bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drinking induced by injection of angiotensin into the brain of the rat
Authors: Epstein A. N. , Fitzsimons J. T. , Rolls Barbara J. 
Published: December 2014

1. When applied directly to the brain, angiotensin II amide, as either the valine5 octapeptide, causes rats in normal fluid balance to drink water.2. The drinking response to angiotensin injections is copious, rapid, repeatable within the same test session, and stable over months of testing in the same animal.3. The response is motivationally potent and specific. After injection the animals move directly to the source of water and drink. There is typically no preliminary hyperactivity or subsequent depression. The animals do not eat, gnaw or exhibit other behaviours that are not normally seen during spontaneous drinking. The injections rouse sleeping animals to drink and interrupt eating in animals deprived of food for two days.4. The region of the brain that is most sensitive to angiotensin includes the anterior hypothalamus, the preoptic region, and the septum including the nucleus accumbens.5. Intracranial renin elicited drinking. Bradykinin and vasopressin did not, nor did adrenaline, noradrenaline or aldosterone. In the most sensitive region, sites positive for angiotensin also yielded drinking to carbachol.6. Responses were obtained with 5 ng (ca. 5 p‐mole) and occurred reliably with 50 ng angiotensin or more. The dose—response curve for amount drunk rose from 5 to 100 ng and levelled off thereafter. Angiotensin is therefore the most potent dipsogen known and is effective at doses that are reasonably within the concentration range for circulating endogenous angiotensin.7. Injections into the sensitive region of doses of angiotensin that were effective for drinking did not produce peripheral haemodynamic changes in lightly anaesthetized rats.8. This work strengthens the suggestion that angiotensin is a natural hormone of drinking behaviour that participates in extracellular thirst by its release from the kidney and subsequent direct action on a specific chemoreceptive region in the anterior diencephalon and limbic lobe.
Spontaneous activity of neurones of nucleus reticularis thalami in freely moving cats
Authors: Mukhametov L. M. , Rizzolatti G. , Tradardi V. 
Published: December 2014

1. Fifty‐four neurones of the caudal part of the nucleus reticularis thalami (nuc. ret.) were recorded during different phases of sleep and wakefulness in unanaesthetized freely moving cats.2. During wakefulness the activity of the neurones was characterized by a continuous, well‐spaced discharge. The mean firing rate was 35·58 ± 15·06 spikes/sec (average ±
S.D.).3. During sleep with synchronized e.e.g. (S‐sleep) the neurones fired in high frequency bursts with long pauses in between. Each burst was formed of 10–15 spikes. Often the bursts were followed by prolonged discharges formed of spikes well spaced one from the other. Bursts followed by prolonged activity were more commonly observed at the beginning of S‐sleep and during the S‐sleep periods preceding sleep with desynchronized e.e.g., whereas bursts immediately followed by silence were more frequent in the S‐sleep periods with e.e.g. delta waves. The long periods of silence between the bursts usually lasted over 200 msec and values greater than 1 sec were frequently found. The mean firing rate of neurones during S‐sleep was 19·22 ± 10·50 spikes/sec.4. During sleep with desynchronized e.e.g. (D‐sleep) the activity of the neurones was, as during wakefulness, characterized by a continuous, well spaced, unclustered discharge. The mean firing rate was 40·00 ± 18·74 spikes/sec. During the rapid eye movements of this phase most units increased the frequency of their discharge, which, nevertheless, maintained the unclustered feature proper to the desynchronized phase of sleep.5. Interspike interval distribution was similar during wakefulness and sleep with desynchronized e.e.g., whereas that for sleep with synchronized e.e.g. was markedly different from those for both the other stages.6. The implications of the striking similarity between the activity of reticularis neurones during wakefulness and sleep with desynchronized e.e.g. are discussed.
Time course of the sodium permeability change during a single membrane action potential
Authors: Atwater Illani , Bezanilla Francisco , Rojas Eduardo 
Published: December 2014

1. A method for measuring the time course of ionic fluxes during a non‐propagated membrane action potential is described; the technique combines intracellular perfusion of the squid giant axon with radioactive tracer methods and with a method for controlling the membrane potential during small time intervals.2. The method is used to determine the temporal course of the sodium extra influx during an action potential.3. The results agree with the time course of the permeability change to sodium ions calculated with the Hodgkin & Huxley equations.4. An average extra sodium influx of 7·13 p‐mole/cm2 per action potential was determined at 12° C and of 5·23 p‐mole/cm2 per action potential at 15° C.
The activity characteristics of the preganglionic pupilloconstrictor neurones
Authors: Sillito A. M. , Zbrożyna A. W. 
Published: December 2014

1. Recordings have been made of pupilloconstrictor unit activity within the small‐celled component of the oculomotor nucleus of the cat. The identity of these neurones was determined by testing unit responses to a sequence of stimuli which produced dilation and constriction of the sympathectomized pupil.2. The frequency range of unit activity was from 0 to 28/sec. A maximal constriction of the pupil was maintained by unit activity in the region of 8/sec. The resting level of unit activity under chloralose anaesthesia was typically in the range 6–10/sec.3. Stimulation in the defence area of the hypothalamus produced a maximal pupillodilation associated with a complete inhibition of unit activity and a block of the light reflex response.4. Onset of retinal illumination produced a burst discharge followed by a transient silent period and then an over‐all increase in the rate of activity.5. Cessation of retinal illumination produced a post‐excitatory depression of unit activity lasting from 190 to 700 msec. It is suggested that this effect is produced by retinal afferents activated by light ‘off’ that exert an inhibitory influence on the pupilloconstrictor neurones.
The form and distribution of the surface evoked responses in cerebellar cortex from intercostal nerves in the cat
Authors: Coffey G. L. , Godwin‐Austen R. B. , Macgillivray B. B. , Sears T. A. 
Published: December 2014

1. The form and distribution of the cerebellar evoked responses to electrical stimulation of intercostal and other thoracic segmental nerves were investigated in anaesthetized cats.2. Low intensity stimulation (< 2 × nerve threshold) evoked short latency, low amplitude (< 20 μV), initially surface positive responses which could only be distinguished with certainty from the electrocorticogram with averaging.3. On the basis of experiments involving sectioning of afferent tracts it is concluded that intercostal evoked responses of less than 7·0 msec latency are conducted in dorsal spino‐cerebellar, ventral spino‐cerebellar and dorsal column (cuneo‐cerebellar) pathways.4. The surface positive waves have a highly punctate distribution with a steep potential gradient extending over an area of about 1 mm diameter. It is postulated that these small fields represent activation of single or few mossy fibre inputs.5. Short latency responses to thoracic inputs were found only in the ipsilateral intermediate cortex and lateral margin of the vermis of the anterior lobe (lateral two thirds of Larsell's lobules IV and V of the accessible cortex). The responses were distributed throughout the fore and hind limb areas of the anterior lobe and no rostro‐caudal or medio‐lateral segmental organization was seen.6. It is suggested that the overlapping distribution of thoracic and fore and hind limb mossy fibre inputs within the cerebellar cortex provides an anatomical basis for the integration of information from the trunk and from the limbs.
The elastic constants of the human lens
Authors: Fisher R. F. 
Published: December 2014

1. When the lens is spun around its antero‐posterior polar axis in an apparatus designed for the purpose, high speed photography can be used to record its changing profile. By this method a variable radial centrifugal force can be applied to the lens which mimics the pull of the zonule.2. If the lens is not stressed at its centre beyond 100 Nm−2 it behaves as a truly elastic body. When stressed beyond this limit visco‐elastic strain is produced at its poles.3. The human lens has isotropic elastic properties at the extremes of life, but at the other times Young's Modulus of Elasticity varies with the direction in which it is measured.4. Young's Modulus of Elasticity of the lens varies with age, polar elasticity and equatorial elasticity, at birth being 0·75 × 103 and 0·85 × 103 Nm−2 respectively, while at 63 years of age both are equal to 3 × 103 Nm−2.5. A comparison of Young's Modulus of the young human lens with that of the rabbit and cat shows that the polar elasticity of the lenses of these animals was 5 times greater in the young rabbit, and 21 times greater in the adult cat. Equatorial elasticities of the rabbit and human lens were equal, while in the cat the equatorial elasticity was four times greater.6. A mathematical model showing the lens substance possessing a nucleus of lower isotropic elasticity than that of the isotropic elastic cortex surrounding it, accounts for the difference between polar and equatorial elasticity of the intact adult lens.7. The implications of these findings are discussed in relation to:(i) accommodation and the rheological properties of the lens;(ii) possible differences in the physical state of the lenticular proteins in the cortex and nucleus which may account for the senile variations in Young's Modulus of Elasticity in these regions of the lens;(iii) the loss of accommodation due solely to an increase in Young's Modulus of Elasticity of the lens between the ages of 15 and 60. This would amount to 44% of the total observed in vivo.
Optical studies on the kinetics of the sodium pump in mammalian non‐myelinated nerve fibres
Authors: Landowne D. , Ritchie J. M. 
Published: December 2014

1. A study has been made of the changes in the fluorescence of desheathed rabbit cervical vagus nerves that occur during and after electrical stimulation of its non‐myelinated fibres.2. Stimulation for 5 sec at 30 shocks/sec produces a maximal decrease, of about 1% of the resting fluorescence. Stimulation for less than 0·5 sec fails to produce responses visible above the inherent noise in the recording system.3. A pharmacological dissection (with ouabain, metabolic inhibitors, and calcium) has revealed four phases of fluorescence change:(a) under conditions where the sodium pump is functioning, there is a prolonged decrease in the fluorescence following electrical activity;(b) even in the absence of pumping the mere entry of sodium into the nerve causes an initial decrease in fluorescence;(c) the entry of calcium ions with electrical activity also causes an initial rapid decrease in fluorescence;(d) following these phases of decreased fluorescence there is a phase of increased fluorescence.4. These changes in fluorescence are related to changes in the NADH concentration in the nerve resulting from:(a) the splitting of ATP during sodium extrusion;(b) the initial binding of sodium to the sodium‐ and potassium‐dependent ATPase, which is the sodium pump;(c) the stimulation of mitochondrial respiration by calcium that has entered during the spike; and(d) an increased glycogenolysis as a result of the calcium entry during activity.
Electrical connexions between horizontal cells in the dogfish retina
Authors: Kaneko Akimichi 
Published: December 2014

1. In dogfish, studies were made of electrical connexions between pairs of cells giving S‐potentials. After recording, the types and locations of the two cells were determined morphologically by electrophoretically injecting two different fluorescent dyes.2. Hyperpolarizing S‐potentials were observed in external and internal horizontal cells; depolarizing responses were seen in bipolar cells. All pairs of external horizontal cells examined were electrically coupled, i.e. intra‐cellular polarization of one horizontal cell gave rise to polarization in its neighbour. Coupling was detected for cells separated by five other cells. The electrical coupling was non‐rectifying. No coupling was found between external and internal horizontal cells or between external horizontal cells and bipolar cells.3. Generally the smaller the distance between cells, the larger the coupling ratio, but some pairs of cells separated by similar distances showed widely different coupling ratios.4. The coupling between cells was also demonstrated by the finding that Procion Yellow injected into one external horizontal cell diffused into one or two neighbouring external horizontal cells. It did not diffuse into internal horizontal cells or bipolar cells.5. Close membrane apposition has been reported between neighbouring external horizontal cells, but not between these and either bipolar or internal horizontal cells. The distribution of electrical connexions observed in the present study agrees with these anatomical findings.
The orientation specificity of two visual after‐effects
Authors: Blakemore Colin , Nachmias Jacob 
Published: December 2014

1. Inspection of a high‐contrast adapting grating produces two visual after‐effects: (a) the contrast threshold is raised for test gratings of similar spatial frequency to that of the adapting pattern and (b) the apparent spatial frequency of test gratings shifts away from that of the adapting grating—higher frequencies seem higher and lower ones lower than they really are.2. Both after‐effects are orientation‐specific. A horizontal adapting grating influences neither the threshold nor the apparent spatial frequency of vertical test gratings.3. The magnitude of the two after‐effects was measured with vertical test gratings as a function of (a) tilt of a high‐contrast adapting grating and (b) contrast of a vertical adapting grating.4. At all frequencies of the test grating, the decline of both after‐effects produced by an increase in tilt of approximately 6¾° could be matched by a reduction in contrast by a factor of 2.5. We take this as evidence for a common neural origin for these two visual phenomena.
Cholinergic regulation of hepatic tyrosine transaminase activity
Authors: Black Ira B. , Reis Donald J. 
Published: December 2014

1. The cholinergic agent carbachol (0·5 mg/kg) produces within 2 hr a two‐ to threefold increase in the activity of hepatic tyrosine transaminase in the adrenalectomized fasted rat.2. The carbachol‐evoked rise in enzyme activity is prevented by pretreatment with atropine.3. Cycloheximide, an inhibitor of protein synthesis, prevents the carbachol‐evoked rise of enzyme activity; actinomycin D, an inhibitor of RNA synthesis, partially reduces it.4. Atropine or unilateral (right or left) vagotomy suppresses the daily rhythm of tyrosine transaminase by attenuating the normal evening peak but not the normal lower daily levels of the enzyme.5. Electrical stimulation of the right vagus results in a significant elevation of tyrosine transaminase activity within 2 hr.6. The observations suggest that activity of vagal cholinergic nerves produces an RNA‐dependent induction of hepatic tyrosine transaminase through a process requiring cholinergic‐receptor stimulation. Intermittent activity of this vagal cholinergic system may contribute to the regulation of the daily rhythm in this enzyme.
Evidence for central timing of rhythmical mastication
Authors: Dellow P. G. , Lund J. P. 
Published: December 2014

1. The origin of the co‐ordination and rhythm of mastication provoked by electrical stimulation of the putamen and corticobulbar pathways was studied in the rabbit.2. Bursts of activity were recorded from the mandibular and hypoglossal nerves and the hypoglossal nucleus, which were in phase with the observed masticatory movements. Discharges occurred alternately in nerves to jaw‐opening and jaw‐closing muscles.3. The rate of burst discharges was not altered by paralysis, or by large variations in the stimulation frequency.4. Regularly recurring bursts of activity continued to occur in the hypoglossal nucleus in response to random frequency stimulation after severing branchial nerves, cervical nerves and the spinal cord of paralysed rabbits.5. Mechanical deformation of the brain of vascular or respiratory origin was discounted as the origin of the rhythm.6. It is concluded that mastication is controlled by a brain‐stem pattern generator which can be activated by adequate inputs from certain higher centres and, as concluded in other studies, from the oral cavity itself.
Cardiovascular responses to tilting in tetraplegic man
Authors: Corbett J. L. , Frankel H. L. , Harris P. J. 
Published: December 2014

1. A study has been made of the effect of head‐up tilt on blood pressure, heart rate, forearm blood flow and occluded vein pressure in the hand and foot in non‐bedridden patients with chronic, closed, complete, localized traumatic transection of the cervical spinal cord.2. In typical responses the blood pressure fell and the heart rate rose progressively for about 2 min, tending to plateau thereafter. The average falls in mean blood pressure for tilts of +30, +45 and +60° were from 68 to 44, 74 to 36 and 70 to 44 mm Hg respectively, and the corresponding heart rate increases were from 67 to 85, 62 to 97 and 62 to 103 beats/min respectively. One patient lost consciousness when his blood pressure was 29/19 mm Hg and one other patient experienced symptoms suggesting cerebral ischaemia.3. Following the return to horizontal, the blood pressure and heart rate usually returned to their previous values within 1 min and the blood pressure tended to overshoot slightly in the following few minutes. No immediate blood pressure overshoot occurred after the tilt except in association with a spasm of skeletal muscles.4. There was consistently a decrease in forearm blood flow, sometimes to unrecordably low levels and a venoconstriction with postural change and it is argued that these changes are the result of spinal cardiovascular reflexes to peripheral vessels. Following the return to the horizontal position, there was occasionally a large immediate increase in forearm blood flow.5. Following the intravenous administration of 3 mg atropine on two occasions, head‐up tilting produced further small heart rate increases.6. Spasms of skeletal muscle occur frequently in these patients and greatly modify the effects of postural stimuli. Bladder percussion also modifies the normal response.
Relative contribution from different nerves to recurrent depression of Ia IPSPs in motoneurones
Authors: Hultborn H. , Jankowska Elẓbieta , Lindström S. 
Published: December 2014

1. The pattern of depression of Ia IPSPs by volleys in recurrent motor axon collaterals was investigated in motoneurones supplying hind‐limb muscles in the cat. The test IPSPs were evoked by stimulation of dorsal roots and the conditioning antidromic volleys by stimulation of motor fibres in different peripheral muscle nerves.2. In all motor nuclei investigated the strongest depression of Ia IPSPs is evoked from motor fibres to muscles whose Ia afferents produce the IPSPs. For example, the Ia IPSP from the knee extensor recorded in motoneurones to a knee flexor is most effectively depressed by antidromic stimulation of motor fibres to the knee extensor.3. The origin of recurrent inhibition of α‐motoneurones and of Ia inhibitory interneurones with the same Ia input display a striking similarity. This suggests that the same population of Renshaw cells mediates effects to motoneurones and to Ia inhibitory interneurones.4. The functional significance of impulses in motor axon collaterals was discussed and it was suggested that they have an important role in the control of the excitatory as well as inhibitory Ia actions to motoneurones. The recurrent inhibition may limit the Ia effects to excitation of homonymous motoneurones, which would provide optimal conditions for control of individual muscles via the γ‐loop.
The significance of changes in the temperature of the skin and body core of the chicken in the regulation of heat loss
Authors: Richards S. A. 
Published: December 2014

1. The relationship between the temperatures of the hypothalamus, colon and skin and the control of heat loss mechanisms at ambient temperatures from 20 to 40° C has been studied in unanaesthetized chickens.2. The temperatures of the core and feathered skin varied by not more than 5° C throughout the full range of ambient temperature but the comb, shank and toe varied by up to 20° C and exhibited wide fluctuations in constant environmental conditions.3. At an ambient temperature of 26–27° C, the fluctuations ceased at all of the naked skin sites and there was evidence of a concurrent decrease in the tissue insulation of the extremities. No such change could be detected in the feathered skin.4. Analysis of the various body temperatures suggested that the onset of thermal panting was consistently related to the increment in hypothalamic temperature and that this relationship was influenced both by the peripheral and extra‐cranial deep body temperatures.
The paramedian reticular nucleus: a site of inhibitory interaction between projections from fastigial nucleus and carotid sinus nerve acting on blood pressure
Authors: Miura Mitsuhiko , Reis Donald J. 
Published: December 2014

1. The interaction between the pressor response to electrical stimulation of the fastigial nucleus (FN), the fastigial pressor response (FPR), and the depressor response to electrical stimulation of the carotid sinus nerve (CSN) was examined in paralysed anaesthetized cats.2. Blood pressure responses evoked by electrical stimulation of the FN and the CSN were mutually inhibitory and summed algebraically.3. The FPR was augmented after denervation of buffer nerves. Lesions of the FN did not alter the depressor response to stimulation of the CSN.4. Bilateral electrolytic lesions of the paramedian reticular nucleus abolished both the FPR and the CSN depressor response without altering base line pressure.5. With micro‐electrode recording neurones were discovered within the paramedian reticular nucleus which responded to electrical stimulation of the FN or the CSN. These neurones were polysynaptically excited by stimulation of either the FN or the CSN but rarely from both, and could be further subdivided into cells responding with either a single spike or a burst discharge.6. The interaction between the FN and the CSN projections to the paramedian reticular nucleus was examined by conditioning‐test studies. Eleven per cent of FN‐ and CSN‐units were inhibited by conditioning stimulation of the heteronymous input. The interaction was exclusively inhibitory and observed only in units with latencies > 4 msec and having burst responses. The latency for inhibition was > 20 msec, peaked around 100 msec and lasted up to 300 msec.7. We conclude that the FRP is buffered by baroreceptors and that there is a mutually inhibitory interaction between projections from the FN and the CSN acting on sympathetic vasomotor neurones. The paramedian reticular nucleus appears to be an important site for the interaction.8. The findings support the view that interneurones mediating pressor and depressor responses are intermixed within the medial reticular formation of the medulla.