bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alterations in histamine metabolism of rat gastric mucosa following vagotomy
Authors: Lundell L. , Rosengren Elsa , Svensson S. E. 
Published: December 2014

1. In female rats subjected to truncal vagotomy with pyloroplasty, pyloroplasty alone or sham operation, the behaviour of gastric mucosal histamine was investigated combining in vivo and in vitro methods.2. Following truncal vagotomy with pyloroplasty mucosal histamine formation, determined in vitro, increased about fivefold and histamine content was significantly elevated. The heightened histamine formation was reflected in increased excretion of histamine in the urine.3. On pentagastrin infusion, mucosal histamine formation increased about twofold following vagotomy with pyloroplasty and sevenfold in the sham‐operated controls. Histamine content concomitantly fell in both groups to about the same level. These alterations were paralleled by increased excretion of histamine in the urine.4. Kinetic studies in which [14C]histidine was injected and the resulting urinary [14C]histamine determined, indicated that during the first hour of pentagastrin infusion newly formed histamine was more slowly mobilized following vagotomy with pyloroplasty than in the controls.5. In rats subjected to a pyloroplasty alone, the increase in urinary histamine on pentagastrin infusion was significantly larger than in the sham‐operated controls. Kinetic studies indicated that this was due to a larger mobilization of preformed histamine.6. The changes in mucosal histamine metabolism are discussed in relation to the pattern of acid secretion following the actual surgical procedures.
Inward spread of activation in frog muscle fibres investigated by means of high‐speed microcinematography
Authors: Sugi H. 
Published: December 2014

1. Single fast muscle fibres of the frog were locally activated by applying current pulses to a pipette whose tip was in contact with the fibre surface, and the resulting local contractions were recorded with a high‐speed ciné‐camera at 1000–3000 frames/sec.2. In some but not all of the fibres examined, a moderate membrane depolarization of 20–30 mV initiated a phasic type of local contraction, which showed a definite threshold and relaxed spontaneously while the depolarization still continued.3. The phasic contraction was sometimes followed by a smaller steady contraction, which lasted as long as the depolarization went on and was regarded to be indentical with the graded type of local contraction.4. With pipettes of 20–40 μm diameter, the phasic contraction was first initiated at the depolarized fibre surface, and spread to some extent inwards with a velocity of 0·7–2 cm/sec at 18–26° C. The velocity of inward spread of contraction had a Q10 of about 2·3.5. With larger pipettes of more than 50–60 μm diameter, the phasic response was first initiated at the inner part definitely distant from the fibre surface, and the extent of contraction was greater at this part than at the superficial part during the course of the response. Furthermore, with depolarizations of nearly the threshold value, the steady contraction following the phasic one was seen only at the inner part, suggesting the reversal of the gradient of depolarization along the T tubules.6. The phasic contraction spread inwards or transversely with a considerable decrement. The response spreading across the whole diameter of the fibre could be observed only in some cases.7. The phasic response was not always sensitive to tetrodotoxin or to the removal of external sodium ions.8. These results not only give information about the nature of the regenerative mechanism within the T system, but also suggest that the organization of the T tubule network is such that the electrotonic depolarization becomes maximum at the T tubules located distant from the fibre surface when a sufficiently large area of surface membrane is depolarized.
Properties of fast and slow alpha motoneurones following motor reinnervation
Authors: Kuno M. , Miyata Y. , Muñoz‐Martinez E. J. 
Published: December 2014

1. The properties of medial gastrocnemius (fast alpha) and soleus (slow alpha) motoneurones of the cat were examined with intracellular electrodes 33–154 days after self‐ or cross‐union of the muscle nerves.2. The original properties of fast and slow alpha motoneurones measured in terms of the axonal conduction velocity, the duration of after‐hyperpolarization and the overshoot amplitude were restored at least in part after self‐union of the muscle nerves.3. Slow alpha motoneurones recovered their original properties whether the muscle nerve was united to the original, slow red muscle or to the fast pale muscle. In two animals, some of the fast muscle fibres seemed to be doubly innervated by both fast and slow alpha motoneurones.4. The degree of restoration of the original motoneurone properties was closely related to the degree of motor reinnervation of the muscle.5. At a given stage of motor reinnervation, the degree of recovery of the motoneurone properties was approximately the same regardless of the presence or absence of functional motor connexions of the motoneurone under study.6. When the dorsal root ganglia were removed immediately before self‐union of the muscle nerves, recovery of the conduction velocity of motoneurones was impeded without significant effect upon the process of motor reinnervation or upon recovery of the overshoot amplitude and the duration of after‐hyperpolarization.7. It is concluded that the ‘dedifferentiated’ properties of fast and slow alpha motoneurones after nerve section may be ‘redifferentiated’ following motor reinnervation to any muscle. The possible signal for restoration of the motoneurone properties is discussed.
The secretion of alkali metal ions by the perfused cat pancreas as influenced by the composition and osmolality of the external environment and by inhibitors of metabolism and Na+, K+‐ATPase activity
Authors: Case R. M. , Scratcherd T. 
Published: December 2014

1. The secretion of sodium, potassium and lithium has been studied in the isolated cat pancreas, perfused with bicarbonate buffered saline solutions of varying composition and osmolality, and stimulated maximally with secretin.2. Under isosmolal conditions, when perfusate sodium chloride was replaced by sucrose, sodium secretion and potassium secretion were directly related to perfusate sodium concentration, [Na]p.3. When osmolality was varied by increasing or decreasing perfusate sodium chloride concentration, the secretion of sodium and of potassium were maximal at [Na]p of about 120 and 80 m
M respectively.4. At a given [Na]p, sodium secretion was greater under hypo‐osmolal conditions than under isosmolal conditions.5. When potassium concentration was varied over the range 0–130 m
M under isosmolal conditions, by adjusting perfusate NaCl concentration, the secretion of potassium and of sodium were maximal at [K]p of about 50 and 10 m
M respectively. Water flux was maximal at a [K]p of 10–15 m
M. The concentration of potassium in the secretion was almost identical with that in the perfusate over the whole concentration range.6. Replacement of perfusate sodium by lithium reduced the volume of secretion, though a small secretion was maintained even in the complete absence of sodium. The concentration of lithium in the secretion was generally slightly greater than that in the perfusate.7. Omission of potassium from the perfusate reduced secretion by about 65%. Rubidium was a complete substitute for potassium; caesium was not.8. Energy for secretion is derived largely from oxidative phosphorylation. Secretion was reduced by more than 90% under anaerobic conditions and in the presence of dinitrophenol or cyanide. Removal of glucose from the perfusate reduced secretion by more than 50% within 30 min; lactate was a complete substitute for glucose.9. Ouabain, ethacrinic acid and frusimide, known inhibitors of Na+, K+‐ATPase activity, all inhibited pancreatic electrolyte secretion.10. The observations are interpreted with reference to the nature of active transport processes involved in pancreatic electrolyte secretion.
Reconstruction of the electrical responses of turtle cones to flashes and steps of light
Authors: Baylor D. A. , Hodgkin A. L. , Lamb T. D. 
Published: December 2014

1. Theoretical equations which predict the electrical response of turtle cones to a wide range of light stimuli are developed from the experiments described in previous papers.2. The central points in the theory are that (a) light starts a chain of reactions leading to the production of a substance which blocks ionic channels in the outer segment, (b) an equilibrium between blocking molecules and open channels is rapidly established, (c) the blocking molecules are removed or inactivated by a chain of reactions, the first of which is autocatalytic, (d) in addition to the conductance which decreases with light there is also a conductance which increases with a delay when the cone is hyperpolarized.3. Parameters in the theory were deduced by approximate equations from the experiments described in the previous papers.4. There was good agreement between the properties of real and model cones in the following cases: (a) the response to 10 msec flashes and 0·7 sec steps of light calculated to give between 20 and 5 × 107 photoisomerizations per cone at times extending to about 2 sec; (b) the complicated changes in the response to a test flash that occur when it is superposed on background lights of increasing intensity; (c) the after‐hyperpolarization and period of reduced sensitivity following a strong flash.5. The main defect of the theory is that the effect of background light in shortening the time to maximum of the response to a flash was more pronounced in a real cone than in the model.
Thallium and the sodium pump in human red cells
Authors: Cavieres J. D. , Ellory J. C. 
Published: December 2014

1. Thallium (Tl) inhibits the ouabain‐sensitive K influx in human red cells in high‐Na medium. At 1 m
M external K concentration [Ko], the ouabain‐sensitive K influx decreases steadily with increasing Tl concentration, up to 0·9 m
M outside; at 0·17 m
M‐Ko, however, Tl stimulates the ouabain‐sensitive K influx below 0·1 m
M‐Tlo and inhibits it at higher concentrations.2. In a K‐free medium in which all except 5 m
M‐Na is replaced by choline, and into which red cells show zero control ouabain‐sensitive Na efflux, Tl is able to support ouabain‐sensitive Na efflux up to 2·1 m‐mole/l. cells.hr following a sigmoid activation curve which is half‐maximal between 0·03 and 0·05 m
M‐Tlo and that follows two‐site kinetics up to 0·1 m
M‐Tlo. Beyond 0·15 m
M‐Tlo, the Tl‐activated ouabain‐sensitive Na efflux attained is inhibited slightly.3. When the ouabain‐sensitive Na efflux is measured at 5 m
M‐Nao and 5 m
M‐Ko, increasing concentrations of Tl have little effect on it, 0·9 m
M‐Tlo inhibiting by some 14%; in similar conditions, the ouabain‐sensitive K influx is inhibited by about 40%.4. The dependence of ouabain‐sensitive K influx on external K concentration at 5 m
M‐Nao, which follows a slightly sigmoid curve in the absence of Tl, changes to hyperbolic at 0·06 m
M‐Tlo at the same time that ouabain‐sensitive K influx is inhibited. The fitted Vmax values for ouabain‐sensitive K influx are the same in the presence and in the absence of 0·06 m
M‐Tlo.5. In high‐Na cells, loaded by nystatin treatment, the ouabain‐sensitive K influx measured at 0·2 m
M‐Nao follows a hyperbolic curve between 0·05 and 0·4 m
M‐Ko, and is inhibited by Tl in a strictly competitive fashion.6. The effects of Tl on ouabain‐sensitive Na efflux and ouabain‐sensitive K influx are interpreted in terms of a high‐affinity substitution for K at the external K sites of the Na pump and suggest that in human red cells Tl can be actively transported inwards in exchange for internal Na.7. Thallium can inhibit about 25% of the ouabain‐insensitive Na efflux into 5 m
M‐Nao and part of this inhibition occurs with a high Tl‐affinity; the ouabain‐insensitive K influx is inhibited by Tl both in high‐Na and in 5 m
M‐Na medium, but with a different concentration dependence than the ouabain‐insensitive Na efflux.
Modification of the postural response of the normal dog by blindfolding
Authors: Talbott Richard E. 
Published: December 2014

1. Normal dogs were trained to stand quietly upon a movable platform. The animals' postural adjustments in response to sinusoidal motion of the platform were assessed in both the normal and the blindfolded condition. The induced postural adjustments were described by the Fourier coefficients for the fundamental of the input together with the coefficients which were integral multiples of the fundamental.2. All of the output variables, including motion at the hind limb joints and of the body, showed modifications when the dogs were blindfolded. The body motion increased in amplitude, as measured by the fundamental Fourier coefficient, and further lagged the input motion. Motion at the knee and phalangeal joints also increased in amplitude and the timing of these movements shifted from the normal in characteristic patterns for different frequencies of input motion.3. The modifications of the postural response due to blindfolding were most pronounced at the lower input frequencies: 0·2–1·0 Hz. At 1·4 Hz or above the fundamental coefficients of most of the output measures resembled those of the normal condition. Even at the higher input frequencies, however, the postural response of the blindfolded dog was more distorted than that of the normal dog.4. It is hypothesized that relatively slow movement of the visual surround provides the dog with information which is essential to normal operations of the postural control system.
The effects of raising alveolar PCO2 and ventilation separately and together on the sensitivity and setting of the baroreceptor cardiodepressor reflex in man
Authors: Bristow J. D. , Brown E. B. , Cunningham D. J. C. , Howson M. G. , Lee M. J. R. , Pickering T. G. , Sleight P. 
Published: December 2014

1. The effects of changes in ventilation and/or alveolar PCO2 on the baroreflex control of heart rate have been studied in seven experiments on six young men and women who had been trained to control tidal volume and respiratory frequency at various levels independent of alveolar PCO2, during hyperoxia.2. Intravenous phenylephrine provoked transient rises of directly measured arterial pressure during which individual systolic pressures (P) were linearly related to the following pulse interval (I). Baroreflex sensitivity was expressed as the slope of the regression of I on P, and reflex setting (Iref) as I at a single reference arterial pressure (= mean P for the experiment).3. Voluntary control of breathing had little effect on heart rate and arterial pressure (baroreflex setting), but diminished reflex sensitivity.4. Hypercapnia regularly caused tachycardia at the reference pressure (i.e. baroreflex setting lowered). The response was completely or partly reproduced by change of PA, CO2 at constant ventilation in four subjects but not in two others; in them change of ventilation at constant PA, CO2 completely mimicked the effect of free‐breathing hypercapnia.5. Values of baroreflex sensitivity were relatively scattered. Hypercapnia caused a fall in baroreflex sensitivity in three subjects whether ventilation was fixed or free to rise. After separating the effect of voluntarily controlling ventilation, ventilation per se was without effect on reflex sensitivity.6. It is concluded that hypercapnia and hyperpnoea have separate effects on the baroreflex, the relative magnitudes of which differ from one subject to another. Baroreflex setting and sensitivity vary independently in response to change of ventilation and of PA, CO2.
Hepatic osmoreceptors?
Authors: Glasby M. A. , Ramsay D. J. 
Published: December 2014

1. The effects of 0·45% saline infusions into the portal vein of conscious and anaesthetized dogs have been compared with similar infusions through a systemic vein.2. Measurements were made of plasma and urinary osmolality, sodium, potassium and chloride concentrations and urine flows; osmolal clearances, free water clearances, the percentage of the infused loads excreted at given times, and rates of sodium and potassium excretion in the urine, were calculated.3. In the conscious and anaesthetized series of experiments no significant differences were found between the portal and systemic routes of infusion.4. For both the portal and systemic routes of infusion there was a significantly smaller diuretic response to the saline infusion in anaesthetized as compared with conscious animals.5. These results do not support the concept of hepatic osmoreceptors occurring in the dog.
The effect of holding potential on the asymmetry currents in squid giant axons
Authors: Meves H. 
Published: December 2014

1. Asymmetry currents were recorded from intracellularly perfused squid axons subjected to an equal number of exactly equal positive and negative voltage clamp pulses. The asymmetry currents consisted of an on‐response at the beginning of the pulses and an off‐response at the end of the pulses.2. The asymmetry currents were markedly reduced by 30 m
M glutaraldehyde applied internally.3. Clamp pulses of varying height, superimposed on a holding potential of — 80 to — 100 mV, were used to study the voltage and time dependence of the asymmetry current. The magnitude of the on‐ and off‐response increased with increasing pulse height along a sigmoid curve. The time constants of the on‐ and off‐response depended on the potential during the depolarizing pulses; the time constant of the on‐response had a maximum at an internal potential of — 12 mV, the time constant of the off‐response was largest at positive internal potentials.4. Holding the membrane at a potential of — 80 to — 100 mV for several minutes led to a slow increase of the size of the asymmetry current.5. Changing the holding potential from — 80 or — 100 mV to a less negative potential caused a decrease of the asymmetry current. At holding potentials less negative than — 65 or — 60 mV the asymmetry current reversed its sign: the transient current at the beginning of the pulses turned into an inward current and the transient current at the end of the pulses became outward. No inactivation of the asymmetry current was seen in the range of holding potentials studied (V < — 3 mV).6. The results are generally consistent with the idea that the asymmetry currents are in some way related to the opening and closing of the Na gates; they suggest, however, that the asymmetrical charge movement does not simply reflect the voltage and time dependence of the m system.
Effects of replacing medium sodium by choline, caesium, or rubidium, on water and ion contents of renal cortical slices
Authors: Hughes Pauline M. , Macknight Anthony D. C. 
Published: December 2014

1. Renal cortical slices from rat, rabbit, and guinea‐pig were incubated in media in which choline, caesium or rubidium replaced sodium.2. Slices of rabbit and guinea‐pig renal cortex incubated in oxygenated choline Ringer decreased in volume initially and did not swell over 3 hr at 25° C. There was a steady loss of potassium. Inhibition of metabolism (N2 + 1 m
M iodoacetamide) caused some swelling. Ouabain, 10 m
M, in choline Ringer affected neither loss of potassium nor tissue water content.3. Slices of rat renal cortex similarly incubated in choline Ringer swelled over 3 hr at 25° C whether or not metabolism was inhibited; ouabain (15 m
M) affected neither tissue potassium loss nor tissue water content.4. Incubation in choline Ringer containing either 0·2 m
M p‐chloromercuribenzoic acid, or 1 m
M ethacrynic acid increased the tissue water content of guinea‐pig renal cortical slices.5. Depletion of cellular potassium (by preliminary incubation in oxygenated potassium‐free sodium Ringer with 10 m
M ouabain at 30° C) resulted in increased tissue water content when rabbit renal cortical slices were subsequently incubated in oxygenated choline Ringer at 25° C for 3 hr.6. There was no evidence of energy‐dependent extrusion of water or ions from either equilibrated rat or rabbit renal cortical slices leached at 0·5° C and then reincubated at 25° C in choline Ringer.7. Rat and guinea‐pig renal cortical slices leached at 0.5° C and reincubated at 25° C swelled in rubidium Ringer and in caesium Ringer. There was no evidence of energy‐dependent water or ion extrusion when metabolism was restored after leaching in either of these media. Metabolizing rat slices but not guinea‐pig slices swelled faster than slices whose metabolism was inhibited.8. These results lend no support to the mechano‐chemical hypothesis which ascribes cellular volume regulation to a contractile mechanism squeezing isotonic extracellular fluid from the cells. Instead it is suggested that cellular water content in these experiments reflects the balance between the rate of loss of potassium (and chloride) from the cells and the rate of uptake of extracellular cation (and chloride) into the cells — these rates reflecting both the electrochemical potential gradients of the ions and membrane permeability to them. The implications in relation to the hypothesis of ouabain‐insensitive cellular volume regulation are discussed.
The effect of anaesthesia on the inhibition of pentagastrin‐evoked gastric acid secretion induced by atropine in the rat
Authors: Hedges A. R. , Parsons M. E. 
Published: December 2014

1. In the anaesthetized, vagally intact rat, with a perfused gastric lumen, atropine produced a maximum inhibition of 60% of maximal pentagastrin‐evoked gastric acid secretion. Sub‐maximal pentagastrin‐stimulated secretion was also inhibited by atropine.2. In the anaesthetized, vagotomized rat, with a perfused gastric lumen, atropine had no inhibitory effect on maximal pentagastrin‐evoked gastric acid secretion.3. In the conscious fistula rat, atropine totally abolished both the basal gastric acid secretion and the maximal gastric acid secretion evoked by pentagastrin. In the anaesthetized chronic fistula rat, doses of atropine up to 1·6 mg.kg−1 administered subcutaneously produced a maximum inhibition of 70% of maximal pentagastrin‐evoked gastric acid secretion. Vagotomy did not affect the response to atropine.4. In the conscious Heidenhain pouch rat, doses of atropine up to 1·6 mg.kg−1 administered subcutaneously produced a maximum inhibition of 70·9% of maximal pentagastrin‐evoked gastric acid secretion. Both anaesthesia and vagotomy, alone or in combination, did not affect the response to atropine.
Sensory fibres in ventral roots L7 and S1 in the cat
Authors: Coggeshall Richard E. , Ito Haruhide 
Published: December 2014

1. Receptive fields were determined for ninety‐eight unmyelinated and 132 myelinated axons in the L7 and S1 cat ventral roots.2. Seventy of the ninety‐eight unmyelinated axons had their receptive fields in somatic structures, the skin and deep tissues.3. Of the seventy unmyelinated axons with somatic receptive fields, thirty‐five were mechanical nociceptors, fifteen were mechanical and thermal nociceptors, eleven were deep nociceptors, six were thermal receptors, and three were low threshold mechanoceptors.4. Twenty‐four of the ninety‐eight unmyelinated axons had their receptive fields in visceral structures: the intestine, bladder and vagina.5. We confirm the work of others that myelinated fibres attached to peripheral receptive fields can be found in ventral roots and that the receptive fields and functional qualities of these fibres are as one would expect of dorsal root fibres for the same segments.6. A previous study demonstrated that approximately 30% of the axons in the L7 and S1 cat ventral roots are unmyelinated and arise from dorsal root ganglion cells. The present study confirms that these axons are sensory and that the axons are predominantly cutaneous nociceptors and visceral afferents. Thus it is concluded that the L7 and S1 cat ventral roots have a major sensory component.