bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dose‐dependent inhibition of sensory nerve activity in the feline dental pulp by anti‐inflammatory drugs
Authors: Ahlberg Karin Forssell 
Published: December 2008

AbstractThe aim of the present study was to investigate whether substances known to antagonize algogenic agents can block an experimentally induced increased sensory nerve activity in the dental pulp of the cat. Increased neural activity following repeated brief heat stimulation has been shown to be characteristic of the individual cat and can be utilized for intraindividual comparative studies on such increased activity. When indomethacin, diclofenac sodium or naproxen were given intravenously as a pretreatment prior to stimulation, a consistent blocking effect on expected impulse activity as compared to the impulse activity in the control teeth was produced. Indomethacin produced a dose‐dependent inhibition (ID500.04–0.2 mg/kg). Diclofenac sodium (5 mg/kg) inhibited nerve activity by 51–91% and naproxen (15 mg/kg) by 92–95%. Methysergide (0.02–0.08 mg/kg) did not show such blocking effect. When the drugs were administered during a state of established increased neural activity no effect on the current impulse activity was obtained. The present results suggest that prostaglandins may be involved in certain stages of heat induced pulp inflammation and act as mediators of increased intradental sensory nerve excitability.
Fluid transfer from skeletal muscle to blood during hemorrhage Importance of beta adrenergic vascular mechanisms
Authors: Lundvall Jan , Hillman Jahn 
Published: December 2008

AbstractVascular reactions in the cat lower leg muscles in response to short‐term (10 min) hemorrhagic hypotension (˜80 mmHg) were studied before and after regional blockade of the β‐adrenoceptors. In the muscle region with intact β‐adrenoceptors, hemorrhage raised vascular resistance by about 80% and caused a dilatation of the precapillary sphincters, the latter effect evidenced in terms of a 35% increase of the capillary filtration coefficient. Concomitantly, an absorption of extravascular fluid to the blood stream occurred, a process tending to compensate for the reduction of intravascular fluid volume. After regional β‐blockade there was quite a marked augmentation of the hemorrhage induced increase of vascular resistance whereas the inhibition of precapillary sphincter tone and the transcapillary fluid absorption were almost abolished. These observations indicate that bleeding is associated with a significant β‐adrenergic dilator influence in both the resistance vessels and precapillary sphincters of skeletal muscle and that the β‐dilator mechanism may be essential for the important, compensatory fluid gain from the extravascular to the intravascular space during hemorrhage. The observed β‐adrenergic mediation of the net transcapillary fluid absorption could be ascribed to resetting of the pre‐/postcapillary resistance ratio, leading to decreased capillary hydrostatic pressure, and to the dilator influence in the precapillary sphincters, leading to an increased number of the patent capillaries available for the transcapillary fluid exchange.
Comparison of β‐adrenoceptors mediating vasodilatation in canine subcutaneous adipose tissue and skeletal muscle
Authors: Belfrage Erik 
Published: December 2008

AbstractBlood flow changes in response to various drugs in simultaneously autoperfused canine subcutaneous adipose tissue and gracilis muscle were compared to study the vascular β‐adrenoceptors. Compared to isoprenaline the β2‐selective agonist salbutamol was 4–6 times more potent as a vasodilator in the muscle than in adipose tissue. Furthermore two β1‐selective agonists (Tazolol and H80/62) caused vasodilatation in adipose tissue but not in the gracilis muscle. When given by close i.a. injection after β‐adrenoceptor blockade, adrenaline was a more potent vasoconstrictor than noradrenaline in both tissues. Before β‐blockade, however, noradrenaline was the more potent vasoconstrictor in the gracilis muscle whereas adrenaline was more potent in adipose tissue. Intravenous infusion of adrenaline in doses causing vasodilatation in the muscle caused vasoconstriction in adipose tissue whereas intravenous infusion of noradrenaline caused vasoconstriction in both tissues. The present findings suggest that the β‐adrenoceptors mediating vasodilatation in skeletal muscle are mainly of the β2‐type, whereas β1‐adrenoceptors seem to predominate in subcutaneous adipose tissue. Since adrenaline is a much more potent β2‐ than β1‐agonist, these differences point to different roles of intravascular adrenaline in the two sites. In skeletal muscle circulating adrenaline is mainly a vasodilator whereas in subcutaneous adipose tissue it mainly acts as a vasoconstrictor.
The in vivo transport of 14C‐α‐aminoisobuturic acid into mouse blastocysts during activation for implantation
Authors: Lindqvist Inger , Einarsson Barbro , Nilsson Ove , Ronquist Gunnar 
Published: December 2008

AbstractThe in vivo transport of 14C‐AIB (14C‐α‐aminoisobuturic acid) into mouse blastocysts was studied during activation for implantation. Mice, kept in experimentally delayed implantation, were given estrogen to induce implantation and then injections of 14C‐AIB i.v. at 0, 4 and 8 h after the estrogen. After in vivo incubation times for 1/3 or 4 h with the labeled amino acid the blastocysts were flushed out of the uterus and collected. A distinct uptake of 14C‐AIB occurred in the blastocysts 8 h (the highest uptake) and 12 h after the induction, provided that the in vivo incubation time was 4 h. At these times the blastocysts are lying free in the uterine lumen and consequently there is a transport of 14C‐AIB from the epithelium via the uterine secretion into the blastocysts. This uptake indicates that amino acids transported by the system A are important nutrients during early activation. The uptake and retention of 14C‐AIB in the uterus was tested at 4 and 8 h after the induction of implantation. The highest uptake was observed when the labeled amino acid was given at 8 h while the longest retention time occured when 14C‐AIB was given at 4 h. Since the transport ratio between the blastocysts and the uterine tissue is not maintained constant it is concluded that the metabolic rates for 14C‐AIB transport are different for the uterus and the blastocysts. The AIB transport into uterine tissue proceeds that into the blastocysts. The AIB transport into the blastocysts is maintained as long as they have a negative surface charge.
Capillary supply of the muscle fibre population in hindlimb muscles of the cat
Authors: Myrhage Rhagnar 
Published: December 2008

AbstractComparative analyses of the fibre content (FG, FOG, and SO fibres) and the capillary density (the number of capillaries surrounding individual fibres and the capillary/fibre ratio) were performed in hind limb muscles of the cat. Cross‐sections from the tenuissimus, the biceps femoris, the lateral head (LG) and the medial head (MG) of the gastrocnemius and the soleus were cut in a cryostat. The sections were stained histochemically for the NADH2‐diaphorase and alkaline (pH 9.4) actomyosin ATPase activity, which enables differentiation of different types of fibres. The endothelium of the capillaries was identified via staining for unspecific alkaline ATPase activity. The number of capillaries surrounding each individual muscle fibre had a positive correlation, first to the oxidative capacity and secondly to the average diameter of the fibres. The thin tenuissimus muscle did not differ in this respect from the thicker muscles. The highest proportion of SO fibres was found in the soleus and the MG muscles. FG fibres of two different types were dominating the fibre mass in the biceps femoris and the LG muscles, while the tenuissimus contained more FOG fibres than these muscles. In general the FG fibres had a larger diameter than the FOG and the SO fibres. The soleus and the MG muscles contained larger fibres than the other examined muscles. FG fibres were surrounded by fewer capillaries than FOG and SO fibres. The soleus and the MG muscles, with a higher percentage of SO fibres and also larger fibres, had the largest number of capillaries around the fibres and the highest capillary/fibre ratio.
Influence of local noxious heat stimulation on sensory nerve activity in the feline dental pulp
Authors: Ahlberg Karin Forssell 
Published: December 2008

AbstractThe present investigation was undertaken to develop an experimental model in which noxious heat stimulation was used to produce increased intradental sensory nerve activity in canine teeth of anesthetized cats. Two techniques were evaluated in which both the method of recording and the nature of the stimulus varied. Slow heating (approx 1 °C/s) to 47°C of the tooth surface (combined with recording from electrodes in open dentinal cavities) did not produce any persistent nerve activity. Repeated periods of brief intense heating (approx 60°C/s) (combined with recording from amalgam electrodes placed on cavity floors) resulted in an immediate response and an afterdischarge (phase 3) generally persisting for 20–60 min. Maximum phase 3 activity was characteristic for the individual cat and ranged from 0.2 to 50.2 imp/s, mean value 10.6 imp/s (S.D. + 9.2). A systematically higher phase 3 activity was recorded in lower compared to upper canine teeth (p < 0.05). The maximum phase 3 response generally occurred after 3–8 stimulations; the median number of required stimuli was 3. Repeated brief heat stimulations combined with the closed cavity recording technique may be used as an experimental model by which the mechanisms behind increases in intradental sensory nerve activity associated with tissue damage can be studied.
The influence of dietary sodium on urinary prostaglandin excretion
Authors: Davila D. , Davila T. , Oliw E. , Anggard E. 
Published: December 2008

AbstractThe influence of dietary sodium chloride on the urinary excretion of prostaglandins (PGs) was studied in unanesthetized female rabbits housed in metabolic cages. Urinary PG levels were determined by radioimmunoassay. bioassay and gas chromatography‐mass spectrometry. In the first experiment rabbits were fed at high (2.5%) and later a low (0.25%) sodium chloride diet ad libitum. A 2–5 fold increase in excretion of immunoreactive PGF2α (iPGF α) and iPGE2 was noticed when animals were given the low salt diet. Since it could not be excluded that dietary factors other than sodium chloride contributed to the changes a second, more controlled, experiment was undertaken. Rabbits were fed 30 g/kg per day of diets differing only in the content of sodium chloride, 2 % and 0.37 % respectively. On the high salt diet the rabbits excreted 0.1 ± 0.04 μg/day of PGE, and 2.0 ± 0.5μg/day of iPGF‐2α. After equilibration on the low salt diet the PGE2 excretion rate increased to 1.5 ± 0.3 μg/day (p < 0.001) and that of iPGF2α to 3.4 + 0.4 μg/day (p < 0.01). These results thus point to an inverse relationship between renal sodium excretion and the activity of the renal prostaglandin system.
The postnatal development of the inferior oblique muscle of the cat: II. Effects of repetitive stimulation on isometric tension responses
Authors: Lennerstrand By Gunnar , Hanson Jerker 
Published: December 2008

AbstractThe changes with postnatal age in post‐tetanic potentiation (PTP) and fatigue of the inferior oblique muscle have been studied in the cat. PTP of the twitch amplitude increased steadily with age up to 20 weeks after birth. Twitch contraction time (ct) and half relaxation time (hrt) was not significantly changed. The potentiation of the tetanic response also became more prominent with age. The young muscles (10 weeks and below) were slightly more susceptible to fatigue than older muscles, but recovery was rapid in muscles of ail ages. Intensive stimulation induced post‐tetanic depression of twitch responses in muscles older than 1 week, but none in the muscles of new‐born cats. Ct and hrt were greatly prolonged in muscles above six weeks of age. In these muscles, but never in the very youngest, repetitive firing could be observed in response to post‐tetanic single nerve stimulation. The results are compared with those obtained in similar experiments on hind‐limb muscles by other workers. They further support the idea, raised in a previous paper, that slow eye muscle fibres develop quicker and reach maturity earlier than fast fibres.
Binding of thiamine to nicotinic acetylcholine receptor in Torpedo marmorata and the frog end plate
Authors: Waldenlind Lennart , Elfman Lena , Rydqvist Bo 
Published: December 2008

AbstractThiamine was found to bind to the isolated nicotinic receptor (nAChR) from Torpedo marmorata (KD ‐ 3 ‐5 10‐5 M). The binding was reversible and inhibited by α‐neurotoxin from Naja naja siamensis. Acetylcholine binding was not inhibited by thiamine. When thiamine (5 × 10‐4 M) was applied to frog sartorius muscles a decrease of miniature end plate potential amplitudes was seen. This effect was readily reversible after the perfusion fluid of the muscle was changed to normal Ringer solution. Thus both biological and electrophysiological studies indicated a binding of thiamine to the nAChR.
Pharmacological properties of curare‐sensitive receptors mediating post‐tetanic potentiation in rat masseter muscle
Authors: Waldenlind Lennart 
Published: December 2008

AbstractPost‐tetanic potentiation (PTP) of single muscle twitches after “tetanic” stimulation at 1 to 20 Hz in rat masseter muscle has been studied. PTP was inhibited by d‐tubocurarine (2–6 μg/kg), hexamethonium (1.75‐2.25 mg/kg), succinylcholine(5–7μg/kg), prostigmin (1.0–1.5μg/kg), lidocain (3–4 mg/kg) and ouabain (215–240 μg/kg). The doses did not affect the control twitches. Prostigmin could not reverse the blocking effect on the PTP caused by these drugs. Atropin was without any effect on the PTP. The nicotinic receptors mediating PTP differ from both end‐plate and ganglionic receptors since drugs blocking both types of receptors are effective. The sensitivity to the blocking agents is higher or the same (in the case of hexamethonium) as for the two other types of nicotinic receptors. Thus the PTP is dependent on activity of a “nicotinic” receptor active during physiological conditions, suggesting the presence of an additional mechanism for neuromuscular transmission in rat twitch fibres.
Rabbit lung plasma and erythrocyte volumes. Lung hematocrit in relation to total body hematocrit
Authors: Aarseth P. , Waaler B. A. , Nicolaysen G. 
Published: December 2008

AbstractThe total body hematocrit has been reported to be 85–90% of packed cell volume (PCV) in several species. We have found similar values in rabbits. An “extra” plasma volume must exist somewhere in the vascular bed to explain this observation. We have looked for such an extra plasma volume in the pulmonary vasculature. The dynamic hematocrit was estimated in isolated, perfused rabbit lungs from distribution volumes for plasma and erythrocyte tracers. Estimation was also obtained from indicator‐dilution curves using bolus‐injections of such tracers avoiding their recirculation. It was thus possible to calculate mean transit times for the tracers from their dilution curves directly or applying monoexponential extrapolation from the first part of the downslope of the curves. The dynamic hematocrit of the lung vessels was about 94% of perfusate PCV and there was no difference between the results obtained by the different methods. We concluded that in the rabbit only a very small part of the extra plasma volume is located in the lung vessels. The lung plasma volume is not underestimated by the indicator‐dilution technique.
Histochemical fiber composition of lumbar back muscles in the cat
Authors: Carlson Hans 
Published: December 2008

AbstractA histochemical analysis has been performed of the activity of myofibrillar ATPase, NADH2tetrazolium‐reductase, succinic dehydrogenase and phosphorylase and of the content of fat and glycogen in the muscles of the cat's lumbar back region. The correlation between the fiber composition and the previously studied contraction properties of the muscles was analyzed. All muscles contain fibers with a low activity (type I) and such with a high activity (type II) of myofibrillar ATPase following preincubation at pH 9.4. Type II fibers showed either a low (type II A) or an intermediate (type II B) reaction when stained for ATPase, preincubation at pH 4.6. Type 1 fibers have a high, II A an intermediate‐high and II B fibers a low activity of oxidative enzymes. The longissimus, iliocostalis and sacrocaudalis dorsalis lateralis muscles are characterized by high percentages of type II B fibers and low proportions of type I and type II A fibers. The central region of the longissimus which is connected to a well developed intermuscular septum is composed of a high proportion of type I fibers. The multifidi, interspinales and intertransversarii mediales muscles have higher proportions of type I and type II A fibers than the other muscles in the region.
The release of serotonin from rat duodenal enterochromaffin cells by adrenoceptor agonists studied in vitro
Authors: Pettersson Gösta , Dahlström Annica , Larsson Inger , Lundberg Jan M. , Ahlman Häkan , Kewenter Jan 
Published: December 2008

AbstractThe serotonin (5‐HT) content of enterochromaffin cells (EC) was studied by a cytofluorimetric method in biopsies from rat duodenal mucosa after in vitro incubation with different adrenoceptor agonists and antagonists and acetylcholine (ACh). Noradrenaline (NA), Adrenaline (A) and Isoprenaline (IP) caused a decrease of 5‐HT in EC down to 40–60% and for NA and A this effect was concentration‐dependent. The effect was antagonized by d,1‐propranolol but not by d‐propranolol, metoprolol, phentolamine or phenoxy‐benzamine indicating that the 5‐HT release from EC is probably mediated via a true β‐adrenoceptor mechanism possibly of the β2 type. ACh also decreased the 5‐HT content of EC but was much less potent than the adrenergic substances. Dopamine (DA) had no effect.
Aspects of temperature regulation in harp seal pups evaluated by in vivo experiments and computer simulations
Authors: ØRitsland Nils A. , Ronald Keith 
Published: December 2008

AbstractTemperature regulation in harp seal pups (Pagophilus groenlandicus) has been studied by in vivo measurements of oxygen consumption, body temperatures and in vitro determinations of the thermal values of a fur sample. The experimental animals were restrained and exposed to natural weather conditions. Solar irradiance above 600 W/m (global radiation) caused hyperthermia. Computer simulations based on the thermal values of the fur indicated that heat dissipation from primarily the limbs is a prerequisite for avoiding hyperthermia under natural weather conditions. Further simulations showed that the lower critical temperature of a lean newborn harp seal pup with standard metabolism is only – 1oC while it is depressed to –59oC as the pup grows, aquire a 10 cm thick layer of blubber and the metabolism increases to 1.5 times standard. High metabolism and tolerance to low deep body temperatures (35oC) seems a prerequisite for thermal balance in the harp seal pup under cold conditions.
Intra‐abdominal pressure changes during natural movements in man
Authors: Grillner Sten , Nilsson Johnny , Thorstensson Alf 
Published: December 2008

AbstractThe weight of the upper part of the trunk is partially transmitted to the pelvis via the vertebral column. If the muscle walls around the abdominal cavity are contracted, a high pressure can be generated within the cavity (>200 mmHg). The abdominal space can then transmit part of the weight to, e.g., the upper part of the body. Intra‐abdominal pressure recordings have been performed during locomotion and other natural movements with intragastric pressure recordings. With each step, there is a phasic variation in pressure, with its peak coinciding with that of the peak vertical force exerted by the leg against the ground. The peak values increase progressively with the speed of walking/running up to a mean of 38 mmHg and with trough values of 16 mmHg. The phasic variations with each step is due to a phasic activation of the abdominal muscles, with an EMG activity starting 50 ms or more before foot contact. If an extra load is put on the back, the posture changes and at the highest speed of running the pressure values are significantly higher than without this additional load. After a jump down from a moderate height of 0.4 m, the average increase is 89 mmHg and can often exceed 100 mmHg. These pressure changes are large and will presumably act to unload the spine under the prevailing biomechanical conditions and, in addition, there will no doubt be an effect on the circulatory system.
Phosphoryl group transfer from Ehrlich cells prelabeled in vivo with (32P)‐orthophosphate and (14C)‐glucose to unlabeled glioma cells
Authors: ÅGren Gunnar , Ronquist Gunnar 
Published: December 2008

AbstractA transfer of (32P)‐labeled phosphoryl groups has been demonstrated to occur between prelabeled Ehrlich cells (donor cells) and glioma cells (acceptor cells). The Ehrlich cells were generally prelabeled in vivo by an intraabdominal injection of (32P)‐orthophosphate 24 hours prior to scarifice of the tumor‐bearing mice. In some experiments two injections of (14C)‐glucose were given to the animals in addition to the injection of (32P)‐orthophosphate prior to sacrifice. The prelabeled Ehrlich cells were mixed with the glioma cells, that were still attached to the culture plates, and incubation took place in vitro. Labeled (32P)‐phosphoryl (14C)‐serine was isolated from the glioma cells as well as from the Ehrlich cells. The 32P/14C‐ratio of (32P)‐phosphoryl (14C)‐serine of the glioma cells (acceptor cells) was significantly higher than found for the Ehrlich cells (donor cells). This was indicative of an interactive mechanism between the cells partly due to binding of membrane fragments from the Ehrlich cells on to the surface of the glioma cells and partly due to a phosphoryl group transfer between the two types of cells. Interaction experiments with a plasma membrane fraction prepared from the prelabeled Ehrlich cells vis à vis the glioma cells clearly showed that the phosphoryl group transfer mechanism between the cells was dominating and only a minor part of the interaction was due to adhesion. This transphosphorylation reaction represents a new type of interaction between cells. It was not influenced by either adenosine 3′,5′‐monophosphate or adenosine 5‐diphosphate.
Electrochemical forces for chloride transport in the proximal tubules of the rat kidney
Authors: Sohtell Morgan 
Published: December 2008

AbstractThe electrochemical forces for chloride transport in the proximal tubule of the rat kidney were studied using micropuncture techniques. Electrical transmembrane potentials were recorded in randomly punctured tubules with Ling‐Gerhard electrodes. Chloride activities in the luminal, cellular and interstitial compartments were measured with ion selective micro‐electrodes. Electrical potential measurements between cell to interstitium and lumen to interstitium were ‐72.1 ± 2.6 mVand ± 0.5±1.4mV(mean ± S.D.)respectively. The calculated chloride concentrations for lumen, cell and interstitium were 133.0±10.3 mM, 8.5±1.0 mM and 99.1 ± 3.2 mM (mean ± S.D.) respectively. The net electrochemical forces, qualitatively, offer a passive chloride ion pathway through the tubular wall and a chloride equilibrium over the luminal membrane seems to exist.