bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water diuresis in the domestic fowl
Authors: Dicker S. E. , Haslam J. 
Published: December 2014

1. The exteriorization of ureters in domestic fowls allows the collection of urine uncontaminated by faeces.2. When water is administered by stomach tube to a fowl, water is stored in the crop, from which it is slowly released into the proventriculus.3. Immediately after water gavage, there is a sharp rise of urine flow accompanied by an increase in endogenous creatinine excretion and a fall in the osmolarity of the urine. This initial increase in urine flow is of short duration, and is followed by a normal curve of diuresis with a peak at about 90 min after hydration.4. The first rise in urine flow following the filling of the crop appears to be of reflex origin, as distension of the crop with paraffin produces an enhanced excretion of urine and of creatinine.5. Changes in urine flow and in creatinine excretion are closely correlated.6. After water deprivation for 18 hr, the urine is slightly hyptertonic to blood. The maximum urine concentration observed was of the order of 600 m‐osmole/l.
Evidence that the secreting adrenal chromaffin cell releases catecholamines directly from ATP‐rich granules
Authors: Douglas W. W. , Poisner A. M. 
Published: December 2014

1. Cats’ adrenal glands were perfused with Locke's solution and stimulated through the splanchnic nerves or by acetylcholine.2. In response to such stimulation there appeared in the venous effluent, in addition to catecholamines, large amounts of AMP and adenosine and smaller amounts of ATP and ADP. Like the catecholamines, these substances had their origin in the chromaffin cells as was shown by their failure to appear when the splanchnic nerves were stimulated during perfusion with drugs blocking the adrenal synapses.3. During stimulation the ratio of catecholamines: ATP and metabolites in the venous effluent corresponded closely with the reported ratio of catecholamines: adenine nucleotides in the ‘heavy’ chromaffin granules.4. Adenine nucleotide appeared in the adrenal effluent pari passu with catecholamines within a second or two of beginning stimulation.5. It is concluded that the nucleotide‐rich granules are the immediate source of catecholamines released from the stimulated adrenal chromaffin cell, and that the other two intracellular ‘pools’ that have been described, nucleotide‐poor and ‘free’ cytoplasmic catecholamines, contribute little or not at all.
Input organization of two symmetrical giant cells in the snail brain
Authors: Kandel E. R. , Tauc L. 
Published: December 2014

1. The ventral surface of the snail brain contains two symmetrical giant cells which are readily identifiable in each preparation. These cells lie in the left and right metacerebrum, a cerebral integrative structure which makes afferent and efferent connexions with the periphery and with the infraoesophageal ganglia on each side by means of four ipsi‐ and four contralateral peripheral nerves and three ipsi‐ and three contralateral connectives.2. In order to examine the functional consequences of this anatomical symmetry single or double micro‐electrodes, for intracellular recording and for direct stimulation, were placed in one or both of the ventral metacerebral giant cells.3. Responses from 6 ipsi‐ and 6 contralateral inputs were examined for orthodromic and antidromic components. The results of these experiments revealed that the output organization (the pathways of the three axonal branches of the giant cells) as well as the input organization were completely symmetrical in the two cells. The anatomical symmetry therefore seems to have been functionally preserved. Simultaneous recordings from both cells failed to reveal direct interconnexions, but did show that the cells do share in common the output of at least two interneurones.4. By recording from both cells it was also possible to demonstrate, for each of the symmetrical nerves and connectives, that laterality of an input was signalled by latency and by synaptic efficacy; the ipsilateral input produced EPSPs that were consistently more effective and of shorter latency than the contralateral ones.5. Pharmacological studies revealed that both cells fall into the category called D cells by Tauc & Gerschenfeld (1961); they responded with depolarization to iontophoretic injection of ACh and all excitatory synaptic inputs were blocked by d‐tubocurarine.6. With none of the twelve afferent inputs was synaptic inhibition observed. The results support the notion that D cells do not receive inhibitory input.
The mechanism of insulin action. The effect of insulin on the allosteric properties of intracellular haemoglobin
Authors: Dormandy T. L. 
Published: December 2014

1. The results in three experimental series have suggested that a number of modifying factors must be taken into account in considering the allosteric behaviour of structurally bound intracellular, as distinct from free, haemoglobin. It seems that intracellular haemoglobin maintains its maximal internal stability during oxygen uptake and release by configurational changes which involve not only its acid—base‐binding groups but also partial electron‐transfer complexes with the stromal macro‐molecular framework. Conversely, the affinity of intracellular haemoglobin for oxygen reflects the positive or negative electron pressures prevailing at the haemoglobin‐stromal complexing sites.2. Active glucolysis in intact cells entails continuous poising of metabolic redox potential changes by the stromal material (in the same way as it entails continuous buffering of acid metabolic products). The consequent shifts in stromal redox potential and capacity are transmitted to haemoglobin and are reflected in a changing affinity for oxygen.3. The behaviour of the intracellular haemoglobin‐stromal complex is further modified by extracellular electron donors and acceptors and by the capacity of the cell/extracellular interface to act as an electrochemical barrier between them. It is probably the last variable which is directly influenced by insulin.4. Two parameters have been introduced as empirical measures of the distinctive allosteric properties of cell‐bound haemoglobin: (i) D—pH to represent the apparent cell/extracellular pH gradient; and (ii) D—O2 to represent the volume of oxygen evolved when cells are lysed at a constant PO2. Under a variety of experimental conditions insulin affected both these parameters.5. The insulin effects were consistent with a concept which rests on three main contentions. (i) Insulin has an immediate physical action on the cell/extracellular interface, altering the redox potential gradient (electron conductance) across the plasma membrane. (ii) Conversely, the formation of an insulin‐membrane complex depends, among other factors, on the prevailing trans‐membrane redox potential difference. (iii) The consequences of insulin‐membrane interaction are both immediate and sustained, and, under appropriate conditions, they are reflected in the affinity of intracellular haemoglobin for oxygen.6. At a more general level it has been shown that in many respects haemoglobin behaves as a built‐in intracellular redox indicator dye. Like most synthetic redox indicators, it is pH dependent.
The relation between sarcomere length and active tension in isolated semitendinosus fibres of the frog
Authors: Edman K. A. P. 
Published: December 2014

1. The relation between sarcomere length and tetanic tension at various states of shortening was investigated in single frog semitendinosus fibres that were subjected to different degrees of prestretch (2·45‐3·0 μ).2. The capacity to produce tension changed in a characteristic way during shortening, the tension output at each length being determined by the actual sarcomere spacing without reference to the striation spacing at the onset of contraction.3. The capacity to shorten against a given load was independent of the initial striation spacing, provided the load was not great enough to cause fatigue of the fibre.4. The findings strongly suggest that the functionally relevant structure of the contractile system of the intact muscle cell is always in the same state at a given sarcomere length independent of how the previous length change has been achieved, by passive extension at rest or by active shortening from a prestretched position. This probably means that contraction involves a structural change of the contractile system, which, at least in so far as it is of relevance to function, is a true reversal of the change produced by passive extension of the resting fibre. These aspects of the contractile behaviour of the intact muscle fibre are in full accord with the concepts of the sliding‐filament hypothesis of muscular contraction.
The distribution of cholinesterases in the cat carotid body
Authors: Biscoe T. J. , Silver Ann 
Published: December 2014

1. The distribution of acetyl‐ and butyrylcholinesterase in the carotid body of the cat has been examined histochemically. Studies were made on normal carotid bodies and on carotid bodies from cats in which certain nerves had been cut some time previously. The nerves sectioned were the sinus nerve, the post‐ganglionic sympathetic branch of the superior cervical ganglion or the preganglionic cervical sympathetic trunk.2. It was confirmed that more butyrylcholinesterase than acetylcholinesterase is present. Both enzymes are found in three sites: (i) as strands, (ii) as plexuses, (iii) inside a few cells.3. The distribution is unaffected by cutting the sinus nerve or preganglionic cervical sympathetic nerves. Disorganization and depletion of the cholinesterases in the strands and plexuses occurs when the post‐ganglionic branch of the superior cervical ganglion is cut. The cholinesterase in cells is unaffected.4. In carotid bodies in which vessels were filled with red blood cells or in which the vascular bed was injected with carmine‐gelatine, it was seen that strands and plexuses are associated with blood vessels, and with blood vessels and cells respectively.5. It is suggested that a cholinergic pathway controlling carotid body blood vessels runs in the post‐ganglionic cervical sympathetic.
The distribution of ions in the smooth muscle of the guinea‐pig taenia coli
Authors: Buck B. , Goodford P. J. 
Published: December 2014

1. Tracer movements and ionic composition have been observed in the smooth muscle of the guinea‐pig taenia coli in vitro at 4, and 35° C. The muscle was quiescent at 4° C, and did not show spontaneous electrical nor mechanical activity for 25 min after re‐warming. It was therefore possible to make observations on the quiescent tissue at 35° C.2. The rate of loss of tracer sodium was sensitive to changes of temperature, with an average Q10 of 3·4 ± 0·4 on warming in the range 4‐35° C. Exponential analysis of 24Na efflux at 35° C showed an initial rapid phase, a second phase with t½ = 2 min, and a slowly exchanging phase. The second phase was most sensitive to changes of temperature and contained 15 m‐mole Na/kg fresh wt. The corresponding transmembrane flux in spontaneously active muscle at 35° C would then be 30 p‐mole cm−2 sec−1, and 20% of the available metabolic energy would be needed to maintain this exchange.3. The rate of loss of tracer sodium was reduced in potassium‐free or sodium‐free solutions, but the effects were not impressive.4. The cell size increased at 4° C, and fell again on warming while Na and Cl left the cell and K was taken up. Cell chloride content was linearly related to cell size.5. The observations are interpreted on the assumption that the cytoplasm is osmotically isotonic and electrically neutral, and that some Na, K and Cl are sequestered elsewhere in the tissue. It is concluded that the quiescent smooth‐muscle cell membrane is rather more permeable to sodium than the skeletal‐muscle cell membrane.
The interrelation of thermoregulatory and baroreceptor reflexes in the control of the blood vessels in the human forearm
Authors: Crossley R. J. , Greenfield A. D. M. , Plassaras G. C. , Stephens Dorothy 
Published: December 2014

1. The interrelation of thermoregulatory and baroreceptor reflexes in the control of the circulation through the forearm has been investigated in eight men.2. The results are compatible with the current hypotheses that thermoregulatory reflexes employ exclusively blood vessels in the skin, and that baroreceptor vasodilator reflexes excited by transfer of blood from the legs to the trunk employ exclusively blood vessels in the muscles. They are compatible with the hypothesis that baroreceptor vasoconstrictor reflexes excited by transfer of blood from the trunk to the legs employ blood vessels in muscles, but not with the hypothesis that they do so exclusively.3. The results indicate that when blood is transferred from the trunk to the legs, vasoconstriction over‐rides thermoregulatory vasodilatation, presumably in the blood vessels of the skin.4. The circulation through the skin appears, therefore, to be under baroreceptor as well as thermoregulatory reflex control, and over the short period of time examined, namely 1 min, the baroreceptor control takes precedence.
Time course and nature of temperature‐induced changes in sodium‐glucose interactions of the goldfish intestine
Authors: Smith M. W. 
Published: December 2014

1. Glucose‐evoked potentials measured at low incubation temperatures were found to be highly temperature dependent (phase 1), but less so at high incubation temperatures (phase 2) and acclimatization of an 8°C fish to 25° C resulted in the extension of phase 1 up to the environmental temperature of the fish. This change was only part of the mechanism controlling the acclimatization of sodium transport across the intestine.2. The temperature at which the glucose‐evoked potential changed from phase 1 to phase 2 was approximately equal to the temperature at which glucose began to raise the steady transmural potential of the intestine.3. No changes in intestinal electrical parameters could be detected when fish, acclimatized to 8° C, were heated at 25° C for 15 hr, but after 20 hr at the higher temperature, acclimatization to the new temperature was complete.4. Intestines from fish acclimatized to 8° C, but which had first spent 15 hr at 25° C and then 10 hr at 8° C, still behaved qualitatively like 8° C — intestines but the magnitude of the glucose‐evoked potentials was slightly reduced.5. It is suggested as a working hypothesis that acclimatization of the sodium‐glucose interaction to different environmental temperatures involves the synthesis of new carrier molecules, qualitatively different from the old ones.
The characteristics of spontaneous and evoked action potentials recorded from the rabbit's uterine nerves
Authors: Bower E. A. 
Published: December 2014

1. A method is described for recording in vivo the action potentials of afferent and efferent fibres in whole nerves supplying the rabbit's uterus.2. Examination of these nerves under the light microscope and the electron microscope showed them to be composed almost entirely of non‐myelinated fibres.3. Two types of spontaneous action potential were observed; one travelled at about 4 m/sec and probably came from the myelinated fibres, the other travelled at 0·4‐1·4 m/sec and certainly came from non‐myelinated fibres.4. The efferent fibre spikes were shown to be faster and higher than the spikes from uterine afferent fibres, but slower and smaller than spikes from broad ligament afferent fibres.5. Apart from differences in conduction velocity and height, all spikes were basically similar, lasting about 1·5 msec. The height was related to the square of the velocity. Some more complex spikes were also observed.6. The compound action potential evoked by stimulation of the uterine nerve had three peaks, conducted at 1·3, 0·8 and 0·6 m/sec, respectively, and thought to correspond to the fast afferent fibres, the efferent fibres and the slow afferent fibres, respectively. There were also some late peaks due to reflexion of the antidromic action potentials from the ganglion cells.7. Stimulation of the hypogastric nerve also evoked a compound action potential in the uterine nerves. Stimulation of the pelvic nerves had no effect.8. By means of ganglion blocking agents, the uterine ganglia were shown to lie in the pelvic plexus, peripheral to the hypogastric nerve, but central to the uterine nerves.9. It is argued that the spontaneous action potentials came from individual fibres rather than Remak bundles, and that the recording technique used detected the activity of all but the smallest fibres.
Intracellular and extracellular compartments of mammalian central nervous tissue*
Authors: Ames A. , Nesbett Frances B. 
Published: December 2014

1. Isolated rabbit retina was used as a prototype of grey matter to study the partition of water and electrolytes between the intracellular and extracellular phase. Previously published morphologic, chemical, and functional evidence has shown that it can be maintained in vitro in a nearly physiological state.2. Following equilibration with mannitol or inulin, retinas were eluted in isotonic tris acetate at 0° C, and measurements were made of the rates at which K+, Na+, Cl− and inulin or mannitol diffused from the tissue.3. K+ was eluted slowly according to a single exponential decay. The Na+ and Cl− elution curves demonstrated two phases which could be dissected into a rapid, multicomponent regression superimposed upon a slow exponential decrease.4. The volume of distribution of the readily elutable Na+ equalled that of the readily elutable Cl− and corresponded closely to the volume of distribution of mannitol and inulin. On the basis of these and previously published data, the interstitial fluid was estimated to constitute 31% (w/w) of rabbit retina and 22% of rabbit brain.5. The composition of the extracellular fluid of retina resembled closely that of the medium in which the tissue had been previously incubated.6. Inulin, mannitol, and NaCl diffused through the less accessible portions of the extracellular space at rates which differed from one another as predicted from the diffusion coefficients of these solutes. Their diffusion through the more accessible portions of the extracellular space was apparently affected by bulk flow of the fluid.7. The intracellular concentrations of K+, Na+, and Cl− were estimated to be 148, 31, and 17 m
M respectively.8. Na+ and K+ moved across the cell membranes at almost precisely the same rate under the conditions of the elution.
An investigation of the post‐tetanic potentiation of end‐plate potentials at a mammalian neuromuscular junction
Authors: Gage P. W. , Hubbard J. I. 
Published: December 2014

1. End‐plate potentials (e.p.p.s) were recorded intracellularly from neuromuscular junctions in curarized or Mg‐paralysed rat diaphragm‐phrenic nerve preparations in vitro. In Mg‐paralysed preparations after 1000 impulses at 100/sec the amplitude of e.p.p.s elicited at 1/sec before and after the tetanus was on average greater than the control amplitude for 120 ± 30 sec.2. The post‐tetanic potentiation (
P.T.P.) of e.p.p. amplitudes was not thought to be dependent upon post‐tetanic hyperpolarization (
P.T.H.) of nerve terminals as it lasted longer than the hyperpolarization generated by an identical tetanus; was unaffected by hyperpolarizing currents which reduced
P.T.H. or depolarizing currents which prolonged
P.T.H.; and was diminished in solutions containing 30% of the normal NaCl concentration or 1% ethyl alcohol, both of which procedures prolong
P.T.H. The magnitude and duration of
P.T.P. were influenced by the pH of the bathing solution in the range 7‐7·5 although there was no change in
P.T.H. under these conditions. The inability of polarizing currents to influence
P.T.P. was also thought inconsistent with the hypothesis that
P.T.P. is due to an increase in available transmitter.3.
P.T.P. was not thought to be due to sodium accumulation in nerve terminals, for
P.T.P. was reduced or abolished by procedures which would be expected to increase the intraterminal sodium ion concentration. These procedures were: exhibition of metabolic inhibitors (1·8 × 10−6
M antimycin A, 3‐5 m
M sodium azide or 1 m
M sodium iodoacetate), exhibition of cardiac glycosides (7·7 × 10−6
M digoxin or 0·42 m
M ouabain), and omission of glucose or potassium ions from the bathing solution. Abolition of
P.T.P. by potassium‐free solutions was also thought to be inconsistent with the hypothesis that
P.T.P. is due to a reduction in the potassium concentration in nerve terminals.4.
P.T.P. was not thought to be due to terminal volume changes, for no consistent effect upon the quantal content of e.p.p.s could be detected in hypo‐ or hyperosmotic solutions.5. It was concluded that the only hypothesis for
P.T.P. not excluded by our experiments was that
P.T.P. is due to some change in ionized calcium at a membrane site important in transmitter release.
Blocking of the impulse and depression of the receptor potential by tetrodotoxin in non‐myelinated nerve terminals in pacinian corpuscles
Authors: Nishi K. , Sato M. 
Published: December 2014

1. The effect of tetrodotoxin on the impulse and the receptor potential of the non‐myelinated nerve terminal in Pacinian corpuscles has been investigated.2. Tetrodotoxin at a concentration of 1 × 10−7 g/ml. raises the threshold for initiating an impulse at the terminal. 5 × 10−7 g/ml. tetrodotoxin blocks the initiation of impulses.3. The receptor potential magnitude is reduced to about 60% of the control value by 5 × 10−7 g/ml. tetrodotoxin within 30‐60 min and maintains this value for a logn time. The amount of the maximum reduction in the receptor potential by 1 × 10−6 and 2 × 10−6 g/ml. tetrodotoxin is not significantly greater than the one by 5 × 10−7 g/ml. tetrodotoxin.4. No difference in the time constant of the falling phase of the receptor potential was found before and after application of tetrodotoxin.5. The mechanism underlying the generation of the receptor potential has been discussed and the difference of its mechanism from the one concerned with the junctional potential pointed out.
Calcium metabolism in normal and thyro‐parathyroidectomized goats
Authors: Payne J. M. , Sansom B. F. 
Published: December 2014

1. The effects of thyro‐parathyroidectomy on calcium metabolism in the goat have been investigated using stable calcium balance techniques and the isotopes 45Ca, 47Ca and 85Sr.2. Thyro‐parathyroidectomized goats, whether receiving supplementary thyroxine or not, are in negative calcium balance, whereas normal or thyroidectomized animals are in positive balance.3. Gastro‐intestinal absorption of 45Ca is less in thyro‐parathyroidectomized goats, whether receiving supplementary thyroxine or not, than in either normal goats or thyroidectomized goats receiving thyroxine supplements.4. The rate of endogenous secretion of calcium into the gastro‐intestinal tract is unchanged by either thyroidectomy or thyro‐parathyroidectomy. Urinary excretion of calcium is also apparently unchanged.5. The bone calcium accretion rate is reduced to approximately the same extent in thyroidectomized and thyro‐parathyroidectomized goats. Thyroxine supplements restore the bone accretion rate of both groups of animals to normal or greater than normal levels.6. The bone calcium resorption rate is greater in thyro‐parathyroidectomized goats, whether receiving thyroxine supplements or not, than in either normal goats or thyroidectomized goats receiving thyroxine supplements.