bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractAhlman, 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

AbstractThe 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.
Parallelism between Mechanical and Metabolic Responses to Cholecystokinin and Prostaglandin E2in Extrahepatic Biliary Tract
Authors: Andersson K.‐E. , Andersson R. , Hedner P. , Persson C. G. A. 
Published: December 2008

AbstractThe mechanical effects of the prostaglandins Ei, E2 and F2u were investigatedin vitroin isolated preparations of guinea‐pig gallbladder, cat gallbladder, and cat sphincter of Oddi. The actions of the prostaglandins, and particularly the effects of prostaglandin Ea, proved similar to those of cholecystokinin,i.e.contraction of the gallbladder and relaxation of the sphincter of Oddi were produced; the responses were not influenced by tctrodotoxin or by blockade of adrenoceptors or cholinoceptors. In the anesthetized cat, prostaglandin E2increased the intraluminal gallbladder pressure and decreased the resistance to flow through the sphincter of Oddi. The contractile responses in guinea pig gallbladder after prostaglandin E2were preceded by a decrease in the tissue levels of cyclic AMP and an activation of phosphodiesterase. The relaxation produced by prostaglandin Ea in the cat sphincter of Oddi was associated with an increase in the cyclic AMP content of the tissue, despite an inci'eased phosphodiesterase activity. These metabolic changes were similar to those observed in response to cholecystokinin. The similarities in mechanical and metabolic effects between prostaglandin Ea and cholecystokinin and the possible role of prostaglandin Ea in mediation of the actions of cholecystokinin on the extrahepatic biliary tract are discussed.
Brain Uptake of Lactate, Antipyrine, Water and Ethanol
Authors: Gjedde Albert , Anderson Jan , Eklöf Bo 
Published: December 2008

AbstractBrain uptake of antipyrine, water and ethanol was studied in rats under normo‐, hypo‐ and hypercapnic conditions. Brain uptake of D‐ and L‐lactate was studied in normal rats. The uptake was determined with the Oldendorf method, using single common carotid arterial injections of a mixture of 14C‐labeled test substance and tritiated reference substance. The results demonstrate that L‐lactate is taken up by the brain in significant amounts. The results also demonstrate marked differences in the uptakes of antipyrine, water and ethanol. The brain uptake of antipyrine is lower, the brain uptake of etnanol higher, than of water. The brain uptake of all 3 substances was shown not to be affected by changes in cerebral blood flow, although a decrease of brain uptake of antipyrine relative to cthanol was observed during hypo‐ and hypercapnia.
Influence of Peritubular Hydrostatic and Oncotic Pressures on Fluid Reabsorption in Proximal Tubules of the Rat Kidney
Authors: ÅGerup Bengt 
Published: December 2008

AbstractProximal tubular reabsorption was measured with the split droplet technique under the following conditions. Group I. Star vessel perfusions with ultrafiltrate in the presence of human serum albumin (HSA) and with ultrafiltrate alone. Group 2. Capillary perfusions, under locally high flow rates, with ultrafiltrate in the absence or presence of HSA. Group 3. Subcapsular perfusions with ultrafiltrate of high HSA concentrations but under low hydrostatic pressure and ultrafiltrate of low HSA concentrations but under elevated hydrostatic pressure. In Group I, the presence of HSA increased the reabsorptive rate, whereas ultrafiltrate alone had no provable effect on the reabsorptive rate. In Group 2, a flow dependent decrease of the reabsorptive rate, that was not influenced by the presence of HSA, was observed. Finally, in Group 3, high concentrations of HSA did not alter the reabsorptive rate, whereas elevation of the hydrostatic pressure decreased the reabsorptive rate. The results cannot be explained on the basis of a simple passive mode of action of colloid osmotic and hydrostatic pressure on the reabsorptive rate. The possibility of a direct tubulae capillary transport route is discussed.
Observations of the Early Diuretic Response after Intravenous Administration of Bumetanide and Furosemide in Dogs
Authors: Olsen Uffe Bang 
Published: December 2008

AbstractA transient natriuretic peak was observed in dogs the third minute after the i.v. administration of the highly active diuretics bumetanide and furosemide. The peak is dependent on the sodium balance such that it is potentiated during positive sodium balance and is not observed in sodium depleted dogs. A relationship exists between the simultaneous occurrence of the peak and abolition of the cortico‐medullary electrolyte gradient.
Atropine Sensitivity of the Rat Urinary Bladder during Nerve Degeneration
Authors: Elmér Mats 
Published: December 2008

AbstractThe pressure response of the rat urinary bladder to electrical stimulation of the pelvic nerve at a low stimulation frequency was found to be almost completely atropine resistant. However, the response to stimulation of the degenerating pelvic nerve 20–30 h after section of the nerve postganglionically using maximal stimulation frequency was totally abolished by atropine or the parasympatholytic agent Hoechst 9980. The responses were not affected by hexamethonium or dihydroergotamine, but were potentiated by eserine. The non‐adrenergic portion of the bladder response to stimulation of the degenerating hypogastric nerves was also abolished by atropine or Hoechst 9980. It is concluded that the transmitter activating the detrusor muscle at stimulation of the pelvic nerve or the non‐adrenergic part of the hypogastric nerve probably is acetylcholine.
Effects on the Ventral Spinocerebellar Tract Neurones from Deiters' Nucleus and the Medial Longitudinal Fascicle in the Cat
Authors: Baldissera F. , Roberts W. J. 
Published: December 2008

AbstractEffects from the vestibulospinal tract (VST) and from fibres descending in the medial longitudinal fascicle (MLF) on the cells of origin of the ventral spinocerebellar tract (VSCT) have been studied with intracellular recording. Out of 110 VSCT neurones, the VST evoked monosynaptic EPSPs in 27, di‐ or polysynaptic EPSPs in 56 and disynaptic lPSPs in 26. In 93 tested VSCT cells, MLF stimulation evoked monosynaptic EPSPs in 26, monosynaptic IPSPs in 2, di‐ or polysynaptic EPSPs in 25 and disynaptic IPSPs in 21, Convergence of monosynaptic EPSPs from VST and MLF was found in a small proportion of cells whereas the two descending pathways evoked reciprocal effects in another small group of neurones. Convergence of monosynaptic EPSPs from VST or MLF and from group 1 afferents was also modest. In 9 VSCT neurones there was convergence of monosynaptic excitation and disynaptic inhibition from the vestibulospinal tract and the same pattern from MLF was recorded in 9 neurones. The results are discussed in view of the hypothesis that VSCT neurones carry information on the interneuronal transmission in the spinal cord.
In Vitro Uptake of Bile Acids by Choroid Plexus, Kidney Cortex and Anterior Uvea. I. The Iodipamide‐sensitive Transport Systems in the Rabbit
Authors: Bárány Ernst H. 
Published: December 2008

AbstractRenal cortex, anterior uvea, lateral choroid plexus and terminal ileum accumulate14C‐cholate, glycocholate, deoxycholate and chenodeoxycholate to considerable tissue/medium ratios. Iodipamide partly inhibits accumulation by kidney, uvea and plexus but not ileum. In renal cortex the sensitive part is ˜10, 60 and 90% for dihydroxy acids, cholate and glycocholate respectively. Hippurate depresses uptake in kidney and uvea but hardly in plexus. Simultaneous uptake by renal cortex and uvea of14C‐cholate or glycocholate,125I‐iodipamide and131I‐o‐iodohippurate was studied with unlabelled iodipamide and hippurate as inhibitors. The concentration‐dependence of the inhibition required the assumption of 4 partly overlapping iodipamide‐sensitive transport systems handling the 4 test substances: the hippurate (H‐) system, one moderately (L1) and one very hippurate‐resistant (L2) part of the liverlike L‐system and a fourth system called BS, more evenly inhibitable by iodipamide and hippurate than the others. The L2‐system carries iodipamide but very little bile acids. No iodipamide‐sensitive system clearly specialized for bile acid transport was found. The systems have only moderate affinity for bile acids and probably treat them just as large organic anions. A new mathematical procedure to test the degree of complexity of composite transport systems without kinetic assumptions was used.
Cerebral Blood Flow and Oxygen Consumption in the Rat in Hypoxic Hypoxia
Authors: Jóhannsson Halldór , Siesjö Bo K. 
Published: December 2008

AbstractIn order to measure cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRo2) at pronounced degrees of hypoxic hypoxia the Pao2 of artificially ventilated and normocapnic rats was reduced to between 47 and 22 mm Hg for 15–25 min with subsequent measurements of CBF, using a 133Xenon modification of the Kety and Schmidt technique, and of the arteriovenous difference in oxygen content, the venous blood being obtained from the superior sagittal sinus. When the Pao2 was reduced to minimal values of 22 mm Hg CBF increased 4‐ to 6‐fold, the increase in CBF being unrelated to changes in blood pressure or Paco2. The CMRo2 remained unchanged at all levels of hypoxia. It is concluded that the maintenance of a normal, or near‐normal, cerebral energy state even at extreme degrees of hypoxic hypoxia depends solely on a homeostatic increase in CBF.
Adrenergic and Cholinergic Innervation of the Rat Urinary Bladder
Authors: Alm Per , Elmér Mats 
Published: December 2008

AbstractThe autonomic innervation of the rat urinary bladder was studied using histochemical methods and nerve stimulations. A sparse adrenergic innervation of the detrusor muscle was found. It was supposed to originate from long adrenergic neurones. The trigonum area had a rich supply of adrenergic fibres, probably derived from short adrenergic neurones. A uniformly rich supply of acetylcholine‐esterase (AChE)‐positive nerves was found in the whole bladder. Postganglionic sympathetic denervation caused no detectable change of adrenergic or AChE‐positive nerves in the bladder, while parasympathetic decentralization or denervation produced a total disappearance of adrenergic fibres. The AChE‐positive nerves were appreciably reduced in number after parasympathetic decentralization and not detectable after postganglionic denervation. Neither adrenergic nor AChE‐positive ganglion cells could be demonstrated in the bladder wall. Electrical stimulation of the hypogastric nerves or the pelvic nerves distal to the pelvic ganglia elicited contraction of the detrusor muscle. The responses were not affected by hexamethonium, dihydroergotamine or propranolol but were slightly reduced by guanethidine, reduced to about 40% by atropine and potentiated by eserine. Stimulation of the pelvic nerve proximal to the pelvic ganglion was partially blocked by hexamethonium. It is concluded that the urinary bladder of the rat is supplied by postganglionic adrenergic fibres mainlyviathe pelvic nerves and only to a lesser extentviathe hypogastric nerves. Probably cholinergic fibres pass to the bladder mainlyviathe pelvic nerves but alsoviathe hypogastric nerves, having their cellbodies outside the bladder wall, partly proximal to the pelvic ganglia.
Selective Localization of Histamine to Electron Densen Granules in Antigen‐Challenged Sensitized Rat Mast Cells and to Similar Granules Isolated from Sonicated Mast Cells: An Electron Microscope Autoradiographic Study
Authors: Anderson Per , Uvnäs Börje 
Published: December 2008

AbstractThe subcellular localization of histamine was studied in sensitized rat mast cells following antigen challenge and in granules obtained from sonicated cells, using an electron microscope autoradiographic technique. The mast cells were furnished with labelled histamine by incubation in3H‐histidine. The silver grain distribution (reflecting the localization of radioactive histamine) was highly non‐random. The highest silver grain densities occurred over homogeneous, electron dense (normal) granules and moderately electron dense granules. Swollen, less electron dense (“changed”) granules with a reticular appearance and devoid of a limiting membrane had the lowest density of all subcellular structures studied and were therefore probably almost free of histamine. There was a good correlation between the percentage of electron dense granules, the histamine content and the silver grain density in saline‐washed granule fractions isolated after sonication of mast cells for different times. These results support the hypothesis that histamine release occurs during the sequential exocytosis of storage granules, and during the sonication of mast cells, probably as a cation exchange between the amine, which is ionically bound to the heparin‐protein complex of the granule matrix, and cations from the extracellular fluid. The exchange will occur as soon as the perigranular membrane becomes permeable to water and cations.
Postnatal Ontogenetic Development of Neurogenic and Myogenic Control in the Rat Portal Vein
Authors: Ljung Bengt , (McMurphy) Dorothy Stage 
Published: December 2008

AbstractThe postnatal ontogenetic development of neuro‐effector control in vascular smooth muscle of the singleunit type has been studied in the rat portal vein. Contractile activity was recorded isometrically in isolated preparations from rats 2–38 days of age and in adults rats. Spontaneous activity, characteristic of the adult portal vein, appeared abruptly during the third postnatal week. Whereas, induced responses to noradrenaline (NA) and acetylcholine (Ach) appeared early during the first week and responses to transmural nerve stimulation occurred at the end of the first week. The appearance of spontaneous activity was accompanied by significant increases in sensitivity to NA (log Ed50) and to transmural nerve stimulation (frequency giving half maximum response), but not to Ach. Also, maximum responses for NA and nerve stimulation relative to Ach responses tended to increase during the first there weeks. It is concluded that the development of a mechanism supporting myogenic propagation as revealed by highly synchronized spontaneous contractions is an important factor for promoting the effectiveness of sympathico‐adrenergic control in this type of vascular smooth muscle.
Levels of Cyclic AMP and Electrical Events during Inhibition of Contractile Activity in Vascular Smooth Muscle
Authors: Ljung Bengt , Isaksson Olle , Johansson Börje 
Published: December 2008

AbstractThe possible relationship between changes in electrical and mechanical activity and in tissue levels of cyclic AMP (cAMP) during relaxation of the myogenically active rat portal vein has been elucidated in response to different inhibitory stimuli. Isoproterenol, 10‐5M, caused an initial pronounced inhibition of spike discharge and contractions followed by a partial recovery over the 15 min exposure period. This inhibitory response was associated with doubling of tissue cAMP after 1 min and a less pronounced increase in later measurements (5 and 15 min). Papaverine, 10‐4M, caused, in contrast, an inhibition of electrical and mechanical activity which developed gradually over the entire 15 min exposure period. The levels of cAMP at 1, 5 and 15 min all exceeded the corresponding values obtained with isoproterenol. The two drugs in combination gave a biphasic inhibitory response associated with a sustained large increase in the level of cAMP. These drug induced inhibitions were thus accompanied by increased levels of cAMP, but the different time courses of the electromechanical responses could not be related to corresponding variations in the content of cAMP. Hyperosmolality (+ 150 mM sucrose) and mechanical vibrations (100 Hz) elicited differentiated inhibitions of smooth muscle activity without changes in tissue cAMP. The mechanical effects elicited by isoproterenol, papaverine and hyperosmolality were accompanied by approximately parallel changes in electrical spike discharge. It is concluded that increased levels of cAMP are not indispensible for vascular smooth muscle relaxation, and that the magnitude of pharmacologically induced inhibitions are not always closely related to the total tissue content of the nucleotide.
Release of Gastrin and Vagal Stimulation in the Cat
Authors: Uvnäs B. , Uvnäs‐Wallensten K. , Nilsson G. 
Published: December 2008

AbstractGastrin released by electrical vagal stimulation was measured in the portal blood of eviscerated cats. Blood flow was recorded by a drop chamber technique and the total gastrin output calculated. Basal peripheral gastrin levels averaged 65 pg/ml and basal portal levels 225 pg/ml. On unilateral vagal stimulation with frequencies above 3–4 Hz gastrin release rapidly increased, reaching a peak within 5–10 min. In spite of continued stimulation and independent of frequency, the gastrin levels declined and returned to basal values after a total of 2–3 000 stimuli. A new maximal response could be induced first after a recovery period of 15–30 min. In the same cat stimulation of either the left or the right vagus released equal maximal amounts of gastrin (average 32 000 pg). The maximal gastrin output on vagal stimulation corresponds to less than 1% of the total content of antral gastrin determined with radioimmunoassay.
The Pressure‐Flow Relationship of Different Nephron Populations in the Rat
Authors: Kállskog Ö. , Lindbom L. O. , Ulfendahl H. R. , Wolgast M. 
Published: December 2008

AbstractThe mechanisms behind the autoregulation of the total renal blood flow and the glomerular filtration rate are unclear. In this investigation a modified microsphere technique was applied to measure the blood flow at different depths in the renal cortex during normotensive and hypotensive conditions. No autoregulation was found in the outer cortex while it was well pronounced in the inner one. During similar conditions, glomerular capillary pressure, welling point pressure and intratubular pressure were recorded. By combining these results with the blood flow data, the preglomerular and postglomerula resistances were calculated. It was then found that the preglomerular resistance decreased and the postglomerular resistance increased when the blood pressure was lowered. The results indicate a redistribution of blood flow from the outer parts to the inner parts of the cortex when the blood pressure is decreased. The redistribution of the blood flow might explain the well known linear relationship between the arterial pressure and the urine flow. The single nephron filtration rate of the outermost glomeruli could be calculated and the results seem to indicate a non‐equilibrium at the end of the glomerular capillaries.
Effect of Central Depressants on the Acoustic Middle Ear Reflex in Rabbit: A method for quantitative measurements of drug effect on the CNS
Authors: Borg E. , Møller A. R. 
Published: December 2008

AbstractThe respective effects of pentobarbital‐sodium, enibumal‐sodium, urethane, urethane‐chloralose and lidocaine on the function of the acoustic middle ear reflex in the rabbit were studied. The response of the middle ear muscles was measured by recording changes in both ears' acoustic impedance when the reflex was elicited by applying pure tone stimuli (2000 Hz) to the two ears one at a time. In that way both the crossed and the uncrossed reflexes were studied. All the drugs were found to depress the reflex in such a way that a higher sound intensity was required after administration to achieve the same impedance change as before. The effect of the anesthetics was roughly proportional to their known anesthetic power. Lidocaine produced only a slight depression of the reflex. The crossed reflex showed a greater susceptibility to the general anesthetics than did the uncrossed reflex which suggests a greater complexity of the crossed reflex. Because the method of recording the reflex response does not require any surgery and is equally well applicable in unrestrained rabbits and in humans, it is suggested as a way of testing the effect of drugs on the central nervous system.
Vasomotor Nerve Control of Isolated Arteries and Veins
Authors: Ljung Bengt , Bevan John A. , Pegram Barbara L. , Purdy Ralph E. , Su Mary 
Published: December 2008

AbstractIn order to compare neuro‐effector function in different blood vessels, frequency‐response relationships were determined for the following preparations: 1) Isolated rings of the proximal saphenous, distal saphenous and ear arteries, the parietal branch of the internal iliac vein and the small saphenous vein from the rabbit, 2) spiral strips of the rabbit pulmonary artery and 3) longitudinal preparations of the rat portal vein. In each rabbit tissue only one low (≤4 Hz) and one high (≥8 Hz) transmural nerve stimulation frequency was applied until steady state responses were obtained and these were expressed as a percentage of a maximum response to exogenous noradrenaline (NA) applied in each experiment. The general shape of the frequency‐response curves was similar, but differences in steepness and amplitude of the maximum neurogenic response relative to exogenous NA were found. The steepness of the frequency‐response relationships of the veins tended to be greater than those of the arteries. It appears that factors such as close neuro‐muscular contacts, presence of terminal nerve fibres within the media and the operation of mechanisms for myogenic propagation of activity contribute to the effectiveness of neurogenic vascular control as revealed by frequency‐response curves.In vivo,geometrical factors can greatly augment the hemodynamic significance of the observed differences.