bluuebunny/crossref_metadata_2025_split huggingface dataset:
An uptake mechanism for L‐noradrenaline in the cat spleen, associated with the nerves but distinct from uptake1
Authors: Blakeley A. G. H. , Powis G. , Summers R. J. 
Published: December 2014

1. The characteristics of the uptake of [3H]
L‐noradrenaline from 1 μg pulses injected close arterially to the isolated blood perfused cat spleen are described.2. The spleen took up 355·0±16·0 ng from a first pulse and 321·1±43·6 ng from a second.3. Uptake from a second pulse was 254·0±30·3 ng in the presence of the Uptake1 inhibitor desmethylimipramine (DMI) (3·3 × 10−5
M) and the Uptake2 inhibitor 17‐β‐oestradiol (17β0) (1·8 × 10−4
M).4. Uptake from small 10 ng pulses was also insensitive to DMI and 17β0.5. Uptake from pulses was abolished by surgical denervation of the spleen, or pre‐treatment with phenoxybenzamine (PBA) (8·8 × 10−5
M).6. The pulse uptake process was impaired by omission of red cells from the perfusate.7. Stimulation of the splenic nerves at 3Hz halved the pulse uptake.8. Uptake from infusion in the presence of DMI and 17β0 occurred only during the first few minutes of the infusion.9. It is concluded that an uptake process for
L‐noradrenaline distinct from Uptakes1 and 2 is present in the spleen and this might be important physiologically.
The compensation of post‐traumatic oedema in the rabbit at different ages
Authors: Little R. A. 
Published: December 2014

1. The compensation of fluid loss from the circulation after an LD50 period of bilateral hind‐limb ischaemia in a thermoneutral environment has been studied in the rabbit from birth until young adulthood.2. The fluid loss from the circulation was calculated from the increase in the great vessel haematocrit value as the red cell volume and Fcells were unchanged after limb ischaemia. This ‘apparent’ fluid loss was compared with the ‘actual’ fluid loss calculated from the increase in water content of the injured limbs.3. The 0‐ to 1‐day‐old rabbit was better able to restore fluid, and protein, to the circulation than the older animal and suffered a smaller percentage reduction in arterial blood pressure after an LD50 period of ischaemia.4. The better compensation of post‐traumatic fluid loss during the first 48 hr of life may be explained by the high capillary filtration coefficient and the post‐traumatic increase in plasma protein osmotic pressure found at that age.5. The more efficient restoration of the plasma volume by the 0‐ to 1‐day‐old rabbit may account for the increased ability to withstand post‐traumatic fluid loss at that age.
Ion fluxes through the sodium channels of garfish olfactory nerve membranes
Authors: Henderson Richard , Strichartz Gary 
Published: December 2014

1. The efflux of 22Na from garfish olfactory nerves, after treatment with ouabain and equilibration with 22Na, occurs in two components of almost equal size. One component represents efflux from the extracellular space and the other, much slower, component represents efflux from the intracellular space through the axonal membrane.2. The rate of efflux of 22Na through the membrane is increased from 0·038 to 0·055 min−1 by veratrine, and restored back to 0·036 min−1 by the additional application of tetrodotoxin or saxitoxin (10−7
M).3. 50% inhibition of this increased sodium ion flux occurs at tetrodotoxin and saxitoxin concentrations of 12 and 6 n
M respectively.4. The tetrodotoxin‐sensitive efflux of 22Na is almost unchanged in nerves equilibrated with hypertonic 0·85
M‐NaCl, whereas it is largely eliminated in nerves equilibrated with 0·85
M‐LiCl. We interpret this to indicate that there exists within the sodium channel a specific metal cation site which is responsible for the co‐ordination of the ions during their passage through the membrane. Lithium ions bind to this site relatively strongly, with a dissociation constant of 0·2–0·3
M, whereas sodium ions bind less strongly, with a dissociation constant greater than 0·75
M. Other evidence indicates that this site is the site at which tetrodotoxin and saxitoxin act.5. Batrachotoxin has a similar action to veratrine but is effective in concentrations at least 100 times lower.
Morphine hyperglycaemia
Authors: Feldberg W. , Gupta K. P. 
Published: December 2014

1. To find the site where morphine acts when producing hyperglycaemia on injection into the cerebral ventricles in unanaesthetized cats, morphine sulphate was infused or injected through an implanted Collison cannula into different parts of the liquor space in an amount of 0·75 mg except on microinfusion into the posterior hypothalamus, when the amounts were 80 or 160 μg. The glucose was determined in blood samples collected from the inferior vena cava.2. Microinfusions of morphine into the posterior hypothalamus did not produce hyperglycaemia.3. Infusion of morphine into the liquor space at the entrance of the aqueduct or of the fourth ventricle produced hyperglycaemia. Any structures in the walls of the third ventricle as well as the peri‐aqueductal grey are thus excluded as the site of action.4. Infusion of morphine into the subarachnoid space just above the corpora quadrigemina or below the ventral surface of the brain stem produced hyperglycaemia. With these routes the morphine does not enter any part of the ventricular cavities and the action would appear to be on structures at the ventral surface of the brain stem.5. Injection of morphine into the cisterna magna produces hyperglycaemia when the doses are larger than those already effective on injection into the cerebral ventricles. This also suggests an action on structures at the ventral surface of the brain stem, as this surface is reached more readily from the ventricles than from the cisterna.6. It is concluded that on injection into the cerebral ventricles, the morphine has to pass into the subarachnoid space, through the foramina of Luschka, in order to produce hyperglycaemia. It then reaches the ventral surface of the brain stem and probably acts there on structures in the upper part of the medulla oblongata.7. Infusion of morphine into the corpora quadrigemina near the caudal end of the superior corpora can produce profound hypoglycaemia.8. Anaesthesia depresses the morphine hyperglycaemia, but when the dose injected into the cerebral ventricles is increased four times or more, hyperglycaemia is also produced in pentobarbitone sodium anaesthesia.
Temperature regulation during fever: change of set point or change of gain? A tentative answer from a behavioural study in man
Authors: Cabanac M. , Massonnet B. 
Published: December 2014

1. Four subjects were immersed in a stirred water‐bath maintained at either 30 or 40° C. The left hand was placed out of the bath in a glove receiving water at a temperature selected by the subject as most pleasurable. Experiments were conducted during the euthermic state and during either spontaneous or induced fever.2. The results of control experiments confirm a previous observation using the same method, that preferred hand skin temperature was a linear function of internal temperature but also indicated an influence by mean skin temperature.3. The general pattern of response during fever was identical to that when fever was absent except that the regulated steady state internal temperature was higher and the slopes of preferred temperature plotted against internal temperature were steeper.4. The results seem to support the concept of a change in set point rather than that of a change in the gain of the thermoregulatory processes during fever.
Identification of cone mechanisms in graded responses of foveal striate cortex
Authors: Gouras Peter , Padmos Pieter 
Published: December 2014

1. The earliest electrical response detectable in foveal striate cortex of anaesthetized Rhesus monkeys following light stimulation is a graded potential which is positive at the cortical surface and negative in the grey matter and has a peak latency of about 60 msec. The response is similar at both the on‐ and the off‐phase of a light stimulus.2. The relationship of this graded potential to the depth of the recording electrode, to the latency of extracellular impulses and to post‐synaptic potentials suggests that it is generated by the depolarization of cortical cells.3. Action spectra obtained in the presence of strong selective chromatic adaptation indicate the participation of all three cone mechanisms in this response.4. Each cone mechanism contributes a similar potential to the response but antagonism between cone mechanisms is apparent. The proportion in which a cone mechanism contributes to the response varies from one area to another implying topographical differences in the representation of cone mechanisms in striate cortex.
New techniques for calibrating the Lloyd—Haldane apparatus
Authors: Cormack R. S. , Heath J. R. 
Published: December 2014

1. A new way of measuring the graduation error in the stem of the Lloyd—Haldane burette is described, in which a fixed mass of water is made to occupy different parts of the stem. This gave the same answer as the gravimetric method, but was much easier.2. Two independent methods of measuring the ‘meniscus error’ gave values of 0·006 and 0·008 ml. respectively. It is concluded that the bulb volume can be measured gravimetrically with the burette inverted, provided that the value so obtained is corrected by adding about 0·007 ml.3. Alternatively, this estimation can be made with the burette the right way up, no correction then being needed. To do this the lower end of the burette must be blocked and a method of doing this without the need to fuse on a glass tap is described.4. After calibration by the above methods analyses on fresh air for CO2 + O2 gave a mean value of 20·98%, which, in the authors’ view, is the correct value.5. The observer error was measured and from this the theoretical maximum accuracy of gas analysis by Haldane's method was calculated. It is concluded that the calculated% should be correct to the second decimal place in about half the analyses, the rest having an error of ± 0·01%. Results approaching this were obtained.
Acetylcholine synthesis from recaptured choline by a sympathetic ganglion
Authors: Collier B. , Katz H. S. 
Published: December 2014

1. The recapture and re‐use of choline formed by the hydrolysis of released acetylcholine (ACh) was studied in the superior cervical ganglion of the cat using radioactive tracer techniques. The ganglion's ACh store was labelled by perfusion, during preganglionic nerve stimulation, with Krebs solution containing [3H]choline.2. Preganglionic stimulation (5 Hz for 20 min) of ganglia containing [3H]ACh released similar amounts of radioactivity when perfusion was with neostigmine—choline—Krebs or with hemicholinium—Krebs. This indicated that neostigmine does not increase transmitter release.3. The amount of radioactivity collected from stimulated ganglia during perfusion with choline—Krebs was 39% of the amount of radioactivity collected during perfusion with medium containing neostigmine or hemi‐cholinium. This difference in release was almost (85%) accounted for at the end of the experiment by extra radioactive ACh in the ganglia perfused with choline—Krebs. It is concluded that during preganglionic nerve stimulation approximately 50–60% of endogenously produced choline is recaptured for ACh synthesis; thus, during activity preganglionic nerve terminals appear selectively to accumulate choline.4. However, chronically decentralized ganglia accumulated as much choline as did acutely decentralized ganglia, and this was interpreted as indicating that at rest preganglionic nerve terminals do not selectively accumulate choline.5. Increased exogenous choline concentration increased the amount of radioactivity collected during nerve stimulation in the absence, but not the presence, of an anticholinesterase agent. The spontaneous efflux of radioactivity was little affected by changes in external choline levels. It is concluded that exogenous choline and choline made available from released transmitter compete for uptake into nerve terminals.
Inhibition of thermoregulatory non‐shivering thermo‐genesis by trauma in cold‐acclimated rats
Authors: Stoner H. B. 
Published: December 2014

1. Heat production and blood flow in the interscapular brown adipose tissue of 3° C acclimated rats have been measured by the heated thermo‐couple technique.2. When the environmental temperature (Ta) was reduced from 30 to 3° C heat production by the brown adipose tissue began to increase at the lower limit of the thermoneutral zone and then increased linearly.3. Blood flow also increased when Ta was reduced but was not so well correlated with Ta. There was however a good positive correlation between blood flow and heat production.4. During the first hour after a 4 hr period of bilateral hind‐limb ischaemia in a 20° C environment the percentage of rats not producing heat in the interscapular brown adipose tissue increased and the tissue blood flow fell.5. By varying the Ta of the injured rat it was found that the Ta at which heat transfer from the interscapular brown adipose tissue commenced was significantly lower than in the controls although the slope of the regression lines relating heat production and Ta was unaltered.6. Blood flow also increased in the injured rat when Ta was lowered but the increase in the tissue blood flow per unit increase in heat production was less than in the controls.7. In a 5° C environment heat production in the interscapular brown adipose tissue of the injured rat was further increased by the
S. C. injection of
L‐isoprenaline or
L‐noradrenaline.8. It is concluded that the central control of thermoregulatory non‐shivering thermogenesis is inhibited after injury in the rat.
The carotid sinus baroreceptor reflex in the pregnant rabbit
Authors: Humphreys P. W. , Joels N. 
Published: December 2014

1. The reflex responses to baroreceptor stimulation have been compared in eight pregnant and eight non‐pregnant anaesthetized female rabbits.2. The vascularly isolated, innervated carotid sinus was exposed for 30 sec to a series of non‐pulsatile pressures ranging from 30 to 230 mmHg. The contralateral sinus nerve and both aortic nerves were cut. Systemic arterial pressure and heart rate were measured at each sinus pressure.3. The range of arterial pressure change which could be evoked from the isolated innervated sinus was less in the pregnant than in the non‐pregnant rabbits. Mean changes were 98 and 61 mmHg respectively. On the other hand changes in heart rate were similar in the two groups (45 and 43 beats/min respectively).4. The smaller blood pressure response in the pregnant animals resulted from a lesser rise in systemic arterial pressure at low levels of sinus pressure. At high sinus pressures the blood pressure fell to a similar level in both groups of animals.5. Pressure on the great vessels by the gravid uterus was not a factor since there was no consistent difference between the responses obtained with the rabbit lying on its back or on its side.6. Mechanisms which might be responsible for the difference found are discussed.
The projection of the vestibular nerve to the cerebral cortex in the cat
Authors: Mills K. R. , Taylor A. 
Published: December 2014

1. The cerebral cortex in the cat has been examined for responses to contra‐lateral vestibular nerve shocks and to natural stimuli.2. Stimulation of the nerve produces short latency (3·5 msec) surface positive responses in very restricted areas. Within these areas, unitary discharges occur during the equivalent negative phase below the surface.3. It has not been possible to evoke unitary activity in these areas by natural stimulation during light anaesthesia with pentobarbitone, chloralose or urethane.4. The distribution and properties of the shock evoked responses have been studied with special attention to the problem of stimulus spread. They are shown to be overlapped by somato‐sensory and auditory projections, but to be distinguishable from them. Evidence is presented that previously reported longer latency responses were probably due to stimulus spread.5. Reasons are discussed for the extreme sensitivity of the vestibulocortical pathway to anaesthesia.
Discharge of type B atrial receptors during changes in vascular volume and depression of atrial contractility*
Authors: Gilmore Joseph P. , Zucker Irving H. 
Published: December 2014

1. Single unit recordings from type B atrial receptors were obtained from slips of the left cervical vagus nerve during acute increases and decreases in atrial pressure produced by infusion of isotonic saline and withdrawal of blood.2. Atrial receptor discharge reached a peak frequency at the peak of the ‘v’ wave of the atrial pulse, a time when the rate of change of atrial pressure was zero.3. The receptor discharge exhibited hysteresis when increases in atrial pressure were compared to decreases in atrial pressure during circulatory volume expansion and haemorrhage, respectively. This hysteresis was not due to a change in atrial compliance.4. The hysteresis was still observed when the pulse pressure of the ‘v’ wave was plotted against receptor discharge.5. Type B atrial receptors did not show adaptation after 15 min of a sustained increase in left atrial pressure.6. Acute depression of atrial contractility with propranolol increased resting fibre discharge as a result of the associated increase in atrial pressure.
Renal response of the new‐born dog to a saline load: the role of intrarenal blood flow distribution
Authors: Kleinman Leonard I. , Reuter John H. 
Published: December 2014

1. The renal response to an intravenous saline load was studied in thirty new‐born mongrel dogs aged 1–30 days and in seven adult dogs.2. After the infusion of isotonic saline at a rate of 2·0 ml. min−1 kg−1 for 15 min and then at a rate of 0·5 ml. min−1 kg−1 for an additional 105 min, the puppies excreted a significantly smaller fraction of the infused sodium than did the adults (P < 0·01).3. Both puppies and adults increased their glomerular filtration rates after the saline load. However, adults excreted a larger fraction of their filtered sodium than did the puppies (P < 0·01).4. There was no correlation between age and the ability to respond to a saline load during the first month of life.5. Intrarenal blood flow distribution was measured by the radioactive microsphere technique. After saline infusion in the puppy there was an increase in outer cortical blood flow but inner cortical blood flow remained relatively constant. The result was a decrease in the ratio of inner to outer cortical blood flow (IC/OC ratio). In contrast the IC/OC ratio tended to increase in the adult dog after saline expansion.6. There was no correlation between the magnitude of change of sodium excretion and the change of intrarenal blood flow distribution in the puppy.7. These results confirm that the natriuretic response of the new‐born dog kidney is less efficient than that of the adult dog. This is due primarily to the failure of the puppy kidney to decrease fractional sodium reabsorption. Although the new‐born dog alters intrarenal blood flow distribution in response to saline loading this alteration does not appear to play a significant role in sodium excretion.
The effect of fasting on hexose transfer in rat intestine
Authors: Sanford P. A. , Smyth D. H. 
Published: December 2014

1. A technique has been developed whereby accurately defined segments of rat intestine can be isolated in vivo, and this technique was used to study the influence of fasting on hexose transport.2. In the distal ileum the transport of glucose and galactose was stimulated by fasting. The effect was specific as neither amino acid transport nor the permeability of the luminal membrane of the absorbing epithelium was altered by fasting. The increased hexose transport was accompanied by a reduced accumulation of hexose in the gut wall. In the proximal jejunum hexose transport was not stimulated by fasting.3. The results of in vitro experiments show the relative importance of hexose metabolism in providing energy for transport in different regions of the small intestine in both fed and fasted animals. In conditions where hexose metabolism was reduced, e.g. by fluoride, the proximal jejunum behaved more like the distal ileum and a stimulation of hexose transport in response to fasting was demonstrable in vivo.4. Motility studies showed that phenol red introduced into the stomach reached the ileum sooner, achieved a higher concentration and remained there for a longer period of time in the fasted animal.5. The changes in carbohydrate metabolism, hexose transport capacity and gastrointestinal motility are discussed in relation to adaptations of the rat to fasting.
The effect of vasopressin upon the vasculature of the isolated perfused rat kidney
Authors: Cross R. B. , Trace J. W. , Vattuone J. R. 
Published: December 2014

The timed uptake of 131I‐labelled human serum albumin was used as an index of regional perfusion in the isolated rat kidney.1. Arginine vasopressin in doses of 1, 5 and 10 μu./ml. of perfusate decreased papillary perfusion. Total renal perfusion was decreased only by the 5 μu. dose.2. Ornithine‐8‐vasopressin in doses of 5 and 10 μu./ml. of perfusate decreased papillary perfusion. Total renal perfusion was decreased only by the 10 μu. dose.3. When the relative viscosity of the perfusate was increased to a value of 2·0 from the control value of 1·7, both papillary perfusion and total renal perfusion were reduced.4. Arginine vasopressin further reduced papillary flow in kidneys perfused with high viscosity artificial plasma.
The effects of infusions of synthetic adrenocorticotrophin in the conscious calf
Authors: Edwards A. V. , Hardy R. N. , Malinowska Krystyna W. 
Published: December 2014

1. A technique is described by which the whole of the effluent blood from the right adrenal gland can be collected as required from conscious, unrestrained calves. The technique may be used to measure adrenal blood flow gravimetrically and to compute the output of adrenal hormones under various conditions in the normal calf.2. In a group of seven calves mean cortisol output from the right adrenal gland was found to vary between 20 and 40 ng.kg−1 min−1 and corticosterone between 6 and 18 ng.kg−1 min−1 during a 2 hr period, 24 hr after surgery.3. Intravenous infusions of synthetic adrenocorticotrophin (5 ng.kg−1 min−1) produced a significant increase in the output of both cortisol and corticosterone within 5 min. The output of both hormones rose to maximal values within 10–20 min and mean values of approximately 300 ng.kg−1 min−1 (cortisol) and 120 ng.kg−1 min−1 (corticosterone) were maintained thereafter for the duration of the infusion (120 min). The output of both steroids fell to values comparable with those observed initially within 45–60 min after the infusion was discontinued.4. These changes in glucocorticoid output in response to adrenocorticotrophin produced a significant rise in the concentration of both cortisol and corticosterone in peripheral plasma. It is noteworthy that the rise in the mean corticosterone concentration in the peripheral plasma was substantially less than that which might be expected from relating the rise in mean plasma cortisol concentration to cortisol output.5. The results of control experiments have eliminated the possibility that the sampling procedure might itself increase steroid output or peripheral plasma concentration. Comparison of results from calves of widely disparate ages (8–38 days) provided no evidence that either the resting output of cortisol or corticosterone or the response to adrenocorticotrophin changes with age within the range examined.6. Infusion of adrenocorticotrophin (5 ng.kg−1 min−1) also stimulated an abrupt rise in adrenal blood flow; mean resting flow (210 ± 23 μl.kg−1) increased by approximately 30% within 5 min and attained peak values (355–365 μl.kg−1 min−1) between 10 and 30 min. Thereafter, adrenal blood flow steadily decreased and then fell rapidly to within the resting range when the infusion was terminated. No significant changes in heart rate or aortic blood pressure occurred during these infusions.7. The results are discussed in relation to those obtained in other species and under differing conditions by other workers.