bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transmission from preganglionic fibres in the hypogastric nerve to peripheral ganglia of male guinea‐pigs
Authors: Blackman J. G. , Crowcroft P. J. , Devine C. E. , Holman Mollie E. , Yonemura K. 
Published: December 2014

1. Intracellular records were obtained from ganglion cells of the pelvic plexus of male guinea‐pigs.2. The input resistance of cells which responded to intracellular stimulation varied from 40 to 150 MΩ. Slope resistance decreased when the membrane was hyperpolarized. Time constants varied from 5 to 200 msec. Resting membrane potentials ranged from 40 to 70 mV.3. Action potentials in response to direct stimulation were followed by a prolonged phase of after‐hyperpolarization.4. A second type of cell was also impaled which did not respond to electrical stimulation. These cells had resting membrane potentials in the range 60–70 mV, input resistances of less than 20 MΩ and time constants of less than 3 msec.5. In most ganglion cells, stimulation of the hypogastric nerve evoked action potentials which were often followed by a secondary phase of depolarization indicating continuing transmitter action.6. Orthodromic responses were generally ‘all‐or‐nothing’ and could not be graded with changes in stimulus strength. The latency of orthodromic responses indicated that ganglion cells were innervated by both B and C fibres in the hypogastric nerve.7. Orthodromic responses were blocked by tubocurarine, 5 × 10−5 g/ml., and dihydro‐β‐erythroidine, 10−5 g/ml.8. Spontaneous, excitatory post‐synaptic potentials of up to 4·8 mV in amplitude were observed. The frequency of their discharge was greatly increased by repetitive stimulation of the hypogastric nerve.9. The ultrastructure of the pelvic ganglia was studied by electronmicroscopy. Two types of ganglion cell process were observed, fine (0·1 μ) branching tufts thrown up from the soma within the surrounding capsule and longer, thicker (1 μ) extracapsular processes. Synapses were found to occur most frequently between the varicose terminal segments of preganglionic axons and the small intracapsular processes.10. Similarities between the properties of the pelvic ganglia innervated by the hypogastric nerve and those of the parasympathetic division of the autonomic nervous system are discussed.
Chicken cerebrospinal fluid: normal composition and response to insulin administration
Authors: Anderson D. K. , Hazelwood R. L. 
Published: December 2014

1. With the exception of Na, K and Cl clear cerebrospinal fluid (c.s.f.) obtained from chickens varying in age from 6 weeks to 2 years did not reveal significant alterations in composition as could be related to age per se.2. Considerably higher levels of total protein and glucose are found in chicken c.s.f. than are found in mammalian fluid; slightly more chloride is found in chicken than most mammalian c.s.f.'s.3. Intravenous beef insulin depressed chicken cerebrospinal fluid glucose levels; insulin placed intracisternally had no effect on the avian glycogen body glycogen content indicating that c.s.f. glucose constancy, with or without glycogen body assistance, is not responsible for the resistance of the chicken to pharmacological doses of insulin.4. Bovine insulin injected into the cisterna magna of chickens depresses plasma glucose partially by acting over vagal pathways to release endogenous insulin and partially by diffusion across the c.s.f.—blood barrier to exert a peripheral effect.
Osmotic responses demonstrating the extracellular character of the sarcoplasmic reticulum
Authors: Birks R. I. , Davey D. F. 
Published: December 2014

1. Changes in the dimensions of the sarcoplasmic reticulum in frog sartorius muscles exposed to hypertonic and hypotonic solutions have been studied with the electron microscope.2. The volume of the sarcoplasmic reticulum has been found to be linearly related with a negative slope to the reciprocal of the osmotic pressure. Over the range 0·75 to 3·5 × normal osmotic pressure the reticulum volume has been calculated to change from 11·5 to 18·5% of normal cell volume.3. These changes in sarcoplasmic reticulum volume correspond to the calculated changes in the volume of the intra‐fibre sucrose compartment, postulated by earlier workers on the basis of studies on changes in cell volume with changes in osmotic pressure in living muscles.4. To explain these and other related findings on the distribution of electrolytes in muscle, it is proposed that the sarcoplasmic reticulum of skeletal muscle is an extracellular compartment.5. The significance of this hypothesis for the mechanism of excitation‐contraction coupling is discussed.
Respiratory responses to electrical stimulation of the cervical sympathetic nerves in decerebrate, unanaesthetized cats
Authors: Mills E. , Sampson S. R. 
Published: December 2014

1. The effects of respiration of electrical stimulation of the peripheral cut end of the cervical sympathetic nerve were studied in seventeen decerebrate, unanaesthetized cats.2. The tidal volume increased and the end‐tidal CO2 fell within 2‐3 breaths after the onset of stimulation in fourteen cats.3. In three experiments tidal volume and respiratory rate fell during stimulation and increased above the control when the stimulus was interrupted.4. All respiratory responses to sympathetic stimulation were abolished after cutting the carotid sinus nerves and are attributed to activation of chemo‐ and baroreceptor afferents.5. With the carotid sinus nerves intact, respiratory responses could be eliminated completely only by cutting the post‐ganglionic sympathetics that pass directly to the carotid body and the post‐ganglionic sympathetics that join the glossopharyngeal nerves to course with the sinus nerves to the carotid bifurcation.6. Pentobarbitone (10 mg/kg) or chloralose (40 mg/kg) given intravenously depressed spontaneous ventilation and responses to sympathetic nerve stimulation.7. Stimulation changed blood pressure slightly in fourteen experiments; in ten it fell and in four it increased 10 mm Hg or less. After pentobarbitone or chloralose, stimulation elicited a pronounced pressor response.8. The results of the study indicate that activation of sympathetic pathways to the carotid body constitutes an effective stimulus to ventilation.
Quantum efficiency and false positive rate
Authors: Hallett P. E. 
Published: December 2014

1. This paper presents an analysis of the efficiency of performance at the absolute threshold of human vision. The data are from the same series as the previous papers (Hallett, 1969b, c) and consist of frequency‐of‐seeing curves, thresholds, false positive rates and equivalent background measurements, accumulated as small samples over a number of days.2. Quantum efficiency is defined here as the ratio of the thresholds of an ideal and a real detector performing the same task with the same sampling error. This avoids the problem as to whether the frequency‐of‐seeing curve of the real detector is exactly a Poisson sum or not.3. The long‐term quantum efficiency can be low (about 0·04) as a result of drifts in the mean threshold.4. The average short‐term quantum efficiency is in the region of 0·1, which is roughly the physiological limit set by Rushton's (1956b) measurements of rhodopsin density in the living rods. If this is correct, then the absorption of a quantum, and not the bleaching of a rhodopsin molecule, is sufficient for the generation of a neural event.5. Application of a simple signal/noise theory to the data gives solutions close to those suggested by Barlow (1956) and shows that false positives almost invariably arise from errors subsequent to the signal/noise decision process.
The response of motor neurones to intramuscular injection of botulinum toxin
Authors: Watson W. E. 
Published: December 2014

1. The dry mass and nucleic acid content of both nerve cell bodies and their nucleoli were measured by interference microscopy and ultra‐violet absorption microspectrography respectively: succinoxidase and acetylcholine hydrolase activities were also determined. Autoradiography was used to follow synthesis of deoxyribonucleic acid (DNA) by glial cells, and to follow nucleic acid and protein metabolism in muscle fibres.2. After injection of botulinum toxin the synthesis of ribosomal RNA by the neurone followed closely the pattern found after axotomy.3. After injection of toxin neuronal dry mass increased before the rate of ribosomal RNA synthesis was raised. This early increase, which was not due to increased protein synthesis, probably represents a ‘damming back’ of proteins within the nerve cell body.4. After injection of toxin no local accumulation of microglial cells synthesizing DNA was found around the affected neurones: it is suggested that this reflects the intact system for intra‐axonal transport under these conditions.5. The affected muscles show increased nucleic acid and protein synthesis.6. It is suggested that the results obtained indicate that membrane expansion or synthesis which occurs both in muscle and in neurone under these circumstances is the factor responsible for inducing directly or indirectly the changes found in nucleic acid metabolism after injection of botulinum toxin and after axotomy.
Oxygen uptake and cardiac performance in the sheep
Authors: Brockway J. M. , McEwan E. H. 
Published: December 2014

1. In four ewes no relationship was found between heart rate and oxygen consumption in response to cold stimulus; such a correlation was found in one wether sheep.2. Direct Fick studies of cardiac output showed a significant correlation between heart output and oxygen uptake in two ewes and one wether. The relationship between stroke volume and heart rate was poor in the case of the ewes.3. It is suggested that the 6‐month training period which the ewes had received, before the estimates were made of heart rate and oxygen consumption, was insufficient to allay emotional disturbance affecting the relationship between these parameters.
Changes in the flow and composition of the urine induced by the 18 monoacetate of D‐aldosterone, in cats
Authors: Lockett Mary F. 
Published: December 2014

1. Isolated hearts release a steroid‐like substance into the blood stream when venous return is decreased. This substance very closely resembles the 18 monoacetate of
D‐aldosterone (18 MA) in physicochemical and biological properties.2. Hence the changes in the flow and composition of the urine caused by infusions of the 18 MA have been examined in cats.3. The threshold effect of both 18 MA and of antidiuretic hormone (ADH) may be antidiuretic, but higher concentrations of both substances usually produce diuresis in cats under chloralose anaesthesia.4. Both ADH and 18 MA are antidiuretic in decerebrate cats.5. In decerebrate cats and in cats under chloralose anaesthesia the renal actions of 18 MA, 0·003–0·02 μg/kg.min are abolished by hypophysectomy: responses to ADH remain unchanged.6. 18 MA, 0·012 μg/kg.min causes the appearance of thioglycollate labile antidiuretic activity in blood taken from the terminal descending portion of the left lateral sinus.7. 18 MA, 0·05–0·15 μg/kg.min causes diuresis followed by antidiuresis in cats under chloralose anaesthesia. Hypophysectomy abolishes the diuretic phase of the response and uncovers the short latency of the antidiuretic. The antidiuresis is accompanied by reduction in the concentration of urinary Na and a fall in the ratio Na/K of the urine.
Preserved vagal visceromotor function following destruction of the dorsal motor nucleus
Authors: Kerr Frederick W. L. 
Published: December 2014

1. The dorsal motor nucleus of the vagus was destroyed in cats and after survival periods greater than 10 days, the response of the heart, bronchioles, oesophagus and duodenum to electrical stimulation of the cervical vagi was investigated. The responses obtained from the vagus ipsilateral to the destroyed dorsal motor nucleus were compared to those obtained from the contralateral vagus and with normal controls. No significant differences were demonstrable.2. The responses obtained from stimulation of the cervical vagus following chronic intracranial rhizotomy of the IXth, Xth and XIth nerves were also examined. Visceromotor responses were abolished in three experiments and atypical responses were obtained in two experiments.3. It is concluded that the dorsal motor nucleus does not supply the vagal fibres which produce contraction of the smooth muscle of the bronchioles, oesophagus and duodenum, and that it is not the source of the cardio‐inhibitory fibres4. A simple method of destroying a longitudinal column of neurones is described.
The action of chlormadinone acetate (6‐chloro‐Δ6‐dehydro‐17α‐acetoxyprogesterone) upon experimentally induced ovulation in the rabbit
Authors: Harris G. W. , Sherratt R. M. 
Published: December 2014

1. The ovulation response to electrical stimulation of the median eminence, or to the intrapituitary infusion of median eminence extract, was observed in control rabbits and animals pre‐treated with chlormadinone acetate.2. Chlormadinone acetate pre‐treatment did not significantly reduce the proportion of rabbits ovulating in response to electrical stimulation. However, there was a significant reduction in the average number of ruptured follicles when compared with the animals in the control group.3. Chlormadinone acetate pre‐treatment significantly reduced the proportion of animals ovulating in response to the intrapituitary infusion of median eminence extract as compared with the control series. However, there was no significant reduction in the average number of ruptured follicles (in those rabbits that ovulated) when compared with the control groups.4. Chlormadinone acetate pre‐treatment produced no significant effect upon either the proportion of animals ovulating, or the average number of ruptured follicles, following
I.V. injection of 50 μg LH.5. The conclusion drawn is that chlormadinone acetate blocks copulattion‐induced ovulation in the rabbit by action at a site in the central nervous system located above the median eminence. The possible effects of chlormadinone acetate upon the secretion of FSH, the pituitary sensitivity to releasing factors and the ovarian sensitivity to LH are discussed.
Early changes in the forearm circulation following transient increase of local external pressure*
Authors: Foley T. H. , Greenberg J. L. 
Published: December 2014

1. The pressure at the surface of a segment of forearm enclosed in a plethysmograph was abruptly raised from atmospheric level to +40 mm Hg, held at the new level for 4 sec, and abruptly dropped to atmospheric level.2. Forearm circumference (Vf) equivalent to the volume of a small segment of forearm, was monitored with a mercury‐in‐rubber strain gauge. Pressure was measured in the cylinder (Pp) in veins exposed to external compression (Pv, e), and in the radial artery exposed to compression (Pra).3. Forearm blood flow was measured by venous occlusion plethysmography before, and after, release of external compression. There was, on average, over the 3rd and 4th second after release of pressure, a 2·4‐fold increase of inflow, as compared with resting level.4. By the 15th second after release of compression, forearm blood flow had returned to its previous resting level.5. The increase in blood flow after compression appears to be due to active reduction in vascular resistance, for refilling of the arteries and arterioles would be completed before the increased flow was recorded; venous backflow can be excluded, and the pressure difference for flow (arterial minus venous) is virtually unchanged.
Post‐tetanic potentiation at the neuromuscular junction of the frog
Authors: Rosenthal Jean 
Published: December 2014

1. Post‐tetanic potentiation (PTP) was studied at the neuromuscular junction of the frog. The magnitude and time course of PTP was dependent on the number of stimuli in the tetanus, rather than on the frequency or duration of the tetanus. At low temperature the maximum amplitude of PTP was unchanged, but the time course was prolonged.2. The magnitude and time course of PTP was accounted for quantitatively by estimated changes in the fraction of transmitter released per stimulus.3. As external [Ca] was reduced, the time for decay of PTP was decreased. The maximum amplitude of PTP, measured with respect to control amplitude at the same [Ca], was unchanged, but occurred at earlier times. The time course of PTP was dependent only on the [Ca] present during the tetanus.4. It is concluded that PTP is associated with an intracellular accumulation of Ca during the tetanus.
The yellow colour of the lens of man and other primates
Authors: Cooper G. F. , Robson J. G. 
Published: December 2014

1. Measurements have been made of the absorption spectra of the lenses of human, baboon (Papio), rhesus monkey (Macaca), squirrel monkey (Saimiri sciureus) and bush baby (Galago crassicaudatus).2. In all these species an absorption maximum was found between 365 and 368 nm.3. The pigment responsible for this absorption was water‐soluble and aqueous extracts were examined. Protein‐free aqueous extracts showed an additional maximum at 260 nm which could be only partially accounted for by the presence of ascorbic acid.4. Chromatography of the protein‐free solution from human lenses yielded a fast‐moving yellow component with a blue fluorescence. Its absorption spectrum was very similar to that of the original protein‐free solution. A fast‐moving yellow component from the baboon lens had a yellow fluorescence.5. The human lenses appeared to contain more of the yellow, water‐soluble pigment at birth than in adult life. The concentration remains constant during adult life.6. There is evidence for the appearance of another pigment in the human lens in later adult life. It is not water‐soluble and has an absorption maximum at about 330 nm.
Termination and functional organization of the dorsolateral spino‐olivocerebellar path
Authors: Larson B. , Miller S. , Oscarsson O. 
Published: December 2014

1. Pathways ascending in the lateral funiculus of the spinal cord and terminating as climbing fibres in the anterior lobe of the cerebellum have been investigated in decerebrate cats with the cord partially transected in the third cervical segment, sparing only part of the left lateral funiculus. The climbing fibre responses evoked in Purkinje cells by electrical stimulation of peripheral nerves were studied by recording from single cells and by recording the mass activity at the cerebellar surface.2. Two pathways have been distinguished. One ascends through the dorsal part of the lateral funiculus and relays in the inferior olive. It is denoted the dorsolateral spino‐olivocerebellar path (DLF—SOCP) and forms the subject of this paper. The other path occupies in part a more ventral position in the lateral funiculus and it is not known if it relays in the inferior olive. It is denoted the LF—CF—SCP (lateral funiculus—climbing fibre—spinocerebellar path).3. The DLF—SOCP is activated predominantly by cutaneous afferents from restricted areas in the ipsilateral paws. The relay in the spinal cord is almost certainly monosynaptic, but a long delay in the brain stem suggests that the path is interrupted by several synapses at this level. The pathway terminates in the pars intermedia in sagittal zones with a somatotopical organization (Fig. 12).4. Components of the DLF—SOCP and the dorsal spino‐olivocerebellar path converge onto the same olivary neurones which project to the pars intermedia and it is concluded on this evidence that the DLF—SOCP also relays in the inferior olive.5. The DLF—SOCP is compared with the other known spinocerebellar paths terminating as climbing fibres in the anterior lobe. The functional role of these paths and the general significance of the sagittal projection patterns are discussed.
The catecholamine content of hypothalamic nerve cells after acute exposure to cold and thyroxine administration
Authors: Lichtensteiger Walter 
Published: December 2014

1. In female rats, the intensity of the catecholamine fluorescence was determined in nerve cells of the arcuate and periventricular hypothalamic nuclei by means of a microfluorimetrical technique which is based on the fluorescence method of Falck & Hillarp. Frequency distributions were established by grouping the nerve cells according to their fluorescence intensity which was referred to that of a noradrenaline standard.2. When rats were exposed to a cold environment (4° C) on dioestrous day 1, the frequency distribution of relative fluorescence intensity was shifted towards classes of higher fluorescence intensity within 10 min. The mean relative fluorescence intensity and the symmetry of the distribution did not change further during the next 20 min.3. The change in the frequency distribution was almost completely prevented by
L‐thyroxine (50 μg/kg) administered 3 hr before exposure to cold.4. The direction of the cold‐induced change in the frequency distribution is interpreted as reflecting an increase in neuronal activity. Since it was observed in nerve cells which belong to catecholamine‐containing tubero‐infundibular neurones, it might be related to the release of thyrotropin. Differences in the frequency distributions of the anterior and posterior tuberal regions are discussed with regard to possible functional implications.
The use of [125I]polyvinyl pyrrolidone K. 60 in the quantitative assessment of the uptake of macromolecular substances by the intestine of the young rat
Authors: Clarke Rufus M. , Hardy R. N. 
Published: December 2014

1. A method has been developed which allows the quantitative estimation of the uptake of labelled polyvinyl pyrrolidone (PVP) of mean mol. wt. 160,000 (K. 60) by the wall of the small intestine of young rats.2. Four hours after feeding a standard dose of [125I]PVP by stomach tube, the small intestine was thoroughly washed out, and the radioactivity of the intestinal wall measured. Under these conditions, the small intestine of animals less than 18 days old took up more than 50% of the radioactivity which had left the stomach. There was no increase in PVP uptake if the duration of absorption exceeded 4 hr. The PVP was taken up by the epithelial cells of the villus, and its intracellular localization has been demonstrated by fluorescence microscopy and can be related to vacuolation in the cells.3. In animals between 18 and 20 days old the uptake of PVP declined progressively, until, in animals more than 20 days old, less than 5% of the radioactivity was taken up by the intestinal wall.4. There is good agreement between the reported age of termination of antibody absorption in young rats and the age at which PVP uptake ceased in the present experiments. It is suggested that the loss of ability of the intestine to take up substances of high mol. wt. may be the factor which limits the duration of the period of antibody absorption in this species.