bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of splanchnic nerve stimulation on gastric acid secretion and mucosal blood flow in the anaesthetized cat
Authors: Reed J. D. , Sanders D. J. , Thorpe Valerie 
Published: December 2014

1. Electrical stimulation of the vagus nerves produced a parallel increase in gastric acid secretion and gastric mucosal blood flow.2. Gastric acid secretion and mucosal blood flow, stimulated by pentapeptide infusions or by vagal stimulation, were markedly and equally reduced by electrical stimulation of splanchnic nerve fibres.3. The splanchnic stimulated reduction in acid and mucosal blood flow occurred only when the rise in blood pressure, normally associated with splanchnic stimulation, was prevented by inclusion of a pressure reservoir in the circulation.4. There was evidence that the effect of the splanchnic nerves was not mediated by release of adrenaline from the adrenal medulla.
The intracellular localization of kallikrein, trypsin and amylase in dog pancreas
Authors: Bhoola K. D. , Dorey Gundula 
Published: December 2014

1. Subcellular organelles containing kallikrein (‐ogen), trypsinogen and amylase have been isolated from homogenates of dog pancreas and found on discontinuous sucrose density‐gradients to equilibrate with 1·7–1·775
M sucrose.2. The electron microscopic appearance of the isolated enzyme‐containing organelles appeared to be identical with that of the secretory (zymogen) granules seen in situ in the acinar cells of the pancreas.3. The sequence of events associated with the storage and intracellular transport of pancreatic secretory enzymes is reviewed. The results obtained in this study have been used to delineate the probable intracellular pathway taken by kallikrein, trypsin and amylase from synthesis to secretion.4. The physiological role of the glandular kallikreins is discussed.
Hyperplasia of the gastric mucosa during pregnancy and lactation in the rat
Authors: Crean G. P. , Rumsey R. D. E. 
Published: December 2014

1. The growth of the gastric mucosa during pregnancy and afterwards has been studied by comparing the stomachs of rats, killed at weekly intervals after impregnation, with the stomachs of virgin rats of the same age and starting weight. The rate of growth of the gastric mucosa in both groups was determined from the changes observed in the weight of the whole stomach, the weight and surface area of the fundus, the volume (mass) of the fundic mucosa and the total parietal and total peptic cell populations.2. Hyperplasia of the gastric mucosa occurred during pregnancy and lactation, the effect being characterized by increases in the surface area and volume (mass) of the gastric mucosa, and in the total parietal and total peptic cell populations.3. The data suggest that the effect developed shortly after conception. Hyperplasia of the gastric mucosa continued throughout pregnancy and reached maximal values after the second week of lactation and waned thereafter; the maximal changes obtained for individual observations such as surface area and the total parietal and total peptic cell populations represented increases of the order of 40% above corresponding control values.4. From the observations that were made on food intake it seemed unlikely that the hyperplasia of the gastric mucosa was due to hyperphagia. It also seemed unlikely that the effect could be accounted for by the increase that occurred in body weight during pregnancy.
Recurrent inhibition from motor axon collaterals of transmission in the Ia inhibitory pathway to motoneurones
Authors: Hultborn H. , Jankowska Elẓbieta , Lindström S. 
Published: December 2014

1. The effects of impulses in recurrent motor axon collaterals on reflex transmission from different types of primary afferents to motoneurones were investigated in the cat by conditioning of PSPs evoked in motoneurones.2. IPSPs evoked by volleys in large muscle spindle (Ia) afferents were effectively decreased when preceded by an antidromic stimulation of ventral roots. Some IPSPs from group II muscle afferents and low threshold cutaneous afferents were also slightly depressed, while other PSPs were unaffected.3. The depression of the IPSPs could be evoked by antidromic volleys, which produced neither conductance changes in the motoneurones nor depolarization of Ia afferent terminals.4. The effect on the Ia IPSPs is most likely due to post‐synaptic inhibition of the Ia inhibitory interneurones, evoked through α‐motor axon collaterals and Renshaw cells. The depression of some IPSPs from flexor reflex afferents is explained by a convergence of excitatory effects from these afferents on the Ia inhibitory interneurones.5. The results indicate a selective recurrent control from motor axon collaterals of the interneurones in the reciprocal Ia inhibitory pathway to motoneurones.
The Purkinje shift in cat: extent of the mesopic range
Authors: Hammond P. , James C. R. 
Published: December 2014

1. The mesopic range, defined for cats with fully dilated pupils, extends from −1·0 to +1·4 log cd/m2. The technique employed involves measurement of the relative shift in threshold with adaptation level, between two wave‐lengths respectively selective for cones and rods at threshold. The magnitude of this shift is compared with that predicted from the Dartnall nomogram for visual pigments 556 and 507 (the in situ cone and rod absorption maxima).2. The result is based on monochromatic increment threshold determinations for 149 on‐centre or off‐centre fibres, isolated in the optic tract posterior to the chiasma, under a variety of adaptation levels. All units included receive dual input — from 500 nm rods and from a single class of cones with maximum sensitivity at 556 nm. No units receive input from 450 nm cones; six units with input mediated purely by rods are excluded from the sample.
The effects of hypercapnia, hypoxia and ventilation on the baroreflex regulation of the pulse interval
Authors: Bristow J. D. , Brown E. B. , Cunningham D. J. C. , Goode R. C. , Howson M. G. , Sleight P. 
Published: December 2014

1. The effects of moderate degrees of hypercapnia in hypoxia and in hyperoxia on the baroreceptor‐cardiodepressor reflex have been studied in nine normal men.2. The beat‐by‐beat relation between pulse interval (I) and systolic pressure (P) during transient elevations of arterial pressure induced by intravenous injections of angiotensin II and phenylephrine was used to assess the sensitivity (ΔI/ΔP) and setting (I at a single reference arterial pressure) of the reflex.3. There was no consistent change in reflex sensitivity in any of the conditions studied.4. In hyperoxia (PA, O2 ∼ 200 torr) hypercapnia was associated with significant re‐setting of the reflex in the direction of tachycardia. The extent of the re‐setting was correlated with the degree of hypercapnia and with the accompanying increase in breathing.5. When hyperoxia with hypercapnia was replaced by hypoxia (PA, O2 ∼ 55 torr) with hypercapnia (which causes substantial arterial chemoreceptor activity), pulse interval at constant arterial pressure was further decreased.6. The tachycardia of hypoxia could not be accounted for by change of arterial pressure, PA, CO2 or pulmonary ventilation, since it was most clearly demonstrable at constant values of pressure and either PA, CO2 or ventilation.
Removal of an insulin inhibitor from the rat heart by perfusion
Authors: Young D. A. B. 
Published: December 2014

1. Insulin‐stimulated efflux of galactose from the perfused rat heart increased when the Krebs bicarbonate medium was prepared with gassing with CO2.2. Analysis of the kinetics of efflux in the light of the carrier theory is used to justify the interpretation of the increased rate of efflux as an increased response to insulin.3. With medium prepared with CO2 gassing, the photoperiodic reduction in insulin response seen previously was not found; but it was seen when cardiac contractility was reduced or eliminated during the period of galactose loading.4. The relation between the increase in galactose efflux with insulin and the insulin concentration conforms to the Michaelis—Menten equation, for perfusates prepared both with and without CO2 gassing, indicating in the latter case the presence of a competitive inhibitor of insulin.5. It has been previously shown that preparing the perfusate with CO2 gassing results in increased contractility of the perfused heart and a much increased rate of interstitial washout. The conditions of the enhanced response to insulin are consistent with the removal of the inhibitor from the heart due to the increased rate of interstitial washout. The possible role of the inhibitor in the control of lipid and carbohydrate metabolism is discussed.
The effect of quinine on tension development, membrane potentials and excitation‐contraction coupling of crab skeletal muscle fibres
Authors: Huddart H. 
Published: December 2014

1. The effect of quinine on tension development and membrane potentials of crab skeletal muscle was examined using strain gauges and intracellular electrodes.2. In low concentrations (0·1–0·5 m
M), quinine caused transient potentiation of twitch tension which then rapidly declined along with progressive depression of the tetanus. These actions are correlated with the decline of both action and resting potentials during quinine treatment.3. In moderate concentrations (1–5 m
M), quinine induced phasic contractures, but the attendant depolarization made the muscles refractory to stimulation and potassium activation, but not to caffeine activation.4. Quinine did not induce contractures in depolarized muscle, which suggests that the action of quinine in inducing calcium release from the sarcoplasmic reticulum may be blocked by potassium depolarization, unlike the calcium‐releasing action of caffeine. Quinine appeared to have no effect on the mechanical threshold of crab skeletal muscle fibres.5. To explain its depression of contractility in crab muscle, it is suggested that quinine may deplete the calcium store of the sarcoplasmic reticulum, leading to extinction of the terminal stages of the excitation—contraction coupling process and loss of contractility.
Noradrenaline action on nerve terminal in the rat diaphragm
Authors: Kuba K. , Tomita T. 
Published: December 2014

1. The mechanism by which noradrenaline increases the release of transmitter from the nerve terminal was investigated in the rat diaphragm.2. Increase of the frequency of the miniature end‐plate potential (m.e.p.p.) was exponential when plotted against the intensity of a constant current which depolarized the nerve terminal. Noradrenaline (5 × 10−6 g/ml.) did not change the slope of the curve showing the relationship between the logarithm of the frequency of m.e.p.p.s and the depolarizing current (m.e.p.p.‐current relationship), but simply shifted the curve along the axis of the current towards weaker intensities.3. End‐plate potentials (e.p.p.s) were evoked by passing a brief depolarizing pulse to the nerve terminal in the presence of tetrodotoxin (1 × 10−7 g/ml.). A sigmoidal relationship was obtained between the amplitude of e.p.p. and the intensity of the current pulse (e.p.p.‐current intensity relationship). Noradrenaline (5 × 10−6 g/ml.) shifted the e.p.p.‐current intensity relationship along the axis of the current intensity to smaller values, without any change in the maximum amplitude of e.p.p.s.4. The frequency of m.e.p.p. was increased, as the [Ca]0 was raised from 0·01 to 7·5 m
M. An increase in [Ca]0 beyond the normal concentration (2·5 m
M) had no remarkable effect on the action of noradrenaline. However, when [Ca]0 was reduced, the action of noradrenaline became weaker.5. A kinetic model in which the transmitter release is modified by the binding of Ca with a specific site in the nerve terminal may explain the results. According to this model, noradrenaline did not change the dissociation constant of the reaction between Ca and the specific site (X), but increased the rate constant of the Ca complex (CaX) for releasing acetylcholine.6. The action of noradrenaline was potentiated when [Na]0 was reduced, and suppressed when [Mg]0 was increased. The results may be summarized: that noradrenaline augments the probability of release of transmitter quanta from the resting nerve terminals and that this action can be intensified by first raising the probability of release by some other means. Depolarization of the nerve terminals by current, increase of the external Ca concentration, decrease of Na and decrease of Mg are all effective in promoting the action of noradrenaline.
Inhibition of gastric secretion by atropine in conscious rats
Authors: Johansson Irene , Lundell L. , Svensson S. E. 
Published: December 2014

1. The effect of atropine on acid and pepsin secretion, stimulated by feeding, vagus excitation or infusions of gastrin, histamine and methacholine, was studied in conscious rats provided with a Pavlov or a Heidenhain pouch.2. The acid and pepsin secretion in response to food was substantially suppressed by atropine in the Pavlov pouch.3. The strong stimulatory effect of 2‐deoxy‐D‐glucose on acid and pepsin secretion in the Pavlov pouch was almost abolished by atropine.4. A plateau secretion of acid obtained by infusion of submaximal doses of hog gastrin II, was significantly inhibited by atropine in the Pavlov and the Heidenhain pouch.5. Methacholine‐induced acid and pepsin secretion in the denervated Heidenhain pouch was nearly completely inhibited by atropine.6. A plateau secretion of acid evoked by infusing histamine in a near maximal dosage was inhibited by atropine to the same extent as the gastrin‐induced secretion in the Pavlov pouch.7. The mode of action of atropine as a gastric secretory inhibitor is discussed.
An analysis of acetylcholine responses of junctional and extrajunctional receptors of frog muscle fibres. With an Appendix
Authors: Feltz Anne , Mallart Alberto , Kahn R. , le Yaouanc A. 
Published: December 2014

1. An analysis has been made of the distribution and rise time of the responses induced by electrophoretic application of ACh on junctional and extrajunctional receptors of the neuromuscular junction of the frog.2. The junctional and the extrajunctional responses appear to constitute two independent groups with no overlapping characteristics: (a) the responses evoked from junctional receptors show always a high ‘sensitivity’ (30–100 mV/nC) and a rise time usually shorter than 10 msec that does not lengthen as the ACh dose is increased; (b) the responses evoked from extrajunctional area show a lower sensitivity (0·5–10 mV/nC) and a slow rise time that is a linear function of the dose Q⅔ of ACh.3. The lengthening of the rise time of extrajunctional response with increasing doses of ACh is interpreted by supposing that larger doses saturate larger areas of a membrane of low sensitivity uniformly covered with receptors. On the contrary, at junctional spots the does of ACh would be insufficient to saturate the receptors and rise time will be independent of dose.4. Relatively unresponsive zones may exist between junctional spots and extrajunctional areas and between neighbouring extrajunctional areas.5. Extrajunctional areas are subjected to significant seasonal variations; in summer they are practically absent, in autumn they appear as elongated areas of about 20 μ wide and 50 μ long, and late in winter they fuse together and all the ‘end‐plate’ zone becomes sensitive to ACh.
Experimental alteration of the relationshp between the external calcium concentration and the contractile force generated by auricular trabeculae isolated from the heart of the frog, Rana pipiens
Authors: Chapman R. A. 
Published: December 2014

1. The contractile strength generated by isolated frog auricular trabeculae has been determined by perfusion with high‐K Ringer over a range of [Ca]o.2. Experiments are described in which the cubic relationship between the contracture tension and [Ca]o has been changed to a square or a linear relationship.3. These results have been interpreted by proposing that three Ca compounds, whose concentrations are proportional to [Ca]o, act co‐operatively at some stage of the process leading to the generation of tension.4. The change in contractile strength, determined by regular electrically evoked twitches, has been investigated at different temperatures and the results have been explained by assuming that the concentrations of the three hypothetical activating compounds vary at different rates when [Ca]o is altered.5. The staircase response is supposed to develop as the consequence of an increase in the concentrations of the two activating Ca compounds with the slowest time constants.6. The possible physical representations of the hypothetical activating compounds are discussed.
Inhibition by prostaglandin E1 of gastric secretion in the dog
Authors: Nezamis James E. , Robert André , Stowe David F. 
Published: December 2014

1. The effect of prostaglandin E1 (PGE1) on gastric secretion was studied in dogs equipped with gastric fundic pouches, either innervated (Pavlov) or denervated (Heidenhain).2. PGE1 inhibited gastric secretion (volume, acid concentration, acid output, pepsin output) when given either by constant intravenous infusion or by single intravenous injection. The degree of inhibition was dose dependent.3. The antisecretory effect of PGE1 was demonstrated against gastric stimulants which operate through different mechanisms. Thus, PGE1 counteracted the secretogogue effect of:(a) histamine dihydrochloride; the ED50 was 0·5–1·0 μg/kg. min for a submaximal dose, and 1·0–1·5 μg/kg. min for a maximal dose;(b) pentagastrin; the ED50 was around 0·25 μg/kg. min;(c) food; the ED50 was 0·5 to 0·75 μg/kg. min;(d) 2‐deoxyglucose; the ED50 was less than 0·1 μg/kg. min.4. Although in some experiments, nausea and vomiting were observed during administration of PGE1, the antisecretory property of the substance is not related to a vomiting reflex, since(a) an antiemetic, such as atropine, prevented vomiting without interfering with the effect of PGE1, and(b) profuse vomiting elicited by apomorphine did not reduce gastric secretion stimulated by either histamine or pentagastrin.5. The mechanism by which PGE1 inhibits gastric secretion is unknown. Studies by others have shown that the compound reduces gastric mucosal blood flow, inhibits acid formation from gastric mucosa when applied in vitro and may change the rate of formation of gastric cyclic AMP. It is likely that PGE1 interferes with biochemical processes, within parietal and chief cells, which lead to elaboration of gastric juice.6. Unlike most gastric inhibitors, PGE1 appears to act as a protective shield against most, if not all, gastric stimulants. Since prostaglandins of the E series are naturally occurring substances and are normally present in the stomach, they may play a role in the regulation of gastric secretion.
A study of the inferior mesenteric and pelvic ganglia of guinea‐pigs with intracellular electrodes
Authors: Crowcroft P. J. , Szurszewski J. H. 
Published: December 2014

1. Ganglion cells in the inferior mesenteric ganglion (IMG) and the pelvic plexus of the guinea‐pig were studied using intracellular micro‐electrodes.2. Ganglion cells had resting membrane potentials of 55–65 mV. Threshold for initiation of an action potential ranged from 10 to 20 mV depolarization. Action potentials often exceeded 100 mV in amplitude and were followed by an after‐hyperpolarization of up to 20 mV.3. Synaptic responses were recorded from cells in the IMG in response to stimulation of the right and left hypogastric nerves, ascending mesenteric, inferior splanchnic and colonic nerves. It has been established that more than forty preganglionic fibres converge on any one cell. Preganglionic fibres to the IMG were also observed in the pelvic nerves.4. In contrast to the IMG, ganglion cells in the pelvic plexus received up to ten preganglionic fibres.5. Ganglion cells responded to supramaximal preganglionic stimulation with up to four action potentials.6. In the IMG, action potentials in response to synaptic action were followed by a prolonged period of hyperpolarization (after‐hyperpolarization) and a later phase of prolonged depolarization (after‐depolarization). The time course of these after potentials depended on the pattern of firing of action potentials during the period of stimulation. In the presence of dihydro‐β‐erythroidine, or if synaptic action was insufficient to evoke action potentials, only the after‐depolarization was observed.7. Other cells were impaled whose properties differed from those described above. In one group of cells the resting membrane potentials were higher (up to 85 mV), input resistances lower and the threshold for initiation of an action potential was higher. The other group were inexcitable, had high resting membrane potentials (up to 85 mV), low input resistances and underwent a slow depolarization in response to repetitive stimulation of preganglionic fibres.8. This study indicates that marked convergence of presynaptic fibres occurs on to ganglion cells of the IMG. The ganglion cells in the pelvic plexus receive a relatively small number of fibres, many of which exert intense synaptic activity ensuring a direct connexion to the central nervous system.
Further evidence for the involvement of microtubules in the intra‐axonal movement of noradrenaline storage granules
Authors: Banks P. , Mayor D. , Tomlinson D. R. 
Published: December 2014

1. Constricted cat hypogastric nerve/inferior mesenteric ganglion preparations maintained in vitro for 48 hr have been used to study the effects of different concentrations of colchicine on axonal microtubules and on the proximo‐distal movement of catecholamine containing dense‐cored vesicles in non‐myelinated axons.2. In low concentrations (0·03–0·3 μg/ml.), colchicine had no effect on the number of microtubules per axon and did not diminish the amount of noradrenaline accumulating proximal to the constriction.3. Higher concentrations of colchicine (1·0–10 μg/ml.) produced a dramatic reduction in the number of microtubules per axon. This was associated with marked reductions in the number of dense‐cored vesicles and the amount of noradrenaline accumulating above the constriction.4. There was some morphological evidence for a structural relationship between dense‐cored vesicles and microtubules.5. These results further support the view that axonal microtubules are involved in the relatively fast proximo‐distal transport of noradrenaline containing dense‐cored vesicles in non‐myelinated sympathetic axons.
Circadian rhythms in human salivary flow rate and composition
Authors: Dawes C. 
Published: December 2014

1. Unstimulated whole saliva and parotid saliva stimulated at a constant flow rate of 1·0 ml./min were collected from eight subjects at about 07.00, 11.00, 14.00, 17.00 and 22.00 hr and oral temperature was recorded several times daily for time spans of between 4 and 26 days. A least‐squares cosine wave was fitted to the data to test for the presence and characteristics of circadian rhythms.2. Estimates of mean level, amplitude, acrophase and period were obtained for different components and the results were subjected to cosinor analysis.3. Unstimulated whole saliva showed significant circadian rhythms in flow rate and in the concentrations of sodium and chloride but not in protein, potassium, calcium, phosphate or urea.4. Stimulated parotid saliva showed significant circadian rhythms in the concentrations of protein, sodium, potassium, calcium and chloride but not in phosphate or urea5. Oral temperature showed a circadian rhythm which, like the salivary rhythms, was of a 24.0 hr periodicity.