bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of testosterone upon sexual maturation in the rat
Authors: Smith W. N. Adams , Peng M. T. 
Published: December 2014

1. Testosterone injected into the neonatal female rat induces permanent sterility. This study was carried out in an endeavour to determine where this change is induced.2. Hypophysectomized, but otherwise normal, female rats bearing anterior pituitary transplants from androgen‐sterilized female rats under the median eminence of the hypothalamus and vascularized from it, show oestrous cycles in the vaginal smear, have corpora lutea in the ovaries and are fertile.3. Hypophysectomized androgen‐sterilized female rats bearing anterior pituitary transplants from normal female rats under the median eminence and vascularized from it show persistent oestrus in the vaginal smear, have small ovaries containing large follicles but no corpora lutea and are sterile.4. Testosterone injected into the female rat, and leading to sterility and ovarian malfunction, does not act at the level of the anterior pituitary, which retains the ability to function normally. It is considered that it may act upon the central nervous system to cause a disturbance of the gonadotrophin‐releasing mechanism.
Handling of glycerides of acetic acid by rat small intestine in vitro
Authors: Barry R. J. C. , Jackson M. J. , Smyth D. H. 
Published: December 2014

1. When mono‐, di‐ and triacetins are incubated with sacs of rat everted intestine, they enter the epithelial cells and are hydrolysed to free glycerol and acetic acid.2. The rate‐limiting step in the process is the entry of glyceride into the epithelial cell.3. The three acetins enter the epithelial cell at the same rate, and the mechanism of this remains unknown.4. The acetate released appears in higher concentrations on the serosal side, and the relation of this to the mechanism for transfer of volatile fatty acids is discussed.5. It is not necessary to postulate a special mechanism for entry of volatile fatty acids into the cell.
An electrophysiological study of 5‐hydroxytryptamine receptors of neurones in the molluscan nervous system
Authors: Gerschenfeld H. M. , Stefani E. 
Published: December 2014

1. 5‐Hydroxytryptamine (5‐HT) has been iontophoretically applied to the membrane of central neurones of Cryptomphallus aspersa; CILDA neurones (cells with inhibition of long duration) (Gerschenfeld & Tauc, 1964) are the only cells sensitive to 5‐HT. The responses to 5‐HT is always a depolarization. The CILDA cells studied were also depolarized by ACh.2. From experiments in which pulses of 5‐HT and ACh were applied from a double‐barrelled micropipette to the CILDA cell soma, it has been calculated that 5‐HT and ACh receptors were located at different distances from the injecting micropipette tip. It has also been calculated from the diffusion equation that in the same CILDA cell a 5‐HT concentration of 8·2 × 10−9
M and a ACh concentration of 1·3 × 10−8
M caused a similar peak depolarization.3. CILDA neurones show ‘anomalous’ rectification. 5‐HT increases the membrane conductance of CILDA.4. 5‐HT receptors of CILDA neurone are desensitized by repeated application of 5‐HT. The desensitization lasts for ca. 40 sec.5. 5‐HT receptors are blocked by lysergic acid diethylamide and its derivatives. Morphine chlorhydrate blocks them non‐competitively.6. Some inhibitors of monoamine oxidase (trancylpromine, isocarboxazide, iproniazide and nialamide) have been tested. They do not prolong the action of 5‐HT, but block the 5‐HT receptors.7. No crossed desensitization between 5‐HT and ACh has been observed. Atropine blocks both ACh‐receptors and 5‐HT receptors, 5‐HT receptors appear to be blocked to a greater extent.8. The data presented support the assumption of a excitatory transmitter role of 5‐HT to CILDA neurones, but further evidence is necessary to confirm this hypothesis.
Electrical and mechanical response of arteries to stimulation of sympathetic nerves
Authors: Keatinge W. R. 
Published: December 2014

1. When common carotid arteries of sheep were studied in vitro by the sucrose‐gap method, application of acetylcholine or nicotine caused small irregular spikes of depolarization. The discharge was prevented by hexamethonium, Hydergine, phentolamine, or chronic denervation, indicating that it represented electrical activity of groups of smooth muscle cells induced by the stimulation of sympathetic nerve fibres.2. The size of spikes produced by acetylcholine or nicotine, together with counts of the total number of smooth muscle cells in cross‐sections of the arterial strips, indicated that the larger groups of smooth muscle cells activated by one sympathetic nerve fibre contained approximately 1300 cells.3. Sections of arteries treated with hot formaldehyde vapour contained numerous fluorescent fibres which were intensified by previous injection of noradrenaline into the animal and were scanty or absent after chronic sympathetic denervation. They are therefore believed to be post‐ganglionic sympathetic nerve fibres.4. Most of these fibres ran circularly in the outer ½‐¾ of the media. A few ran longitudinally in the adventitia. There were none in the inner ¼‐½ of the media.5. Electrical stimulation of the cervical sympathetic nerve of anaesthetized sheep caused large contractions of the common carotid artery of the same side, reducing its external diameter by 30‐39%.
Action potentials in parasympathetic and sympathetic efferent fibres to the trachea and lungs of dogs and cats
Authors: Widdicombe J. G. 
Published: December 2014

1. Action potentials were recorded from seventy‐four single and twenty‐nine small multifibre nerve strands efferent to the trachea and lungs of cats and dogs. From the pathway (vagal or sympathetic), spontaneous activity, conduction velocity and responses to various interventions the efferent fibres were classified in the following way.2. Group I, vagal. These had a mean conduction velocity of 9·7 m/sec, and had a respiratory but seldom a cardiac rhythm. Their discharge was inhibited during hypertension caused by injections of adrenaline and during inflation of the lungs, but was increased during tracheal occlusion, stimulation of peripheral chemoreceptors and irritation of the larynx. The fibres are thought to be constrictor to the airways.3. Group II, sympathetic. These had a mean conduction velocity of 0·85 m/sec and usually had inspiratory and cardiac rhythms. Their discharge usually responded qualitatively as that of group I fibres to the various interventions, but with clear quantitative differences. They are divided into three subgroups on the basis of their responses to injections of adrenaline and to asphyxial stimuli.4. Group III, vagal and sympathetic. These had a mean conduction velocity of 9·0 m/sec, very slow discharge rates and often an expiratory and cardiac modulation. They were activated during hypertension due to adrenaline and often by tracheal occlusion, chemoreceptor stimulation, laryngeal irritation and lung inflation. Their motor action is unknown.5. Group IV, vagal and sympathetic. These had conspicuous cardiac rhythms resembling those of vascular baroreceptors, but their discharge could not be correlated with arterial blood pressure. Their mean conduction velocity was 6·6 m/sec. Some were active after combined vagotomy and sympathectomy. Together with some unclassified fibres, those of group IV are thought to be aberrant afferent nerves or collateral afferent branches, and possibly to subserve local reflexes.6. The results are discussed in relation to nervous control of effector tissues in the airways and autonomic nervous control generally.
The effect of oligomycin and some nitrophenols on acid secretion and oxygen uptake by gastric mucosa of the frog
Authors: Bannister W. H. 
Published: December 2014

1. The ability of the three nitrophenols, m‐nitrophenol, p‐nitrophenol and 2,4‐dinitrophenol, to inhibit acid secretion and stimulate oxygen uptake by gastric mucosa paralleled their extent of dissociation at physiological pH.2. Oligomycin inhibited oxygen uptake by gastric mucosa, and showed a tendency to inhibit acid secretion.3. 2,4‐dinitrophenol lowered the value of the ratio between acid secretion and the associated oxygen uptake. Oligomycin did not affect the value of this ratio.4. It would appear that a non‐phosphorylated high‐energy intermediate of oxidative phosphorylation might be involved in acid secretion by gastric mucosa.
Polarized light and the human fundus oculi
Authors: Weale R. A. 
Published: December 2014

1. Measurements were made of the relative fractions of diffuse and specular reflexions in the fovea and periphery of the human fundus oculi.2. All the light emerging from the eye is scattered or reflected behind the receptors as bleaching the retina affects both fractions equally.3. Bruch's membrane is the most likely surface at which specular reflexion occurs whereas the choroid and sclera are probably involved in scattering.4. Both diffuse and specular components show marked directional effects that vary with wave‐length.
Active transport of sodium and potassium in mammalian skeletal muscle and its modification by nerve and by cholinergic and adrenergic agents
Authors: Dockry Margaret , Kernan R. P. , Tangney Aileen 
Published: December 2014

1. Active transport of Na+ and K+ by Na‐rich extensor digitorum and soleus muscles of rat was found to be increased considerably when muscles were innervated during enrichment with Na+ in K‐free modified Krebs solution containing 160 m
M‐Na at 2° C and recovery in a similar fluid with 10 m
M‐K and 137 m
M‐Na at 37° C, bubbled with oxygen.2. Addition of acetylcholine (2·0 μg/ml.) to recovery fluid containing denervated extensors increased active transport, whereas addition of eserine (50 μg/ml.), decamethonium (0·1 μg/ml.) and to a lesser extent tubocurarine (0·26 μg/ml.) inhibited active transport. Blocking of nerve conduction in innervated extensor inhibited K+ uptake more than Na+ excretion.3. The membrane potential of Na‐rich extensor muscles measured soon after re‐immersion in recovery fluid was higher in denervated than in innervated muscles. In the latter it was close to the K‐equilibrium potential (EK). It is suggested that denervation here makes the Na‐pump electrogenic by decreasing K+ uptake either by decreased permeability or by inactivating a K‐pump. Evidence is presented that the latter is more likely.4. Addition of isoprenaline to Na‐rich soleus muscles in recovery fluid increased active transport and reduced the membrane potential measured soon after re‐immersion in recovery fluid. The Na‐pump still remained electrogenic in the presence of isoprenaline. It was suggested that isoprenaline might also stimulate the Na‐pump, perhaps through activation of lactic dehydrogenase.
Cardiovascular and metabolic responses to noradrenaline in man, before and after acclimatization to cold in Antarctica
Authors: Budd G. M. , Warhaft N. 
Published: December 2014

1. Four men of European descent were infused with noradrenaline at rates of 0·038, 0·075, 0·150 and 0·300 μg/kg.min in Australia, and again after 29 weeks' residence at Mawson, Antarctica. A concurrent study of their responses to whole‐body cooling showed that they acclimatized to cold in Antarctica.2. Blood pressure rose and heart rate fell in proportion to the dose of noradrenaline infused. The response was much less after than before acclimatization in three of the four subjects. Subjective effects of the drug decreased in proportion to the decrease in the pressor effect.3. Finger temperature fell in proportion to the dose infused, in three subjects. The response was unchanged or increased after acclimatization.4. Oxygen consumption was initially unaffected by noradrenaline, but after acclimatization it apparently increased in proportion to the dose infused. The increase in pulmonary ventilation during infusion was slightly greater after acclimatization.
The effect of the replacement of calcium by strontium on excitation‐contraction coupling in frog skeletal muscle
Authors: Edwards Charles , Lorković Hrvoje , Weber Annemarie 
Published: December 2014

1. In frog skeletal muscle strontium can replace calcium in potassium contractures for 5 hr, though it is less effective than Ca. Sr can restore the responsiveness to K after it had been lost in the presence of Mn.2. Muscles refractory to caffeine following repeated exposure to it in the absence of Ca, recover in part following addition of Sr.3. The uptake of 85Sr was increased during mechanical activity, whereas the uptake of 58Co was not changed. Resting uptake of 58Co was 3‐4 times greater than that of 85Sr.4. Sr fully activated the myofibrillar adenosine triphosphatase (ATP‐ase), though its affinity was about 30 times less than Ca.5. The sarcoplasmic reticulum took up Sr, though less effectively than Ca.
The use of labelled vitamin B12 in the measurement of glomerular filtration rate
Authors: Ekins R. P. , Nashat F. S. , Portal R. W. , Sgherzi A. M. 
Published: December 2014

1. Two preparations of radioactive vitamin B12 labelled respectively with 57Co and 58Co have been employed in the estimation of the glomerular filtration rate (
G.F.R.) in dogs. The intravenous injection of these preparations at an interval of 20 min resulted in a changing ratio of their activities in plasma and urine and so permitted a relation in time to be established between the urine and the plasma from which it was filtered.2. When urine and plasma were sampled at short intervals an effective renal delay or transit time could be derived from their isotope ratio curves and used as a correction in the clearance equation. This allowed serial clearances of either isotope to be calculated despite a falling plasma concentration.3. This method was applied to the study of the
G.F.R. in fourteen dogs using short urine collections of 2 or 4 min for periods up to 80 min. The results under stable conditions and with deliberately induced changes in the
G.F.R. are illustrated and discussed.4. Application of the technique in four patients undergoing differential renal function studies gave results comparable with those in the experimental work.5. The plasma binding of administered vitamin B12 in serial blood samples in dogs and man was investigated.
The effects of ventilation of dogs with different gas mixtures on airway calibre and lung mechanics
Authors: Green M. , Widdicombe J. G. 
Published: December 2014

1. Dead space (CO2‐front method), lung compliance, cervical tracheal volume change and total lung resistance were measured simultaneously in anaesthetized dogs, paralysed or open‐chest, and the responses to nerve section and stimulation and to ventilation of the dogs with different gas mixtures were studied.2. Bilateral cervical vagotomy changed all four parameters in a way consistent with airway dilation, and bilateral vagal stimulation had the opposite actions. A weak airway dilator role was indicated for the sympathetic nerves.3. Ventilation with 4% CO2, 8% CO2 or 10% O2 changed all four parameters as if the airways had constricted, and 100% O2 caused oppossite, but weaker, responses.4. The responses to the three airway constricting gas mixtures were present, but reduced in intensity, after bilateral cervical vagotomy and some even weaker responses were present after additional bilateral sympathectomy.5. During restoration of airway smooth muscle tone by electrical stimulation of the distal ends of the cut vagus nerves, administration of CO2‐rich or hypoxic gas mixtures had no greater effect than during controls with vagi cut but without stimulation.6. No dilator responses to hypercapnia or hypoxia were seen, either in innervated or denervated trachea and airways.
Micro‐electrode studies on mammalian vascular muscle
Authors: Steedman Wilma M. 
Published: December 2014

1. Transmembrane potentials were measured in smooth muscle cells in the walls of small arteries in the frog tongue and skin of the lateral abdomen. Resting potentials had mean values of 64·7 and 43·6 mV respectively, and action potentials of up to 60 mV amplitude and 100‐200 msec duration could be elicited by electrical stimulation in the tongue vessels.2. Micro‐electrodes were inserted into smooth muscle cells in the walls of small arteries and arterioles of the rat mesenteric circulation. Intracellular potentials varied continually and maximum polarization averaged 39·4 mV.3. Rhythmic slow waves with a period varying from 4·5 to 7·8 sec were observed, and their amplitude but not their frequency was affected by the level of anaesthesia.4. Spike potentials were recorded, amplitude up to 35 mV, with occasional overshoot, and duration 40‐50 msec; these were followed by a positive after‐potential, 100‐150 msec duration and amplitude up to 8 mV.5. Experiments using chemical and surgical means of interfering with the autonomic nervous system showed that the amplitude, but not the frequency, of the slow waves and the occurrence of action potentials were markedly affected by nervous influences.6. Stimulation of the smooth muscle by asphyxia, electrical stimulation of the splanchnic nerves, and local application of adrenaline, noradrenaline and vasopressin increased the frequency of action potentials and the amplitude of the slow waves, and inhibiting agents such as acetylcholine and removal of the nerve supply depressed the electrical activity.
Radioisotopic studies of the binding, exchange, and distribution of 5‐hydroxytryptamine synthesized from its radioactivity precursor
Authors: Gershon M. D. , Ross L. L. 
Published: December 2014

1. The synthesis, distribution, storage, and subsequent metabolism of 5‐hydroxytryptamine (5‐HT) produced in mice from the administration of its radioactive precursor, 5‐hydroxytryptophan, has been investigated to form the basis for a similar study to be conducted by radioautography.2. Intravenous injection of the radioactive material was found to be essential for significant uptake of radioactivity by tissue. The duration of the period during which radioactive material was available for uptake by the tissue was 2 hr.3. The relative distribution of radioactivity in individual organs was studied and the radioactive compounds present in each were identified and quantitatively assayed. No unrelated routes of metabolism of the labelled material were found and radioautographic results may be interpreted in terms of the metabolic picture which emerged.4. Radioactive 5‐HT was bound in tissues in preference to both its precursor, and metabolite, 5‐hydroxytryptamine‐O‐glucuronide, and the radioactive 5‐HT produced in vivo after the injection of labelled 5‐hydroxytryptophan probably entered and labelled the endogenous 5‐HT pool.5. Fixatives prepared with buffer solutions made hypertonic by the addition of sucrose could rapidly and effectively halt the movement of radioactive 5‐HT out of tissues and prevent its subsequent extraction during histological processing.6. It is concluded that localization of sites concerned with 5‐HT metabolism by means of radioautography is feasible and the 5‐HT so localized will probably reflect the physiological compartmentalization of the amine.
Uterine distension and the function of the corpora lutea in the guinea‐pig
Authors: Bland K. P. , Donovan B. T. 
Published: December 2014

1. The presence of two glass beads (7 × 3 mm) in each horn of the uterus was associated with a reduction of 3‐4 days in the length of the oestrous cycle.2. Two beads inserted into each uterine horn between days 2 and 4 exerted a greater effect on the oestrous cycle than either one bead in each horn or four beads in one horn only. Two beads located in one horn failed to affect cycle length.3. Measurement of the volume of the corpora lutea showed that distension of the uterus induced a premature regression in the size of the luteal bodies.4. When glass beads were present in one uterine horn, early and unilateral regression of the corpora lutea in the ovary adjacent to the distended horn was observed. Regression of the corpora lutea in the opposite ovary proceeded normally.5. In view of the local effect of uterine distension and other information, it is concluded that each uterine horn can produce a luteolytic substance which is conveyed to the neighbouring ovary to act upon the corpora lutea.
The volume of vascular compartment in rat hind limb muscles
Authors: Law R. O. , Phelps C. F. 
Published: December 2014

1. A non‐recirculatory perfusion system has been developed suitable for the perfusion of the hind limbs of small experimental animals.2. By means of it a solution of T. 1824‐labelled serum albumin has been introduced into the vascular compartment of the hind limbs of female rats under isogravimetric conditions. Excision and analysis of certain muscles has been used to provide information concerning the percentage distribution of the labelled albumin within these muscles.3. Experiments have been carried out in vivo employing [131I]labelled serum albumin and [51Cr]labelled erythrocytes in order to compare the vascular volumes determined under in vivo conditions and in perfusions, and to estimate the capillary haematocrit in vivo.4. The physiological validity of the methods used and the results obtained has been discussed.
The size of the sucrose, raffinose, and inulin spaces in the gastrocnemius muscle in the rat
Authors: Law R. O. , Phelps C. F. 
Published: December 2014

1. The sucrose, raffinose and inulin spaces within the gastrocnemius of the female rat have been estimated at 12·0 ± 2·2%, 10·7 ± 0·6%, and 10·0 ± 0·3% respectively, expressed as a percentage of the total muscle volume.2. The mucopolysaccharide and hexosamine contents of the gastrocnemius have been found to be inversely dependent upon the weight of the muscle.3. The possibility that a relation exists between the saccharide spaces and the muscle musopolysaccharide content has been discussed in terms of saccharide molecular radii.
The effects of adrenaline and noradrenaline on venous return and regional blood flows in the anaesthetized cat with special reference to intestinal blood flow
Authors: Greenway C. V. , Lawson Anne E. 
Published: December 2014

1. In cats, a venous long‐circuit technique was used to measure the blood flows in the superior vena cava and the hepatic, renal and iliac segments of the inferior vena cava. The sum of these flows gave the venous return (minus coronary and bronchial flows). In further experiments using an electromagnetic flowmeter, flow in the portal vein and in the superior mesenteric and coeliac arteries was measured.2. Approximately two‐thirds of the hepatic blood flow is derived from the portal vein.3. After block of conduction in the cervical region of the spinal cord, the proportions of the venous return coming from each region during the control periods were not significantly altered although the arterial pressure and total venous return were decreased.4. Intravenous infusions of adrenaline caused an increase in venous return which was associated with a marked increase in hepatic blood flow. The increase in hepatic blood flow was due to an increase in flow in the superior mesenteric artery and portal vein. Flow in the coeliac artery remained unchanged. This response was unaffected by block of the cervical region of the spinal cord and by atropine or pentolinium.5. Intravenous infusions of noradrenaline caused little change in venous return or regional blood flows. Small increases in superior mesenteric artery flow were occasionally seen and on cessation of the infusion a large but brief increase occurred. These facts suggest that noradrenaline has a similar action to adrenaline but this is masked by concomitant vasoconstriction.