bluuebunny/crossref_metadata_2025 huggingface dataset:
The identification of four prostaglandins in dog brain and their regional distribution in the central nervous system
Authors: Holmes S. W. , Horton E. W.
Published: December 2014

1. Experiments were carried out to determine whether the prostaglandins, which have been identified as natural constituents of the brain, are widely distributed or concentrated in special regions of the central nervous system.

2. Prostaglandins E1, E2, F1α and F2α have been identified in dog brain using solvent partition, column and thin layer chromatographic and bio‐assay techniques.

3. Each of these prostaglandins is distributed throughout all regions of the central nervous system investigated (cortex, hippocampus, caudate nucleus, hypothalamus, cerebellum, medulla and pons, cortical white matter and spinal cord).

4. This distribution suggests that the role of prostaglandins in the central nervous system is not confined to any specific region.
A method of analysing the responses of spindle primary endings to fusimotor stimulation
Authors: Bessou P. , Laporte Y. , Pagès B.
Published: December 2014

1. The superposition of records of ‘instantaneous’ frequency of discharge of spindle primary endings after stimulation of single fusimotor fibres leads to the construction of graphs called ‘frequencygrams’.

2. The superposition is made on the screen of a storage oscilloscope, the time base of which is synchronized with the stimulus. It is essential that the stimulus be delivered at all possible intervals with respect to the impulse of the resting discharge which precedes it.

3. Frequencygrams obtained by stimulating some static fusimotor fibres by single stimuli display a response with a fast rising phase, a pause, and a slower decreasing phase.

4. Frequencygrams may give some information on the time course of the contraction of intrafusal muscle fibres elicited by stimulating their motor axons.
Termination and functional organization of the ventral spino‐olivocerebellar path
Authors: Oscarsson Olov
Published: December 2014

1. The spino‐olivocerebellar path ascending through the ventral funiculus (VF‐SOCP) was investigated in decerebrate cats with the cord transected in the third cervical segment except for the left ventral funiculus. The climbing fibre responses evoked in Purkinje cells were studied by recording from single cells and by recording the mass activity at the cerebellar surface or in the molecular layer.

2. In the spinal cord the forelimb component of the VF‐SOCP occupies a medial part and the hind limb component a lateral part of the ventral funiculus.

3. The main projection of the limb nerves through the VF‐SOCP is to the lateral two thirds of the vermis of the anterior lobe. The projection area consists of three sagittally arranged bands: a lateral band receiving olivary axons activated exclusively from the ipsilateral hind limb, an intermediate band receiving olivary axons activated bilaterally from the hind limbs, and a medial band receiving olivary axons activated bilaterally from the forelimbs. Some olivary neurones are activated from all four limbs.

4. The latency of the climbing fibre responses was about 22 msec on stimulation of ipsilateral hind limb nerves and about 20 msec on stimulation of ipsilateral forelimb nerves. The responses evoked from contralateral nerves had a latency which was about 3 msec longer than the latency of the corresponding ipsilateral responses.

5. The olivary neurones were usually activated from all tested muscle and skin nerves in the limb(s) constituting the receptive field. Cutaneous afferents and groups II and III muscle afferents were responsible for the excitation elicited by single shock stimulation of the nerves. Brief repetitive stimulation revealed additional activation from mainly Ib, but also Ia, afferents in ipsilateral hind limb nerves.

6. Natural stimulation of receptors evoked responses in about half of the olivary neurones tested. The responses were elicited by strong pressure against deep structures. Inhibitory effects were seldom observed.
The identification and characteristics of sacral parasympathetic preganglionic neurones
Authors: de Groat W. C. , Ryall R. W.
Published: December 2014

1. Sacral parasympathetic preganglionic neurones were identified by intracellular and extracellular micro‐electrode recording of antidromic potentials in response to stimulation of the pelvic nerve or the second or third sacral ventral roots.

2. The segmental distribution of autonomic neurones varied in different cats. In some cats they were mainly in S2 segment, in others in S3 and in the remainder, in both S2 and S3.

3. The antidromic potentials showed initial segment‐somadendritic (IS‐SD) inflexions and delayed depolarizations and were slightly less prolonged than those of sympathetic neurones but more prolonged than those of spinal motoneurones. After‐hyperpolarization was observed after the antidromic spike potential.

4. The conduction velocities for sacral parasympathetic preganglionic fibres were less than 12·5 m/sec and thus were similar to those of sympathetic preganglionic fibres.

5. Parasympathetic neurones were not excited by micro‐electro‐phoretically applied 5‐hydroxytryptamine, noradrenaline or acetylcholine.
Factors controlling the washout of the interstitial space of the isolated, perfused rat heart
Authors: Young D. A. B.
Published: December 2014

1. The time course of the washout of the extracellular markers, inulin, raffinose, sucrose and sorbitol, has been determined for the isolated rat heart perfused for 20 min with Krebs bicarbonate medium containing the marker, and washed out with marker‐free perfusate.

2. The filtration problem for the perfused rat heart was found to be due to omission of the gassing of the concentrated sodium bicarbonate solution with CO2 in the preparation of the perfusate. This probably caused calcium phosphate to be precipitated. The reduced contractility of the heart was reflected in the washout of the extracellular markers.

3. The logarithmic plot of the heart content of the marker against time showed two components. The slower was an exponential process, the rate of which was linearly related to the diffusion coefficient for the various markers.

4. The faster component was absent in the quiescent heart, and in the beating heart its contribution to the washout of the interstitial space was related to the strength of contraction.

5. Similar washout curves were obtained for Evans Blue‐albumin conjugate, which readily penetrates the interstitial space of the isolated rat heart.

6. It is suggested that the two components of efflux are a diffusion process limited by perfusate flow, and bulk movements of fluid.
Fine structure of tortoise skeletal muscle
Authors: Page Sally G.
Published: December 2014

1. The fine structure of tortoise skeletal muscle has been studied with the electron microscope.

2. The packing of the A filaments (1·6 μ long) and the I filaments (2·35 μ long) within the myofibril is similar to that in frog twitch fibres.

3. The position of the N line within the I band is found to vary with the sarcomere length.

4. The T‐system tubules in these muscles form a three‐dimensional network across the fibre at the level of the I band. On either side of the Z line it forms triad relationships with the other network of tubules of the sarco‐plasmic reticulum.
Conduction failure in myelinated and non‐myelinated axons at low temperatures
Authors: Franz D. N. , Iggo A.
Published: December 2014

1. The effects of low temperature on conduction in single myelinated and non‐myelinated axons of the feline saphenous nerve were examined and compared. Nerves were cooled by a conventional thermode, but thermal gradients were minimized by an insulating layer of agar‐saline gel over the nerve and the face of the thermode.

2. The mean blocking temperature of thirty‐one non‐myelinated axons, 2·7° C, was significantly lower than that of 111 myelinated axons, 7·2° C. No evidence for a differential block of myelinated axons according to their normal conduction velocity could be demonstrated.

3. Reductions in the proportional conduction velocities of both myelinated and non‐myelinated axons were nearly identical between 17 and 37° C. However, below 17° C the rate at which the proportional conduction velocity of the non‐myelinated axons fell during cooling was significantly less than for the myelinated axons and was sufficient to account for their lower blocking temperatures. As a result, critical minimum conduction velocities were reached at higher temperatures in myelinated axons than in non‐myelinated axons.

4. The conduction velocity of successive impulses in a train slowed progressively to a constant value which depended on the frequency of stimulation. Consequently, the early impulses were separated by intervals that exceeded those between stimuli and were not affected by temperatures that blocked later impulses. The pattern of block was consistent with an increasing refractoriness of the axons as the temperature fell.

5. The maximal frequency of discharge that myelinated axons could carry at temperatures between normal and 12° C was related directly to fibre size. Non‐myelinated axons could conduct low frequency trains of impulses at temperatures that blocked such activity in myelinated axons. In all axons, high frequency trains of impulses could be completely blocked at temperatures which permitted lower frequency trains to pass uninterrupted.

6. Hysteresis in the blocking temperatures of axons was related to the hysteresis in their conduction velocities.
Depolarizing and hyperpolarizing receptor potentials in the non‐myelinated nerve terminal in Pacinian corpuscles
Authors: Nishi K. , Sato M.
Published: December 2014

1. Pacinian corpuscles or non‐myelinated nerve terminals in Pacinian corpuscles, from which lamellae had been removed, were stimulated with linearly increasing compression of varying rate, which decayed linearly after a maximum compression.

2. An impulse was initiated with a compression having a rate of increase greater than a critical slope. The critical slope was 1·1‐1·2 rheobase/msec in both intact corpuscles and decapsulated terminals.

3. The receptor potential of the terminal increased in magnitude and rate of rise with an increase in the rate of compression. Its rate of rise was linearly related to the rate of compression.

4. Hyperpolarization was observed on removal of compression, and an impulse was initiated upon recovery of the hyperpolarized membrane potential.

5. In some corpuscles or decapsulated terminals hyperpolarization was produced on compression and a depolarizing response was produced upon removal of compression. After rotation by 90° along their long axis, they produced depolarization on compression.

6. Difference in the directional sensitivity of corpuscles and decapsulated terminals was confirmed and was explained on the basis of the shape of the terminal.

7. On‐ and off‐responses of variable latency recorded from a central portion of the axon to Pacinian corpuscles were explained by the depolarizing and hyperpolarizing responses in the terminal.
The dynamics of small saccadic eye movements
Authors: Thomas J. G.
Published: December 2014

1. The mechanical characteristics of the system comprising the eyeball and its attachments have been determined, by applying rotational forces to the eyeball, and using an accelerometer on a contact lens to measure the resulting movement.

2. The angular acceleration‐versus‐time curves of small saccades have been recorded. Some of these saccades are made whilst the eye is being vibrated by external forces.

3. A mechanical model of the orbital system has been formulated. This is considered to bear a relationship to the structures in the orbit.

4. The model has been used to deduce the force pattern of the active component in the extraocular muscles during the execution of a saccade. It is concluded that a saccade is initiated by a rapid rise of tension. After a short time, the tension falls to a lower level, which is the new steady‐state level. The present findings are therefore basically different from those of previous workers, in that we deduce a change in the force pattern during the course of the movement.

5. In the execution of saccades of various sizes, both the strength and duration of the brief heightened tension are found to vary. For a 4 degree saccade, the transient tension is approximately 36 g, lasting for approximately half of the duration of the saccade.

6. Characteristic features of saccades are interpreted in terms of variations in the duration of the transient excess tension.

7. Differences in the time course of horizontal and vertical saccades are attributed to differences in the elasticity of the muscles involved in the movements.

8. It is suggested that, in view of the similarity of the acceleration‐versus‐time wave forms, the muscular force pattern which is responsible for rapid head movements is of a similar type to that which has been deduced for saccades.
The mechanism of oscillatory activity at low membrane potentials in cardiac Purkinje fibres
Authors: Hauswirth O. , Noble D. , Tsien R. W.
Published: December 2014

1. The mechanism of oscillations at low membrane potentials in Purkinje fibres has been investigated using voltage clamp experiments.

2. The oscillations are generated by time‐dependent variations in an outward current component, ix1, that is activated over the voltage range ‐40 to 10 mV. During normal activity, this current is responsible for initiating full repolarization to the resting potential (Noble & Tsien, 1969b) so that the oscillations represent a failure of the normal repolarization process, probably as a consequence of a small change in background (leakage) current.

3. These oscillations are distinct from the normal pacemaker activity of Purkinje fibres which is generated by a separate time‐dependent current, iK2 (Noble & Tsien, 1968). iK2 shows no time‐dependence when the membrane potential variations are entirely positive to ‐65 mV and cannot, therefore, be involved in the oscillatory activity apart from contributing a background outward current.

4. The amplitude and frequency of the oscillations are very sensitive to applied currents less than 1 μA/cm2. Larger currents abolish the oscillatory activity.

5. The mechanism of the oscillations is discussed in relation to the possible mechanisms underlying the natural pacemaker activity of the sino‐atrial (SA) node.
The occurrence, structure and innervation of slow and twitch muscle fibres in the tensor tympani and stapedius of the cat
Authors: Fernand V. S. V. , Hess A.
Published: December 2014

1. The muscle fibres of the tensor tympani and stapedius of the cat have been examined in the light microscope in teased preparations after cholinesterase staining and in the electron microscope.

2. In both muscles, two kinds of fibre have been found: those with an individual end‐plate and those with multiple nerve terminals.

3. The stapedius fibres with an end‐plate have fibrils regularly separated from each other by sarcoplasmic reticulum, a straight Z line, transverse tubular T system elements regularly occurring at the junction of A and I bands, an M line, an extensive sole plate area, and numerous post‐junctional sarcolemmal infoldings under the nerve terminal. This type of muscle fibre in the tensor tympani has all of these features except that the fibrils are not well separated from each other, T system elements are absent in some sarcomeres, and a typical M line is absent.

4. Compared to the individually innervated fibres, the fibres with multiple endings have fibrils poorly separated from each other by sarcoplasmic reticulum, a jagged Z line, very few T system elements, a less extensive sole plate area, and essentially no folds under the nerve terminal. These fibres in both muscles have M lines.

5. Muscle fibres have thus been found in both the tensor tympani and stapedius of the cat which conform in their innervation, the structure of their motor nerve endings, and their internal structure to many of the morphological characteristics which are exhibited by slow muscle fibres elsewhere.
The relation between environmental temperature and oxygen consumption in the new‐born baby
Authors: Hey E. N.
Published: December 2014

1. Oxygen consumption (V̇O2) has been measured serially in sixty‐eight infants during the first 10‐35 days of life, when naked in a Perspex metabolic chamber, by recording the changes in circulating gas volume. Air speed in the chamber was 4‐5 cm/sec, and absolute humidity ∼ 18 mm Hg.

2. When environmental temperature (TE) was 35‐38° C minimal V̇O2 rose from 5 to 7 ml.O2/kg.min during the first 2 days of life in infants weighing over 2·5 kg, and more slowly in the first 7‐10 days in infants under 2 kg at birth.

3. Physical activity and V̇O2 both increased when TE fell below 33° C: the increase appeared to be linearly and inversely related to TE, but the rise in heat production was seldom enough to prevent a fall in rectal temperature. In infants over 2·5 kg at birth the mean increase amounted to 0·56 ml.O2/kg.min for each 1° C fall in TE when 4‐12 hours old, and 1·27 ml.O2/kg.min when between 4 and 20 days old. In infants weighing 1–2 kg at birth the mean increase was similar in the first 12 hr, but the coefficient rose more gradually with age.

4. The maximum V̇O2 in infants over 2·5 kg at birth and over 2 days old was about 2½ times the minimum V̇O2; the maximum was rather lower in most infants of low birth weight.

5. In seven infants who were motionless and apparently asleep after sedation with chloral hydrate, the increase in V̇O2 at low TE was reduced but still significant.

6. It is concluded that the new‐born baby responds to a cool environment with a considerable immediate increase in heat production; visible muscular activity appears to account for only part of this increase.
Elastic constants of the human lens capsule
Authors: Fisher R. F.
Published: December 2014

1. A technique is described whereby the elasticity of the human lens capsule has been determined at birth and throughout life. This technique requires three separate determinations: (a) thickness; (b) stress and strain; (c) Poisson's ratio; (a) the capsule was clamped between accurately perforated ground glass plates and its thickness determined by noting the change in depth of focus between Latex spherules adhering to its upper and lower surfaces; (b) the undisturbed capsule was then placed in a specially designed glass distension apparatus and the relationship between volume and pressure recorded when it was distended with isotonic saline. The permeability of the capsule was also measured; (c) in some cases Poisson's ratio was determined by measuring the change of thickness of the capsule and the height to which it rose when distended with isotonic saline at different pressures. An apparatus was designed for this purpose.

2. The average thickness of the anterior capsule increases from birth until about the 60th year but thereafter it decreases slightly.

3. Poisson's ratio was about 0·47 for both cat and human capsule, and no significant variations with age in human capsule could be detected.

4. Corrected volume pressure curves obeyed Hook's law almost to the point of capsule rupture.

5. In childhood Young's Modulus of elasticity is about 6 × 107 dyn/cm2 and decreases to 3 × 107 dyn/cm2 at 60 and 1·5 × 107 dyn/cm2 in extreme old age.

6. The ultimate tensile stress was 2·3 × 107 dyn/cm2 in young capsules and 0·7 × 107 dyn/cm2 in old ones. The maximum percentage elongation was 29 per cent and independent of age.

7. The implications of these findings are discussed in relation to

(a) the mechanical properties of the lens capsule;

(b) the ageing of the lens capsule and basement membranes; and

(c) the decrease in elasticity of the lens capsule as a cause of presbyopia.
Effects of catecholamines on the cholinergic neuromuscular transmission in fish red muscle
Authors: Hidaka T. , Kuriyama H.
Published: December 2014

1. The effects of adrenaline and noradrenaline on neuromuscular transmission and the question of whether these catecholamines act on the presynaptic nerve terminal or on the post‐synaptic membrane were investigated using the fin muscles of the silver carp.

2. Noradrenaline (10−8‐10−6 g/ml.) had no effect on membrane potential or input resistance of the membrane. In contrast, adrenaline (10−8‐10−6 g/ml.) hyperpolarized the membrane and increased the input resistance.

3. Noradrenaline had no effect on the amplitude of the miniature junction potentials but caused them to become more frequent.

4. Adrenaline enhanced the amplitude of the miniature junction potentials and slightly increased their frequency. These effects of adrenaline were partly due to the increased input resistance of the post‐synaptic membrane, and probably did not involve the presynaptic terminals.

5. Both noradrenaline and adrenaline increased the amplitude and prolonged the falling phase of the excitatory junction potentials (e.j.p.s).

6. Noradrenaline enhanced the amplitude and prolonged the duration of the extracellularly recorded excitatory junction current. No such effect was observed with adrenaline.

7. Adrenaline but not noradrenaline enhanced the amplitudes of acetylcholine potentials evoked by iontophoretic application of acetylcholine.

8. Noradrenaline and adrenaline had no effect on the compound action potentials of the nerve supplying the red muscle, recorded by the sucrose gap method.
Renal receptors evoking a spinal vasometer reflex
Authors: Beacham W. S. , Kunze Diana L.
Published: December 2014

1. Certain afferent fibres in the renal nerves show an increased rate of discharge in response to small increases in renal vein pressure and to substantial increases of ureteral pressure. Such fibres enter the spinal cord largely through the upper lumbar dorsal roots.

2. In spinal cats, stimuli exciting these afferent fibres evoke a reflex discharge in sympathetic nerves to the kidney and a fall in systemic arterial pressure. Change in flow or peripheral resistance, independent of arterial pressure, could not be demonstrated for the renal vascular bed. In spite of a lack of evidence for a renal vasomotor effect, the existence of the reflex fall in arterial pressure following excitation of receptors sensitive to venous pressure strongly implies that there is a form of circulatory regulation at the spinal cord level.
Cyanide stimulation of the systemic arterial chemoreceptors in foetal lambs
Authors: Dawes G. S. , Duncan Sheila L. B. , Lewis B. V. , Merlet Claudie L. , Owen-Thomas J. B. , Reeves J. T.
Published: December 2014

1. In foetal lambs, delivered by Caesarean section under light chloralose anaesthesia, injection of sodium cyanide into the left atrium or ascending aorta caused a rise of arterial pressure and femoral vasoconstriction. The response to 0·77 mg/kg was barely present at 0·6 of term; by 0·8 of term there was a large response to one third of this dose.

2. The cardiovascular response to cyanide injection into the left atrium or ascending aorta was diminished either by section of the vagi or by carotid denervation, and was abolished by cutting both sets of nerves.

3. Injection of sodium cyanide into both common carotids simultaneously caused a substantial cardiovascular response and often a respiratory effort, abolished by carotid denervation, whereas injection into a single carotid rarely caused an effect.

4. It is concluded that the carotid chemoreceptors in mature foetal lambs can be excited by a stimulus of sufficient intensity, even though they do not respond to moderate hypoxaemia.
5‐Hydroxytryptamine uptake and release in relation to aggregation of rabbit platelets
Authors: Baumgartner H. R.
Published: December 2014

1. The aggregation of blood platelets was measured in vitro at different time intervals after the addition of 5‐hydroxytryptamine (5‐HT) or of reserpine to platelet‐rich plasma of untreated rabbits and of rabbits injected with reserpine and 5‐HT, i.e. while the platelets were taking up 5‐HT or releasing it under the influence of reserpine.

2. When 5‐HT was added to stirred platelet‐rich plasma the platelets aggregated reversibly within 1 min. The velocity of aggregation increased with 5‐HT concentrations of 0·1–30 μ
M and decreased with higher concentrations.

3. (—)‐Adrenaline, which alone did not produce aggregation, markedly accelerated the aggregation caused by 5‐HT. The acceleration was greatest when 5‐HT and adrenaline were added simultaneously.

4. 5‐HT added to the platelet‐rich plasma in amounts that exceeded the 5‐HT capacity of the platelets progressively diminished the velocity of aggregation produced by 5‐HT plus adrenaline until aggregation was completely inhibited. Smaller amounts of 5‐HT produced a transient inhibition of aggregation.

5. The aggregation of platelets from reserpinized rabbits was inhibited by less 5‐HT than the aggregation of platelets from normal rabbits.

6. (—)‐Adrenaline aggregated platelets of untreated rabbits but not those of reserpinized rabbits or of rabbits injected with 5‐HT when reserpine was added in vitro 1‐30 min previously.

7. Platelets obtained from rabbits treated first with reserpine and subsequently injected with 5‐HT were not aggregated by 5‐HT plus adrenaline. During incubation in vitro these platelets progressively recovered their aggregability but this recovery was delayed by the monoamine oxidase inhibitor Pargyline.

8. Imipramine in concentrations which did not influence platelet aggregation by adenosine diphosphate (ADP) abolished aggregation produced by 5‐HT or by 5‐HT plus adrenaline.

9. The inhibitory effect of adenosine on platelet aggregation was concentration‐dependent and similar whether aggregation was produced by ADP, 5‐HT or 5‐HT plus adrenaline.

10. It is proposed that aggregation brought about by 5‐HT is connected with its active uptake into the platelets and is caused by ADP formed from ATP during the active uptake of the amine. When 5‐HT is no longer actively taken up, it also ceases to cause or to potentiate aggregation.
Permeability of lung capillaries to macromolecules in foetal and new‐born lambs and sheep
Authors: Boyd R. D. H. , Hill June R. , Humphreys P. W. , Normand I. C. S. , Reynolds E. O. R. , Strang L. B.
Published: December 2014

1. The permeability of lung capillaries to macromolecules was investigated in immature and mature foetal lambs, new‐born lambs and young sheep. The placental circulation of the foetal animals was maintained intact after delivery by Caesarian section. New‐born lambs and sheep were mechanically ventilated. Samples of plasma and lymph that had drained from the lung via the thoracic duct were collected over a period of 1–5 hr.

2. The proteins in plasma and lymph samples were separated by fractionation on columns of Sephadex G‐200. Plasma yielded three peaks of protein concentration. The Kav value of each peak was determined, and, by calibrating the columns with known proteins, the mean radius of equivalent sphere (a) of the proteins in peak I was shown to be similar to that of fibrinogen ≥ 110 Å, peak II to γ‐globulin ≈ 54 Å and peak III to albumin ≈ 34 Å. Lung lymph contained the same three constituent peaks as plasma but in lower concentration. In all four groups mean lymph/plasma concentration (L/P) ratio was significantly different for each of the three peaks, being lowest for the largest molecules (peak I) and highest for the smallest (peak III).

3. In five mature foetal lambs polydisperse polyvinylpyrrolidone labelled with 125I ([125I]PVP) was injected
I.V. early in the experiment: count rates in fractionated samples showed for plasma a continuous decline with time after injection, and for lung lymph an increase to a maximum then a decline. Steady‐state L/P ratios for eleven fractions of PVP of differing molecular size ranging from 110 to 17 Å were derived by compartmental analysis. For a given molecular size PVP L/P ratios were similar to protein L/P values.

4. The regression of PVP L/P ratio on Kav was linear (correlation coefficient r = 0·99), and the slope of the regression of protein L/P ratio on Kav was significantly steeper for new‐born lambs than for mature foetuses (P < 0·025) and sheep (P < 0·005), and steeper for immature foetuses than sheep (P < 0·01).

5. PVP and protein L/P ratios (mature foetuses) plotted against a showed a sigmoid relation with agreement between the two sets of L/P ratios. The goodness of fit between our experimental results and Landis & Pappenheimer's (1963) capillary pore theory (eqn. (1)) was examined: L/P ratios for the larger molecules (≥ 75 Å) appeared to be too high. By recalculating ratios on the assumption that the largest molecules (110 Å) escape unrestricted from the capillary via leaks, the discrepancy disappears.

6. Values for pore radius (r), and pore area per unit path length (A/Δx) have been calculated for each of the four groups; r ranged from 90 to 150 Å, A/Δx from 3·3 to 0·2 cm × 103.kg−1. In new‐born lambs the value of r was significantly smaller, and A/Δx larger than that of any other group. The inferences to be drawn from these results are discussed.
The projection of splanchnic afferents on the cerebellum of the cat
Authors: Newman P. P. , Paul D. H.
Published: December 2014

1. The projections of the ipsilateral and contralateral splanchnic nerves on the cerebellum were studied in cats under sodium thiopentone anaesthesia.

2. The splanchnic nerves were electrically stimulated. Evoked potentials and single unit discharges were recorded by means of 2·5
M‐NaCl‐filled glass micropipettes. A responsive region was found in the intermediate cortex of lobules Vb to f of the anterior lobe.

3. The Aγδ fibres of the splanchnic nerve had a bilateral cerebellar representation. The Aβ fibres were represented only on the ipsilateral side.

4. At the level of the upper cervical spinal cord, fibres from the ipsilateral splanchnic nerve were conveyed in both the dorsal and lateral funiculi; fibres from the contralateral nerve were restricted to the ipsilateral lateral funiculus.

5. On the basis of the characteristic potential fields generated in the cerebellar cortex, it is concluded that the majority of the splanchnic afferents studied terminate in the cerebellum as climbing fibres. A few responses of short latency may have been due to a mossy fibre input.

6. In interaction experiments, a conditioning stimulus to one splanchnic nerve depressed the response to stimulation of the other nerve for up to 80–100 msec, the effect being most pronounced at 40–50 msec. During this period, spontaneous activity of the cerebellar unit was also suppressed.

7. The organization of the splanchnic pathways to the cerebellum and their terminal connexions are discussed.
Contribution of the diaphragm and the other inspiratory muscles to different levels of tidal volume and static inspiratory effort in the rabbit
Authors: Mognoni P. , Saibene F. , Sant'Ambrogio G.
Published: December 2014

1. The contribution of the diaphragm and that of the other inspiratory muscles at different levels of tidal volume and during static inspiratory efforts of various strength has been studied in supine rabbits by blocking phrenic conduction with an electrotonic current. The rabbits were lightly anaesthetized with urethane and pentobarbitone.

2. The volume displaced by the extradiaphragmatic muscles (VtEDM) in vagotomized rabbits increases linearly with the tidal volume (Vt), according to the function VtEDM = − 3·27 + 0·32 Vt. The relative contribution of extradiaphragmatic muscles (VtEDM/Vt × 100) for resting ventilation is 12% and becomes ca. 25% for the maximum Vt value attained during re‐breathing.

3. When the vagi are left intact, the VtEDM is always higher because of the compensatory hyperactivity of the extradiaphragmatic muscles due to Hering—Breuer reflexes during the phrenic block.

4. The pressure exerted by the extradiaphragmatic muscles, during inspiratory efforts with closed airways, increases linearly with the strength of the effort, without any difference between intact and vagotomized rabbits. The relationship between the pressure exerted by the extradiaphragmatic muscles (PEDM) and the pressure exerted by all the inspiratory muscles (P) is expressed by the function PEDM = − 3·29 + 0·38P.

5. These results indicate that the diaphragm is the main inspiratory muscle at all levels of inspiratory activity.
The relation between sweat rate and weight loss when sweat is dripping off the body
Authors: Brebner D. F. , Kerslake D. McK.
Published: December 2014

1. The relation between the rate of sweat production, Ṡ, and the rate of weight loss, Ẇ, has been examined under conditions in which the rate of evaporation was small.

2. Ṡ could be found from Ẇ provided that a film of liquid was maintained over the skin surface. This could be achieved initially by immersing the subject in water containing detergent. Thereafter the film was maintained so long as the rate of weight loss exceeded about 10 g/min.

3. When the rate of weight loss was changing and the rate of evaporation was constant, Ṡ could be calculated as Ẇ + 2·5 Ẅ.

4. When the subject was constantly sprayed with water while being weighed, the correction for Ẅ became negligible. In this case there was no lower limit to the sweat rate which could be measured, but spraying considerably reduced the accuracy of the measurement.

5. The output of sweat from a ventilated capsule on the forearm correlated well with estimates of central sweating drive based on weight measurements corrected for hidromeiosis.
The interaction of presynaptic polarization with calcium and magnesium in modifying spontaneous transmitter release from mammalian motor nerve terminals
Authors: Landau E. M.
Published: December 2014

1. The relationship between motor terminal polarization and miniature end‐plate potential (m.e.p.p.) frequency was examined in the presence of various Ca, Mg and K concentrations ([Ca], [Mg] and [K]) and also at modified bathing osmolarity levels. The polarization changes were obtained with ‘electrotonic’ and ‘focal’ polarizing currents and with rapid changes in bathing [K].

2. M.e.p.p. frequency increased exponentially with electrotonic depolarizing currents, but failed to decrease similarly with hyperpolarizing currents. An increase in bathing [K] to 15 mM increased the sensitivity of the terminals to presynaptic hyperpolarization.

3. The slope, on semilogarithmic coordinates, of the function relating m.e.p.p. frequency to electrotonic polarizing currents (the release‐current function) was unchanged when bathing [Ca] was raised from 2 to 8 mM. When [Ca] was reduced to 0·5 mM the slope of this function was reduced initially but eventually approached the same slope as in control [Ca]. A similar effect was also found in the presence of 15 mM‐KCl.

4. The relationship between m.e.p.p. frequency and log [K], at various [Ca], resembled the relationships between m.e.p.p. frequency and presynaptic polarizing currents.

5. An increase in bathing [Mg] or osmolarity had a similar effect to a reduction of [Ca].

6. Tetrodotoxin (TTX) at a concentration of 10−6 g/ml. was found to reduce m.e.p.p. frequency, at various [K], by a constant fraction of about 30%.

7. In some of the junctions ‘anodic break‐down’ was observed. An examination of this phenomenon with focal polarizing currents disclosed an unusual type of ‘anodic break‐down’, with rapid ‘on’ and ‘off’ responses. This phenomenon may indicate that release depends on the influx of positively charged particles into the nerve terminals.

8. It is concluded that nerve terminal depolarization accelerates exponentially the activity of a membrane component bearing three Ca molecules, the rate of acceleration being independent of bathing [Ca].
Dorsal column projection of fibres from the cat knee joint
Authors: Burgess P. R. , Clark F. J.
Published: December 2014

1. Stimulation of the cervical dorsal columns excited an average of nine knee joint fibres in the cat posterior articular nerve, eleven fibres in the cat medial articular nerve and thirteen fibres in the monkey posterior articular nerve.

2. Joint fibres projecting to cervical levels were shown to be rapidly adapting by recording with micro‐electrodes from single fibres in intact cat posterior articular nerves. The numerous slowly adapting fibres could not be antidromically excited from the cervical dorsal columns.

3. Several control experiments suggested that the antidromic stimulation method accurately defined the dorsal column projection of joint fibres.
The activity of lung irritant receptors during pneumothorax, hyperpnoea and pulmonary vascular congestion
Authors: Sellick Hilary , Widdicombe J. G.
Published: December 2014

1. The activity of lung irritant receptors during pneumothorax, hyperpnoea and pulmonary congestion has been studied by recording from single vagal nerve fibres from the receptors in rabbits.

2. The receptors were stimulated during induction and during removal of pneumothorax.

3. Pneumothorax caused a greater depression of minute volume in bilaterally vagotomized rabbits, compared with those with intact vagus nerves.

4. Hyperpnoea due to breathing through an added dead space increased the discharge of the receptors. Experiments on paralysed and artificially ventilated rabbits showed that this was not a direct action of the asphyxial changes in blood gas tensions.

5. Pulmonary congestion, induced by inflating a balloon in the left atrium, stimulated the receptors in paralysed artificially ventilated rabbits.

6. The evidence that the receptors cause vagal reflex hyperpnoea and bronchoconstriction is discussed, together with their role in the reflex ventilatory and bronchomotor changes in the conditions studied.
Hind leg ataxia of cervical origin and cervico‐lumbar spinal interactions with a supratentorial pathway
Authors: Abrahams V. C. , Falchetto S.
Published: December 2014

1. Unilateral section of the nerves to an extensor muscle of the head, biventer cervicis, leads to an ataxia of the hind legs in cats.

2. In chloralose anaesthetized cats, shocks to the central end of the cut biventer cervicis muscle nerves leads to direct discharges over lumbosacral ventral roots, to a facilitation of monosynaptic reflexes in flexor and extensor muscles and to a prolonged inhibition of spino‐bulbo‐spinal reflexes. Such effects are not unique, but follow stimulation of skin and muscle nerves of the forepaw.

3. Supratentorial pathways are involved in descending spinal interactions in the chloralose anaesthetized cat, but are more critical for interactions taking origin in biventer cervicis nerve than in forepaw nerves.

4. In non‐anaesthetized spinal cats showing interactions from forepaw nerves, no interactions could be found taking origin in biventer cervicis nerves. Descending interactions from forepaw nerves could be reduced or abolished by anaesthetic doses of chloralose.

5. The rich pathway from biventer cervicis nerve to the superior colliculus does not appear to be involved in the descending interactions reported here as neither stimulation nor ablation of the superior colliculi has any effect on descending interactions.
Gustatory impulse discharges in response to saccharin in rats and hamsters
Authors: Ogawa H. , Sato M. , Yamashita S.
Published: December 2014

1. Impulse discharges produced by saccharin sodium as well as four basic gustatory stimuli were recorded in chorda tympani fibres of rats and hamsters.

2. Units predominantly sensitive to NaCl showed a concentration—response magnitude curve for saccharin sodium similar in shape to that for NaCl but smaller in magnitude. Units of this category did not respond to 0·01
M saccharin buffered with tris(hydroxymethyl)aminomethane. Response to saccharin sodium in these units are considered to result from stimulation of receptor molecules by Na ions.

3. Units predominantly sensitive to sucrose showed a concentration—response magnitude curve for saccharin sodium with a maximum magnitude at about 0·01–0·1
M. Impulse discharges produced by sucrose and saccharin sodium showed rhythmic burst‐like firing. Units of this category responded well to 0·01
M saccharin. Responses to saccharin sodium in these units are attributed to the reaction between saccharin molecules and receptor sites.

4. The optimum concentration at which a greatest response magnitude was found varies from one unit to the other and is inversely related to sucrose sensitivity, units highly sensitive to sucrose showing a low optimal concentration. Presence of the optimum concentration is explained by a mechanism known as the non‐competitive auto‐inhibition.

5. Off‐responses were observed in units predominantly sensitive to sucrose when 0·03–1
M saccharin sodium applied to the tongue was rinsed with water.

6. Neural information for saccharin sodium is described quantitatively in relation to that for four basic gustatory stimuli.
Cable properties of external intercostal muscle fibres from myotonic and nonmyotonic goats
Authors: Bryant S. H.
Published: December 2014

1. In preparations of about 200 fibres each from thirty‐nine biopsies of external intercostal muscle taken from nine myotonic and six nonmyotonic goats, cable properties were determined at 38° C for individual fibres with a pair of intracellular micro‐electrodes.

2. In each preparation the mean fibre dimensions, determined histologically and corrected for shrinkage, were used to calculate the mean membrane resistance, Rm, fibre capacitance, Ct, and myoplasmic resistivity, Ri. In the 124 nonmyotonic fibres the mean values were: Rm, 1897 Ω.cm2, Ct, 4·1 μF/cm2, and Ri, 112 Ω.cm. In 151 myotonic fibres Rm was 5589 Ω.cm2, Ct, 4·4 μF/cm2, and Ri, 103 Ω.cm.

3. Conductance of the fibre core times unit length increased with cross‐sectional area, and fibre capacitance per unit length increased with perimeter. There was little correlation of membrane resistance per unit length of fibre with either fibre perimeter or resting potential.

4. The principal abnormality of cable properties in the myotonic fibre is its threefold higher membrane resistance, which accounts for its decreased electrical current rheobase.
Change of tubular reabsorption of sodium and water after denervation
Authors: Bonjour Jean-Philippe , Churchill Paul C. , Malvin Richard L.
Published: December 2014

1. Renal function was compared in dogs before and after denervation, with normal or reduced glomerular filtration rate (GFR). GFR was reduced by one of two means, aortic clamping or injection of plastic microspheres into one renal artery.

2. The data showed that the tubular rejection fraction of denervated kidneys increased at a time when the same value for the control kidney decreased, indicating that denervation diuresis is not simply a result of increased filtered load of Na and water.

3. Changes in excretion after aortic clamping are not due solely to reduced filtered load. A reduction in renal blood pressure itself appears to have a direct effect on Na transport since Na excretion was significantly decreased before there were any changes in GFR, renal plasma flow and urine volume.

4. When GFR in a denervated kidney was reduced by microsphere injection it was demonstrated that a significant natriuresis (UNa V) and diuresis (V) occurred when. GFR was reduced by as much as 40%.

5. These experiments support the hypothesis that denervation diuresis does not result solely from increased filtered load, but entails altered Na transport.
The absorption of polyvinyl pyrrolidone by the new‐born pig intestine
Authors: Hardy R. N.
Published: December 2014

1. The intestinal absorption of [131I]polyvinyl pyrrolidone of mean mol. wt. 160,000 (K. 60) and 40,000 (K. 30) after oral administration has been measured in unsuckled conscious pigs less than 20 hr old. Absorption was assessed by the measurement of the concentration of [131I]PVP in venous blood during the 6 hr after feeding and also by the distribution at the end of the experiment of [131I]PVP between homogenates of the alimentary tract and homogenates of the rest of the animal.

2. The concentration of [131I]PVP in the peripheral blood after feeding was dependent upon the mol. wt. of the polymer, when comparable amounts had been absorbed from the intestine. PVP K. 60 attained higher blood concentrations than PVP K. 30 and the blood concentrations of PVP K. 60 were close to the values to be expected if all the material which had left the intestine had remained in the blood. The lower blood concentrations found when PVP K. 30 was fed were associated with the disappearance of labelled solute from the gut and were thus the consequence of the relatively rapid escape of labelled solute from the plasma after absorption had taken place.

3. The ability of the intestine to absorb [131I]PVP K. 60 declined progressively after birth but did not terminate abruptly unless the animal was fed colostrum. In unsuckled animals the rate and extent of absorption at 3 hr was much greater than at 20 hr after birth, but some absorption was still present at least 65 hr after birth.

4. The transfer of PVP K. 60 to the peripheral blood was dependent upon factors in sow colostrum, since significant absorption did not occur when PVP was fed in water or simple salt solutions.

5. The factors which accelerated absorption were present in colostrum from the goat, cow and ewe as well as that from the sow; they remained in the whey, but, in contrast to the factors which accelerate absorption in the calf, were largely inactivated by boiling. Similarly, neither phosphate, lactate, pyruvate, nor lower volatile fatty acid salts, which were effective in the calf, accelerated absorption in the pig.

6. The absorption of [131I]PVP K. 30 was found to be much less dependent upon the composition of the solvent than the absorption of [131I]PVP K. 60, although absorption was most rapid when PVP K. 30 was fed in colostrum.
Bovine splenic nerve: characterization of noradrenaline‐containing vesicles and other cell organelles by density gradient centrifugation
Authors: Hörtnagl H. , Hörtnagl Heide , Winkler H.
Published: December 2014

1. Homogenates of bovine splenic nerves were subjected to differential and sucrose density gradient centrifugation. From the low‐speed supernatant a high‐speed sediment (mitochondria, lysosomes, microsomes and noradrenaline (NA) vesicles) was obtained. By density gradient centrifugation of this sediment it was shown that NA vesicles are slightly less dense than mitochondria, but denser than microsomes.

2. In further experiments a mitochondrial and a microsomal sediment were obtained. The mitochondrial sediment was fractionated with a short centrifugation time over a density gradient ranging from 0·6 to 1·2
M sucrose. Mitochondria (fumarase and succinate‐dehydrogenase) and lysosomes (acid ribonuclease and deoxyribonuclease) sedimented to the bottom of the tube. The highest concentration of NA vesicles was found in a medium position. There was only a small amount of microsomes (glucose‐6‐phosphatase) present.

3. The microsomal sediment was centrifuged for 150 min over a density gradient ranging from 0·8 to 1·4
M sucrose. The microsomes remained on the top of the gradient. There were also some mitochondria and lysosomes present. The NA vesicles were found in highest concentration in the middle of the gradient (at about 1·2
M sucrose).

4. With the use of these two density gradients, the subcellular distribution of dopamine‐β‐hydroxylase, monoamine oxidase and ATPase was studied. Dopamine‐β‐hydroxylase was found to be localized in the NA vesicles. Monoamine oxidase was mainly recovered in mitochondria; a small part of the enzyme appeared to be microsomal. ATPase was present in microsomal elements.