bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of unitary spikes recorded extracellularly from frog olfactory receptor cells and axons
Authors: Getchell Thomas V. 
Published: December 2014

1. Differences in unitary spike conformation were systematically investigated with extracellular recordings at different depths in the frog's olfactory epithelium. Platinum‐black metal‐filled micro‐electrodes were used in the unit recordings. Their properties were carefully investigated and compared with those of micropipettes.2. Three basic types of spikes were recorded: a diphasic spike with a positive—negative voltage sequence, a diphasic spike with a negative—positive voltage sequence and a triphasic spike with a positive—negative—positive voltage sequence.3. The triphasic spike was correlated with the action potential in the axon. The initially negative diphasic spike was correlated with the action potential initiated in the cell body region. The initially positive diphasic spike was correlated with the spread of the impulse into the receptor cell dendrite.4. A model is discussed which accounts for the differences in spike conformations and provides a basis for analysing impulse activity in spontaneously active and stimulus‐driven olfactory receptor cells.
Ionic properties of the neuromuscular junction of the frog: effects of denervation and pH
Authors: Mallart A. , Trautmann A. 
Published: December 2014

1. The effects of denervation, reinnervation and pH on the ionic permeability changes mediated by junctional receptors have been studied in muscle fibres of the frog sartorius.2. The reversal potential of acetylcholine responses in denervated junctions was about 25 mV more negative than in normal junctions.3. The delay of the change in the ionic properties of junctional receptors was proportional to the nerve stump length: 10 and 14 days for lengths of 12 and 33 mm, respectively.4. When the motor nerve reinnervates the junction, the reversal potential of the acetylcholine responses comes back to the normal value before the neuromuscular transmission is restored.5. The Na/K conductance change decreases in high pH solutions. After denervation, the pH profile of this ratio is shifted to the acid values by about two pH units.6. These observations can be explained by assuming that the Na and K channels differ by the pK of their anionic groups and that the denervation induces an alteration of the sites that bear the charges.
The regional distribution of emotional sweating in man
Authors: Allen Judith A. , Armstrong Janet E. , Roddie I. C. 
Published: December 2014

1. Emotional sweating was induced in normal subjects by mental arithmetic at environmental temperatures of 29 and 26° C and estimated from continuous records of body weight loss.2. The sweat output from four independent regions of the body — (a) the head and neck, (b) the arms and legs, (c) the trunk, and (d) the hands and feet — was studied separately, the remainder of the body being covered in each case by plastic bags. The evaporative water loss from each skin region increased markedly during mental arithmetic.3. The sweat contribution from each region was a substantial fraction of the total body sweat response and appeared to be roughly proportional to the calculated number of sweat glands in each region.4. There is no evidence from these experiments to indicate that the sweat glands of the skin of the hands and feet behave differently to those of the skin of the rest of the body in response to emotional stress.
Patterning in the regeneration of type I cutaneous receptors
Authors: Burgess P. R. , English Kathleen B. , Horch K. W. , Stensaas L. J. 
Published: December 2014

1. Type I sensory fibres in cat hairy skin innervate structures characterized by twenty to fifty specialized epithelial (Merkel) cells aggregated in a small dome‐shaped elevation. Only one fibre enters each dome and it branches repeatedly to supply at least one terminal to each Merkel cell. After the nerve is cut, the Merkel cells and the dome ultimately disappear.2. The distribution of domes on the posterior thigh was mapped before interruption of the femoral cutaneous nerve and after its regeneration. Regeneration after nerve crush was apparently complete, producing a coincidence pattern similar to those seen in control studies where the nerve was not damaged. After cutting the nerve fewer domes returned, but coincidence of regenerated femoral cutaneous domes with old sites generally was significantly greater than would be expected by chance alone. Non‐femoral cutaneous fibres sprouting into the denervated femoral cutaneous field tended to form domes at old sites. Domes were also reformed on scars where domes had been excised.3. Domes appearing at new locations and on excision scars were often small and close together (clustered). Individual domes in a cluster could be innervated by different Type I fibres.4. Type I fibres are directed by some mechanism to sites formerly occupied by domes and to sites where domes are being induced.
Mechanisms for differential block among single myelinated and non‐myelinated axons by procaine
Authors: Franz Donald N. , Perry Roger S. 
Published: December 2014

1. The differential sensitivity of saphenous nerve fibres in the cat to block by procaine HCl was re‐examined by recording identifiable unit action potentials from small nerve filaments.2. Small myelinated axons were blocked more quickly than large myelinated axons, but this differential effect could not be accounted for by differences in anaesthetic concentration requirements.3. The onset of block in non‐myelinated axons was slower than or equal to that of small myelinated axons depending on anaesthetic concentration.4. Absolute differential block of non‐myelinated and small myelinated axons was obtained by limiting the length of axons exposed to procaine to 2 mm.5. Differential rates of blocking among myelinated axons appear to depend on differences in the length of axons that must be exposed to blocking concentrations of procaine and to arise from the irregular distribution of such concentrations within an exposed nerve.
The effect of antidiuretic hormone on human sweating
Authors: Allen Judith A. , Roddie I. C. 
Published: December 2014

1. Changes in insensible perspiration and sweating were followed in normal subjects by continuously monitoring total body weight loss in environmental temperatures of 18, 29 and 37° C.2. Pharmacological doses of ADH had no effect on cutaneous water loss at 18° C.3. Pharmacological doses of ADH are capable of increasing the rate of cutaneous water loss in human subjects who are close to or above the thermal sweating threshold.4. Physiological doses of ADH had no effect on cutaneous water loss in either cool or hot environments.5. At normal rates of secretion in the body, ADH probably does not influence human sweat secretion.
Anode break excitation in denervated rat skeletal muscle fibres
Authors: Marshall M. W. , Ward M. R. 
Published: December 2014

1. Anodal break action potentials were found to be a feature of denervated rat skeletal muscle fibres.2. Depolarized innervated fibres failed to respond to anodal break stimulation in the same way as denervated fibres.3. The critical level for action potential generation is related to membrane polarization in denervated fibres but not in innervated fibres. This relationship is inhibited by the
I.P. administration of actinomycin D, which also prevents the onset of anodal break action potentials in 3‐day denervated fibres.
The effect of lowering the 5‐hydroxytryptamine content of the rat spinal cord on analgesia produced by morphine
Authors: Vogt Marthe 
Published: December 2014

1. Injection of 5,6‐dihydroxytryptamine (5,6‐DHT, 50 μg) into a lateral cerebral ventricle of male rats lowered the 5‐hydroxytryptamine (5‐HT) content of the lumbar cord to 12·8% and reduced the analgesic effect of low doses of morphine (0·64‐1·63 mg/kg), tested by exerting pressure on the foot; after doses of morphine of 1·33‐1·63 mg/kg, the analgesic response was reduced or abolished in 33% of the rats, and after 0·64 mg/kg, 58% of the animals failed to respond normally.2. Two days after an
I.P. injection of p‐chlorophenylalanine (pCPA, 320 mg/kg), the loss of analgesic potency of morphine was more pronounced than after intraventricular 5,6‐HDT. The 5‐HT content was lowered to about 8% in the lumbar cord, and to 20% or less in pons and medulla.3. The experiments show that interference with the descending tryptaminergic axons innervating the cord is by itself sufficient to reduce analgesia due to morphine, but they do not exclude the possibility that other tryptaminergic neurones take part in the effect of pCPA. The contribution to the analgesic effect of morphine made by the interaction of tryptaminergic axons with the interneurones ‘gating’ the afferent impulses in the posterior columns is discussed.
The sensitivity of Helix aspersa neurones to injected calcium ions
Authors: Meech R. W. 
Published: December 2014

1. When calcium chloride was injected into Helix aspersa neurones there was a fall in membrane resistance and the membrane potential became hyperpolarized.2. The reversal potential of the response was dependent on the concentration of potassium in the external solution.3. Injection of a calcium—EGTA buffer containing 9 × 10−7
M free calcium reduced the membrane resistance by 25%. When calcium chloride was injected it was necessary to increase the total intracellular calcium concentration by about 10−3
M to produce similar change of resistance.4. In sodium‐free (Tris) solution there was a slow fall of membrane resistance as if the intracellular calcium concentration had increased. There was a similar resistance change in the presence of 2,4‐dinitrophenol and iodoacetate.5. A series of repetitive depolarizing pulses produced a long lasting reduction in membrane resistance which was enhanced by 2,4‐dinitrophenol and iodoacetate.6. It is concluded that (a) injection of calcium causes an increase in potassium permeability, (b) the injected calcium is rapidly pumped from the cytoplasm by a sodium‐dependent mechanism and by mitochondria, and (c) 1–2 msec depolarizing pulses stimulate an influx of calcium. This influx is rapid enough to trigger potassium activation during an action potential.
The role of the carotid body chemoreceptors and carotid sinus baroreceptors in the control of cerebral blood vessels
Authors: Ponte J. , Purves M. J. 
Published: December 2014

1. Cerebral blood flow was measured in 17 baboons, anaesthetized with pentobarbitone, paralysed with gallamine and mechanically ventilated and in which the right sinus and both aortic nerves had been cut and the left carotid sinus vascularly isolated. Later in each experiment, the head was artificially perfused with femoral arterial blood via the innominate artery.2. Stimulation of the carotid body chemoreceptors with venous blood invariably caused a rise in regional cerebral blood flow whether the head was naturally or artificially perfused. This response was almost completely abolished if the VIIth cranial nerves were cut intracranially.3. Regional cerebral blood flow varied inversely with carotid sinus pressure.4. After the remaining (left) sinus nerve had been cut, the cerebral vascular response to hypoxia was negligible and the response to hypercapnia was markedly reduced. Blood flow then varied with perfusion pressure.5. These results provide further evidence that cerebral blood vessels are reflexly controlled and that the peripheral arterial receptors are involved. Their action is most conspicuous in the vascular response to hypoxia and together with intrinsic factors in the cerebral vascular bed, they determine the size of the vascular response to changes in CO2 and pressure.
Effects of vagotomy, atropine, hexamethonium and adrenaline on the destination in the stomach of liquids sucked by milk‐fed lambs and calves
Authors: Newhook J. C. , Titchen D. A. 
Published: December 2014

1. The normal passage to the abomasum of liquid sucked by lambs and calves was confirmed in radiographic studies to be changed to passage of liquid to the reticulum and rumen after cervical or abdominal vagotomy.2. The effects of hexamethonium (8–10 mg kg−1 I.V.) were similar to those of vagotomy.3. Atropine (200–800 μg kg−1 I.V.) had either no detectable effect on the destination in the stomach of liquid sucked by lambs or caused a partial failure of the reticular groove mechanism.4. Fluid sucked by lambs passed wholly to the abomasum after adrenaline (5–40 μg kg−1 I.V.).5. Atropine and adrenaline caused a greater dysfunction of the reticular groove mechanisms in calves than in lambs.6. Contraction of the reticular groove was observed via rumen fistulae in three lambs. Eversion of the caudal oesophagus into the reticulum which occurred when saliva was swallowed into the reticulum and rumen was not observed when liquids were sucked from a bottle.7. The continued passage to the abomasum of sucked liquid in atropinized lambs has been taken as an indication of the importance of caudal oesophageal reactions, tonic activity of the reticular groove and the atropine‐resistant vagally induced opening of the reticulo‐omasal orifice in the reticular groove mechanism.
Electrically induced release of acetylcholine from denervated Schwann cells
Authors: Dennis M. J. , Miledi R. 
Published: December 2014

1. Focal electrical stimulation of Schwann cells at the end‐plates of denervated frog muscles elicited slow depolarizations of up to 30 mV in the muscle fibres. This response is referred to as a Schwann‐cell end‐plate potential (Schwann‐e.p.p.).2. Repeated stimulation sometimes evoked further Schwann‐e.p.p.s, but they were never sustained for more than 30 pulses. Successive e.p.p.s varied in amplitude and time course independently of the stimulus.3. The Schwann‐e.p.p.s were reversibly blocked by curare, suggesting that they result from a release of acetylcholine (ACh) by the Schwann cells.4. ACh release by electrical stimulation did not seem to occur in quantal form and was not dependent on the presence of calcium ions in the external medium; nor was it blocked by tetrodotoxin.5. Stimulation which caused release of ACh also resulted in extensive morphological disruption of the Schwann cells, as seen with both light and electron microscopy.6. It is concluded that electrical stimulation of denervated Schwann cells causes break‐down of the cell membrane and releases ACh, presumably in molecular form.
The hippocampal control of neuronal discharges in the septum of the rat
Authors: McLennan H. , Miller J. J. 
Published: December 2014

1. Records of field potentials and of the firing patterns of single neurones evoked by stimulation of the fimbria and fornix have been obtained from the septal nuclei of the rat.2. Fimbrial stimulation caused orthodromic activation of lateral septal neurones which was followed by a lengthy inhibition. In the medial septum such stimulation could elicit an antidromic response; but inhibition whose duration depended upon whether the neurones were firing irregularly or in synchronized bursts was obtained without prior activation.3. Stimulation of the medial septum evoked an antidromic response in the lateral septal neurones, which was followed by inhibition.4. For all of these inhibitory phenomena, bursts of action potentials of small amplitude and correlated with the start of the inhibitory periods were observed, and are believed to indicate the firing of inhibitory interneurones.5. Stimulation of the fornix caused excitation of medial septal neurones but was without effect on those in the lateral septum.6. A scheme is proposed in which the direct inhibition of medial septal neurones from the fimbria is suggested to act as a ‘reset’ mechanism, while the phasic input from lateral septum resulting from the recurrent inhibitory pathways regulates the frequency of bursting in the medial septum.
Left atrial receptors and the antidiuretic hormone
Authors: Kappagoda C. T. , Linden R. J. , Snow H. M. , Whitaker Elaine M. 
Published: December 2014

1. Stimulation of left atrial receptors by distending balloons located at the junction between the pulmonary veins and the left atrium and in the body of the left atrium resulted in a diuresis in anaesthetized dogs.2. In the same dogs the diuresis was not consistently associated with a reduction in the antidiuretic activity of plasma as compared with that during the initial control period. The antidiuretic activity of dog plasma was assayed in water‐loaded rats anaesthetized with ethanol.3. Intravenous injections of vasopressin suppressed a water diuresis in water‐loaded dogs anaesthetized with chloralose. The changes in antidiuretic activity of dog plasma which resulted from these injections were reliably detected by the bio‐assay in the rat.4. It is concluded that the diuretic response to the stimulation of left atrial receptors is not accompanied by a reduction in the plasma antidiuretic hormone level.
Carviobascular alterations associated with bursts of panting in the exercising dog
Authors: Dampney R. A. L. 
Published: December 2014

1. In conscious dogs exercising on a treadmill variations in arterial blood pressure and heart rate which were correlated with bursts of panting were observed. The blood pressure variations reflected similar variations in the total peripheral vascular resistance.2. During exercise a change in respiration from slow breathing to panting was followed by a systemic vasodilatation and fall in blood pressure, but a rise in heart rate. Analysis of the time course of these effects demonstrated that the heart rate increase occurred later than the blood pressure fall.3. The correlation between panting and blood pressure changes was not abolished by either of the receptor‐blocking drugs atropine sulphate or propranolol, nor by either of the following surgical procedures: acute bilateral cervical vagotomy, and denervation of the carotid sinus baroreceptors and carotid body chemoreceptors.4. The vasodilatation which followed a burst of panting appeared to be due to a decrease in adrenergic vasoconstrictor sympathetic nerve activity, and not to a change in the chemical composition of the arterial blood.5. It is concluded that the vascular changes are not reflex responses to stimulation of peripheral receptors by the bursts of panting. Instead, it is suggested that both the bursts of panting and associated falls in blood pressure are parallel effects resulting from activation at a suprabulbar level of the central nervous system. It is also concluded that the variations in heart rate are mediated by the baroreceptor reflex mechanism, activated by the changes in mean blood pressure.
Influence of temperature on retinal ganglion cell response and e.r.g. of goldfish
Authors: Schellart N. A. M. , Spekreijse H. , van den Berg T. J. T. P. 
Published: December 2014

1. Extracellular recordings were made from the colour and spatial coded ganglion cells in the isolated goldfish retina.2. Electroretinograms (e.r.g.s) were obtained from unanaesthetized goldfish.3. For both types of responses the amplitude and phase characteristics were determined at various temperatures by means of Gaussian noise modulated light.4. The shape of these characteristics, depicted as Bode plots, is invariant with temperature. For the ganglion cell responses this holds from 7 to 19° C, whereas for the e.r.g.s invariance is found over the entire range of temperatures used (6–30° C).5. To obtain overlapping Bode plots shifts along the frequency axis are needed that are in accordance with the Arrhenius relation. The Q10 of the e.r.g. is about 1·9 and of the spike response about 2·7.6. These relatively low values of Q10 indicate that the dynamics of retinal signal transformations are dominated by diffusion controlled reactions. This implies that real transport delays can be neglected in retinal input—output relations.7. To verify whether a relationship exists between temperature and spectral coding, as has been suggested on the basis of behavioural studies, photopic e.r.g. action spectra were recorded and the spectral coding of ganglion cells were determined as a function of temperature.8. The results point to a temperature invariance of both the photopic e.r.g. action spectra and the colour coding of ganglion cell responses.9. The general conclusion of this study is that ‘rules’ found in the poikilothermic goldfish are not bound by temperature.
Relationships between motor nerve conduction velocities and motor unit contraction characteristics in a slow twitch muscle of the cat
Authors: Bagust J. 
Published: December 2014

1. Isometric contractions of cat soleus muscles and of functionally isolated motor units have been measured under conditions similar to those of Bagust, Knott, Lewis, Luck & Westerman (1973).2. The muscle lengths at which motor unit twitch and tetanus tensions were maximal were close to the optimal lengths of the parent muscles.3. Motor unit contraction times and tensions were shown to be related to the conduction velocities of the nerve axons supplying them. These relationships were obscured when a number of small samples from several experiments were grouped together.4. The ratios of the twitch to the tetanic tensions of the motor units were directly related to their times to peak tension.
Different properties of synapses between a single sensory neurone and two different motor cells in the leech C.N.S
Authors: Muller K. J. , Nicholls J. G. 
Published: December 2014

In leech ganglia, an individual sensory cell that responds specifically to noxious mechanical stimulation of the skin (N cell) excites two different motoneurones. One raises the annuli of the skin into ridges (the AE cell), while the other innervates logitudinal muscles and thereby shortens the body segment (L cell). A comparison has been made of the way in which these two synapses behave when their common presynaptic cell is stimulated in various conditions.1. Using previously described criteria, N sensory cells have been shown to make monosynaptic chemical connexions with both the AE and L motoneurones (Nicholls & Purves, 1972). Following a single stimulus, the excitatory synaptic potential recorded in the AE motoneurone was only about one tenth the size of that in the L cell (approximately 0·5 mV compared to 5 mV). Trains of impulses in the same N sensory cell gave rise to synaptic potentials in the AE and the L motoneurones that underwent phases of facilitation and depression; the facilitation, however, was characteristically greater and longer lasting at synapses upon the AE motoneurone.2. The differences between the two synapses were accentuated in Ringer fluid containing increased concentrations of Ca and also in the cold. Under both of these conditions repetitive firing by the N sensory cell could give rise to synaptic potentials in the AE motoneurone which progressively increased in amplitude, while those in the L motoneurone became smaller.3. The results suggest that the differences in synaptic transmission can be accounted for by variations in the amount of transmitter released at the presynaptic N cell terminals, rather than by differences in the post‐synaptic cells. The animal's behaviour corresponds to expectations from the physiology of the synapses.