nerve was locally blocked by repeatedly injecting long‐acting local anesthetic (Marcaine®‐adrenaline) dorsally to the collum femoris of newborn rat for 7 days. Structural alterations of the postsynaptic muscle fibre membrane occurring during the development were followed with a light microscope after the activity of myoneural acetylcholinesterase (E.C.3.1.1.7) enzyme was histochemically demonstrated. Unlike anatomical denervation by cutting the sciatic nerve, nerve blockage with the anesthetic did not prevent structural development of the myoneural junction from occurring as in normal untreated muscles. The observations would seem to indicate that chemical agents other than acetylcholine are responsible for the regulatory effect of the nerve on the structural alterations of the postsynaptic part of the muscle fiber membrane.
Interaction between the Fastigial Pressor Response and the Defence Reaction
Authors: Lisander Björn , Martner Jan
Published: December 2008

Experiments were performed on chloralosed cats with recording of blood pressure, heart rate and regional blood flows. Electrical stimulation of the fastigial nucleus produced a pressor response. During stimulation of the hypothalamic defence area, fastigial stimulation decreased the muscle vasodilation and augmented the concomitant vasoconstriction in the skin and intestinal beds. These effects from fastigial stimulation could be accounted for by activation of α‐adrenergic mechanisms. However, a fastigial inhibition of hypothalamically induced cholinergic vasodilation was also observed in the innervated, cross‐circulated limb in which adrenergic blocking drugs had been administered. This suggests that fastigial stimulation can interfere with the activation of the dilator fibres at some level within the central nervous system as well as in the periphery. Both defence area and fastigial stimulation can also cause an adrenomedullary activation. The defence reaction may include a weak activation of the adrenergic outflow to the, muscles which is not readily apparent, because of the baroceptor activation secondary to the widespread systemic adrenergic activation.
Intramural Blood Flow and Blood Volume in the Small Intestine of the Gat as Analyzed by an Indicator‐Dilution Technique
Authors: Biber Björn , Lundgren Ove , Svanvik Joar
Published: December 2008

The mucosal red cell and plasma flow and volume in the cat small intestine were studied at various levels of smooth muscle vascular tone by means of an indicator‐dilution technique. 32P‐labelled red cells and plasma particles as well as 198Au‐labelled colloid particles were used. The monitored tissue region includes when using 32P most of the mucosa, while only the villi were “seen” with 198Au. During “rest” (total intestinal blood flow about 25 ml/min × 100 g) “mucosal” plasma flow was somewhat lower than total intestinal blood flow while “villous” plasma flow was of the same order of magnitude. “Mucosal” and “villous” plasma volumes measured about 2.0 and 1.5 ml/100 ml, respectively. As the intestinal vascular bed was maximally dilated (total intestinal blood flow 200–250 ml/min × 100 g) by an i.a. infusion of isopropylnoradrenaline, “villous” plasma flow increased to 275 ml/min × 100 ml tissue while “mucosal” blood flow was the same as total intestinal flow. Concomitantly, “mucosal” and “villous” plasma volumes increased to 3.0 and 4.0 ml/100 ml, respectively. Mean transit time through the villous hairpin loop decreased from 5–6 s at rest to about 1 s at maximal vasodilatation.
Effects of Alcohol, Hot Drinks, or Smoking on Hand and Foot Heat Loss
Authors: Goldman Ralph F. , Newman Russel W. , Wilson Ove
Published: December 2008

Using precision calorimetric techniques for measuring extremity heat loss, possible contraindications or advantages of alcoholic or hot drinks or smoking just prior to cold exposure were assessed. Ten subjects were given 60‐min exposures with one hand and one foot immersed in 15° C water, following the drinking of 1. 200 ml of 23° C water (control), 2. 200 ml of 23° C water containing 22 ml of absolute alcohol, 3. 200 ml of 55° C bouillon, 4. 200 ml of 23° C water and smoking 2 cigarettes. No significant effects were noted in the foot, but significant differences were observed in hand heat loss to the calorimeter; smoking depressed hand heat loss, alcohol elevated it. Smoking had a persistent influence, but the effect of alcohol had disappeared after 30 min. Bouillon had an effect similar to alcohol, but of shorter duration, and also resulted in a significantly reduced heat loss after 30 min. Alcohol produced a significantly higher amount of cold induced vasodilatation (CIVD) with greater total temperature elevation in 3 fingers than did smoking, although smoking did not prevent CIVD. With intake of bouillon, CIVD appeared earlier than with alcohol, and during the 1st 15 min, total temperature elevation in the 3 fingers was markedly higher than in the control run, but not as large as with alcohol. All differences were relatively small and would seem to be of little practical importance.
Evidence for a Depressor Reflex Elicited from Left Ventricular Receptors during Occlusion of One Coronary Artery in the Cat
Authors: Thorén Peter
Published: December 2008

Circulatory responses to shortlasting occlusions of one coronary artery (left anterior descendent or right coronary artery) were studied in chloralose‐anesthetized cats. — When the carotid sinus baroreceptors were left functionally intact, coronary occlusion induced moderate reflex reductions of heart rate and blood pressure and slight increases of resistance and capacitance vessel tone in the calf muscles. When the buffering influences from the baroreceptors were largely eliminated by bilateral carotid occlusion, the reflex fall of blood pressure and heart rate became more pronounced and a clearcut vasodilatation was now observed. After cold block of the cervical vagi, the blood pressure fall upon coronary obstruction was markedly diminished, the heart rate response was reversed to a slight tachycardia and a marked peripheral vasocon‐striction ensued. After i.v. administration of local anesthetics (lidocaine 3–4 mg/kg b.wt.) the reflex response to coronary obstruction and to shortlasting occlusions of the ascending aorta were almost completely eliminated. — It is concluded that acute occlusions of one coronary artery induce a reflex bradycardia and vasodilatation, in all probability due to activation of left ventricular mechanoreceptors. The vascular responses in this inhibitory reflex seem to be significantly moderated by influences from the arterial baroreceptors.
Kinetic Observations on Cholinesterase Activities of Rat Brain and Sympathetic Ganglion towards Biochemical and Histochemical Substrates
Authors: Eränkö Lisa
Published: December 2008

Cholinesterase activities of homogenates of rat brain and superior cervical ganglion were measured by automatic titration at pH 8. Acetylcholine, acetylthiocholine, acetyl‐β‐methylcholine, propionylcholine, propionylthiocholine, α‐naphthyl acetate, butyrylcholine, butyrylthiocholine and benzoylcholine were used as substrates. As selective inhibitors of specific and nonspecific cholinesterases, 1: 5‐bis‐(4‐allyl dirnethylammoniumphenyl) pentan‐3‐one diiodide (284 C 51) and tetra‐isopropylpyrophosphoramide (iso‐OMPA) were used, respectively. Acetyl‐β‐methylcholine and α‐naphthyl acetate were mainly split by specific cholinesterase, butyrylcholine was predominantly hydrolyzed by non‐specific cholinesterase, while acetylcholine, acetylthiocholine, propionylcholine and propionylthiocholine were readily split by both enzymes. Michaelis—Menten constants, determined by the Lineweaver‐Burk procedure, were equal for acetylcholine and propionylcholine, on the one hand, and for acetylthiocholine and propionylthiocholine, on the other. The specific (284 C 51‐sensitive) components of the cholinesterase activities of these 4 substrates showed strong inhibition by excess substrate, while the non‐specific activity towards the same substrates increased with increasing substrate concentration. When 2 of these substrates were in turn used together as substrates, no additive increase of activity was observed. It is concluded that propionylcholine and propionylthiocholine serve, like acetylcholine and acetylthiocholine, as substrates of both specific and non‐specific cholinesterases in rat brain and sympathetic ganglion.
Mechanical Properties of Guinea Pig Taenia Coli Muscles
Authors: Lowy J. , Mulvany M. J.
Published: December 2008

Conditions have been established under which taenia coli muscles give consistent responses to electrical stimulation in experiments lasting up to 8 h. Using a new definition of resting length different muscles show similar mechanical characteristics. In agreement with previous investigations the mechanical behaviour of taenia coli is found to be qualitatively similar to vertebrate skeletal muscles. Compared with frog sartorius (a) the active tension per unit area is similar, (b) the maximum power output about 80 times less, (c) 90% of he maximum active tension is developed over a range of lengths abaut twice as great. Experiments with iodoacetic acid indicate that a condition of rigor can exist in this muscle.
Unit Activity of Ganglionic and Medullary Second Order Neurones in the Eel Lateral Line System
Authors: Alnæs Egil
Published: December 2008

Unitary spike activity has been investigated in the ganglion and the central terminational field of the R. lat. post. N. X. No dorsal root reflex is observed in the intracranial rootlet. There is an excitatory coupling between ganglionic cells in the N. lat. post. which can lead to multiple firing in these cells by stimulation of afferents in the trunk nerve. Second order neurones were identified by their location and variable spike latency to peripheral nerve stimulation. These cells are driven by a large number of active primary afferents from extended parts (order of magnitude 15 cm) of the trunk lateral line. The statistics of spontaneous discharges were studied and compared with that of primary afferent nerve fibres. About 1/3 of secondary neurones are either excited or inhibited from the contralateral lateral line nerve. No evidence was found for inhibition from ipsilateral lateral line sensory organs.
Differential Effect of Graded Contraction of Middle Ear Muscles on the Sound Transmission of the Ear
Authors: Teig Erik
Published: December 2008

The middle ear muscles in cats have been brought to different degrees of contraction by electric stimulation through electrodes placed in the proper nuclei in the brain stem. The resulting change in the amplitude of the cochlear microphonic potentials produced by pure tones from 250–7000 Hz has been used to determine the change in the sound transmission of the ear. Later the muscle tension produced by the same stimulus strengths have been determined myographically. The main effect of weak contractions involving only a relatively small number of motor units was more selective than the effect of stronger muscle contractions. Contractions of the stapedius muscle involving only up to 10–15 per cent of the maximal contraction force reduced the microphonics below 2000 Hz, with most marked effect on the lowest frequencies tested. Stronger tensions produced an additional modest reduction, equally pronounced for all sound frequencies. The most marked effect of contractions of the tensor tympani, amounting to 10–15 per cent of the maximal contraction force, was a reduction of microphonics of frequencies below 750 Hz, while higher frequencies could be either slightly enhanced or reduced. Stronger contractions had a less selective effect with respect to various frequencies and gave less reduction of the sound transmission per gram tension.
The Formation of 14C‐Histamine from Orally Administered 14C‐1‐Histidine in Pigs
Authors: Eliassen Knut Arnet
Published: December 2008

The object of the present study has been to examine to what extent dietary L‐histidine is converted to histamine in pigs, a species which excretes large amounts of histamine in the urine. During the first 24 h after oral administration of 14C‐L‐histidine only, about 1/10 to 1/3 of the adminstered radioactivity was recovered in the urine. Free 14C‐histamine accounted for about 1% of the urinary radioactivity while the values for 14C‐1.4‐mathylhistamine and 14C‐1.4‐methylimidazoleacetic acid were about 0.5 and 40%, respectively. The values for 14C‐histamine may be overestimated, but the high values for the methylated 14C‐metabolites of histamine indicate that 4–20% of orally administered 14C‐L‐histidine is converted to Hi. This is far superior to what has been found in other species. Oral administration of 10 g L‐histidine monohydrochloride to pig resulted in the excretion of a much smaller fraction as histamine and as methylated metabolites of histamine than would be expected from the experiments with 14C‐L‐histidine.
Ionic Currents at Resting Potential in Nerve Fibres from Xenopus laevis. Potential Clamp Experiments
Authors: Arhem Peter , Frankenhaeuser Bernhard , Moore L. E.
Published: December 2008

The ionic currents in myelinated nerve fibres were measured while the membrane potential was held at its resting value and the external solution with one ionic composition was changed to a solution with a different composition. Equations were derived, based on the independence principle by which the net sodium, potassium and chloride currents can be calculated from the change in current associated with the concentration changes. The chloride currents were found to be negligibly small compared with INa and IK. The ratio INa/IK was found to be about – 5.8, which deviates significantly from — 1. This deviation either shows that the independence principle does not apply to INa and/or Ik at rest or that the membrane at rest has some other current carrier in addition to Na+, K+ and Cl. The slope conductance of the membrane was measured and the measured slope conductance was compared with the sum of the sodium and potassium slope conductances at resting potential calculated from the measured current changes caused by concentration changes. The measured slope conductance was was 2.7 times larger than the sum of the calculated ionic conductances. It is concluded that resting potential of the myelinated nerve is not satisfactorily described as a potassium electrode with a ‘sodium error’.
Effects of Increasing Glucose Concentrations on the Glucose Metabolism in Arterial Tissue and Intestinal Smooth Muscle
Authors: Arnqvist Hans J.
Published: December 2008

The effect of increasing glucose concentrations (0–44.4 mM) on the glucose metabolism in bovine mesenteric arteries and rabbit colon smooth muscle was studiedin vitro.The glucose uptake in both these tissues increased when the concentration of glucose in the medium was raised, with saturation at higher glucose concentrations. The rise in glucose uptake was most pronounced in the range 0–11.1 mM. The effect of glucose concentrations on lactate elimination was similar in both tissues to that on glucose uptake. Increases in the tissue levels of glycogen and lactate were observed up to a medium concentration of 5.6–11.1 mM glucose. A further rise in the medium glucose had no effect on the glycogen and lactate contents. In bovine mesenteric arteries the intracellular accumulation of glucose carbon from14C‐labelled glucose did not change significantly when the glucose concentration was raised from 5.6 to 44.4 mM. The membrane transport of glucose in bovine mesenteric arteries was characterized by saturation kinetics of the Michaelis‐Menten type with a Km of 4.0 mM. These results suggest that the glucose metabolism in bovine mesenteric arteries and rabbit colon smooth muscle is proportionally affected to a greater extent by variations in glucose concentration near the physiological level than by extreme hyperglycemia.
The Liver‐like Anion Transport System in Rabbit Kidney, Uvea and Choroid Plexus. II. Efficiency of Acidic Drugs and Other Anions as Inhibitors
Authors: Bárány Ernst H.
Published: December 2008

In vitrouptake of labelled iodipamide in the presence of a large excess of hippurate is due to a distinct, possibly complex, anion uptake system, the L‐system, present in kidney cortex, ciliary processes and lateral choroid plexus. A large number of organic anions of very different structure, many of them drugs, have now been screened for ability to inhibit the L‐system in rabbit tissues. The L‐system is depressed much more by cholegraphic than by urographic radio‐contrast agents. A majority among substances known to be excreted by the liver depressed the L‐system. Substances of mol.wt. below 175 have little effect, among heavier anions inhibition is common. This size dependence is similar to that for biliary excretion. No structural specificity can be discerned. In all these respects the L‐system is liver‐like. Certain liver‐excreted anions have little effect on the L‐system. This indicates that the organic anion transport system of the liver is composite. The affinity of many drugs to the L‐system is bound to affect their pharmacokinetic behaviour and can give rise to drug interactions.
Ultrastructural Studies on Circulating Cat Blood Platelets after in Vivo Stimulation with Collagen
Authors: Hognestad J. , Hovig T. , Nicolaysen Anne
Published: December 2008

In cats an extensive platelet aggregation in the lung was achieved by repeated intravenous injections of a collagen extract. An ultrastructural study of circulating platelets was done after one, two and several injections of collagen. When collagen injections no longer gave pressor responses in the lung vasculature, the platelets obtained from arterial blood showed pronounced changes in shape, loss of organelles and disappearance of a‐granules and mitochondria. The pronounced vacuolization with openings to the surrounding medium probably represent a release phenomenon.
Effects of Acetylcholine and Some Other Smooth Muscle Stimulants on the Electrical and Mechanical Responses of the Guinea‐Pig Vas Deferens to Nerve Stimulation
Authors: Sjöstrand By Nils O.
Published: December 2008

Sjöstrand, N. O. Effects of acetylcholine and some other smooth muscle stimulants on the electrical and mechanical responses of the guinea‐pig vas deferens to nerve stimulation. Acta physiol. scand. 1973. 89. 1–9.

The effect of acetylcholine (Ach), histamine, 5‐hydroxytryptamine, Ba2+and bradykinin on the electrical and mechanical responses of the guinea‐pig vas deferens to nerve stimulation was investigated with the sucrose gap technique. The agonists produced a depolarization of the smooth muscle membrane. Because of this the membrane came closer to the threshold for firing of action potentials (AP:s). The AP:s also increased in size in the presence of the agonists and the contractions became larger. Atropine abolished the effect of Ach. The results indicate that the agonists enhance the motor response of the vas deferens by a direct action on the smooth muscle cell membrane.
Mucosal Hemodynamics in the Small Intestine of the Cat during Regional Sympathetic Vasoconstrictor Activation
Authors: Svanvik By Joar
Published: December 2008

Svanvik, J. Mucosal hemodynamics in the small intestine of the cat during regional.sympathetic vasoconstrictor activation. Acta physiol. scand. 1973. 89. 19–29.

The hemodynamics of the small intestinal mucosa of the cat was studied during electrical stimulation of the regional sympathetic vasoconstrictor nerves. The indicator‐dilution technique used allowed for a quantitative and separate investigation of the “mucosal” as well as of the “villous” intravascular flows and volumes. After an initial, marked “mucosal” vasoconstriction, the “villous” intravascular plasma flow increased above control during prolonged sympathetic nervous activation in the face of a reduced intestinal venous outflow. Concomitantly blood flow of the entire mucosal layer stabilized at about control. Upon cessation of the nerve stimulation total venous outflow as well as “mucosal” blood flow showed an hyperemic response while “villous” plasma flow remained unchanged. The results thus suggest that blood flow in the intestinal villi is increased while flow in a more deeply situated region of the mucosa is decreased during regional sympathetic vasoconstrictor activation.
Colonic Motility in the Cat
Authors: Rostad Hans
Published: December 2008

Rostad Colonic motility in the cat. 11. Extrinsic nervous control. Acta physiol. scand. 1973. 89. 91–103.

Experiments were performed on cats lightly anesthetized with pentobarbital sodium and a neuromuscular blocking agent, pancuronium bromide, in order to study the distribution of the extrinsic colonic nerves and their influence on the motility of various parts of the colon. The motility was recorded in its proximal, middle and distal part with sensitive extraluminal strain gage transducers and arterial blood pressure and respiratory movements were recorded using pressure transducers. The influence of the extrinsic nerves on the colonic motility was investigated both by sectioning of the nerves and by electrical stimulation of the peripheral ends of the cut nerves. There was no marked functional differences between the proximal and distal portions of the colon. The vagal and splanchnic nerves, containing pure motor and inhibitory fibres, respectively, have their functional distribution throughout the greater part of the colon, although most marked in the proximal part. The parasympathetic pelvic, nerves supply the whole colon with motor fibres. At just suprathreshold stimulation of these nerves the responses in the proximal part of the colon were of lower amplitude and longer latency than in the remaining portions. The sympathetic lumbar colonic nerves distribute to all parts of the colon with mainly inhibitory fibres, but have some excitatory fibres as well.
Arginase Activity in Rat Small Intestinal Mucosa
Authors: Harri M.‐P. , Hartiala K.
Published: December 2008

Harri, M.‐P. and K. Hartiala. Arginase activity in rat small intestinal mucosa. Acta physiol. scand. 1973. 89. 126–129.

When the arginase activity of rat small intestinal mucosa was compared with that of the liver it was found to be 5 to 10 per cent to 1 g of tissue. The mucosa of the glandular part of the stomach showed almost no arginase activity. The intestinal activity was highest in jejunal mucosa and as a whole higher in male than in female rats.
Vascular Reactions in the Small Intestine of the Cat during Hemorrhage
Authors: Haglund Ulf
Published: December 2008

Haglund, U., Vascular reactions in the small intestine of the cat during hemorrhage. Acta physiol. scand. 1973. 59. 129–141.

The reactions within the consecutive vascular sections of the cat small intestine during and after 2.5 h hemorrhagic hypovolemia was studied using a plethysmographic technique. The cats were bled 20 or 35 per cent of their estimated total blood volume. The animals bled 35 per cent were divided into a “shock” and a “non‐shock” group according to the level of blood pressure prior to retransfusion. Upon bleeding a moderate increase in intestinal blood flow resistance was observed but during the latter half of hypovolemia flow resistance decreased markedly in the “shocked” animals and was not normalized upon retransfusion. The capillary surface area available for exchange remained unchanged during the hypovolemia except in the “shocked” cats where a small increase was recorded. Tissue volume decreased rapidly upon bleeding due to a venoconstriction but late in the hypovolemia and after retransfusion a continuous tissue volume increase was often seen, partly due to a certain “pooling” of blood but mainly caused by transcapillary transfer of fluid. A great part of this fluid was found in the intestinal lumen at postmortem examination, which also revealed hemorrhagic lesions in the mucosa of most of the animals.
Salivatory Fibres in the Trigeminal Part of the Lingual Nerve to the Mandibular Salivary Gland of the Monkey
Authors: Hellekant Göran , Kasahara Yasuo
Published: December 2008

Hellekant, G. and Y. Kasahara. Salivatory fibres in the trigeminal part of the lingual nerve to the mandibular salivary gland of the monkey. Acta physiol. scand. 1973.89. 208–212.

In the monkey electrical stimulation at different frequencies was applied to the peripheral ends of the centrally cut trigeminal and facial branches of the chorda‐lingual nerve, while the secretion from the mandibular salivary gland was studied. It was found that a) a secretion could be elicited from the gland by stimulation of either of the two branches, b) the secretion elicited by stimulation of the trigeminal branch was slightly smaller than elicited by the facial branch. which is said to be the sole source of secretory fibres to this gland in the nerve, c) the sodium and potassium contents of the saliva elicited by the two nerve branches did not differ and were similar to that observed in human saliva.
Osmotic Fluid Transfer from Tissue to Blood during Hemorrhagic Hypotension
Authors: Jarhult Johannes
Published: December 2008

Jarhult, J.Osmotic fluid transfer from tissue to blood during hemorrhagic hypotension.Acta physiol. scand. 1973.89.213–226.

Arterial and venous plasma osmolality and glucose concentration, and net transcapillary fluid movements were studied in the cat lower leg muscles during hemorrhagic hypotension (50 mm Hg). Arterial plasma osmolality increased rapidly after bleeding and exceeded after 20 min the control value by about 20 mOsm/kg H2O, a level maintained during the remainder of the 90 min observation period. Popliteal venous osmolality rose much more slowly and did not reach the arterial level until some 50 min after the bleeding. Studies of plasma glucose concentration showed that the arterial and regional venous hyperosmolality almost entirely could be ascribed to a concomitant hyperglycemia, in particular during the first 30 min of hemorrhage. A clearcut arterio‐venous osmolar difference in the muscle (reflecting a transcapillary osmolar gradient) was thus present in the early (≅50 min) stages of bleeding. In the sympathectomized muscle region an absorption of extravascular fluid to the blood stream occurred as long as this arterio‐venous osmolar difference existed, strongly indicating that the fluid transfer was caused by osmosis. Comparative studies on the innervated and the sympathectomized muscle region showed that the extravascular fluid absorption due to reflex decrease of hydrostatic capillary pressure was most prominent in the early (< 20 min) stages of bleeding, whereas the osmotic fluid absorption was maintained for a more prolonged period of time. Both mechanisms no doubt are important for plasma volume restoration after hemorrhage.
Factors Determining Stroke Volume during Intracoronary Adminstration of Calcium‐Gluconate and Isoproterenol
Authors: Bugge‐Asperheim B.
Published: December 2008

Bugge‐Asperheim, B. FACTORS DETERMINING STROKE VOLUME DURING INTRACORONARY ADMINISTRATION OF CALCIUM‐GLUCONATE AND ISOPROTERENOL. ACTA PHYSIOL. SCAND. 1973. 89. 249–259.

The stroke volume (SV) response to inotropic stimulation of the heart has been studied in open‐chest dogs after implantation of an aortic flowmeter, pressure recording equipment, and piezo‐electric ceramics for measuring myocardial chord length (MCL) in the left ventricle. Following rapid injections of 1 fig isoproterenol or 100 mg calcium‐gluconate into the left coronary artery, myocardial contractility rose markedly, as evidenced by increases of 50–70 % in the rate of rise of left ventricular pressure (dP/dt) and aortic flow (dF/dt). The SV response was dependent upon left ventricular filling. At small ventricular volumes induced by reducing venous return, SV remained unchanged during inotropic stimulation. In dilated ventricles similar stimulation effected marked increases in SV. There was little difference in the increase in SV whether the left ventricle was dilated by increasing preload or afterload. End‐diastolic MCL decreased regularly during inotropic stimulation, but the decrease was smaller in a large than in a small ventricle. On the other hand, myocardial shortening (end‐diastolic MCL minus end‐systolic MCL) increased less in a small ventricle. It is concluded that the SV response to inotropic stimulation of the heart is primarily dependent on the end‐diastolic dimension of the left ventricle.
An Autoradiographic Study of the Intestinal Absorption of Palmitic and Oleic Acid
Authors: Haglund By Ulf , Jodal Mats , Lundgren Ove
Published: December 2008

Haglund, U., M. Jodal and O. Lundgren. An autoradiographic study of the intestinal absorption of palmitic and oleic acid. Acta physiol. scand. 1973. 89. 306–317.

The distribution of intraluminally incubated long chain fatty acids (LFA; ;3H‐palmitic acid, :3H‐oleic acid) within the intestinal villi were studied during in vivo conditions with an autoradiographic technique which prevented tracer losses from the tissue. The results show that LFA are fairly diffusely localized throughout the whole epithelial cell and, to some extent, also in the lamina propria after 1 or 20 min incubation. Intense vasodilatation or a 7% albumin solution administered intraluminally after the tracer incubation is able to “extract” a large amount of the absorbed LFA from the epithelial cells. These observations strongly suggest that LFA enter the epithelial cells faster than they are reesterified into triglycerides, resulting in a pool of diffusible LFA within the cells. Although the cells are in close contact with the subepithelial capillary network, any subsequent rapid absorption via the blood stream does not occur. It is proposed that the hindrance to net blood absorption of the lipid soluble LFA is a “short circuiting” of the easily diffusible LFA in the mucosal countercurrent exchanger.
Recurrent Control from Motor Axon Collaterals of la Inhibitory Pathways to Ventral Spinocerebellar Tract Neurones
Authors: Gustafsson B. , Lindström S.
Published: December 2008

The effects of impulses in recurrent motor axon collaterals on transmission in different inhibitory pathways to ventral spinocerebellar tract (VSCT) neurones were investigated in the cat by conditioning of IPSPs evoked in intracellularly recorded VSCT cells. Disynaptic IPSPs from large muscle spindle (la) afferenls were depressed in many but not all VSCT cells following an antidromic stimulation of ventral roots. The effect was found in VSCT neurones which themselves did not receive recurrent inhibition from motor axon collaterals. In cells with affected la IPSPs also some polysynaptic IPSPs evoked from ipsi‐ and contralateral group II muscle afferents and low threshold cutaneous afferents were depressed by a ventral root volley as well as disynaptic IPSPs from fibres descending on the ipsilateral side of the spinal cord. In unanesthetized preparations recurrent facilitatory potentials similar to those in motoneurones were evoked in VSCT neurones with la IPSPs. The findings indicate that some VSCT neurones receive collateral connexions from the interneurones which mediate la recipiocal inhibition to motoneurones and support the hypothesis that the VSCT conveys information about transmission in inhibitory reflex pathways to motoneurones (Lundberg 1971).
Projections to the Cat's Cerebral Cortex from Low Threshold Joint Afferents
Authors: Clark F. J. , Landgren S. , Silfvenius H.
Published: December 2008

The projections to the cerebral cortex from the contralateral low threshold afferents of the musculocutaneous branch to the elbow joint (Ejt) and the posterior knee joint nerve (Kjt) were investigated in cats anesthetized with chloralose. Graded electrical stimulation of the nerves was used to evoke the cortical potentials. Three discrete joint projection areas were found in the cytoarchitectonic area 3 of the posterior sigmoid gyrus, i.e. one Ejt and two Kjt loci. These loci overlapped with the projections from group I muscle afferents. One Ejt and one or two Kjt loci were observed in positions corresponding to cytoarchitectonic areas 1 and 2. They did not receive input from group I muscle afferents. A separate locus with overlap between forelimb joint and muscle afferents was located in area 4 y. Components 1 and II of the joint nerve volley evoked short latency potentials in all cortical loci. Low threshold cutaneous afferents evoked responses in all joint loci. The spinal course of the ascending Ejt path was mainly located in the dorsal column. Kjt component I afferents travelled mainly in the dorsal columns and component I and II afferents in the dorsolateral fascicle. The Kjt path in the dorsolateral fascicle ascended uncrossed to the level of Ci.
LDH Isozymes in Skeletal Muscles of Endurance and Strength Trained Athletes
Authors: Karlsson J. , Sjödin B. , Thorstensson A. , Hultén B. , Frith K.
Published: December 2008

Muscle biopsy samples were obtained from arm and leg muscles of endurance and strength trained athletes, respectively. Total LDH activity as well as occurrence and activity of LDH isozymes were determined. Comparing the results from the athletes with those from non‐trained subjects with corresponding fibre compositions, it was found that the endurance athletes had a lower total LDH activity, a higher relative activity of the most heart‐specific isozymes, LDH (1 + 2), and, on electrophoretic separation, a complete absence of LDH (4 + 5) in both arm and leg muscles. As compared to the untrained material the strength trained athletes tended to have a higher total LDH activity, a similar distribution of relative isozyme activities, and, in the leg muscles, a strong electrophoretic band corresponding to LDH 5, the most skeletal muscle specific isozyme.
A Comparison between Direct and Indirect Measurements of Blood Flow in the Follicular Ovary of the Rabbit
Authors: Janson Per Olof , Selstam Gunnar
Published: December 2008

A comparison was carried out between direct and indirect measurements of blood flow in follicular ovaries of anaesthetized laparotomized rabbits: Direct measurements by timed quantitative sampling of ovarian venous blood yielded blood flow values 3 times higher than those found with the use of 15 μm radioactive microspheres. However, when simulating the surgical trauma associated with direct measurements, the microsphere technique gave the same high ovarian flow values, indicating that this type of trauma caused ovarian hyperemia. It is concluded that direct measurements of blood flow, as performed in the present study, are unsuitable for investigations of circulatory events in the ovary. Mechanically induced ovarian vasodilatation is probably a factor which helps to explain the diverging data on blood flow obtained with direct and indirect methods. The radioactive microsphere technique appears to provide a means for reasonably reliable ovarian blood flow measurements in laboratory animals.
Regional and Single Glomerular Blood Flow in the Rat Kidney Prepared for Micropuncture. A Methodological Study
Authors: Källskog Ö. , Lindbom L. O. , Ulfendahl H. R. , Wolgast M.
Published: December 2008

Regional renal and single glomerular blood flow was investigated in rats using 141‐Ce and 85‐Sr labelled microspheres. The kidneys were prepared for micropuncture and also the artery was catheterized with a steel cannula in order to make injections of 133‐Xenon and vasoactive substances selectively into one kidney. The microspheres were first separated by sedimentation into a narrow fraction and then injected as a plasma suspension into the carotid artery; the two batches were infused at half an hour intervals. Single glomeruli were sampled from kidney sections with the aid of silicon rubber casts allowing the identification of the glomeruli both with respect to their localisation and their postglomerular appearance. The results showed a relatively high blood flow in the superficial and juxtamedullary glomeruli of above 100 nl/min per 100 g rat whereas in the other glomeruli the blood flow was about 70 nl/min per 100 g rat. No differences could be observed between the right untouched kidney and the left prepared for micropuncture. Furthermore no discrepancies between the results from the two injections could be found. The data on the total renal blood flow obtained by the 133‐Xenon wash‐out method agreed well with the microsphere method.
Quantitative Studies of the Capillary Structure in the rete mirabile of the Eel, Anguilla vulgaris L.
Authors: Stray‐Pedersen Sverre , Nicolaysen Anne
Published: December 2008

The capillaries of the counter‐current capillary organ, rete mirabile, have been studied by light microscopy and electron microscopy. The vasculature of this rete was found to have a cross‐sectional area of about 5.25 mm2, and it consisted of 34000 efferent(= arterial)and 22 000 afferent(= venous) capillaries. The total surface area was the same for the two types of capillaries. The capillary endothelial cells showed numerous pinocytotic vesicles, scattered giant vacuoles and cytoplasmic extrusions (microvilli) at the luminal surface. The majority of the intercellular junctions appeared to have patent gaps with a width of 110–120 Å. The arterial capillaries appeared in many ways to be morphologically similar to skeletal muscle capillaries of mammals, whereas the fenestrated venous capillaries resembled those in the intestinal mucosa of mammals. Measurements of the ionic composition of the rete tissue indicated that the endothelial cells contained much less K+ than other cells, the rete containing approximately equimolar amounts of K+ and Na+. The functional significance of the structural and chemical observations are discussed.
The Effect on Total Renal and Tubular Function and Plasma Renin of a Moderate Isotonic Saline Load in Rats Anesthetized with Amytal and Inactin
Authors: Leyssac Paul P. , Frederiksen Ole , Skinner Sandford L.
Published: December 2008

The renal effects of i.v. saline loading equal to 1% body weight (b.wt.) were studied in 2 groups of rats:group Iwas anesthetized with Amytal (15 mg/100 g b.wt. plus supplementary doses),group IIwith Inactin (12.5–15.0 mg/100 g b.wt).In group Ithe saline load caused an increase in urine flow (+ 92%), solute excretion (+ 67%), inulin clearance (CIN) (+ 24%), PAH clearance (+ 31%) and absolute proximal reabsorption rate (+ 27%). Proximal fractional reabsorption and filtration fraction (FF) remained unchanged, while plasma oncotic pressure (COP) decreased by 10%. Plasma renin fell and there was an inverse relationship between renin concentration and proximal reabsorption rate. Ingroup IIurine flow and solute excretion increased after saline (+ 85% and 110%, respectively); CINand absolute proximal reabsorption rate was lower than in group I and failed to increase after saline. Proximal fractional reabsorption was also lower and decreased after saline. COP as well as renin decreased as in group I, but no relationship between renin concentration and proximal reabsorption rate could be demonstrated. The data indicate that Inactin depresses both resting proximal tubular reabsorptive capacity and the tubular response to a physiological volume expansion. The results are compatible with the hypothesis that the renin‐angiotensin system is significantly involved in regulation of proximal tubular function, while they are incompatible with the idea that peritubular COP plays any major role in this adjustment.
The Permeability of Fish Gills with Comments on the Osmotic Behaviour of Cellular Membranes
Authors: Steen Johan B. , Stray‐Pedersen Sverre
Published: December 2008

The permeability of eel gills to ions, lipid‐soluble and ‐insoluble substances has been measured under steady‐state conditions. The results obtained support the multi‐pathway model for transcapillary transport (Stray‐Pedersen and Steen 1975). The gills are 7.5 times more permeable to THO than to Na+ or K+. Metabolic inhibitors do not affect the transfer of substances across the gills. Exposure to EDTA or MS‐222 changes the permeability properties to resemble those of an aquous barrier. The gills are 10 times less water permeable than the capillaries of the rete mirabile.
Effects of Catecholamine‐Infusions and Hypoxia on Pulmonary Blood Volume and Extravascular Lung Water Content in Cats
Authors: Aarseth P. , Karlsen J. , Bø G.
Published: December 2008

The effects of catecholamine‐infusions and of hypoxia on lung blood volume and on extravascular lung water content have been studied in anesthetized cats with opened chests. To this end a biopsy technique, with isotope labelling of blood and with successive removal of the smaller lung lobes, was employed. Mean pulmonary arterial pressure increased by 30–75% upon infusing catecholamines or upon inducing general hypoxia, the latter stimulus being the more powerful one. Pulmonary blood volume did not increase during these procedures, where an active constriction of pulmonary vessels thus apparently took place. The extravascular lung water content was found to be reduced in animals infused with noradrenaline or ventilated by hypoxic air, whereas a small increase was observed in the animals receiving adrenaline. This difference might reflect domination of precapillary vasoconstriction in the former groups, whereas post‐capillary vasoconstriction could be more pronounced with adrenaline.
The Importance of Asphyxia for the Development of Diving Bradycardia in Ducks
Authors: Blix Arnoldus Schytte
Published: December 2008

Upon submersion, the domestic duck normally displays a prompt but modest cardiac retardation, which, after a short delay, is reinforced into a pronounced state of bradycardia. The present study has revealed that arterial asphyxia is a prerequisite for the reinforcement of the initial slight bradycardia.
Metabolic Characteristics of Fibre Types in Human Skeletal Muscle
Authors: Essén B. , Jansson E. , Henriksson J. , Taylor A. W. , Saltin B.
Published: December 2008

Muscle biopsy samples were obtained from healthy subjects in order to evaluate quantitative differences in single fibres of substrate (glycogen and triglyceride) and ion concentrations (Na+ and K+) as well as enzyme activity levels (succinate‐dehydrogenase, SDH; phosphofructokinase, PFK; 3‐hydroxyacyl‐CoA‐dehydrogenase, HAD; myosin ATPase) between human skeletal muscle fibre types. After freeze drying of the muscle specimen fragments of single fibres were dissected out and stained for myofibrillar‐ATPase with preincubations at pH's of 10.3, 4.6, and 4.35. Type I (“red”) and II A, B, and C (“white”) fibres could then be identified. Glycogen content was the same in different fibres, whereas triglyceride content was highest in Type I fibres (2–3 × Type II). No significant differences were observed for Na+ and K+ between fibre types. The activity for the enzymes studied were quite different in the fibre types (SDH and HAD, Type I ≊ 1.5 × Type II; PFK Type I ≊ 0.5 × Type II; Myosin ATPase Type I ≊ 0.4 × Type II). The subgroups of Type II fibres were distinguished by differences in both SDH and PFK activities (SDH, Type II C > A > B; PFK, Type II B > A ≊ C). It is concluded that contractile and metabolic characteristics of human skeletal fibres are very similar to many other species. One difference, however, appears to be that no Type II fibres have an oxidative potential higher than Type I fibres.
The Influence of Rheological and Collapse Factors on Pre‐ and Post‐Capillary Flow Resistances in the Skeletal Muscle Vascular Bed of the Cat
Authors: ÖBerg Bengt , Little Rod , Rippe Bengt , Folkow Björn
Published: December 2008

The importance of passive‐elastic changes of vascular dimensions and shifts in regional effective viscosity for the pre‐/postcapillary resistance ratio (RA/RV), and hence mean capillary pressure (PC), was analyzed in cat calf muscles. Reductions of mean venous distending pressure below 6–8 mm Hg induced marked R, increases due to escalating venous collapse. This mechanism tends to delimit the PC reductions and rate of transcapillary fluid absorption during intense precapillary vasoconstriction. Comparisons of RA/RVfor erythrocyte suspensions (Hct 40–50) and cellfree perfusates at identical vascular dimensions showed that RA/RV was considerably higher, and P, correspondingly lower, for the erythrocyte suspension except at very low flows. This RA/RV difference increased with increasing flow and at very high flows P, was about 10 mm Hg lower during perfusion with the erythrocyte suspension. These findings apparently diverge from the known influence of tube radius and linear flow velocity on effective in vitro viscosity of blood. Since distal precapillary and proximal capillary sections, both having smaller diameters than the erythrocytes, are located upstream to the point of filtration‐absorption equilibrium, they contribute in this respect to RA. It is therefore suggested that the increasing RA/RV with erythrocyte perfusion, particularly at higher flows, is not due to genuine viscosity factors but to friction losses when cells in “bolus flow” are squeezed through the narrowest precapillary sections.
Kinetics of the Glomerular Ultrafiltration in the Rat Kidney. A Theoretical Study
Authors: Källskog Ö. , Lindbom L. O. , Ulfendahl H. R. , Wolgast M.
Published: December 2008

The glomerular filtration process was evaluated theoretically from micropuncture data obtained from Sprague‐Dawley rats. The hydrostatic pressures in the glomerular capillaries and Bowman's space minus the oncotic pressure in systemic plasma gave the net driving force at the proximal end of the glomerular capillary. From the single nephron filtration fraction the mean net driving force over the glomerular membrane was calculated to be 20 mm Hg during normotension, decreasing to 12 mm Hg during a perfusion pressure of 80 mm Hg. The hydraulic permeability for one glomerulus was 0.7‐0.8 nl/min. 100g b. wt. mmHg. The pressures at the distal end of the glomerular capillaries were 13 and 6 mm Hg under the above two conditions, indicating non‐equilibrium of the filtration process at the end of the glomerular capillary. It was shown that the glomerular filtration rate is mainly influenced by the driving pressures. During hypotension an increased plasma flow dependency was evident. Brenner et al. found a filtration equilibrium and a plasma flow dependent glomerular filtration rate in a mutant Wistar rat strain. The discrepancy between their results and ours is due to the low glomerular plasma flow and hydrostatic pressures in the Wistar rats. It is concluded from our results that both pre‐ and postglomerular resistances may influence the glomerular filtration rate and glomerular plasma flow independently.
Quantitative Aspects of the Vagal Control of Gastrin Release in Cats
Authors: Uvnäs‐Wallensten K. , Uvnäs B. , Nilsson G.
Published: December 2008

Gastrin concentrations were measured in the gastric blood of eviscerated cats. Blood flow was recorded concomitantly thus enabling quantitative determination of the gastrin output. Electrical vagal stimulation within the “physiological” frequency range (0.5–3 Hz) did not regularly result in any detectable changes in the peripheral gastrin level but an increase in this level was always observed on stimulation with frequencies above 3 Hz. A constant gastrin release per stimulus was then obtained, as long as the total number of vagal stimuli did not exceed 2000–3000. A larger number of impulses resulted in rapid fatigue of the release mechanism, indicating either a rapid and sustained fatigue of the neural control mechanism or the existence of a rather small pool of gastrin for immediate release—amounting to less than one per cent of the total antral store of immunoreactive gastrin. The rate at which such a releasable pool was refilled would suffice to compensate for the depletion induced by vagal stimuli at physiological frequencies, i.e. < 3–4 Hz only. The two vagi innervate separate gastrin pools, which behave independently as far as release and refilling are concerned.