bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of isoprenaline and cooling on histamine induced changes of capillary permeability in the rat hindquarter vascular bed
Authors: Rippe Bengt , Grega George J. 
Published: December 2008

AbstractHistamine infused intra‐arterially into artificially perfused, maximally dilated rat hindquarters markedly increased fluid filtration and CFC but had essentially no effect on the diffusion capacity to small molecules. Isoprenaline largely prevented the increase in fluid filtration and CFC if infused prior to the start of the histamine infusion and, if infused after the start of the histamine infusion, promptly reduced fluid filtration and CFC to near control levels. Additionally, it was noted that severe cooling of the perfusate also largely prevented the marked increase in fluid filtration and CFC by histamine. This antagonism of histamine induced increases in macromolecular permeability represents a direct action of isoprenaline on the microvascular membrane which effectively counteracts that of histamine. The data also suggest that the large pores created by histamine are different from the large pore through which macromolecules normally transverse the microvascular membrane, and that catecholamines may exert a regulatory function in the control of microvascular permeability to macromolecules in pathophysiological states associated with massive histamine release.
Antilipolytic effect of adenosine in isolated perifused fat cells
Authors: Hjemdahl Paul , Sollevi Alf 
Published: December 2008

AbstractAdenosine markedly inhibits cyclic AMP accumulation in isolated fat cells, whereas inhibitory effects of adenosine on lipolysis have been difficult to demonstrate. The present study has been performed on isolated “perifused” fat cells where continuous monitoring of the lipolytic rate is possible and where modulating substances, such as adenosine, are not allowed to accumulate. Adenosine deaminase was ineffective as a lipolytic agent in perifused fat cells, suggesting no important background activity of adenosine in this system. Micromolar concentrations of adenosine inhibited lipolysis induced by noradrenaline (0.3‐1 μM) and theophylline (1 mM). Theophylline was an effective lipolytic agent also in perifused fat cells suggesting that antagonism of adenosine is not the major mode of action of this drug on fat cells.
Bronchial and cardiovascular actions of prostaglandin endoperoxides and an endoperoxide analogue
Authors: Hedqvist Per , Strandberg Kjell , Hamberg Mats 
Published: December 2008

AbstractEffects of PGG2, PGH2 and the endoperoxide analogue, EPA, on bronchial and vascular smooth muscle were studied in vivo and in vitro. In the cat PGG2, PGH2 and particularly EPA proved potent stimulators of airway resistance, and they were all significantly more active than PGF2α. They also increased pulmonary vascular resistance but EPA alone was more active than PGF2α. In guinea pigs EPA was 90–190 times more active than PGF2α in increasing tracheal insufflation pressure. Human bronchi contracted in response to PGG2, PGH2 and EPA. PGG2 and PGH2 were equiactive with PGF2α and EPA was more than 500 times as potent. PGG2 and PGH2 lowered systemic arterial blood pressure and increased heart rate in cats. They were as active or more active than PGE2. EPA, on the other hand, resembled PGF2α in producing biphasic changes of blood pressure and heart rate or decrease of blood pressure and bradycardia in guinea pig and cat. The results obtained in this study indicate that PGG2, PGH2 and EPA are potent stimulators of bronchial and pulmonary vascular smooth muscle. The data are also consistent with the view that a significant proportion of effects resulting from prostaglandin generation in the lung is due to prostaglandin endoperoxides rather than primary prostaglandins.
The influence of supraspinal impulse activity on the intra‐axonal transport of acetylcholine, choline acetyltransferase and acetylcholinesterase in rat motor neurons
Authors: Dahlström Annica , Heiwall Per‐Olof , Bööj Serney , Dahllöf Ann‐Gret 
Published: December 2008

AbstractThe effect of supraspinal impulse activity upon the intra‐axonal transport of acetylcholine (ACh), AChesterase (AChE) and cholineacetyltransferase (CAT) in rat sciatic nerve has been studied. A decreased impulse activity was obtained by spinal cord transsection (SCT) in the thoracic region 18 h, 6 days or 20 days before killing the rats. An increased neuronal activity was obtained by exercising the rats in a commercial rodent treadmill a couple of hours per day for 14 days. The amounts of substances which had accumulated in the sciatic nerve segments relative to a nerve crush performed 12 or 18 h. earlier were used to calculate the intra‐axonal transport. The amounts of proximo‐distally transported ACh decreased markedly with time after the SCT, while the proximo‐distal transport of AChE‐activity increased. Physical exercise appeared to increase ACh‐transport. Thus, input to motor pericarya from supraspinal centres may regulate intra‐axonal transport from the cell body of motor neurons into their axons.
Effect of intralobular substitution of Na+ and Cl‐ ions on the operation of the tubuloglomerular feedback
Authors: Müller‐Suur R. , Gutsche H.‐U. 
Published: December 2008

AbstractHenle's loops of surface nephrons in rat kidneys were perfused orthogradely with various solutions of different compositions, while the stop‐flow pressure (SFP) was monitored in the early proximal tubulus as a measure of the tubuloglomerular feedback response. Modified Ringer solution or iso‐osmotic solutions of NaCl, KC1, LiCl, RbCl, choline‐Cl, and Na‐acetate used to perfuse Henle's loop led to significant SFP decrease indicating an intact operation of a tubuloglomerular feedback mechanism. Increased rates with isoosmotic solutions of sodium sulphate, potassium sulphate and mannitol did not yield SFP alterations. In order to estimate intratubular sodium and chloride concentration at the macula densa during Ringer‐, LiCl‐, choline‐Cl‐, and Na‐acetate perfusion, early distal tubular fluids were collected at low and high perfusion rates, corresponding to an absent or a maximal feedback response. Analysis was performed by microflame photometry and microchloride titration. The results showed that there does not exist a common threshold for the early distal sodium or chloride concentration at which the feedback starts to operate. We conclude that the intraluminal signal at the macula densa, initiating a tubuloglomerular feedback response is not necessarily coupled to a single ion species. Either an unspecific ion transfer or more passive events of ionic interaction with the macula densa cells might operate as the initiating step in the feedback loop.
Localization of kallikrein and its relation to other trypsin‐like esterases in the rat pancreas. A comparison with the submandibular gland
Authors: ØRstavik Torill B. , Glenner G. G. 
Published: December 2008

AbstractKallikrein was located by the direct immunofluorescence technique to the granule‐containing luminal portion of pancreatic acinar cells. For the demonstration of the intracellular distribution of pancreas kallikrein, in vivo fixation of the gland was necessary. No kallikrein was found in the duct cells or in the islets of Langerhans. Quantitation by single radial immunodiffusion showed that the concentration of kallikrein in the pancreas was 132 ± 51 μg/g wet weight, i.e. 1/91 that of the rat submandibular gland. Bz‐Arg‐OEt‐esterases were in |the pancreas found as pro‐enzyme but as active enzyme in the submandibular gland. Trypsin‐like esterases, hydrolyzing σ‐amino caproic acid naphtol‐AS‐D‐ HBr (ACA), were found in the active form in both submandibular gland and pancreatic homogenates. The submandibular gland contained per g wet weight 6 times as much ACA‐esterase activity as the pancreas. In the submandibular gland, kallikrein and ACA‐esterase activity were found together in practically all granular tubular cells. Thus, the granular tubular cell contains kallikrein as well as other trypsin‐like enzymes like the ACA‐esterase, and is in this way comparable to the pancreatic acinar cell. An extraglandular function of kallikrein is suggested for the pancreas in contrast to other kallikrein‐containing exocrine organs.
Muscle fatigue and its relation to lactate accumulation and LDH activity in man
Authors: Tesch Per , Sjödin Bertil , Thorstensson Alf , Karlsson Jan 
Published: December 2008

AbstractThe lactate concentration in different muscle fibre types was determined in biopsy specimens from human vastus lateralis muscle after 30 and 60 s of maximal dynamic leg exercise. In addition, muscle fibre type distribution, total lactate dehydrogenase (LDH) activity, and isozymes of LDH were determined. In accordance with previous studies (Thorstensson and Karlsson 1976, Nilsson et al. 1977) it was found that an increasing proportion of slow twitch (ST) fibres corresponded to better sustained muscle force. Lactate was found preferentially in fast twitch (FT) fibres after 30 s, but after 60 s this difference was abolished. Differences between the two main muscle fibre types in muscle lactate, total LDH activity, and M‐LDH activity were correlated to muscle fatigue. It was concluded that lactate or associated pH changes primarily in FT fibres could be one factor responsible for the impaired muscle function.
Observations on stretch reflexes in lumbar back muscles of the cat
Authors: Carlson Hans 
Published: December 2008

AbstractReflex responses to brief muscle stretch and to electrical stimulation of dorsal roots were studied in cat longissimus and iliocostalis muscles by myographic and electromyographic recordings in spinal and anesthetized preparations. Brief stretch applied simultaneously to both muscles, by pulling at an isolated segment of the iliac bone, elicited contractions only in the central region of longissimus, composed of slowly contracting fibers, the time to peak tension varying between 70 and 100 ms. No reflex responses were observed in the faster contracting parts of this muscle or in the iliocostalis under the stimulation conditions used. The total reflex time usually varied from 4.5 to 7 ms which is shown to correspond to intraspinal conduction times, approximately between 2 and 5 ms. Only exceptionally was a central reflex delay corresponding to a monosynaptic transmission observed. Reflexes evoked by dorsal root stimulation (L4, L5) have a central conduction time similar to those elicited by adequate stimulation. The possibility that the central pathway for stretch reflexes in longissimus may involve more than two neurons is considered. In decerebrate preparations the central region of longissimus displays a prominent tonic stretch reflex. With the longissimus in situ the magnitude of the reflex is highly dependent on the position of the lumbar spine relative to the pelvic girdle.
Contralateral influence on recruitment of curarized muscle fibres during maximal voluntary extension of the legs
Authors: Secher Niels H. , Rørsgaard Susanne , Secher Ole 
Published: December 2008

AbstractThe force of maximal voluntary contraction (MVC) was compared during extension of one leg alone and during simultaneous extension of both legs. In 6 subjects MVC of two leg extension was 75 + 3.6 (S.E.) % of the sum of the single one leg MVC. This may indicate a reduced muscle fibre involvement during two leg extension as compared with one leg extension. We investigated the possibility that either red (type I) or white (type II) muscle fibre recruitment was restricted during two leg extension. The neuromuscular transmission in the two types of fibres was partially blocked with d‐tubocurarine (dtc) or decamethonium (C10) for either type 1 or II, respectively. In 5 subjects receiving dtc the ratio between the reduced two leg and one leg extension forces (75 ± 2.3%) did not change. During administration of C10, however, this ratio decreased by 16 ± 3.1 %. Partial blocking with dtc caused a two component curve during tension development with a first maximum at 0.22 s, and another maximum at 1.03 s of a 3 s attempt to reach MVC. During partial blocking with C10 the first maximum disappeared indicating human fast twitch fibres to be blocked by C10. Thus, partial blocking with C10 results in muscle contractions where a relatively large amount of type I muscle fibres are contributing to the force developed. The experiment suggests that type I fibre recruitment is restricted during severe static exercise in normal muscles. Furthermore, it demonstrates that fibre recruitment can vary in the same muscle function performed with one leg or two legs.
Ultrastructural evidence for an innervation of epithelial enterochromaffine cells in the guinea pig duodenum
Authors: Lundberg Jan M. , Dahlström Annica , Bylock Anders , Ahlman Håkan , Pettersson Gösta , Larsson Inger , Hansson Hans‐Arne , Kewenter Jan 
Published: December 2008

AbstractThe innervation of the duodenal enterochromaffine cells (E.C.) of the guinea pig was studied at the electronmicroscopic level. Pretreatment with 5‐OH‐dopamine was performed to visualize catecholaminergic (CA) nervous elements. Near the basement membrane of all examined E.C. in the crypts, bundles of unmyelinated nerve processes were observed, only partly ensheathed in a Schwann cell cover. At least 4 types of processes could be observed. 1) Boutons containing only small clear vesicles, probably cholinergic fibres; 2) boutons with small clear vesicles, and in addition large (200 nm) granules with a dense matrix (P‐type‐fibres); 3) boutons with small electron‐dense vesicles, probably CA‐fibres; and 4) processes with few vesicles but having the appearance of dendrites. No typical synaptic arrangements were observed, but the minimal distance between the E.C. and the nerve bundles was 150 to 250 nm, thus well within the functional limits of the “autonomic gap”. Thus, epithelial E.C. may be influenced by several types of nervous elements, including CA‐fibres.
Nervous control of blood flow in the dental pulp in dogs
Authors: Heyeraas Tønder K. , Næss G. 
Published: December 2008

AbstractPulpal blood flow (PBF) was measured by H2‐gas clearance in 30 dogs during electrical nerve stimulation, denervation and close intraarterial infusion of noradrenaline (NA). Electrical stimulation of the cervical sympathetic nerve and NA infusion always resulted in decreased PBF. The constrictor effect was reduced by α‐blockers, but was never abolished or reversed to a vasodilation. Thus, no evidence for β‐receptors in the dental pulp blood vessels was found. The fall in PBF produced by cervical sympathetic stimulation could be prevented by cutting the inferior alveolar nerve in the mandibular canal. Stimulation of the cut inferior alveolar nerve in the mandibular canal produced variable pulpal flow changes: Both a marked increase and decrease were measured. The flow changes during inferior nerve stimulation were unaffected by α‐receptor blockade, while atropine reduced the vasoconstrictor respons or augmented the dilatory response. Electrical stimulation of the mandibular nerve before its entrance in the canal caused vasodilation, proposing a sensory antidromic axonreflex in the dental pulp. Sympathetic denervation had little or no effect on PBF, while cutting of the inferior alveolar nerve in the canal increased PBF in lower canine from 0.159 to 0.219 ml/min. g. The experiments show that pulp blood vessels of the dog may be controlled by both vasodilator and vasoconstrictor nerve fibers.
Frequency selectivity of the peripheral auditory analyzer studied using broad band noise
Authors: Møller Aage R. 
Published: December 2008

AbstractThe sharpness of the frequency tuning of single auditory nerve fibers was studied in the rat on the basis of responses to broad band noise. The cross‐spectra between the sound stimulus and the sound‐to‐stimulus locked discharge rate were used as estimates of the transfer functions of the peripheral auditory analyzer. The sharpness of the tuning obtained in that way was measured as Q3db and Q10db It was found that these Q‐values decreased with increasing stimulus intensity but that the decrease was different when it was based on measurements at 3 dB points of the obtained transfer functions compared with measuring it at 10 dB points. The change in width was less for fibers with low CF. In all the fibers studied the frequency of maximal response (CF) decreased with increasing sound intensity. The implication of these findings for pitch perception and for noise induced hearing loss is discussed.
The relationship between cortical recruiting responses and ponto‐geniculo‐occipital waves during paradoxical sleep in the cat
Authors: Laihinen A. , Valleala P. 
Published: December 2008

AbstractIn an earlier study it was found that during paradoxical sleep (PS) thalamo‐cortical recruiting responses (RRs) and rapid eye movements usually did not appear simultaneously. As shown elsewhere, ponto‐geniculo‐occipital (PGO) wave activity and rapid eye movements are during PS closely related to each other in time. Similarly, in the present study it was observed that during paradoxical sleep in cats in which the center median nucleus of the thalamus was being stimulated at a rate of 7–9 Hz PGO waves in the geniculate nuclei did not in the rule occur in the presence of RRs recorded from the motor cortex. This effect was most pronounced with respect to series of PGO waves which usually occur at a rate of 4–7 Hz. On the basis of these experiments it was concluded that PGO waves and RRs are reciprocal events and mutually exclusive. Considering the well‐known fact that RRs represent synchronization. this negative correlation between RRs and PGO waves indicates that the desynchronizing tendency typical to paradoxical sleep is most pronounced during the occurrence of PGO waves.
The influence of scrotal warming on testicular blood flow and endocrine function in the rat
Authors: Damber Jan‐Erik , Janson Per Olof 
Published: December 2008

AbstractThe effects of local heating on testicular and epididymal vascular resistance in sodium pentobarbitone anesthetized rats was measured with a microsphere technique. When exposing the left scrotum to 33 and 37°C for 30 min. no significant effects on blood flows were observed in comparison to those of the right side. Exposure to 41°C caused a significant (p<0.05) decrease in vascular resistance of both testes and epididymides. The response was more pronounced at 4°3. The Leydig cell function, as judged from the testosterone concentrations in plasma and testicular tissue after LH stimulation, was significantly (p<0.01) depressed at 41 and 43°C. It was concluded that the impaired Leydig cell function was unrelated to testicular blood flow.
Studies on calcium uptake by myornetrial microsomes with particular reference to the dependence on inorganic phosphate and oxalate
Authors: Batra S. 
Published: December 2008

AbstractCa uptake by microsomes isolated from non‐pregnant rabbit myometrium was potentiated by both inorganic phosphate (Pi) and oxalate anions. Both Piand oxalate bad little effect on the initial rate of uptake but a pronounced effect on the capacity of Ca uptake measured after 20 min which was greater in the presence of oxalate than that of Pi (5 mM each). The presence or absence of sucrose in the uptake medium had a significant effect on oxalate‐induced potentiation of Ca uptake but not on that potentiated by Pi or that measured in the absence of either potentiating anion. A part of Ca accumulated additionally under the influence of sucrose could be removed by washing microsomes with KCI.Another significant difference between the pontentiating effect of oxalate and Pi was observed when the pH of the incubation medium was varied. In the presence of oxalate the pH optimum was between 6.46.8, whereas that in its absence or in the presence of Pi the optimal pH was around 7.2. Reduction in pH from 7.2 to 6.8 along with the substitution of KCI by sucrose resulted in 3‐fold increase in Ca uptake when oxalate was used as the potentiating anion. The results suggest that Ca is taken up by a different mechanism in the presence of oxalate than that in its absence or when oxalate anion is substituted with inorganic phosphate.
Oxidative and lysosomal capacity in skeletal muscle of mice after endurance training of different intensities
Authors: VIHKO VEIKKO , SALMINEN ANTERO , RANTAMAKI JARI 
Published: December 2008

AbstractThe activity of certain enzymes of energy metabolism (cytochrome c oxidase, citrate synthase, malate dehydrogenase, and lactate dehydrogenase) and of lysosomes (β‐glucuronidase, β‐N‐acetylglucosaminidase, arylsuphatase, ribonuclease, deoxyribonuclease, acid phosphatase, and cathepsin D) was assayed from m. rectus femoris of mice trained 5 days per week, 1 h per day for 4 weeks according to 4 different programmes: I. running speed 20 m/min, horizontal track, II. 25 m/min, horizontal track, III. 20 m/min 8° uphill inclination, and IV. 25 m/min 8° uphill inclination. Oxidative capacity increased and anaerobic capacity decreased without distinction between the different training programmes. Of acid hydrolases assayed the activities of β‐glucuronidase and cathepsin D were increased independently of training intensity. Simultaneous histochemical observations on β‐glucuronidase and arylsulphatase activities in the contralateral m. rectus femoris showed more intense staining in red as compared to white muscle fibres. It is suggested that training affected the red fibres and that the applied level of loading was probably too low to cause major involvement of white fibres.
Redox state ol the cellular free NAD pools, phosphorylation state of the adenylate system and the (Na+‐K+)‐stimulated ATP‐ase in rat liver
Authors: Kinnula Vuokko L. , Hassinen Ilmo 
Published: December 2008

AbstractThe effect of hypoxia (30 min 10% or 8%, O2,) on the phosphorylation state and redox state of the cytosol and mitochondria of rat liver were studied. Measurements were made both from normal animals and animals which had been exposed to the reduced partial pressure of oxygen (50.5 kPa or 40.8 kPa of air) for one or seven days. Cytosolic free NAD was reduced in the liver both in acute hypoxia and in hypoxia after one or seven days,i.e. the lactate/pyruvate and sn‐glycerol‐3‐phosphate/dioxyacetonephosphate ratios increased markedly. A marked reduction in the mitochondrial free NAD pool occurred only in acute hypoxia and only a slight reduction was observed in animals kept at 40.8 kPa for one or seven days, as evaluated from the hepatic hydroxybutyrate/acetoacetate ratio. Liver ATP concentration decreased rapidly in acute hypoxia without any significant recovery during one or seven days at 40.8 kPa. The hepatic ATP/ADP× Piratio decreased significantly, with a simultaneous decrease in the total adenine nucleotide concentration. A tendency was observed for the ATP/ADP× Piratio to return to normal after seven days,i.e. the values in acute hypoxia were significantly smaller than those noted in hypoxia after seven days, demonstrating an adaptation of the energy metabolism during prolonged hypoxia. Hepatic (Na+‐K+)‐stimulated ATP‐ase activity was not affected by hypoxia.