bluuebunny/crossref_metadata_2025 huggingface dataset:
On the relation between ATP splitting and secretion in the adrenal chromaffin cell: extrusion of ATP (unhydrolysed) during release of catecholamines
Authors: Douglas W. W. , Poisner A. M.
Published: December 2014

1. Cats’ adrenal glands were acutely denervated and perfused, in situ, with Locke's solution.

2. When the medullary secretogogue Ba (2‐10 m
M) was added to the perfusion medium, large amounts of AMP and traces of ATP were found in the venous effluent from the adrenal gland along with the catecholamines. In this respect Ba mimicked the physiological secretogogue, acetylcholine.

3. Control perfusions with known concentrations of ATP showed that under such conditions ATP was rapidly broken down within the adrenal vasculature.

4. When such intravascular hydrolysis of ATP was suppressed by perfusing with a Ca‐free, Mg‐free Locke's solution containing 1–2 m
M EDTA, catecholamine secretion induced by Ba was accompanied by the discharge of large amounts of ATP but relatively little AMP.

5. The ATP that accompanied catecholamine secretion in such circumstances is assumed to derive from the ‘heavy’ nucleotide‐rich chromaffin granules and it is concluded that the mechanism for catecholamine secretion does not depend on hydrolysis of the ATP within these granules.

6. The release of ATP (unhydrolysed) supports the hypothesis that the chromaffin granules discharge their contents at the cell surface by the process of ‘reverse pinocytosis’.
Pulsatile and myelin‐forming activities of Schwann cells in vitro
Authors: Ernyei Susi , Young M. R.
Published: December 2014

1. Sympathetic and dorsal root ganglia from young mice and new‐born rats were cultured in vitro. The activity of the outgrowing Schwann cells was studied with time‐lapse photography.

2. Schwann cells exhibited a pulsatile activity with a contraction rate varying from 1 to 12 min. The occurrence of pulsations depended on the mode of attachment of cells to their surroundings.

3. Fibres of various materials were introduced into the cultures in an attempt to simulate conditions obtaining in vivo. Schwann cells attached themselves to these fibres and rotated about them depositing myelin. Polarized light and histochemical studies showed that myelin was formed as early as four days in vitro.

4. The possible significance of the behaviour of Schwann cells in vitro is discussed.
The origin of the post‐tetanic hyperpolarization of mammalian motor nerve terminals
Authors: Gage P. W. , Hubbard J. I.
Published: December 2014

1. Motor nerve terminals in magnesium‐poisoned rat hemidiaphragm‐phrenic nerve preparations in vitro were stimulated with short depolarizing pulses of approximately threshold strength and the evoked antidromic responses recorded from the phrenic nerve. The percentage of these 1/sec or 0·5/sec stimuli to which there was no antidromic response was used as a quantitative measure of the terminal excitability. After standard tetanic stimulation (1000 impulses at 100/sec) the excitability of the terminals was depressed for an average duration of 60‐70 sec, during most of which time no antidromic responses to stimuli of pretetanic intensity were recorded. There was no significant interaction between stimuli to the terminals at rates of 1 or 0·5/sec.

2. Potassium‐free solutions at first increased, then decreased, the post‐tetanic depression of excitability. Raising [K]o threefold (15 m
M) abolished the post‐tetanic depression and often converted it to an exaltation of excitability.

3. Polarizing currents were applied to the terminals with a second electrode. Depolarizing currents increased, while hyperpolarizing currents decreased, the post‐tetanic depression of excitability.

4. In solutions with 70% of the normal NaCl content replaced by sucrose, the post‐tetanic depression of excitability was reversibly prolonged.

5. In the presence of 7·7 × 10−6
M digoxin or 0·42 m
M ouabain there was a small reversible reduction of post‐tetanic excitability.

6. After exposure to solutions containing no glucose or to solutions containing 3‐5 m
M sodium azide the excitability of the terminals was not altered by the tetanus. After washing with the control solution, post‐tetanic depression of excitability returned. Antimycin‐A (1·8 × 10−6
M) had little or no effect upon post‐tetanic excitability.

7. It was concluded that the post‐tetanic depression of excitability reflected hyperpolarization of the terminals and that this hyperpolarization was caused by a shift of the membrane potential towards the potassium equilibrium potential because of an increase in potassium permeability.
The relationship between ovulation and the changes in thyroid gland activity that occur during the oestrous cycle in rats, mice and hamsters
Authors: Brown-Grant K.
Published: December 2014

1. When ovulation is prevented by the injection of pentobarbitone on the day of pro‐oestrus in female rats, the expected increases in thyroid‐serum concentration ratio (T/S ratio) for 131I and in the uptake of 113I by the thyroid on the day of oestrus do not occur.

2. Ovulation induced by human chorionic gonadotrophin or ovine luteinizing hormone in rats treated with pentobarbitone at pro‐oestrus is not associated with an increase in T/S ratio or 131I uptake at oestrus.

3. These results support the view that it is the neuro‐endocrine changes at the hypothalamic or pituitary level that lead to ovulation rather than changes in the pattern of ovarian steroid secretion before or at ovulation that are responsible for the increased thyroid activity at oestrus in the female rat.

4. Experimental evidence of an increase in thyroid activity after ovulation in mice and hamsters also supports this view.
A study of parotid salivation in the horse
Authors: Alexander F.
Published: December 2014

1. Saliva flowed from the horse's parotid duct only during mastication.

2. The surface‐active local anaesthetic administered by mouth inhibited salivary secretion.

3. Salivary secretion was stimulated by pilocarpine and inhibited by atropine.

4. The volume and composition of saliva secreted in 24 hr from one parotid duct was determined.

5. The concentration of sodium, potassium, calcium, chloride and bicarbonate depended upon the rate of flow. The highest concentrations of these electrolytes were observed during periods of high flow rates.

6. Horse parotid saliva contained a high concentration of calcium.

7. In the absence of a dietary supplement of sodium bicarbonate, the sodium concentration of the saliva fell after about 21 days. There was an associated increase in the potassium concentration. The addition of a sodium supplement restored the sodium concentration of the saliva within 24 hr.
Effects of arterial hypoxia on the cutaneous circulation of the rabbit
Authors: Chalmers J. P. , Korner P. I.
Published: December 2014

1. Changes in blood flow of the skin of the rabbit's ear and hind limb have been studied during arterial hypoxia by a calibrated heat conductivity method, together with changes in arterial pressure and aortic blood temperature.

2. There is little change in the blood flow of the hind‐limb skin during the early phase of arterial hypoxia, reflecting a balance between the local dilator effects of hypoxia and the increased constrictor activity mediated through the sympathetic nerves as a result of arterial chemoreceptor excitation. During more prolonged arterial hypoxia there is a small gradual dilatation of the vessels of the hind‐limb skin as a result of some diminution in the initial intensity of vasoconstrictor activity.

3. There is much more extensive vasodilatation in the ear than in the hind‐limb skin during arterial hypoxia. Vasoconstrictor activity is slight in this region. Comparison of the ear responses to arterial and to primary tissue hypoxia suggests that in the former type of hypoxia stimulation of the arterial chemoreceptors inhibits thermoregulatory vasoconstriction to the ear, whilst in the latter type of hypoxia baroreceptor reflexes maintain or intensify it.
The control of the circulation in skeletal muscle during arterial hypoxia in the rabbit
Authors: Chalmers J. P. , Korner P. I. , White S. W.
Published: December 2014

1. The effects of arterial hypoxia on muscle blood flow were examined in normal unanaesthetized rabbits in relation to simultaneously determined changes in cardiac output, arterial pressure and heart rate. Muscle blood flow was estimated from the difference between total limb flow (local thermodilution) and the estimated skin flow (using a calibrated heat conductivity method). The role of the arterial chemoreceptors and baro‐receptors in the control of muscle blood flow was examined and the nature of the sympathetic efferent discharge analysed.

2. In mild hypoxia (PO2 > 35 mm Hg) in the rabbit, muscle blood flow did not change, although cardiac output increased. During moderate hypoxia (PO2 30‐35 mm Hg) there was initial vasoconstriction in muscle, followed by a return to control values paralleling the changes in cardiac output. In severe arterial hypoxia (PO2 < 30 mm Hg) the initial vasoconstriction was less marked, and during the ‘steady state’ there was a large vasodilatation and increase in muscle blood flow, at a time when the cardiac output was not elevated.

3. The early vasoconstriction in arterial hypoxia is mediated mainly through sympathetic vasoconstrictor nerves as a result of strong arterial chemoreceptor stimulation.

4. Increased secretion of adrenaline is an important factor in restoring muscle blood flow to control values during moderate arterial hypoxia, and in elevating the muscle blood flow above these values in severe hypoxia. The peripheral dilator (β‐) effects of adrenaline oppose the peripheral constrictor (α‐) effects resulting from increased activation of sympathetic constrictor nerves during arterial hypoxia.
The chemical and energetic properties of muscles poisoned with fluorodinitrobenzene
Authors: Dydyńska M. , Wilkie D. R.
Published: December 2014

1. The heat production and mechanical responses of frogs' sartorii have been recorded at 0° C after immersion in normal Ringer solution, and also after poisoning with 1‐fluoro‐2, 4‐dinitrobenzene (FDNB) and nitrogen. The muscles were later analysed chemically for changes in ATP, phosphocreatine (PC), inorganic phosphate (Pi), lactate, total adenine nucleotide and total inosine nucleotide.

2. Analysis of paired resting muscles established that the resting levels of these substances found in our experiments were similar to those reported elsewhere.

3. Resting muscles that had been poisoned with FDNB and N2 contained significantly more PC and less ATP than unpoisoned controls. Moreover, some of their adenine had been deaminated to inosine.

4. In a normal muscle in oxygen, the PC that breaks down as a result of a 30 sec tetanus is restored with a roughly exponential time course whose half‐time is about 10 min. Thus at least 40 min rest must be allowed between the different stages of an experiment.

5. Isometric twitches of the poisoned muscle rapidly decline in size, but small twitches continue to be produced for a very long time. If stimulation is discontinued, substantial recovery takes place. The total tension development is equivalent to at least thirty normal twitches, and correspondingly, the total heat production is greater than could be accounted for even by complete break‐down of the ATP in the muscle. In fact, the ATP break‐down, though highly significant, is not nearly complete.

6. In short series of isometric twitches there is significant break‐down of ATP and, less consistently, of PC; also a significant increase in Pi but no additional deamination of adenine. The rate of development of isometric tension is slightly decreased.

7. The results described under (6) are definitely due to the presence of FDNB. In similar experiments with the muscles in N2 but not otherwise poisoned the only significant change is a break‐down of PC.

8. In a long series of isotonic twitches the chemical effects are similar to those described under (5) and inosine formation is clearly demonstrable. The poisoned muscles show force—velocity curves of normal shape, the Fenn effect and the presence of shortening heat. Thus their contractions are normal or nearly so.

9. The complexity of the chemical reactions that continue in the poisoned muscle makes it impossible to draw up an accurate energetic balance sheet.

10. A new hypothesis is suggested to explain the energetic importance of inosine formation.
The effects of hypoxia in the new‐born lamb before and after denervation of the carotid chemoreceptors*
Authors: Purves M. J.
Published: December 2014

1. Twenty‐seven unanaesthetized new‐born lambs, 6 hr‐10 days old, responded to two levels of inspired oxygen, 125 and 110 mm Hg (alveolar CO2 being controlled) with a sustained increase in minute ventilation (V̇), a small increase in heart rate and a less consistent rise in systemic blood pressure.

2. An increase in V̇ was observed when arterial oxygen tension (Pa, O2) had fallen by 6‐15 mm Hg. There appeared to be no fixed threshold of Pa, O2 at which ventilation started to increase.

3. The increase in ventilation caused by these levels of hypoxia was significantly and directly related to the age of the lamb and to its control alveolar CO2.

4. More severe hypoxia caused a progressive increase in V̇ until Pa, O2 was about 25 mm Hg when respiration failed. This increase at Pa, O2 > 25 mm Hg was markedly potentiated when alveolar PCO2 (PA, CO2) was increased and abolished after bilateral denervation of the carotid chemoreceptors.

5. Significant (> 10%) left‐to‐right shunts were found in ten out of twelve lambs lightly anaesthetized with pentobarbitone sodium, breathing air. Hypoxia diminished the left‐to‐right pressure gradient largely by its pressor effect on the pulmonary circulation. When inspired O2 tension (PI, O2) was 70 mm Hg, all seven lambs studied showed a reversal of the pressure gradient and evidence of right‐to‐left shunts (11‐42%) across the ductus arteriosus.

6. The implications of these findings have been discussed with reference to previous studies of the new‐born response to hypoxia and it is concluded that the peripheral chemoreceptors are fully active at birth and in the new‐born period.
Nerve‐mediated excitation of the taenia of the guinea‐pig caecum
Authors: Campbell G.
Published: December 2014

1. A study was made of the responses of the isolated taenia of the guinea‐pig caecum to stimulation of the intramural nerves.

2. Four types of response are described, made up of a contraction and/or a relaxation occurring during stimulation and an after‐contraction occurring when stimulation is stopped.

3. A delayed relaxation which sometimes occurred at the end of stimulation is also described.

4. Atropine usually abolished the contractions occurring during stimulation. After‐contractions either appeared or were increased in amplitude in the presence of atropine, and delayed relaxations were abolished.

5. The anti‐cholinesterase drug neostigmine could convert the response during stimulation from a relaxation to a contraction. After‐contractions were often abolished by neostigmine and delayed relaxations appeared.

6. It is concluded that the contractions which occurred during stimulation were mediated by cholinergic nerves. The after‐contraction appears to be a rebound phenomenon, following the hyperpolarization of the muscle caused by stimulation of the inhibitory nerves. It is suggested that the delayed relaxation is caused by the effects of persisting inhibitory transmitter substance on cells which do not undergo rebound excitation.
The time course of early changes in the rate of tension development in electrically‐stimulated frog toe muscle: effects of muscle length, temperature and twitch‐potentiators
Authors: Foulks J. G. , Perry Florence A.
Published: December 2014

1. An RC circuit employing a piezo‐electric crystal was used to differentiate the tension output of electrically stimulated frog toe muscle.

2. The rate of tension development curves (dP/dt) usually displayed an initial step‐wise increase in the rate of tension development, and often showed further discernible steps in tension acceleration. The successive stages of tension acceleration tended to be equal in duration, and approximated the length of the latent period (ca. 4 msec at room temperature). These observations suggest a synchronous turnover of the links between the myofilaments during the initial interval following stimulation, with an over‐all cycle time at room temperature of about 8 msec.

3. Lowering the temperature produced proportionate alterations in the duration as well as the magnitude of each successive phase of tension development, with a Q10 of approximately 2.

4. Characteristic changes in the pattern of tension generation were seen with alterations in muscle length, and at lengths greater than 120% of the standard length the irregularities in the dP/dt curves disappeared and the rate of tension development increased in linear fashion. This behaviour could be accounted for by the hypothetical S‐filaments connecting the free ends of the thin actin filaments across the H‐zone.

5. The effects of nine twitch potentiators were studied. Only perchlorate produced prominent increases in the earliest phase of tension development and in maximum tetanus tension—properties expected with an increase in the excitation‐induced release of calcium ion into the sarcoplasm (increased intensity of the ‘active state’).

6. The time of onset of the increases in tension acceleration which were produced by twitch potentiators did not correlate with their capacity to lower the ‘mechanical threshold’, indicating that the amount of calcium released by the action potential is not necessarily altered by a shift in the membrane potential at which calcium release occurs.

7. All potentiators studied proved capable of (a) augmenting the rate of increase of tension generation (slope of dP/dt curves) during their rapid phase, as well as (b) increasing the interval during which the dP/dt curves for twitch and tetanus coincide. These effects occurred separately. It is suggested that both of these effects may be explained on the basis of delayed removal of sarcoplasmic calcium ion, resulting in prolongation of the ‘active state’.
Analysis of some central actions of nicotine injected into the cerebral ventricles of cats
Authors: Hall G. H. , Reit E.
Published: December 2014

1. In unanaesthetized cats intraventricular injections of 2·5‐10 μg nicotine produced blinking, narrowing of the palpebral fissures, retching, vomiting and asynchronous twitching of the ears. With larger doses (30‐100 μg) the ear twitching was interrupted for a short time by laying back of the ears. Respiration first became laboured and deep, then rapid and shallow following which panting occurred. There was salivation, loud calling, micturition and defaecation. With still larger doses (300‐1000 μg) there was torticollis, ataxia and blind charging sometimes followed by a clonic‐tonic convulsion.

2. In cats anaesthetized with chloralose only some of these effects followed the intraventricular injection of nicotine, i.e. the ear response, respiratory changes and salivation. In addition, the pinna reflex was facilitated.

3. The ear response and the facilitation of the pinna reflex did not occur on perfusion of nicotine from a lateral ventricle to aqueduct. They result from an action on superficial structures in the cervical cord between C1 and C2. Applied to this region of the cord, nicotine produced the ear response within 10‐60 sec, sometimes in concentrations as low as 1/100,000. Applied below C2, nicotine was ineffective.

4. Transecting the cord below C2 or cutting the dorsal and ventral roots of C1, C2 and C3 bilaterally did not affect the ear response produced by topical application or by intraventricular injection of nicotine. Transection of the cord above C1 abolished it.

5. Hexamethonium applied to the cervical cord between C1 and C2 inhibited the ear response and the facilitation of the pinna reflex whether produced by nicotine applied topically or injected intraventricularly.

6. The salivation and the respiratory changes produced by intraventricular injections of nicotine did not occur when nicotine was perfused from a lateral ventricle to the aqueduct. They result from an action of the nicotine on structures situated superficially in the brain stem. Nicotine had no sialogogue or respiratory effect when applied to the region of the cord at which it produced an ear response, but perfused through the subarachnoid space from interpeduncular fossa to cisterna magna or injected into the subarachnoid space alongside the brain stem, it produced these effects.

7. Hexamethonium perfused from interpeduncular fossa to cisterna magna inhibited the salivary secretion as well as the respiratory changes produced by nicotine similarly applied.

8. The efferent pathway for the salivation is parasympathetic since it no longer occurred after cutting the chorda‐lingual nerve or after intravenous atropine.

9. Intravenous injections of nicotine also produced the ear response with facilitation of the pinna reflex, salivation and hyperventilation in the anaesthetized cat, but only the ear response and facilitation of the pinna reflex are central effects. The salivation and hyperventilation following intravenous injection are due to peripheral actions of nicotine.
Electrical properties of the smooth muscle membrane of the guinea‐pig vas deferens
Authors: Hashimoto Y. , Holman Mollie E. , Tille J.
Published: December 2014

1. The effects of polarizing current on single smooth muscle cells of the isolated guinea‐pig vas deferens have been studied by means of a bridge circuit in which the same electrode was used to pass current and record membrane potential.

2. Most cells had polarization resistances from 15 to 37 MΩ.

3. Depolarizing currents caused graded spikes up to a maximum amplitude of 75 mV.

4. Self‐regenerative spikes occurred in some cells if the membrane was depolarized by > 35 mV.

5. Currents of long duration and sufficient intensity caused a repetitive discharge.

6. Spikes arising from excitatory junction potentials were always ‘all‐or‐none’ in contrast to the graded responses to intracellular stimulation.

7. Electrotonic potentials declined much more rapidly than spontaneous excitatory junction potentials (EJPs); thus the time course of the EJP cannot be determined by the passive electrical properties of the smooth muscle cell membrane.
The blood flow and oxygen consumption of brown adipose tissue in the new‐born rabbit
Authors: Heim T. , Hull D.
Published: December 2014

1. A direct method for measuring venous outflow from brown adipose tissue in anaesthetized new‐born rabbits is described.

2. During noradrenaline infusion the mean blood flow through brown adipose tissue increased from 87 to 360 ml./100 g tissue (wet wt.).min, and the mean rate of oxygen consumption of brown adipose tissue rose from 9·3 to 60 ml. O2/100 g tissue.min.

3. During cold exposure the mean blood flow through brown adipose tissue increased from 90 to 304 ml./100 g tissue.min.

4. The mean cardiac output was 266 ml./kg body weight.min; during noradrenaline infusion it was 405 ml./kg body weight.min. At rest about one tenth, and during noradrenaline infusion about one quarter of the cardiac output went to brown adipose tissue.

5. It was calculated that most of the extra oxygen consumed during the metabolic response of the anaesthetized new‐born rabbit to noradrenaline infusion or cold exposure was consumed by brown adipose tissue.

6. Hypoxia (breathing 10% O2 in N2) greatly reduced the increase in oxygen consumption but not the increase in blood flow in brown adipose tissue caused by noradrenaline infusion.
An electrophysiological study of odour similarities of homologous substances
Authors: Döving K. B.
Published: December 2014

1. The activity of single bulbar units in the olfactory system of the frog was recorded extracellularly by means of micro‐electrodes. The electro‐olfactogram was recorded simultaneously from the receptor epithelium.

2. The olfactory epithelium was stimulated with substances of homologous series of normal aliphatic alcohols, acetates and ketones.

3. The effect on a bulbar unit was classified as excitatory or inhibitory, and the chi‐square values calculated with one degree of freedom for all pairs in a given series. The statistical values obtained indicated the degree of similarity in olfactory stimulative properties between the odours.

4. The results show that the degree of similarity in olfactory properties is greatest among neighbouring substances and gradually decreases with increasing separation in chain length.

5. Significant rank correlation coefficients were found between the chi‐square values and the molecular weight ratios for alcohols and acetates. The results are discussed in relation to psychophysical findings obtained with the same substances.
Effect of amino acids on sugar absorption
Authors: Hindmarsh J. T. , Kilby D. , Wiseman G.
Published: December 2014

1. Sacs of everted mid‐small intestine of the hamster have been used to study the effect of amino acids on sugar absorption.

2. The sugars employed were
D‐glucose,
D‐galactose, 3‐O‐methyl‐
D‐glucose,
D‐fucose,
L‐glucose, α‐glucoheptose,
L‐fucose,
D‐mannose and
L‐sorbose. The amino acids were
L‐ and
D‐histidine,
L‐ and
D‐methionine,
L‐ and
D‐alanine,
L‐ and
D‐valine,
L‐ and
D‐glutamic acid,
L‐leucine,
L‐proline,
L‐ornithine and
L‐aspartic acid.

3. Actively absorbed amino acids considerably inhibit the transport of actively absorbed sugars. The results give support for the view that
D‐histidine and
L‐glucose are actively transferred. Passively absorbed amino acids and sugars are not involved.

4. As
L‐glutamic and
L‐aspartic acids in the mucosal fluid have no inhibitory effect on
D‐glucose absorption, although mucosal fluid
L‐alanine is quite potent, the step at which the latter exerts its inhibitory action must be before that at which the intracellular transamination of
L‐glutamic and
L‐aspartic acids occurs. It would seem likely, therefore, that
L‐alanine interferes with the process by which epithelial cells capture and concentrate sugars at the luminal border.

5. More than one active transfer system may exist for
D‐glucose.

6. The influence of actively absorbed
L‐amino acids on
D‐glucose active transport seems to be in some way related to the efficiency with which the amino acids are themselves concentrated.

7. Inhibition of
D‐glucose active absorption by an amino acid may be a simple test of an amino acid's participation in an active transport system.
The effects of hyperventilation on the reflex cardiac response from the carotid bodies in the cat
Authors: Scott Mary J.
Published: December 2014

1. Cats were anaesthetized with chloralose and urethane, and ventilated by an artificial intermittent negative pressure applied to the thorax. The carotid body chemoreceptors were isolated and perfused with oxygenated blood. They were stimulated by substituting hypoxic blood obtained from a donor animal.

2. Stimulation of the carotid bodies during constant ventilation caused a bradycardia. When an artificial hyperventilation was induced during carotid body stimulation the heart rate increased.

3. The increase in heart rate during hyperventilation, and while the carotid bodies were being stimulated, was due to at least two mechanisms, first a reflex from the lungs and secondly a fall in arterial blood PCO2, both of which accompany the hyperventilation.
Effects on temperature of monoamines injected into the cerebral ventricles of anaesthetized dogs
Authors: Feldberg W. , Hellon R. F. , Myers R. D.
Published: December 2014

1. In dogs anaesthetized with pentobarbitone sodium an injection of adrenaline or noradrenaline into the cerebral ventricles through a cannula implanted into the left lateral ventricle caused a fall in rectal temperature as a result of cessation of shivering, loss of muscle tone, and skin vasodilatation. 5‐Hydroxytryptamine (5‐HT) similarly applied caused shivering and a rise in rectal temperature.

2. The hypothalamus of the dog thus appears to react to the three monoamines in the same way as in the cat, and not as in the rabbit and sheep.
The effect of uranyl nitrate on intestinal transfer of hexoses
Authors: Newey H. , Sanford P. A. , Smyth D. H.
Published: December 2014

1. Uranyl nitrate in a concentration of 3 × 10−4
M caused reduction in mucosal transfer of glucose but not of galactose nor 3‐O‐methyl‐glucose by sacs of rat everted intestine. At this concentration uranyl nitrate had little effect on glucose metabolism (measured by glucose disappearance).

2. Uranyl nitrate in a concentration of 3 × 10−3
M caused reduction in transfer of glucose, galactose, 3‐O‐methyl‐glucose and fluid, and inhibited glucose metabolism.

3. Uranyl nitrate did not inhibit entry of glucose into the intestine under anaerobic conditions.

4. Glucose was found to inhibit or stimulate galactose transfer depending on the conditions. The inhibitory action is presumably by competition for a common carrier, whereas stimulation indicates that glucose metabolism can supply energy for galactose transfer.

5. It is suggested that there are two different routes for glucose in the cell, one of which is uranyl sensitive and not used by galactose, and the other is uranyl insensitive and shared by both hexoses. The implications of this are discussed in relation to transport and metabolism.
Absence of adrenal influence on ovarian graft activity in male rats castrated at birth
Authors: Smith W. N. Adams
Published: December 2014

1. An investigation was made to see whether the presence of the adrenal gland was necessary for cyclical activity of ovarian transplants in adult male rats which had been castrated at birth.

2. Rats were castrated on the day of birth or at 6‐8 weeks of age and when 3 months old were adrenalectomized and had a transplant of immature ovary placed in the anterior chamber of one eye. Control animals were subjected to the same procedure apart from adrenalectomy.

3. Transplants in rats castrated at birth were observed to undergo full cyclical activity, with follicular rupture and the formation of corpora lutea. Transplants in rats castrated at 6‐8 weeks of age did not cycle and corpora lutea were not formed.

4. Adrenalectomy did not influence the behaviour of the ovarian transplants.

5. It is concluded that the presence of the adrenal gland was not necessary to support cyclical activity in ovarian tissue transplants in male rats castrated at birth.
The release of acetylcholine from the spinal cord of the cat by antidromic stimulation of motor nerves
Authors: Kuno M. , Rudomin P.
Published: December 2014

1. ACh was measured in the effluent from the perfused lumbosacral cord of the cat with or without stimulation of the central ends of the cut left sciatic and femoral nerves after section of the left dorsal roots.

2. In about 30% of the preparations ACh was obtained in the samples collected at rest (average 3·3 ng/min); the amount of ACh release was increased 1·3‐9 times by stimulation of the peripheral nerves. The average amount of ACh collected during stimulation of the peripheral nerves at 5/sec was 6·9 ng/min. Antidromic motor nerve impulses responsible for the ACh release were likely to be only those in alpha motor fibres.

3. There was a depression in ACh release/stimulus as the stimulus frequency was increased more than 10/sec. Such changes in ACh release with various stimulus frequencies were correlated with depression in the response of Renshaw cells to excitation through motor‐axon collaterals.

4. Amounts of ACh release during stimulation of the peripheral nerves at 5/sec were significantly increased for 1 or 2 min after a short tetanic stimulation of the nerves.

5. Intravenous injection of dihydro‐β‐erythroidine did not reduce the amount of ACh release produced by stimulation of the peripheral nerves.

6. It is concluded that antidromic impulses in alpha motor fibres liberate ACh from the presynaptic terminals at the central synapses on Renshaw cells.
Mechanoreceptors in rabbit ear skin innervated by myelinated nerve fibres
Authors: Miller S. , Weddell G.
Published: December 2014

1. The activity of single myelinated fibres innervating mechanosensitive units in the dorsal skin of the ears of New Zealand White and Chinchilla rabbits has been recorded with glass micropipette electrodes, inserted into intact bundles of the great auricular nerve.

2. Only two types of afferent unit were observed: hair units, sensitive to hair displacement, and skin spot units, sensitive to deformation of spot‐like areas of skin between the hair orifices. Hair units were more numerous and no unit contained receptors of both types. Up to nine hairs or six skin spots composed each hair or skin spot unit, respectively. Both types were rapidly adapting.

3. The areas of the receptive fields of the hair units were significantly larger in the New Zealand White than in the Chinchilla strain.

4. In the hair units from the Chinchilla rabbits: (a) there was no correlation between the receptive field areas and the conduction velocities of the afferent fibres; (b) the areas and conduction velocities of the units showed no significant topographical distribution over the ear; (c) the extent of the overlap of the receptive fields was estimated and the sum of the areas is shown to be about 40 times the area of the ear.
Glucose metabolism during ontogeny of intestinal active sugar transport in the chick
Authors: Bogner Phyllis Holt , Braham Ann H. , McLain Paul L.
Published: December 2014

1. Glucose transport, uptake, utilization, and lactate production by intestinal slices from embryos and young chicks have been determined by means of the in vitro tissue accumulation method. Changes in these parameters with age, after feeding, and in the presence of phlorrhizin have been measured, in most cases, under both aerobic and anaerobic conditions.

2. The embryonic intestine, 3 days before hatching, took up and utilized only a negligible quantity of glucose from the incubating medium and net lactate production was limited. The transport and utilization of exogenous sugar thus seem to be minimal at this age.

3. On the day of hatching, the intestine concentrated and utilized glucose, and lactate production was significant as was the inhibition of glucose uptake by phlorrhizin. This capacity to metabolize exogenous sugar appears to be consequent to onset of function of the sugar transport mechanism just before hatching.

4. At 2 days of age intestinal slices concentrated and utilized more glucose than at 0 days of age, if the chicks were not fed. After eating, glucose transport was decreased while lactate production was enhanced. Feeding schedules thus influence sugar transport and metabolism by the young chick intestine.

5. The metabolic parameters measured showed essentially the same relationships in intestinal slices from 8‐ and 36‐day‐old chicks as in 2‐day‐old birds. Although there were indications that intestinal maturation continues well into post‐natal life, the most striking changes in functional capacity, observed in these studies, occurred during the several days around hatching.
Orientational selectivity of the human visual system
Authors: Campbell F. W. , Kulikowski J. J.
Published: December 2014

1. It is known that an object is less detectable when it is viewed against a background containing structures similar to the object. The effect of changing the orientation between the object and background is investigated.

2. Gratings of variable contrast were generated on two oscilloscopes; these were superimposed optically. The angle of orientation between them could be changed. The threshold of one grating, the test grating, was determined in the presence of the other, the masking grating.

3. When the gratings were presented with the same orientation (and locked in phase) the increment threshold of the test grating was found to be proportional to the suprathreshold contrast of the masking grating.

4. As the angle between the test and masking gratings was increased the masking effect fell exponentially.

5. At 12° on either side of a vertical test grating the masking effect was reduced by a factor of two with respect to its maximum value. This angle was independent of the contrast level of masking, the focus, and also the phase coherence of the masking grating.

6. If the test grating was presented obliquely the effect of masking was slightly less.

7. The narrow orientationally tuned channels found psychophysically by this masking technique are compared with the orientationally sensitive cells discovered electrophysiologically in the visual cortex of the cat.
The effect of beta adrenergic receptor blockade on the vasodilator response in the forearm to voluntary hyperventilation
Authors: Brick I. , Hutchison K. J. , Roddie I. C.
Published: December 2014

1. Blood flow was simultaneously measured by venous‐occlusion plethysmography in both forearms of ten healthy men.

2. Voluntary overbreathing to produce about 8 times the resting ventilation caused a vasodilatation similar in both forearms.

3. When one forearm was treated with an intra‐arterial infusion of propranolol, a beta adrenergic blocking agent, the vàsodilator response was reduced by an average of 28%, the reduction was significant (P < 0·01).

4. The failure of propranolol to abolish the vasodilator response was not due to incomplete block of beta adrenergic receptors since the dose of propranolol used reversed the vasodilator response to an intravenous infusion of adrenaline.

5. The results suggest that the vasodilator response to voluntary hyperventilation can be explained partly, but not entirely, by the release into the circulation of an adrenaline‐like substance.
Units in the cerebral cortex of the anaesthetized rat and the correlations between their discharges
Authors: Holmes O. , Houchin Jane
Published: December 2014

1. Extracellular records have been made of spontaneous unitary activity in the cortex of the anaesthetized rat. If the animal is anaesthetized with sufficient urethane almost to abolish reflex contractions of leg muscles when a hind paw is stimulated, two types of spontaneously active unit are found. One type of unit is found in all areas of the cortex which have been studied, and gives high voltage discharges. The other has only been found in restricted areas of cortex and gives low voltage discharges.

2. The activity of the former type of unit has been analysed. In the unstimulated animal, groups of relatively frequent discharges are separated by periods of quiescence. Apart from this, the discharge pattern appears irregular on naked‐eye examination. Synchronous with these periods of frequent discharge, the electrocorticogram exhibits rapid oscillations. Peripheral stimulation of the animal can modify the pattern of discharge of this type of unit. Details of these observations are described.

3. The results are described of experiments in which simultaneous records have been taken from pairs of units in the cerebral cortex. The intensity of correlation between the two units has been measured as a function of temporal displacement (lag) between the two records.

4. With fairly deep urethane anaesthesia, the highest correlation between the two unitary discharges occurs at zero lag if the two units are close together or if they are far apart but in the same coronal line, e.g. if the recording electrodes lie in homologous areas of the two cerebral hemispheres. If one unit is in the anterior pole of a hemisphere and the other in the posterior pole, the discharges are usually synchronous. However, it has sometimes been found that the anterior of the pair of units discharges impulses which precede those of the posterior unit by up to 100 msec. The highest intensity of correlation is then appropriately displaced to 100 msec.

5. The correlation fluctuates rhythmically with a period of 1·8‐2 sec, slowly damps out and is symmetrical around the point of highest correlation.

6. Increasing the sensory bombardment of the cortex reduces or abolishes the correlation between the activity of pairs of units.

7. Under Nembutal anaesthesia sufficient to abolish reflex contractions of leg muscles when a hind paw is pinched, no spontaneous cortical unitary activity has been found. When anaesthesia is ligher, spontaneous activity does occur and consists of bursts of up to six impulses at a frequency of 300‐500/sec. When simultaneous records from two units have been made, no correlation has been found between their activity.
An upper limit to the number of sodium channels in nerve membrane?
Authors: Moore J. W. , Narahashi T. , Shaw T. I.
Published: December 2014

1. A small volume of artificial sea water containing 300 n
M tetrodotoxin (TTX) was applied successively to seven lobster nerve trunks and the cumulative uptake of toxin investigated by bio‐assay.

2. Light and electron microscopy indicated that the nerve trunks had a total axonal area of 0·7 × 104 cm2/g.

3. Sodium analysis gave a sodium space for the nerve trunks of 30%.

4. The amount of toxin taken up by the cells in 1 g of nerve is less than 1·6 × 10−11 moles.

5. It is argued that there are probably fewer than 13 sodium channels/μ2 axon in lobster nerve.
Active sodium transport by the colon of Bufo marinus: stimulation by aldosterone and antidiuretic hormone
Authors: Cofré G. , Crabbé J.
Published: December 2014

1. The isolated colon of Bufo marinus transports sodium actively from the mucosal (lumen) to the serosal side, and this transport is expressed quantitatively by the short‐circuit current.

2. Upon dilution of sodium in Ringer solution on the mucosal side of the preparation, short‐circuit current remained a fair expression of sodium transport from mucosa to serosa.

3. In view of this, the relation between short‐circuit current and dilution of sodium of the luminal side was examined. This relation was curvilinear, which suggests the intervention of a saturable step in the transfer of sodium from lumen to serosal surface of colon.

4. The relation between short‐circuit current on the one hand, and the amount of sodium drawn from the luminal side and recovered in the membrane (‘active sodium transport pool’) on the other hand, appeared (almost) linear instead. This is meant to indicate that the ‘pump’ operates far from capacity. Hence, the observed saturation of sodium transport, when concentration of sodium on the mucosal side was increased, probably occurs at the mucosal border of the preparation.

5. After treatment with aldosterone, the ‘active sodium transport pool’ and short‐circuit current increased to the same extent, from which it is inferred that the hormone merely allows sodium easier access to the ‘pump’ which would react in proportion. Consequently, no direct influence of aldosterone on the ‘pump’ proper need be postulated.

6. Upon exposure of the colon to antidiuretic hormone, there were (modest) increases of short‐circuit current and of osmotic water flow across the wall of the organ.
The experimental production of watery vacuolation in the acinar cells of the submandibular gland
Authors: Tapp R. L. , Trowell O. A.
Published: December 2014

1. Watery vacuolation in the acinar cells of the rat submandibular gland is described. The vacuoles are cytoplasmic, membrane‐walled, and 2‐20 μ in diameter. They are visible in living cells and appear to contain a watery fluid.

2. Vacuolation occurred regularly in the following experimental situations: (1) in vitro—under anoxic conditions (2) post mortem—in animals killed by anoxia, and (3) in vivo—during secretion.

3. By in vitro experiments it was shown that vacuolation occurs only when the cells are both anoxic and exposed to an excess of extracellular fluid containing calcium and bicarbonate. It was further shown that vacuolation is reversible in oxygen and that both its development and recovery are temperature dependent.

4. Evidence is presented that the vacuolation is not a degenerative or necrotic change, that it is accompanied by the entry of fluid into the cells, and that it is not caused by simple osmosis.

5. The mechanism of vacuolation and its possible relation to secretion are discussed. It is suggested that vacuolation represents an imbalance between the ingestion and secretion of water and salts.

6. Similar vacuoles, apparently produced by the same mechanism, were observed in the acinar cells of the parotid gland and the pancreas of the rat.

7. The close similarity of this vacuolation to that previously described in rat liver cells was noted.
Mechanics of horizontal movement of the human eye
Authors: Childress D. S. , Jones R. W.
Published: December 2014

1. The mechanics of the muscle—eyeball system of the human has been re‐investigated by careful examination of the motion of the eye after it is mechanically adducted and released by means of a suction contact lens attached to it.

2. Orbital stiffness during adduction is found to be about 1·25 g/deg which is near the value of 1·2 g/deg reported by Robinson (1965) for abduction. However, the results also show that the stiffness decreases to 0·65 g/deg after approximately 5° of adduction.

3. It is concluded that for horizontal motion the globe may be considered as being in series with an elastic component which has a stiffness of 9·0 g/deg. This series elastance, arising from the extraocular muscles, muscle tendons, and from other orbital tissue appears to increase in stiffness as muscle innervation increases.

4. The experiments show that the muscle—eyeball system of the human is heavily damped which confirms the results of Robinson (1964).

5. Evidence is presented which indicates that the extraocular muscles are dominant factors in horizontal eye motion.
Receptive fields and trigger features of ganglion cells in the visual streak of the rabbit's retina
Authors: Levick W. R.
Published: December 2014

1. A survey of the properties of retinal ganglion cells in the central part of the rabbit retina has been carried out.

2. The five types of unit previously encountered in the peripheral retina were also found in the central region. Their receptive fields were smaller, and tended to be oval‐shaped with the long axis horizontal.

3. In addition, three new types were discovered: orientation‐selective cells, local‐edge‐detectors, uniformity‐detectors.

4. Orientation‐selective cells were sensitive to either vertically or horizontally extended targets. Analysis suggested they were modified concentric units with an incomplete antagonistic surround.

5. Local‐edge‐detectors responded to the appearance or movement of a contrasting border within the receptive field. They were inhibited by similar stimulation of the region surrounding the receptive field. Detailed attention was given to the demonstration of edge‐detection.

6. Uniformity detectors had a relatively high level of ongoing activity in the absence of stimulation. All forms of stimulation (lights flashed on or off, movement of darker or lighter targets) produced a diminution or cessation of ongoing activity.

7. The results are compared with behaviour described in other species.
The regional distribution of the nerve‐stimulating phosphopeptide (nerveside, substance B) in the central nervous system
Authors: Toh C. C.
Published: December 2014

1. The nerve‐stimulating phosphopeptide, nerveside, is present mainly in the cerebrum and brain stem, while the cerebellum contains only a trace amount of it.

2. Nerveside is uniformly distributed over all parts of the cerebral cortex.

3. The cerebral cortex contains the greatest concentration of nerveside. If the nerveside activity of 1 g cerebral cortex is expressed as 100 then the relative activities of the other parts of the
C.N.S. are hippocampus 41, caudate nucleus 21, diencephalon (without hypothalamus) 24, midbrain 19, pons 7, medulla 12 and cerebellum 6.

4. The nerveside activity of the hypothalamus is the same as that of the cerebral cortex.

5. The pattern of distribution of nerveside in the
C.N.S. suggests that it may be part of a corticipetal or corticifugal system.