bluuebunny/crossref_metadata_2025_split huggingface dataset:
The independence of corticomotoneuronal and fusimotor pathways in the production of muscle contraction by motor cortex stimulation
Authors: Koeze T. H. 
Published: December 2014

1. The response of thirty spindle afferents was studied during cortical stimulation of the ‘best point’ for eliciting a contraction of tibialis anticus in baboons anaesthetized with N2O/O2 mixtures supplemented by small doses of barbiturates.2. No evidence of fusimotor activity before a contraction of the muscle was found. Evidence of fusimotor activity during the contraction and after the cortical stimulus was found. The various problems associated with interpretation of this activity are discussed.3. Depression of the spindle afferent response by tetanic cortical stimulation, which produced no detectable tension change, was found for four spindle afferents. This depression was particularly well documented for one spindle afferent. The depression could be explained by a decrease of static fusimotor activity.4. The spindle afferent response to muscle stretch was studied during light anaesthesia. The effect of barbiturates on this response suggested a depression of static fusimotor activity.
Temperature effects of reserpine injected into the cerebral ventricles of rabbits and cats
Authors: Banerjee U. , Burks T. F. , Feldberg W. , Goodrich Cecilie A. 
Published: December 2014

1. In unanaesthetized rabbits and cats reserpine was injected through a chronically implanted cannula in the left lateral cerebral ventricle, and rectal temperature was recorded.2. In rabbits the reserpine (0·5‐0·6 mg) caused a rise in temperature, frequent defaecation and sedation. On repeating the intraventricular injections at 24 hr intervals the rise in temperature was not obtained with the second or third injection, but defaecation and sedation still occurred. When the hyperthermic response to intraventricular reserpine had disappeared the anterior hypothalamus still responded to intraventricular noradrenaline which produced a rise in temperature.3. In cats the reserpine (0·5‐0·75 mg) caused a biphasic change in temperature, i.e. an initial fall followed by a rise, frequent defaecation, and catalepsy. On repeating the intraventricular injections at 24 hr intervals the initial hypothermic phase of the temperature response was not obtained with the second or third injection, but the late rise, defaecation and catalepsy were still produced. When the hypothermic phase had disappeared the hypothalamus still responded to intraventricular noradrenaline or adrenaline which produced a fall, and to intraventricular 5‐hydroxytryptamine (5‐HT) which produced a rise in temperature.4. It is concluded that the rise in temperature in rabbits and the initial fall produced in cats is not due to a direct action of reserpine on the cells of the anterior hypothalamus but to noradrenaline released from adrenergic fibres ending at these cells. When these fibres are depleted of their noradrenaline by one or two injections of reserpine, these effects are not obtained because noradrenaline is no longer available to be released in sufficient amounts to raise temperature in rabbits and to lower it in cats.
Sodium movements in denervated muscle and the effects of antimycin A
Authors: Creese R. , El-Shafie A. L. , Vrbová Gerta 
Published: December 2014

1. Fibre sodium in rat diaphragm exchanged at a faster rate in muscles which had been denervated 8 days previously. The half‐time was 3·7 min for outward movement in denervated muscles and 5·1 min in controls.2. The inward movement of sodium was also faster in denervated muscle as compared with controls, and the calculated permeability to sodium was approximately doubled.3. In the presence of antimycin A (1·8 × 10−5
M), the outward movement of sodium in denervated diaphragm was slowed and the fibres gained sodium and lost potassium.4. Antimycin markedly reduced the twitch produced by stimulation of denervated diaphragm, and also the response to acetylcholine. Similar effects were found in denervated tibialis anterior of the cat.
Application of fourier analysis to the visibility of gratings
Authors: Campbell F. W. , Robson J. G. 
Published: December 2014

1. The contrast thresholds of a variety of grating patterns have been measured over a wide range of spatial frequencies.2. Contrast thresholds for the detection of gratings whose luminance profiles are sine, square, rectangular or saw‐tooth waves can be simply related using Fourier theory.3. Over a wide range of spatial frequencies the contrast threshold of a grating is determined only by the amplitude of the fundamental Fourier component of its wave form.4. Gratings of complex wave form cannot be distinguished from sine‐wave gratings until their contrast has been raised to a level at which the higher harmonic components reach their independent threshold.5. These findings can be explained by the existence within the nervous system of linearly operating independent mechanisms selectively sensitive to limited ranges of spatial frequencies.
The effect of sodium depletion on the renal response to water‐loading in dogs
Authors: Coxon R. V. , Ramsay D. J. 
Published: December 2014

1. Dogs depleted of sodium by peritoneal dialysis with glucose solution (5 g/100 ml.) showed a significant reduction in plasma sodium concentration, in inulin clearance and in plasma and extracellular fluid volume. The plasma protein concentration and haematocrit were increased.2. By the second day of salt depletion the plasma and extracellular fluid volumes, plasma protein concentration and haematocrit all showed some recovery towards normal values.3. A water‐load of 2·5% of body weight did not cause diuresis or natriuresis when given on the first day of depletion, but initiated a water diuresis when given on the second day.4. A water‐load of 5% of body weight caused diuresis but not natriuresis, when given on either day of salt depletion.5. The physiological interpretation of these results is discussed.
Thyroid activity and growth rate in rapidly growing lambs
Authors: Draper S. A. , Falconer I. R. , Lamming G. E. 
Published: December 2014

1. This paper reports a study of the relationship between thyroid gland activity and rate of growth of lambs held in a controlled environment with feeding ad libitum.2. Thyroid activity was assessed by the rate of release of 131I from the thyroid gland over a period of 1–2 weeks following injection. Growth rates were simultaneously recorded on a total of thirty‐one lambs during forty‐six measurements of thyroid activity.3. The results demonstrated a highly significant curvilinear correlation between growth rate and the rate constant for thyroid 131I release (P < 0·001).4. Surgically thyroidectomized animals were demonstrated to have a much reduced rate of growth.5. It was concluded that thyroid activities considerably above or below the optimum have an adverse effect on growth rate.
The function of antidiuretic hormone in the sheep
Authors: Brook A. H. , Radford H. M. , Stacy B. D. 
Published: December 2014

1. With the aim of producing diabetes insipidus in sheep, electrolytic lesions were placed in the ventral medial hypothalamus immediately posterior to the optic chiasm.2. After formation of lesions, the pattern of urine excretion showed a triphasic response consisting of (i) an immediate diuresis reaching a maximum within 4 days, (ii) an interphase of about 12 days wherein rates of urine flow were normal, and (iii) a final phase of permanent polyuria. With the four sheep used in this work, the time between placement of the lesions and onset of permanent hyposthenuria was 19‐22 days.3. In the final polyuric phase, the sheep were unable to concentrate their urine in response to dehydration or to feeding.4. Infusions of arginine vasopressin restored the ability of these animals to excrete urine that was hypertonic to plasma.5. The evidence showed that the hypothalamic lesions were effective in producing permanent diabetes insipidus. It was concluded that anti‐diuretic hormone (ADH) has essentially the same function in sheep as it has in other mammalian species; that is, the hormone facilitates the elaboration of hypertonic urine. There was no evidence to suggest that ADH had a special effect on potassium excretion in the sheep.
Rod/cone rivalry in pigment regeneration
Authors: Rushton W. A. H. 
Published: December 2014

1. The rod branch of the dark‐adaptation curve was studied at two regions 1¼° from the foveal centre (see inset, Fig. 2).2. One region had been bleached by red light, the other by blue of equal scotopic value.3. This equality was established by finding the rod increment threshold against the red or blue backgrounds: they were judged equal when they raised the rod threshold equally.4. If the bleaching exposure lasted 4 min or less, the rod dark‐adaptation curves coincided, though the cone branches did not (since red bleached cones 80%, blue 20%, but rods were bleached equally).5. If the bleaching exposure was prolonged to 16 min the rods recovered more slowly from the red bleach. And this difference was enhanced by a preliminary intense white exposure that bleached everything.6. The effect was due to the presence of cones since repeating the experiment at 15° from the fovea where cones are scarce virtually gave coincident rod dark‐adaptation curves.7. It follows that where cones are regenerating fast (from the 80% red bleach) they extract from the space outside the cone cells some ingredient needed for rod regeneration, and after pronounced and prolonged bleaching, the lack of this ingredient slows rod recovery.8. Most probably the ingredient is 11‐cis retinol returning from the pigment epithelium.
Responses evoked in the cerebellar cortex by stimulation of the caudate nucleus in the cat
Authors: Fox Mary , Williams T. D. 
Published: December 2014

1. Responses evoked in the cerebellar cortex following stimulation of caudate nucleus are described.2. The evoked responses recorded from the surface of the cerebellar cortex were found to be of two types, one with a short (4‐6 msec) latency and one with a longer (12‐17 msec) latency.3. The short latency response was maximal in the lobulus simplex, the longer latency response was maximal in paramedian lobule.4. Following lesions in the inferior olive the longer latency response was absent.5. Recordings from within the cerebellar cortex showed that the short latency response was uniformly distributed throughout the grey matter, the longer latency response was maximal in the region of the Purkinje cell bodies.6. It was concluded that the short latency response was due to activation via the mossy fibres and the longer latency response to activation via the climbing fibres.7. It was found that responses could be evoked in the cerebellum following stimulation of only the latero‐ventral part of the caudate nucleus; stimulation of the rest of the nucleus caused no response in the cerebellum. This division of the caudate nucleus into two parts is similar to the subdivision of the caudate nucleus made by other workers using different criteria.
Cardiovascular response to localized heating of the anterior hypothalamus
Authors: Whittow G. C. 
Published: December 2014

1. The effects, on the systemic and pulmonary circulation, of localized heating of the anterior hypothalamus, at different environmental temperatures, have been studied in the unanaesthetized ox.2. In a cool environment (15° C), heating the hypothalamus elicited panting which was associated with increases in cardiac output, heart rate, pulmonary arterial pressure and central blood volume, and decreases in systemic total peripheral resistance, and the percentage of red cells in mixed venous blood.3. In a hot environment (40° C), the cardiovascular responses were of smaller magnitude than in the cool environment. It was suggested that the smaller responses in the hot environment were probably related to a higher level of blood flow through the skin before the hypothalamus was heated.4. The cardiovascular responses to localized heating of the anterior hypothalamus were similar to those which occur during hyperthermia. However, there were also differences between the effects of the two procedures and it was concluded that hyperthermia involves the stimulation of other receptors in addition to those in the anterior hypothalamus.
Assay of gastrin by means of its gastric acid stimulating activity
Authors: Blair E. L. , Keenlyside R. M. , Newell D. J. , Reed J. D. , Richardson Diana D. 
Published: December 2014

1. A method is described for the bio‐assay of gastrin activity in the anaesthetized cat, based on the acid stimulating activity of gastrin.2. A ‘gastrin’ of unknown potency can be assayed in terms of a stable Standard Gastrin Extract or of Synthetic Human Gastrin I.3. The sensitivity of the method is such that it will detect quantities of Synthetic Human Gastrin I at least as small as those at present described as detectable by radioimmunological techniques.4. The precision of the assay is such that it falls in the category that has been described as very precise and well suited to clinical studies.
Membrane properties of the stretch receptor neurones of crayfish with particular reference to mechanisms of sensory adaptation
Authors: Nakajima S. , Onodera Kayoko 
Published: December 2014

1. Membrane properties of neurones of the two morphologically different types of stretch receptor of crayfish, the slowly adapting (RM1) and the rapidly adapting (RM2) receptors, were investigated with two microelectrodes inserted into the same neurone.2. The action potential was usually larger in the slowly adapting than in the rapidly adapting neurone. But the distributions of the height were not sharply delimited, and there was an overlap from the two groups of neurone.3. There were no marked differences in the current—voltage relationship between the two types.4. Under voltage clamp, depolarizations evoked a large delayed outward current, which slowly diminished during maintained depolarization (K‐inactivation). Under a moderate depolarization, development of the K‐permeability increase was very slow.5. When stimulated by intracellularly applied constant currents, the slowly adapting neurone always adapted slowly, and gave rise to long‐lasting trains of spikes, whereas the rapidly adapting neurone never produced maintained repetitive discharges.6. The same marked differences in the adaptation behaviour of spike discharge between the two types were also observed when the neurones were stimulated by constant currents applied through external electrodes.7. When the stimulating point was shifted along the axon of the slowly adapting neurones, the ability to produce long‐lasting repetitive discharges was found to be confined to the axonal region near the soma, where the diameter was very small, and where impulses were first initiated.8. Possible ionic mechanisms of the adaptation of the spike generating membrane were discussed. The importance of slowly occurring changes in the Na‐ and K‐permeabilities and changes in the electromotive force of the membrane due to electrogenic pump was emphasized.
Responses of normal and denervated cat superior cervical ganglia to some stimulant compounds
Authors: Brown D. A. 
Published: December 2014

1. The effect of preganglionic denervation on the sensitivity of the cat superior cervical ganglion to close‐arterial injections of some stimulant compounds in vivo has been studied.2. Ganglionic responses were assessed (a) by recording simultaneously ganglion depolarization and post‐ganglionic nerve action potential discharges, and (b) by measuring the contractions of the nictitating membrane and applying a correction for the change in sensitivity of the membrane to noradrenaline.3. No change could be detected in the electrical responses of the ganglion to carbachol after denervation.4. Nictitating membrane recording suggested that denervation increased the response of the ganglion to acetylcholine, but had little effect on ganglionic sensitivities to carbachol, nicotine, tetramethylammonium or potassium chloride.5. It was concluded that the neurones of the superior cervical ganglion do not, in general, show any substantial change of sensitivity to cholinesterase‐resistant stimulant compounds after denervation. The supersensitivity to acetylcholine is probably the result of a reduction of ganglionic acetylcholinesterase.
The optical activity of bleached retinal receptors
Authors: Villermet Gabrielle M. , Weale R. A. 
Published: December 2014

1. A study was made of the birefringence of retinal receptors obtained from the retinae of frogs, cats, rabbits and goldfish.2. Normal rods and cones show similar optical activity.3. The effects of fixatives, lipid solvents, de‐ and rehydration, and temperature were examined.4. Rods fixed with formaldehyde preserve normal optical activity for a long time while glutaraldehyde changes it swiftly in a manner similar to that resulting from the application of heat.5. Alcohol acts like a denaturing agent rather than as a solvent for rod lipids.6. The action of glutaraldehyde on goldfish rods is instantaneous but cones preserve their normal activity for up to 1 hr.7. A number of striking parallels between the presence of the R2 component of the early receptor potential (as reported in the literature) and optical activity are listed; it is suggested that normal optical activity is a prerequisite for the recording, if not the elicitation, of R2.
The effect of procaine on snake twitch muscle fibres
Authors: Heistracher P. , Hunt C. C. 
Published: December 2014

1. The effect of procaine on the contractile responses of voltage clamped snake twitch muscle fibres has been investigated. Procaine hydrochloride shortened the duration of contractures produced by long depolarizing pulses. It also reduced the amount of inactivating outward current.2. The rate of repriming was greatly slowed by procaine. At −80 mV, for example, the time to half restoration of contractile response was 6 sec in procaine (5 × 10−3, w/v) as compared to 1·15 sec in tetrodotoxin (TTX), (1 × 10−7 w/v). At −100 mV, repriming was still much slower in procaine. However, at −150 mV, repriming in procaine was quite rapid, the time to half recovery being about 0·4 sec.3. After prolonged exposure to procaine, subthreshold depolarizing pulses produced a marked diminution in the contractile response to a subsequent supermaximal depolarization. In some fibres complete inactivation could be produced in the presence of procaine without any contractile response having occurred.
The circular dichroism of suspensions of frog rod outer segments
Authors: Crescitelli F. , Foster Rachel F. , Shaw T. I. 
Published: December 2014

The circular dichroism (CD) of suspensions of frog rod outer segments has been measured.At wave‐lengths between 600 and 400 nm1. The suspensions show a large positive CD increasing towards shorter wave‐lengths and largely unaffected by bleaching. This probably arises, at least in part, from the preferential scattering of one form of circularly polarized light.2. There is a small reduction in CD on bleaching, slightly larger but similar in sign and wave‐length dependence to that shown by pigment extracts.At wave‐lengths between 250 and 220 nm3. The suspensions show a CD somewhat similar in sign, magnitude and wave‐length dependence to that given by pigment extracts.4. On bleaching there is a reduction of the negative CD at 225 nm again similar to that which takes place when extracts are bleached.The observations suggest that configurational changes, of the kind detected by CD, occur in the bleaching of rhodopsin molecules whether they are present in solutions or in rods.
The metabolic requirements for catecholamine release from the adrenal medulla
Authors: Rubin R. P. 
Published: December 2014

1. The metabolic requirements for catecholamine secretion elicited by acetylcholine or by calcium plus high K+ were studied on acutely denervated perfused cat adrenal glands.2. Glucose‐deprivation plus anoxia caused an increase in the spontaneous catecholamine output from adrenal glands perfused with normal Locke solution, which was abolished by the removal of calcium from the perfusion medium.3. Anoxia plus glucose‐deprivation did not depress the secretory response to repeated exposures of a low concentration of acetylcholine, but did depress the response to a higher concentration of acetylcholine. Glucose‐deprivation and nitrogen, when imposed either separately or together, did not inhibit total catecholamine output in response to calcium. Differential analysis of the calcium‐evoked secretion showed that during anoxia, catecholamine output was maintained primarily by adrenaline secretion.4. Cyanide (0·2 m
M) potentiated the secretory response to calcium in the presence of glucose, but when glucose was omitted from the perfusion medium, cyanide caused a gradual decline in calcium‐evoked secretion. Iodoacetic acid (IAA) (0·2 m
M) depressed the response to calcium by about 50% under aerobic conditions and by 90% under anaerobic conditions.5. The glycogen content of medullae was profoundly depleted under anoxic conditions.6. It is concluded that energy is required for the secretory action of calcium on medullary chromaffin cells. The energy may be derived from glycolysis or oxidative metabolism. A possible interaction between calcium and adenosine triphosphate acid (ATP) in eliciting catecholamine secretion is discussed.7. The alteration in the percent adrenaline and noradrenaline secreted during anoxia indicates that anoxia may regulate medullary catecholamine secretion through a peripheral, as well as a central mechanism.
The immediate haematological response in the rat to experimental exposures of carbon monoxide
Authors: Ramsey J. M. 
Published: December 2014

1. A series of sixty haematocrit determinations, forty Hb evaluations, and fifty‐two blood smears for reticulocyte counts were taken from splenectomized and normal female albino rats before, immediately after, and 48 hr after exposures for 10 min to two different concentrations of carbon monoxide (0·06 and 0·12%). A similar series of all three measurements was administered to lesser numbers of unexposed controls (splenectomized and normals). Both Hb and haematocrit changes show considerable individual variations in the exposed groups.2. The means for haematocrit percentage in the controls and for those exposed to 0·06% carbon monoxide show no significant differences, but the 0·12% exposure mean for both the splenectomized and normal animals show a haematocrit decrease at the immediate post‐exposure examination that is significant (F = 10·7 and 6·06).3. The haemoglobin means show no significant differences in the control group. However, at the 0·12% exposure both the splenectomized and normal animals show a significant increase in the immediate post‐exposure examination (F = 27·53 and 9·25).4. The means for the reticulocyte percentages in the controls show no significant differences. However, the 48 and 72 hr post‐exposure examinations show means in exposed rats that are 46 and 38% greater than immediate post‐exposure means and the differences are significant. In both exposed and control groups there was no significant difference between splenectomized and normal rats in respect to reticulocyte production.5. The correlation of pre‐exposure and post‐exposure differences for haematocrit reduction and Hb increase was extremely insignificant for controls and for those at the 0·06% exposure. It was most positive, though statistically insignificant, at the 0·12% exposure where r = 0·476 (P = 0·16) for the splenectomized and 0·210 (P = 0·55) for those with spleens.6. In the rat the spleen appears to play some role in the haematological response to carbon monoxide hypoxia since splenectomized specimens as a group significantly had a greater but less variable decrease in haematocrit, and a greater increase in Hb than specimens with spleens.