bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of Monosaccharide Permeability in Arterial Tissue and Intestinal Smooth Muscle; Effect of Insulin
Authors: Arnqvist Hans J.
Published: December 2008

Monosaccharide permeability was studied in bovine mesenteric arteries and rabbit intestinal smooth muscle. 14C‐labelled 3–0‐methylglucose was used to study counter‐transport and saturation kinetics. L‐glucose‐1–14C and D‐glucose‐1–14C were used to study substrate stereospecificity. 14C and 3H‐labelled sorbitol were used to estimate the extracellular space. In both bovine mesenteric arteries and smooth muscle from rabbit colon the membrane permeability of mono‐saccharides was characterized by substrate stereospecifici, ty, counter‐transport and saturation kinetics. Monosaccharides were transported down a concentration gradient. These results suggest that monosaccharides penetrate vascular and intestinal smooth muscle cell membranes by facilitated diffusion, In the concentration range 5.6–44.4 mM the distribution of unlabelled glucose in bovine mesenteric arteries corresponded to the distribu, tion of sorbitol‐14C, indicating that the membrane transport of glucose was rate limiting for the glucose metabolism. Insulin (0.1 U/ml) increased to a small degree the membrane transport of 3–0‐methylglucose in bovine mesenteric arteries. Compared with the effect of insulin on monosaccharide transport in skeletal muscle the effects on monosaccharide transport in bovine mesenteric arteries and rabbit colon smooth muscle were very small.
Effective Transmitter Concentrations in the Rat Portal Vein as Reflected by Neurogenic Potentiation of Responses to Exogenous Noradrenaline
Authors: Ljung Bengt , Wennergren Göran
Published: December 2008

In the rat portal vein exogenous noradrenaline (NA) and the transmitter released during nerve activity seem to react with the same set of α‐receptors, located on muscle cells close to the nerve terminals. Very shortlasting, high transmitter concentration peaks have been calculated to occur at the receptors for each nerve impulse. In the present study an indirect approach was utilized to evaluate to what extent these peak concentrations, in view of their short duration, are effective in activating the smooth muscle. Electrical field stimulation of the adrenergic nerve supply of the rat portal vein was applied during fully developed responses to graded concentrations of exogenous NA. Transmural stimulation at 2–32 imp/s was found to increase the established responses to exogenous NA in concentrations up to 10‐5M. These effects were abolished by tetrodotoxin. The findings imply that the high, shortlasting NA concentrations, which occur at the α‐receptors for each nerve impulse, lead to high transient degrees of receptor occupancy during nerve activity. The effective transmitter concentrations, over a wide range of impulse frequencies, thus seem to approach the levels of NA which produce maximum responses when applied exogenously.
Role of Cyclic AMP and Ca++in the Metabolic and Relaxing Effects of Catecholamines in Intestinal Smooth Muscle
Authors: Andersson Rolf
Published: December 2008

In rabbit colon muscle there was a quantitative correlation and a co‐ordination in time between relaxation and an increase in cyclic AMP on stimulation of adrenergic β‐receptors. The cyclic AMP content had increased before the muscle had started to relax. There was an increase in the phosphorylaseaactivity and reduction of the ATP content. The adrenergic β‐receptor blocking agent sotalol inhibited the relaxation and the increase in cyclic AMP content. Reduction of the Ca++content of the muscle decreased the cyclic AMP content and the phosphorylaseaactivity. These effects were restored on addition of Ca++ions. In a Ca‐poor muscle adrenergic β‐receptor stimulation still produced an increase in cyclic AMP content and phosphorylaseaactivity but there was an increase in the ATP content instead. The reduction of cyclic AMP which followed an adrenergic a‐receptor stimulation was eliminated in the Ca‐poor muscle. The existence of a Ca++‐accumulating ATP‐utilizing mechanism, stimulated by cyclic AMP, might explain the relation between relaxation, cyclic AMP and Ca++and adrenergic β‐receptor stimulation.
Effects of Sympathetic Stimulation on Mechanoreceptors of Cat Vibrissae
Authors: Nilsson Bengt Y.
Published: December 2008

In a previous investigation adrenergic nerve terminals were demonstrated in the hair follicles of cat vibrissae. The present study shows that electrical stimulation of the cervical sympathetic trunk produces small but repeatable changes in the dynamic responses of the slowly adapting mechanoreceptors of the vibrissae in that the number of impulses in each discharge is reduced and their latency increased. Changes in the static responses are very small. These effects were abolished by phentolamine. The receptor responses as well as effects of sympathetic stimulation remain unaffected by a brief carotid occlusion. It is concluded that the sympathetic modulation observed is a direct effect of locally released noradrenaline and is not attributable to circulatory changes or to pilomotor activity.
The Effect of Bilateral Carotid Artery Ligation upon the Blood Flow and the Energy State of the Rat Brain
Authors: Eklöf Bo , Siesjö Bo K.
Published: December 2008

The cerebral effects of bilateral carotid artery ligation were studied in ligthly anesthetized rats, either alone or combined with moderate reductions in the mean arterial blood pressure. The relative decreases in cerebral blood flow were estimated from the a‐v differences for O2 and CO2 on the assumption of an unchanged cerebral metabolic rate. Ligation of the carotid arteries alone was found to decrease cerebral blood flow to about 50 % of normal, but to give no significant changes in the energy state of the tissue, as judged from the tissue contents of the ATP, ADP and AMP. When the cerebral blood flow was reduced further by means of an induced decrease in blood pressure, the energy state of the tissue was severely affected. At this point the cerebral venous Po2 was reduced from about 50 to about 30 mm Hg. Since pure hypoxemia with a reduction of venous Po2 to about 10 mm Hg can be tolerated without changes in the energy state of the tissue, it is concluded that ischemia may lead to a grossly inhomogenous reduction in the tissue perfusion.
Microvascular Dimensions and Blood Flow in Skeletal Muscle
Authors: Eriksson Elof , Myrhage Rhagnar
Published: December 2008

In cats anesthetized with chloralose the lengths and diameters of the different vascular segments in the tenuissimus muscle were measured in the vital microscope. The flow characteristics, including red cell velocity, were registered. Fixed and stained muscle specimens were analyzed histologically as well as Indian ink‐perfused muscles treated according to the method of Spalteholz. The average muscle fibre diameter was 44 μm. 62% of the muscle fibres were red (48% B‐fibres, diameter 41 μm and 14% C‐fibres, diameter 26 μm) and the remaining 38% were white (A‐fibres, diameter 55 μm). The average muscle fibre was surrounded by 3.6 capillaries. The capillaries were 1015 ± 16.3 (S.E.) μm long and 5.3 ± 0.0(3) (S.E.) μm in internal diameter. The calculated capillary surface area was 0.9 m2/100 cm3of muscle tissue. Average red cell velocity in the capillaries was found to be 0.5 mm/s, but there was a wide variation with time and between different capillaries. Neither “spontaneous” changes in internal diameters of the microvessels nor a distinct precapillary sphincter activity could be observed. Arterio‐venous anastomoses within the muscle tissue were rare exceptions.
The Action of Physostigmine, Morphine, Cyclopentolate and Homatropine on the Secretion and Outflow of Aqueous Humour in the Rabbit Eye
Authors: Uusitalo Risto
Published: December 2008

The influence on the intraocular fluid dynamics (intraocular pressure, inflow and outflow) of one i.v. injection or a 3 day topical application of physostigmine, morphine, cyclopentolate or homatropine was investigated. Special attention was paid to the inflow of aqueous humour and ATPase activity in the ciliary body‐iris after administration of these drugs. Systemic injection of physostigmine caused a marked decrease in intraocular pressure, which seemed to be due to the decrease in inflow of aqueous humour. On the contrary, three day topical applications of this drug had no effect on the IOP or intraocular fluid dynamics. Intravenous injection of morphine increased both the inflow rate and the outflow facility of the eye. Cyclopentolate and homatropine did not decrease the outflow facility. However, cyclopentolate applied intravenously or topically increased both the inflow rate and the outflow facility slightly. Homatropine intravenously injected had no effect on the intraocular fluid dynamics but applied topically slightly increased the IOP, possibly due to the increased inflow of aqueous humour. None of these drugs caused any significant change in the NaK‐ATPase activity in the ciliary body‐iris. Physostigmine and morphine markedly reduced Mg‐ATPase activity. Physostigmine did not decrease Mg‐ATPase activity when the eye had been sympathectomized 7 days before administrations of the drug. It was concluded that the effect of physostigmine on Mg‐ATPase was possibly mediated by way of the sympathetic nervous system.
Catecholamines and Cholinesterases in the Paracervical (Frankenhauser) Ganglion of Normal and Pregnant Rats
Authors: Kanerva Lasse , Lietzen Ralf , Terävaïnen Heikki
Published: December 2008

Chatecholamines and cholinesterases were studied histochemically in the uterine paracervical ganglion of normal and pregnant rats and after both sympathectomy and sacral parasympathectomy. About one fifth of the ganglion cells revealed intense acetylcholinesterase (AChE) activity. The cells were large and devoid of catecholamines and received AChE‐containing nerves. — About one third of the ganglion cells contained weak to moderate yellow‐green catecholamine fluorescence. They were presumed to be adrenergic although they also exhibited moderate to weak AChE activity. These postganglionic neurons represent “short” adrenergic neurons. The rest of the ganglion cells with moderate to weak AChE activity were presumed to be cholinergic. Increased ganglion cell fluorescence was observed after 2 weeks of pregnancy. There was no change in the cholinesterase activity of the neurons. — Division of the sympathetic or the sacral parasympathetic nerves did not cause changes in the intensity of the histochemical reactions. The small, intensely fluorescent cells (SIF‐cells) did not show AChE activity. Other cholinesterases, although present in the cytoplasm of the ganglion cells and SIF‐cells, were mainly localized in the glial cells.
Effect of Sympathetic and Parasympathetic Stimulation on the Secretion and Outflow of Aqueous Humour in the Rabbit Eye
Authors: Uusitalo Risto
Published: December 2008

The influence of electrical stimulation of the superior cervical sympathetic ganglion or parasympathetic (oculomotor) preganglionic nerves on the IOP and intraocular fluid dynamics of rabbits was investigated. Special attention was paid to the inflow of aqueous humour and the NaK‐ATPase activity in the ciliary body‐iris after these stimulations. Sustained sympathetic stimulation was found to cause a significant decrease in the equilibrium pressure of the eye. This stimulation was found to decrease the rate of secretion of aqueous humour but not to influence significantly the rate of drainage of aqueous humour. Parasympathetic stimulation caused a significant increase in IOP, which was due to an increased inflow of aqueous humour. The NaK‐ATPase activity measured after these stimulations in the ciliary body‐iris was unaffected.
Effect of Physical Training on Hemodynamic Response during Submaximal and Maximal Exercise in 11–13‐Year Old Boys
Authors: Eriksson Bengt O. , Koch Günter
Published: December 2008

Nine healthy boys, mean age 11.7 years (11.0–13.0), height 150.4 cm and weight 45.1 kg, were examined with determinations of maximal oxygen uptake (1.85 1×min‐1), heart volume (499 ml) and total hemoglobin (391 g). Cardiac output was determined at rest and during exercise, including maximal exercise, using the dye‐dilution technique and i.a. pressures were recorded. Cardiac output was approximately 2 1×min‐1 lower and the systemic a‐v oxygen difference (AVD) was correspondingly higher than for young adult men at the same sub‐maximal oxygen uptake. At maximal exercise cardiac output was 12.5 1×min‐1, stroke volume 67 ml, AVD 14.2 ml × 100 ml‐1, systolic, diastolic and mean blood pressure 160, 71 and 105 mm Hg respectively and total peripheral resistance 8.6 mm Hg×1–1×min. After a training period of 4 months a normal increase in height was found in all boys, but body weight was unchanged. Maximal oxygen uptake increased to 2.21 1×min‐1 (p < 0.01), almost entirely due to increased stroke volume (80 ml), resulting in a maximal cardiac output of 14.6 1×min‐1. No significant increase in AVD was found. Mean blood pressure at maximal exercise increased significantly, total peripheral resistance was unchanged. Both heart volume and total hemoglobin showed minor increases, but the changes found were not significantly larger than expected from body growth. The hemoglobin concentration was normal (13 g%) for the age and unaffected by training.
Circulatory Responses to Stimulation of Medullated and Non‐medullated Afferents in the Cardiac Nerve in the Cat
Authors: ÖBerg Bengt , Thorén Peter
Published: December 2008

Recordings of the evoked compound potentials in the right main cardiac nerve in the cat demonstrated the presence of both medullated and non‐medullated fibres. The circulatory responses to afferent stimulation of these two fibre populations were followed in terms of changes in blood pressure, heart rate and skeletal muscle and renal flow resistances. A selective stimulation of the medullated afferents, which probably arise mainly from atrial receptors, induced a moderate reflex rise of blood pressure, an increased heart rate and a vasoconstriction in the skeletal muscle and kidney. Clearcut effects were observed first with high stimulation frequencies, and then only in case the buffering influences from other receptor sites were minimized. Stimulation of the non‐medullated fibres, which probably emanate from ventricular receptors, caused a very marked reflex blood pressure fall, slowing of the heart and vasodilatation in the muscle and the kidney, already with very low stimulation rates. These results suggest that the powerful reflex influence from cardiac receptors on the cardiovascular system is exerted by receptors with non‐medullated afferents, while endings firing in medullated pathways as e.g. atrial receptors, have very small direct effects on the cardiovascular system and then rather of an excitatory nature.
Interaction of Adenosine 5‘‐Triphosphate (ATP) with Histamine Release Induced by Compound 48/80
Authors: Dahlquist Rune , Diamant Bertil , Elwin Kerstin
Published: December 2008

The histamine releasing action of compound 48/80 disappeared after pretreatment of rat mast cells with ATP in the absence of divalent cations. The inhibitory action was evident already with 2 μM of ATP, provided the cells were preincubated with ATP for short periods of time prior to the addition of 48/80. When mast cells were exposed to 48/80 combined with ATP more than 10 μM of ATP was needed to induce inhibition of histamine release. This inhibitory effect was found to be specific for ATP compared with various organic phosphorous compounds tested and was not mimicked by EDTA. With concentrations of ATP less than 10 μM the sensitivity to the action of 48/80 was spontaneously restored after prolonged preincubation of the cells with ATP. The experimental findings suggest that ATP, in the absence of divalent cations, induced configurational changes of the plasma membrane of the mast cells so that 48/80 could no longer exert its degranulating and histamine releasing action.
Effect of Divalent Cations on the Interaction of Adenosine 5‘‐Triphosphate (ATP) with Histamine Release Induced by Compound 48/80
Authors: Dahlquist Rune , Diamant Bertil , Elwin Kerstin
Published: December 2008

The inhibition exerted by ATP on histamine release caused by compound 48/80 from isolated rat mast cells was counteracted by Ca++, Mg++, Ba++, and Sr++, but not by Be++. In addition, after the inhibitory effect had been obtained by pretreatment of mast cells with ATP, addition of Mg++restored the sensitivity of the cells towards 48/80. The spontaneous restoration of the sensitivity of the mast cells towards 48/80 observed after prolonged pretreatment of the cells with ATP (< 10 μM.) was enhanced by the presence of glucose. Glucose did not effect the inhibitionper se.EDTA blocked 1) the protecting effect of divalent cations on the action of ATP on mast cells in regard to their sensitivity towards 48/80, 2) the action of Mg++to restore the sensitivity of mast cells towards 48/80 after rendered insensitive by treatment with ATP, 3) the spontaneous restoration of the sensitivity of ATP‐treated mast cells towards 48/80 observed after prolonged incubation alone, as well as the enhanced restoration observed in the presence of glucose. The results suggest an interaction between divalent cations and ATP on the plasma membrane.
Circulatory Control via Vagal Afferents V. Impairment of the circulatory adjustment to hemorrhage by vagal deafferentation and prolonged hypotension
Authors: Sjöstrand Torgny
Published: December 2008

In order to study the effect of vagal deafferentation on the resistance to bleeding, Sprague‐Dawley rats were subjected to repeated blood loss to an arterial pressure of 40–50 nim Hg. The time to the critical point, when blood had to be reinfused to maintain the pressure, as also the total drawn blood volume, was estimated after partial or complete vagal deafferentation. The time was reduced to, respectively, 64 and 40% compared with controls, and the blood loss to 86%. The bradycardia provoked on the first blood drawing decreased gradually to the critical point. A direct correlation was found between the time to the critical point and the duration of the heart rate depression in controls and partially deafferentated animals. On reinfusion at the critical Foint a phase of increased resistance to bleeding, falling off exponentially, was demonstrated. Subsequently the resistance was lowered in the controls and some animals died in circulatory insufficiency. During the phase of decreased resistance, the animals reacted on a renewed blood loss as after vagotomy. It is concluded that the resistance to bleeding is significantly influenced by vagal afferents, probably mediating impulses from the low pressure side, and that the effect of these receptors is abolished on prolonged hypotension.
Afferent Discharges via the Laryngeal Communicans Related to Respiration in the Rat
Authors: Castenfors Jan , Knutsson Evert , Sjöstrand Torgny
Published: December 2008

Impulse discharges in vagal afferents via the laryngeal communicans and related to respiration have been recorded in Sprague‐Dawley rats. Particular interest has been devoted to 2 types of discharges, one appearing on deflation of the lungs and the other on active inspiration. The former is occasionally seen during ordinary expiration, but especially on application of pressure on the thorax, suction of air through trachea, insufflation of air into the pleural cavity, and on collapse of the lungs by exclusion of artificial breathing with open thorax. On suction of air and light compression of the thorax impulses may appear, after an initial burst, on each expiration.

The discharges during the inspiratory phase appear independently of inflation of the lungs. They are very evident during gasps and auxiliary breathing. Discharges on inflation of the lungs have only occasionally been recorded.
Comparative Studies of Capillary Permeability in Brain and Muscle
Authors: Crone Christian , Thompson Alan M.
Published: December 2008

The permeability of the capillary wall in the brain was compared with that in muscle by means of the ratio between outflow concentrations (relative to inflow concentrations) after single i.a. injections of various combinations of two radioactive tracers. A ratio above 1 means that the solute in the denominator left the capillaries faster than the other tracer, vice versa. The following outflow ratios were obtained: Hind limb: Glucose/K+ and 3‐O‐methyl‐glucose/K+: above 1. Brain: Glucose/K+ and 3‐O‐methyl‐glucose/K+: below 1. The hind limb results show a faster transcapillary transport of potassium than of the sugars—in agreement with the predictions of the Pappenheimer pore model for muscle capillaries. In brain the sugars are transported faster across the capillary wall than tracer potassium. This finding cannot be explained by diffusion through a common interendothelial diffusion pathway (pore). but signify that the sugars are transported through the capillary endothelial cells in brain—a route not available to potassium. The Pappenheimer pore model only applies to the brain capillaries as a limiting case with a pore permeability close to zero, even for small solutes. Thus, the permeability characteristics of the brain capillaries are in closer agreement with those of mono‐layered epithelia than with the Pappenheimer pore model. It is concluded that important blood‐brain barrier functions are carried out in the cerebral capillary walls.
Rise Time of the Spike Potential in Fast and Slowly Contracting Muscle of Man
Authors: Buchthal Fritz , Dahl Kristian , Rosenfalck Poul
Published: December 2008

In 20 muscles of 10 normal Subjects rise times of the spikes of motor unit potentials were recorded during weak voluntary effort by means of a concentric electrode with a small tip area (0.015 mm2). Rise times in the soleus muscle, which consists mainly of slowly contracting fibres, were twice as long on the average as in the lateral head of the brachial triceps, which contains mainly fast contracting fibres (190 ± 10 μs, 145 spike potentials compared to 107 ± 4 μs, 115 spike potentials), In both muscles the distribution of rise times was skewed toward the long rise times. The longer rise times in the soleus muscle could not be accounted for by smaller diameter of the muscle fibres and therefore slower conduction velocity than in the lateral head of the brachial triceps. Therefore the properties of the excitable membrane must be different in the slow fibres of the soleus from those of the fast fibres of the lateral head of the brachial triceps. The difference in rise time of the spikes in the two muscles was not reflected in the total duration ol the motor unit potentials recorded by means of conventional concentric electrodes.
Histochemically Demonstrable Catecholamines and Cholinesterases of the Rat Uterus during Estrus Cycle, Pregnancy and after Estrogen Treatment
Authors: Hervonen Antti , Kanerva Lase , Lietzén Ralf
Published: December 2008

The changes of the adrenergic and cholinergic nerves of the rat uterus were examined during the estrous cycle, pregnancy and after estrogen treatment. During the first 2 weeks of pregnancy and after estrogen treatment the fluorescence intensity and the thickness of the extra‐vascular adrenergic nerve fibres increased, but decreased in the end of pregnancy. The activity and also the density of AChE‐positive nerves increased after estrogen treatment and during the first 2 weeks of pregnancy and decreased at the end of pregnancy. The AChE‐activity and the intensity of fluorescence in the nerves was somewhat stronger in estrus than diestrus.
Relationship between Cyclic AMP, Phosphodiesterase Activity, Calcium and Contraction in Intestinal Smooth Muscle
Authors: Andersson Rolf G. G.
Published: December 2008

Effects of contracting agents on the mechanical and the metabolic activity in smooth muscle have been studied. The contraction induced by carbacholine in colon muscle from rabbit was preceded by a decrease of the cyclic AMP content. After development of the tension, the level of cyclic AMP was increased, the phosphodiesterase activity was reduced, and the phosphorylase SaL activity and glycogenosis were stimulated. These effects were blocked by atropine but not by an adrenergic β‐blocking agent. In the Ca‐poor muscle there was a sustained decrease of the cyclic AMP content by carbacholine. Contraction induced by K+ions showed similar metabolic actions as carbacholine and these effects were Ca++dependent too. The contracting effect of imidazole was preceded by an activation of phosphodiesterase and by reduction of cyclic AMP. The metabolic effects induced by imidazole were not Ca++dependent. Imidazole potentiated the contracting action of carbacholine and K+. Ca++in the same concentrations as those activating the contractile system, inhibited the phosphodiesterase activity in homogenate of colon muscle. The relationship between cyclic AMP, Ca++and contraction in smooth muscle is discussed.
Glycogen Synthesis in Rat Diaphragm in Vivo: a Biphasic Effect of Insulin on Glycogen Synthetase Enzyme
Authors: Adolfsson Sten
Published: December 2008

During enhanced glycogen synthesis an increase in the activity of the enzyme rate‐limiting for glycogen synthesis is expected. This enzyme, glycogen synthetase (UDP‐glucose: α‐1,4‐glucan, α‐4‐glucosyltransferase; EC 2.4.1.11), can be activated by transformation of its D‐form to I‐form. Insulin is known to stimulate glycogen synthesis in skeletal muscle. However, Søvik did not find any change in I‐form in the rat diaphragm 30–240 min after an intraperitoneal (i.p.) injection of insulin, although glycogen synthesis was highly stimulated (O. Søvik, Acta physiol. scand. 1966.68.246–254). In the present study glycogen content and synthetase enzyme activity were measured in rat diaphragms 10–120 min after i.p. injection of insulin. Phosphorylase enzyme activity was also measured. Insulin administration produced a biphasic change in the synthetase enzyme; compared to controls there was an increase of the % I‐form after 10 and 20 min and a decrease after 50, 80 and 120 min. Phosphorylase enzyme activity was unaffected. Glycogen increased continuously up to 120 min. Thus, the increase in I‐form was shown to be a transient effect of insulin. In Søvik's experiment this increase had probably subsided at the time of the first measurement. To account for the increase in glycogen when the % I‐form was decreased, an activation of the synthetase enzyme through an increase of its activator, glucose‐6‐phosphate, may be considered.
Effect of Physical and Chemical Agents on the Blood Mast Cells (Basophil Leucocytes) of Turtles
Authors: Reite Ola B.
Published: December 2008

The histamine‐releasing effect of several physical and chemical agents on basophil leucocytes was studied in blood from the red‐eared turtle,Pseudemys scripta elegans.Hypotonic saline, low and high pH, compound 48/80 and octylamine produced marked histamine release. Polymyxin B, toluidine blue and protamine seemed to be capable of inducing release of smaller amounts of histamine. No significant histamine release was obtained with hypertonic saline, d‐tubocurarine, reserpine, adrenaline and 5‐hydroxytryptamine. It is concluded that compared with the tissue mast cells of the rat, in which the response to histamine‐releasing agents has been thoroughly studied, the basophil leucocytes of the turtle are considerably more resistant to induced release of histamine.
Circulatory Responses to Stimulation of Left Ventricular Receptors in the Cat
Authors: ÖBerg Bengt , Thorén Peter
Published: December 2008

Left ventricular receptors, firing in non‐medullated vagal afferents, were stimulated in chloralose‐anesthetized cats by brief aortic occlusions or by intrapericardial injections of nicotine. The induced reflex effects on heart rate, renal and skeletal muscle resistance vessels and muscle capacitance vessels were followed and compared with the reflex effects of arterial baroreceptor stimulation. Stimulation of the ventricular receptors induced a considerable reduction in heart rate, almost entirely due to vagal activation, and to a reflex dilatation of renal and muscle resistance vessels and of the muscle capacitance vessels. For a given reflex reduction of skeletal muscle flow resistance with the two reflex mechanisms, the concomitant reflex bradycardia and renal vasodilatation was more pronounced when the ventricular receptors were stimulated than upon activation of the arterial baroreceptors. The capacitance vessels seemed, however, to be engaged to the same extent from the two receptor groups. The reflex muscle dilatation, following ventricular receptor activation, was solely due to inhibition of adrenergic vasoconstrictor fibre activity with no evidence of any cholinergic vasodilator fibre activation.
Redistribution of Tissue Histamine Stores (Basophil Leucocytes) of Turtles in Response to Submersion and Cold Exposure
Authors: Reite Ola B.
Published: December 2008

The histamine contents of liver and blood of turtles(Pseudcmys scripta elegans)kept at 20–22° C were compared with those of turtles exposed to cold (4–6° C) for 2–21 days or sub‐merged for 12 hours. Submersion and cold exposure consistently caused a decrease in the histamine content of blood and an increase in the histamine content of liver. The average histamine content of blood was reduced to about half its pre‐exposure value and that of liver was doubled. The results indicate that the basophil leucocytes, which are exceptionally numerous in this species and are the only blood cells known to contain appreciable amounts of histamine, accumulate in the liver when the turtles are submerged or exposed to cold. Influence of cold exposure on the histamine content of liver and blood was also studied in several other species of turtle(Chrysemys picta, Emys orbicularis, Clcmmys caspica leprosa, Terrapcne Carolina, Kinosternon flaucscens), and they all showed a response similar to that observed inPseudemys scripta clcgans.
Lack of Correlation between Profiles of Transmitter Efflux and of Muscular Contraction in Response to Nerve Stimulation in Isolated Guinea‐pig Vas Deferens
Authors: Stjärne Lennart
Published: December 2008

The profile of the nerve stimulation induced contractile response of isolated, superfused guinea‐pig vas deferens was compared with that of transmitter efflux, as monitored by determination of outflow of total tritium, after preincubation with tritium‐labelled nor‐adrenaline. Transmitter efflux increased with time during stimulation up to 60 s and was monophasic, although the contractile response could be made to shift from mono‐to diphasic. Desipramine and normetanephrine added to block local reuptake of noradrenaline altered the slope, but not the monophasic character of the transmitter outflow curve. Phenoxybenz‐amine abolished the delayed contractile response to nerve stirnulation, but potentiated and shortened the latency of the initial “twitch”. In spite of the presence of drugs blocking reuptake of noradrenaline phenoxybenzamine further markedly enhanced nerve stimulation induced transmitter efflux, indicating that blocking of specific α‐adrenoceptors leads to enhanced transmitter secretion. Further addition of prostaglandin E2distinctly potentiated, and prolonged the latency of, the initial “twitch”, but depressed the secretion of transmitter. All these effects increased with the dose of prostaglandin, and were reversible. The results clearly show the sometimes striking lack of correlation between transmitter secretion and the resulting mechanical response; actual determination of transmitter efflux improves on the accuracy of conclusions concerning mechanisms controlling secretory events at this level.
The Effect of Hypertonicity on the Time Course of the Active State in Single Skeletal Muscle Fibres of the Frog
Authors: Andersson K.‐E.
Published: December 2008

The time course of the active state was investigated in single skeletal frog muscle fibres in normal Ringer's solution and in Ringer's solution made hypertonic (1.44–1.67 R) by addition of sucrose. During a single, isometric twitch the plateau phase of the active state was abbreviated in hypertonic solution. During repetitive stimulation there was a progressive increase in the duration of the active state and a slowing of the rate of decay of the activity in the hypertonic medium. The resting membrane potential was insignificantly affected by the hypertonic solutions used. There was a slight decrease in overshoot and also a diminution in the rate of rise and rate of decay of the action potential. As a possible explanation of the results, it is suggested that in a hypertonic medium there is a diminished release of calcium in response to a stimulus. This leads to a shortening of the plateau phase of the active state during a single twitch. Because of a reduced rate of re‐uptake of calcium by the sarcoplasmic reticulum, the duration of the active state is prolonged and the decay of activity slowed during repetitive stimulation.
Differences in the Autoradiographic Localization of Labelled Morphine‐Like Analgesics in the Mouse
Authors: Appelgren Lars‐Erik , Terenius Lars
Published: December 2008

The distribution of the3H‐labelled narcotic analgesics, dihydromorphine and fentanyl and the narcotic antagonist, diprenorphine, was studied by whole‐body autoradiography in male and female (pregnant) mice. Very small amounts of label were found in the CNS after administration of dihydromorphine which was rapidly excreted via the urine. There was very little passage of labelled material over the placental barrier. Pretreatment with nonlabelled diprenorphine did not change the distribution. After the administration of fentanyl a very different picture was seen. Large amounts of label passed into the CNS. In addition to label in urine, large amounts were seen in the gall bladder and in the intestinal contents. Only little passage over the placental barrier was observed. After the administration of diprenorphine rather little label was found in the CNS while high amounts were excreted via urinary pathways and still more via the intestine. There was considerable passage over the placentzl barrier.
Vagal Relaxation of the Stomach Induced by Apomorphine in the Cat
Authors: Abrahamsson Hasse , Jansson Gunnar , Martinson Jan
Published: December 2008

In anesthetized or decerebrate unanesthetized cats administration of the emetic drug apomorphine produced pronounced and long‐lasting relaxation of the stomach. When apomorphine induced somatomotor retching or vomiting movements they were always preceded by gastric relaxation. The gastric relaxatory response to apomorphine could not be blocked by atropine or guanethidine but was completely abolished after vagotomy. Vagotomy, if performed during the relaxed state of the stomach after apomorphine administration, resulted in a prompt decrease of gastric volume. Injection of apomorphine had no essential effect on gastric contractions induced by efferent electrical vagal stimulation, indicating that the splanchnic nerves were of minor or no importance for the apomorphine induced gastric relaxation.—It is concluded that the emetic drug apomorphine produces gastric relaxation by activation of the vagal non‐adrenergic relaxatory nerve fibres to the stomach. The results indicate that the relaxation of the proximal part of the stomach known to appear early in the vomiting act, is mediated by these relaxatory nerve fibres.
Protein Concentration of Interstitial Fluid Collected from Rat Skin by a Wick Method
Authors: Aukland K. , Fadnes H. O.
Published: December 2008

A new method has been developed for studying interstitial fluid protein concentration: A 3 cm long and 0.5 mm thick nylon thread was sewn into subcutaneous tissue of ether anesthetized rats and left for equilibration with interstitial fluid for 35 to 240 min. The wick was then pulled out, both ends cut off, and the middle part quickly transferred to a tared vial containing 2 ml saline and weighed. Blood‐stained wicks, about 1 out of 5, were discarded. After 24 h elution the wick was removed, dried and weighed, allowing calculation of wick fluid volume. Total protein, albumin and hemoglobin concentrations were measured in the eluate. Hemoglobin concentration was less than 0.2 g/100 ml in all but one wick. Implantation of 73 wicks in 24 rats for 35 to 120 min gave an average albumin concentration of 2.10 (S.D. 0.24) g/100 ml, or 63% of plasma albumin concentration. Total protein concentration in 80 wicks averaged 3.44 (S.D. 0.30) g/100 ml, 56% of plasma. The concentrations did not change during this time interval and were reduced by less than 10% by antihistamine/antiserotonin treatment. An irregular rise in concentrations after more than 2 h implantation was delayed by antihistamine/antiserotonin.
Sequential Exocytosis of Storage Granules during Antigen‐Induced Histamine Release from Sensitized Rat Mast Cells in vitro An electron microscopic study
Authors: Anderson Per , Slorach Stuart A. , Uvnäs Börje
Published: December 2008

The morphological changes appearing in sensitized rat mast cells incubated with antigen at 25° C for times ranging from 30 s to 10 min were studied using light and electron microscopy. Histamine release was assayed in parallel. After a latent period of 30 s, during which no histamine release or morphological changes occurred, degranulation and histamine release commenced and increased progressively with time. The first changes were seen in the most peripherally‐located granules, and consisted of a fusion of the cell membrane with the perigranular membrane and a swelling and a reduction of the electron‐density of the granules. With increasing time these changes were seen to spread deeper into the cells, resulting in the formation of labyrinthic cavities contatining changed granules; such granules were also seen outside the cells. Using the extracellular tracer lanthanum these apparently intracellular cavities were demonstrated to be in unbroken communication with the extracellular milieu. Thus when sensitized rat mast cells are incubated with antigen sequential exocytosis of histamine‐storing granules take place. The results agree with the hypothesis that histamine release takes place by ion exchange between histamine and extracellular cations both in granules expelled from the cells and in those retained in cavities open to the exterior.
Potentiation of Anaphylactic Histamine Release from Guinea Pig Lung by Maleate and Succinate
Authors: Chakravarty Nirmal , Sørensen Hans Jørgen
Published: December 2008

Both maleic acid and succinic acid enhance anaphylactic histamine release from guinea pig lungin vitro–the degree of enhancement being of the same order of magnitude. The stimulating effect of both the substrates is inhibited by relatively low concentrations of malonic acid and bromopyruvic acid, and no stimulation occurs in response to either substrate when histamine is released by the antigen in an anaerobic medium. Maleic acid is shown to be metabolized to CO2by guinea pig lung nearly at the same rate as the tissue oxidizes succinic acid to CO2–the conversion of both the substrates to CO2beifig inhibited by malonic acid. Furthermore, D (+) malic acid has been identified as an intermediate product in the metabolism of maleic acid by guinea pig lung. It is suggested that maleic acid follows the same metabolic pathway in guinea pig lung as revealed earlier in rabbit kidney,viz.maleic acid → D (+) malic acid → oxaloacetic acid → CO2. The findings thus suggest that both maleic acid and succinic acid enhance anaphylactic histamine release from guinea pig lung through their metabolic utilization in the tricarboxylic acid cycle.
Potentiation of Dextran‐Induced Histamine Release from Rat Mast Cells by Phosphatidyl Serine
Authors: Chakravarty Nirmal , Goth Andres , Sen Parantapa
Published: December 2008

Phosphatidyl serine in 1–50 μg/ml concentrations markedly potentiates histamine release in‐duced by dextranin vitrofrom the mixed peritoneal cells of rats. The release occurs within one‐half minute, thus resembling the anaphylactic histamine release. The histamine release from isolated pure populations of mast cells, which generally respond poorly to dextran, was largely restored by phosphatidyl serine. The media, employed for the isolation of mast cells, viz. serum albumin, Ficol and acacia, were found to inhibit histamine release. The albumin inhibition could be overcome by phopshatidyl serine, which enhanced the release in spite of the presence of albumin. Serum albumin was found to bind phospholipids, an effect which may be related to the inhibition of histamine release caused by albumin. The effect of some inhibitors of the ATPase system was studied. Ouabain in 1–10 mM concentration neither affected the dextran‐induced histamine release nor its potentiation by phopshatidyl serine. Ethacrynic acid (1 mM) had some inhibitory effect on histamine release by dextran alone and dextran + phosphatidyl serine. Oligomycin (1 μg/ml) had very little effect on histamine release induced by dextran alone, but completely blocked the potentiation of histamine release caused by phosphatidyl serine.
Incorporation of Guanethidine into Isolated Rat Peritoneal Mast Cells and Mast Cell Granules in Vitro
Authors: Gripenberg J.
Published: December 2008

The incorporation of guanethidine into isolated rat peritoneal mast cells was studied in vitro. The incorporation of the drug is dependent upon 1. temperature, 2. the pH of the medium, 3. the presence of Ca‐ions in the medium, it 4. shows saturation characteristics and is 5. inhibited by 5‐hydroxytryptamine and tricyclic antidepressants. Of the metabolic inhibitors tested, only FCCP reduced incorporation of guanethidine. The intracellular location of guanethidine in mast cells is mainly in the amine‐storing organelles. It is concluded that the incorporation of guanethidine is partly due to an active transport mechanism located in the cell membrane, while the incorporation of the drug into isolated membrane‐free mast cell granules is a passive process resulting in binding to sites in the granule matrix.
An Investigation of the Action of Diphenylhydantoin on Sodium Efflux in Barnacle Muscle Fibres
Authors: Bittar By E. Edward , Chen Stephen S. , Danielson Bo G. , Tong Edmund Y.
Published: December 2008

Bittar, E. E., S. S. Chen, B. G. DanielsonAND E. Y. Tong. An investigation of the action of diphenylhydantoin on sodium efflux in barnacle muscle fibres. Acta physiol. scand. 1973. 89. 30–38.

Sodium efflux from barnacle fibres is suppressed by external but not by internal application of diphenylhydantoin (DPH). DPH (10‐4M) at pH 7.8 reduces the Na efflux by 32%,a value slightly less than half that obtained with 10‐4M ouabain. Ouabain has the ability to abolish the remaining Na efflux, whereas DPH incompletely abolishes the ouabain‐insensitive Na efflux. The onset of inhibition by DPH is slower than that by ouabain. At lower external pH the onset of peak action by DPH is more rapid than at pH 7.8. The sensitivity of the Na efflux to DPH is unaffected by external K. However, the residual efflux from fibers poisoned with ouabain following K removal is insensitive to DPH. DPH prevents the Na efflux from responding to external acidification. It also has the power to almost completely reverse the effect of external acidification on the Na efflux. It is provisionally concluded that the T‐system is the site of DPH action.
Histaminuria after Parenteral L‐histidine Administration in Man
Authors: Döhlen Helene , Nornes Helge , Sjaastad Ottar , Sjaastad Ö. V.
Published: December 2008

Dohlen, H., H. Nornes, O. SjaastadAND Ö. V. Sjaastad. Histaminuria after parenteral L‐histidine administration in man. Acta physiol. scand. 1973. 89 51–60.

L‐histidine was given i.v. to 4 healthy male individuals. The dosage was 2.5, 5.0 and 7.5 g of the free amino acid, and the total number of experiments 9. The urinary excretion of histamine was estimated with 3 different methods: Dunér and Pernow's method (ion‐exchange + bioassay), an enzymatic isotopic assay (Snyder et al.1966) and an autoradiographic method. No definite increment in urinary histamine excretion followed the 2.5 g dose, whereas a significant increment followed the 5.0 and 7.5gdosages. The excess histamine was excreted during the first 4 h after L‐histidine loading. The excess urinary histamine probably has its origin in the tissues of the body. The extra endogenous histamine is probably formed as a consequence of the L‐histidine loading.
Effects of Extrinsic Denervation on the Fluorescence of Monoamines in the Small Intestine of the Cat
Authors: Ahlman H. , Enerbäck L. , Kewenter J. , Storm B.
Published: December 2008

Ahlman, H., L. Enerback, J. Kewenterand B. Storm.Effects of extrinsic denervation on the fluorescence of monoamines in the small intestine of the cat.Acta physiol. scand. 1973.89.429–435.

The effects of section of the nerves supplying the small intestine in the cat were studiedin vivoat different times after the operation. Before denervation, biopsies from the jejunum and ileum were studied by a fluorescence method in order to observe the adrenergic innervation and the presence of 5‐hydroxytryptamine (5‐HT). In addition to the adrenergic fibres terminating around the ganglion cells of the intestinal nervous plexuses, other adrenergic fibres were seen in close connection with the muscle fibres in both muscular layers. The only location of 5‐HT seemed to be in the enterochromaffin cells of the mucosa. After nerve section the completeness of the denervation was established in an acute experiment by means of electrical stimulation of the vagal and splanchnic nerves while registering the motility of a jejunal and an ileal loop. Afterwards the small intestinal wall was studied with the same histochemical fluorescence method. No changes were found in the towel habits or in the general state of nutrition of the animals. The intestinal adrenergic innervation completely disappeared after denervation. The adrenergic innervation does not seem to be necessary for adequate peristaltic activity in the small intestine. 5‐HT did not disappear after denervation but was found unchanged in the enterochromaffin cells.
Autoregulation of Blood Flow in Human Cutaneous Tissue
Authors: Henriksen Ole , Nielsen Steen Levin , P. Paaske William , Sejrsen Per
Published: December 2008

The presence of autoregulation of blood flow was investigated in human cutaneous tissue of the skin fold between thumb and forefinger by means of die method of epicutaneous atraumatic application of gaseous xenon‐133. 49 studies were performed on 3 healthy subjects. Blood pressure changes were obtained by passive displacement of the skin fold to various test levels above and below the reference level, the jugular notch. Blood flow remained constant for all subjects in an interval around the reference level. The range of autoregulatory ability showed variation. In extreme positions a decrease of blood flow was observed for some subjects. The significance of these findings is discussed.