bluuebunny/crossref_metadata_2025 huggingface dataset:
THE EFFECT OF HYPOXIA ON MUSCLE GLYCOGEN RESYNTHESIS IN MAN
Authors: Milledge J. S. , Halliday D. , Pope C. , Ward P. , Ward M. P. , Williams E. S.
Published: December 2014

The effect of hypoxia and muscle fibre type on the resynthesis of muscle glycogen was studied in three healthy subjects by means of needle biopsies. Biopsies were taken before and after exercise and after 5 h recovery. In control experiments subjects breathed air during the recovery phase whereas in the test experiments they breathed 10% oxygen in nitrogen during this time. Diet was controlled throughout the experiments and provided an excess of carbohydrate. Biopsies were assayed for total muscle glycogen and were studied histochemically, using microdensitometry on PAS stained sections as a measure of glycogen in individual fibres.

Exercise depleted muscle glycogen to a mean of 26% of control values. After 5 h recovery the mean values had risen to 62% breathing air and 51% on 10% oxygen breathing but this difference was not significant. In biopsies taken after 5 h recovery breathing either air or 10% oxygen, there was a marked contrast in PAS staining between muscle fibre Type I and II, the Type II fibres being more heavily stained. This difference was confirmed by microdensitometry. The contrast was increased by hypoxia in all subjects but this effect did not reach levels of statistical significance.

It is concluded that under these experimental conditions the overall resynthesis of muscle glycogen is not significantly affected by hypoxia. It is shown that Type II fibres resynthesise significantly more rapidly than Type I under both normoxic and hypoxic conditions. Hypoxia may enhance this difference in rate of resynthesis.
THE MITOTIC ACTIVITY OF BLOOD MONOCYTES CULTURED IN AUTOLOGOUS WOUND FLUID
Authors: Greenwood B.
Published: December 2014

Wound fluid was obtained from the subcutaneous tissue of sheep by implanting a perforated Teflon sampling chamber. A catheter from this chamber was brought to the surface.

The types and numbers of cells in this fluid were recorded. Cell free fluid was used at either 100% concentration, or 25% concentration in plasma, as a medium for the culture of autologous blood monocytes. Its ability to support mitosis was compared with that of 100% autologous plasma. Wound fluids taken upon consecutive post‐implantation days were compared.

Cultured monocytes survived in small numbers in wound fluid collected on the days immediately following operation. When mitosis occurred the mitotic indices remained low. The wound fluid did not exhibit that mitogenicity which is apparent in autologous plasma taken on the third or fourth days following implantation.

The results suggest that, following the implantation of Teflon, the wound fluid contains a component which is toxic for blood monocytes cultured upon glass.
THE EFFECT OF SECRETIN AND CHOLECYSTOKININ‐PANCREOZYMIN ON THE SECRETION OF BILE IN THE ANAESTHETIZED RABBIT
Authors: Esteller A. , Lopez M. A. , Murillo A.
Published: December 2014

Effects of secretin and Cholecystokinin‐Pancreozymin (CCK‐PZ) on the secretion of bile in anaesthetized rabbits have been studied. Single injections of secretin (5.0 u.kg‐1) significantly increased the flow of bile irrespectively of whether the cystic duct was free or had been tied. A sustained increase in bile flow could be obtained by the continuous infusion of secretin. Cholecystokinin‐Pancreozymin was effective in increasing the bile flow in doses of 1.0 u.kg‐1. Much of the effect could be attributed to contraction of the gallbladder but a significant increase in flow could stills be elicited after ligation of the cystic duct. Our findings strongly suggest that the biliary secretion in rabbits is not as different from the general pattern as has previously been suggested.
SECRETORY, MOTOR AND VASCULAR EFFECTS IN THE SUBLINGUAL GLAND OF THE RAT CAUSED BY AUTONOMIC NERVE STIMULATION
Authors: Templeton David , Thulin Anders
Published: December 2014

The influence of the autonomic nerves on sublingual glands of rats was studied. Stimulation of the chorda‐lingual nerve evoked a lively flow of saliva and was also thought to contract the myoepithelial cells in the gland. Sympathetic nerve stimulation, on the other hand, usually evoked no secretion and did not cause any motor responses in the sublingual gland. The glandular blood flow was increased by chorda‐lingual nerve stimulation, and this vasodilatation persisted also when atropine had been administered. Sympathetic nerve stimulation decreased the sublingual blood flow; this vasoconstrictor effect was mediated via activation of α‐adrenoceptors.
EFFECT OF POTASSIUM ON THE MECHANICAL ACTIVITY OF TAENIA COLI, UTERUS AND PORTAL VEIN OF THE GUINEAPIG
Authors: Gabella Giorgio
Published: December 2014

The effect of solutions containing 5·9 to 127 mmol.l−1 potassium on the mechanical activity of taenia coli, uterus and portal vein of the guinea‐pig was investigated using isometric and isotonic recording in vitro. In the taenia coli at 37°C an increase of the K+‐concentration from 5·9 (Krebs' solution) to 6·4 or 6·9 was sufficient to elicit mechanical activity. Maximal contractures were obtained with about 24 mmol.l−1 K+, both with isometric and isotonic recording (in the latter case with loads ranging between 1 and 7 g). With higher K+‐concentrations the contractures were not greater or were slightly smaller. In the taenia coli at 37°C the isometric contractures were well maintained (up to 15 min) when obtained with 20‐40 mnmol.l−1 K+. With higher K+‐concentrations the tension declined after 30–60 s, the more noticeably the higher the K+‐concentration. At 18°‐21°C the decline in tension during K+‐stimulations started earlier in time, occurred with lower K+‐concentrations, and was more noticeable. However, even at 15°C K+‐concentrations of about 22–30 mmol.l−1 produced contractures maintained up to 15 min. Isotonic contractures were always better maintained than isometric contractures. Solutions containing over 25 mmol.l−1 K+ produced at 37°C an initial transient relaxation of the taenia coli, which was abolished by tetrodotoxin but not by guanethidine or atropine; it was also present after the adrenergic fibres had been destroyed by 6‐hydroxy‐dopamine. It is suggested that this relaxation is due to stimulation of non‐adrenergic inhibitory nerves. A transient relaxation was also observed when the K+‐concentration was raised during a spontaneous contraction or during stimulation with carbachol. In the uterus maximal contractures were obtained with K+‐concentrations of 20–30 mmol.l−1; smaller contractures were obtained with higher K+‐concentrations. With K+‐concentrations up to 45 mmol.l−1 the isometric contractures were well maintained; with higher K+‐concentrations they declined within 30‐90s. Isotonic contractures were better maintained than isometric contractures. In taenia coli and uterus after stimulation with solutions containing more than 50 mmol.l−1 K+ upon re‐introduction of the Krebs' solution there were powerful contractions (after‐contractions) which lasted longer the higher the K+‐concentration had been. In the portal vein the isotonic contractures were approximately proportional to the K+‐concentration.
EFFECTS OF METHACHOLINE ON THE CAROTID CHEMORECEPTORS
Authors: McQueen D. S.
Published: December 2014

The present electrophysiological study shows that methacholine (MCh), generally regarded as a muscarinic agonist, stimulates the carotid chemoreceptors in pentobarbitone anaesthetized cats. The response consisted of a primary increase in discharge, attributable to nicotinic actions of MCh since it was unaffected by atropine but abolished by mecamylamine, and a delayed secondary increase in discharge, due mainly to bronchoconstriction evoked by MCh. Physostigmine caused similar potentiation of responses to acetylcholine and MCh which implies that acetylcholinesterase is located close to the site(s) at which the drugs act to stimulate chemoreceptor activity. The findings are in agreement with the general principle that chemosensory activity is increased by nicotinic agonists but not by muscarinic agonists.
ACUTE COLD EXPOSURE AND THE METABOLISM OF GLUCOSE AND SOME OF ITS PRECURSORS IN THE LIVER OF THE FED AND FASTED SHEEP
Authors: Thompson G. E. , Manson W. , Clarke P. L. , Bell A. W.
Published: December 2014

Measurements of total body oxygen consumption, visceral and hepatic blood flow, oxygen consumption, exchanges of amino acids, lactate, pyruvate and glucose were made on sheep fed 3–6 h or 21 h before the experiment and exposed for 3 h to a neuatral environment (15°C) or a cold environment (0·5 to 4°C with clipped coat and wind speed 2 m.s−1). Recent feeding significantly increased the total oxygen consumption and the oxygen consumption of the viscera and liver. No general release of amino acids from the viscera or uptake by the liver after feeding was detected although the arterial plasma concentration of essential amino acids did increase significantly after feeding. The plasma concentration of most non‐essential amino acids also increased except that of glycine, which decreased significantly. Cold exposure increased the total oxygen consumption and reduced the respiratory quotient significantly. Release of amino acids from the viscera was stimulated by cold exposure. There was a variable increase in the hepatic uptake of lactate and alanine when the sheep were fasted and cold‐exposed. The liver's glucose output doubled and the blood (arterial) glucose concentration significantly increased in the cold.
ULTRASTRUCTURAL CHANGES IN THE PLACENTA OF THE EWE AFTER FETAL PITUITARY STALK SECTION
Authors: Steven D. H. , Bass Fiona , Jansen C. J. M. , Krane E. J. , Mallon Kathleen , Samuel Carole A. , Thomas A. L. , Nathanielsz P. W.
Published: December 2014

Binucleate cells are a normal component of the ovine chorionic epithelium, but are usually separated from the fetal‐maternal interface by a thin layer of cytoplasm derived from the principal or uninucleate cells of the trophoblast. They are distinguished not only by two distinct and separate nuclei, but also by conspicuous membrane‐bound cytoplasmic inclusions in the form of haloed droplets. After fetal pituitary stalk section binucleate cells move up to and participate in the formation of the fetal‐maternal interface; furthermore they extend clear blunt‐ended pseudopodia into the maternal epithelial syncytium. These activities do not appear to be suppressed by fetal infusion of cortisol or ACTH. The apparent motility of binucleate cells, together with the presence of haloed droplets within the maternal epithelial syncytium, suggests that after fetal pituitary stalk section binucleate cells invade the uterine syncytium, lose their limiting membranes and discharge their contents into the syncytial cytoplasm. Large molecules such as ovine placental lactogen may be transported from fetal to maternal tissues by this mechanism.
IRON METABOLISM IN PIGEONS
Authors: Ramis J. , Planas J.
Published: December 2014

Several haematological parameters such as haemoglobin concentration, haematocrit, erythrocyte number, reticulocyte concentration, plasma iron and total iron binding capacity were determined in 118 urban pigeons of both sexes. No statistically significant sex differences among these parameters were found. In 36 specimens (23 males and 13 females), the plasma iron turnover was determined using 59Fe. The results obtained in this species, expressed per 100 ml−1 blood. day−1 and Kg−1 body weight. day−1, were compared with those of turkeys, ducks and chickens calculated from earlier papers. The highest values versus body weight were observed in pigeons.

Organ (liver, spleen, tibia, heart, leg muscle, ribs, sternal keel, gonads and blood) distribution of 59Fe intravenous injection was analyzed during a period from 5 min up to 120 days (19 different times) in groups of 4 pigeons. At the 6 h period, the organs retained the highest dose (20% of total Fe injected), but by the 2nd day period, the radioiron in the blood represented about 98% of the total injected. A fast iron uptake by the circulatory blood was checked and compared with that of other species (domestic fowl, ducks and turkeys). The reticulocyte count in pigeons normally ranged from 4 to 12%, which was consistent with these results. A linear decreasing radioactivity in blood, with an inflexion point on the 40th day was observed. An inverse correspondence between blood and liver was found. Content in other organs decreased uniformly with time, except the heart where the iron content was practically constant during the whole time. Ribs and sternal keel are erythropoietic organs in young pigeons.
Comparison of Metabolic Effect of Ammonia and Adrenaline Infusions in Sheep
Authors: Garwacki Stanislaw , Wiechetek M. , Barej W.
Published: December 2014

Intravenous infusions of ammonium chloride (62·3 µmol.kg‐1.min‐1) for 30 min caused a significant increase in blood glucose, lactate, pyruvate and free fatty acid (FFA) levels. A similar effect was also observed during infusion of adrenaline. Propanolol—‐a β‐ receptor blocking agent—completely prevented the rise of blood pyruvate and lactate after adrenaline when 8·3 µg.kg‐1.min‐1 of propranolol were infused, but not after NH4C1 administration. Lipolytic actions of adrenaline were completely prevented but that of NH4CI was only significantly diminished by blockade of β‐receptors with propranolol. It was concluded that the influence of ammonium ions on blood lactate and pyruvate and FFA was not entirely mediated by adrenaline.
Oxygen Consumptions and Potassium Contents of Slices of Rat Renal Cortex
Authors: Cooke K. R.
Published: December 2014

An oxygen electrode respirometer for determining the oxygen consumption of slices of mammalian renal cortex is described and assessed.

Though rat renal cortical slices incubated in potassium‐free medium for one hour lost 102 + 14 mmol of potassium/kg dry weight, there was only a small, nonsignificant fall in oxygen consumption. In contrast the oxygen consumption of slices incubated in potassium‐free medium with 10 mmol.l–1 ouabain was markedly reduced ( by 32 ± 6%), while such slices lost 180+15 mmol of potassium/kg dry weight. These disproportionate effects on potassium loss and inhibition of oxygen consumption suggest that in renal cortical slices the loss of potassium in low potassium medium is not primarily due to inhibition of the conventional sodium pump.
The Effect of Ammonium Ion Concentration on the Activity of Adenylate Cyclase in Various Rat Tissues in vitro
Authors: Wiechetek Maria , Breves G. , Höller H.
Published: December 2014

The effects of three different ammonium ion concentrations (0·143; 14·3; 14 3 mmol.l–1) on adenylate cyclase activities in liver, muscle, fat and brain tissue in vitro were studied in the rat. At physiological levels, ammonium ions reduced adenylate cyclase activity in liver and fat by about 30%, did not affect enzyme activity in muscle tissue but increased adenylate cyclase activity in brain by 40%. Similar effects were observed at higher ammonium ion concentrations though there were no statistically significant correlations between ammonium ion concentration and the degree of change of enzyme activity.
The Ultrastructure of Frog Mesenteric Capillaries of Known Filtration Coefficient
Authors: Mason J. C. , Curry F. E. , White Ingrid F. , Michel C. C.
Published: December 2014

The capillaries of the frog mesentery were investigated by transmission electronmicroscopy. The mean diameter of these vessels was 20µm and a single layer of five to six endothelial cells (on average) contributed to each circumference. Their ultrastructure was very similar to that of mammalian capillaries of the continuous type [Bennett, Luft and Hampton, 1959]. The endothelial cells, which contained many vesicles, were joined by specialized junctions and surrounded by a continuous basement membrane. Eleven capillaries were examined after the filtration coefficient of their walls had been investigated by the microperfusion micro‐occlusion technique of Michel, Mason, Curry and Tooke [1974]. No abnormal appearances were observed even after the vessels had been perfused with protein free solutions which have been shown to increase filtration coefficient five fold. No morphological differences between capillaries were seen to accompany large differences in the filtration coefficients.
Sodium Appetite and the Oestrous Cycle in Sheep: Effect of Oestrogen, Progesterone and Changes in Food Intake
Authors: Michell A. R.
Published: December 2014

Previous studies of voluntary sodium intake and electrolyte excretion in sheep suggested that the pattern of intake associated with the oestrous cycle was not a response to alterations in sodium balance. The pattern thus seemed likely to be dictated by changes in either hormonal levels or food intake. These possibilities were examined in experiments with ovariectomized sheep. Physiological doses of oestrogen or progesterone had no effect on sodium preference, whether given in isolation or succession. Depression of food intake by 25% (as at oestrus) did affect preference slightly (though significantly) but in the opposite direction to the change at oestrus. It is concluded that none of these 3 factors is responsible for the varying sodium preference during the oestrous cycle and that direct hypothalamic control of this pattern is an interesting possibility.
The Effect of Naloxone on the Inhibition of Nociceptor Driven•Neurones in the Cat Spinal Cord
Authors: Sinclair J. G. , Fox R. E. , Mokha S. S. , Iggo A.
Published: December 2014

The functional role of the opiate receptors and enkephalins found in high concentration in the superficial dorsal horn of the spinal cord has not been ascertained but may be the modulation of transmission in nociceptive pathways. In cats anaesthetized with α‐chloralose the narcotic antagonist, nalozone, was tested on various types of inhibitory input to spinal cord neurones which responded to both noxious and non‐noxious stimulation of their receptive fields (Class 2 neurones). Naloxone (0·3–2·0 mg/kg i.v.) failed to alter the response of these neurones to noxious radiant heat, to tonic descending inhibition or to inhibition evoked by stimulation of the dorsal columns or contralateral plantar nerve. Thus the endorphins do not appear to be involved in mediating the types of inhibition examined. On the other hand, i.v. morphine reduced the response of Class 2 neurones to noxious heating of the skin, an effect that was reversed by naloxone.
Role of Angiotensin II and Bradykinin in the Diuresis Caused by Stimulation of Atrial Receptors
Authors: Knapp M. F. , Linden R. J. , Mary D. A. S. G. , Pearson M. J.
Published: December 2014

The diuretic response to stimulation of left atrial receptors, by distending balloons located either at the pulmonary vein‐left atrial junctions or in the body of the left atrium, was studied during blockade of the generation of angiotensin II using a continuous infusion of angiotensin converting enzyme inhibitor, SQ 14,225, in anaesthetized dogs. Despite blockade of angiotensin conversion, known also to potentiate the activity of bradykinin, a diuretic response was obtained in each dog; the response was similar to that observed in dogs without blockade of angiotensin conversion. Angiotensin II and bradykinin did not significantly influence the rate of secretion of Malpighian tubules of Rhodnius prolixus, which have been shown capable of detecting the blood‐borne agent known to mediate the diuretic response. It is concluded that neither angiotensin II nor bradykinin is likely to be the blood‐borne agent released by stimulation of atrial receptors.
The Effects of Colchicine on Milk Secretion, Mammary Metabolism and Blood Flow in the Goat
Authors: Henderson A. J. , Peaker M.
Published: December 2014

Mammary function in the conscious goat was studied during colchicine‐induced depression of milk secretion in one mammary gland. Milk yield of the treated gland was reduced to approximately a quarter of previous, while where were significant increases in afternoon milk yield from the untreated glands on the 2nd and 3rd days after treatment in goats in late lactation. Milk composition in the untreated glands was not significantly affected. In the treated gland, milk [Na+], [Cl+], [citrate] amd [protein] increased while [K+] and [lactose] decreased, although the time course of these changes differed; milk [fat] was unaffected.

Mammary extractions ((A‐V)/A) of glucose, acetate and most amino acids were significantly decreased during the period of maximal inlibition of secretion. There were no significant changes in arterial plasma concentrations of glucose, acetate or any essential amino acids. In another series of experiments, mammary blood flow increased and then returned to normal after colchicine treatment even though milk yield and mammary glucose uptake decreased markedly; oxygen uptake was not significantly affected.

The results are discussed in relation to the actions of colchicine on the mammary secretory cell, to the normal control of mammary blood flow and to the mechanism of compensation by the untreated gland.
A COMPARISON OF THE EFFECTS OF PROSTAGLANDINS E2 AND I2 ON RENAL FUNCTION AND RENIN RELEASE IN SALT‐LOADED AND SALT‐DEPLETED ANAESTHETIZED DOGS
Authors: Jones R. L. , Watson M. L. , Ungar A.
Published: December 2014

Prostaglandin E2 (PGE2) and prostaglandin I2 (PGI2) were infused into the renal artery of either sodium‐loaded or sodium‐depleted dogs. Systemic blood pressure was decreased and arterial plasma renin concentration increased in the sodium‐loaded dogs by infusion of PGI2 (1200 ng/min). Both compounds increased renal blood flow but PGE2 had a much more potent effect than PGI2 on increasing urine flow and sodium excretion. In the sodium‐depleted dogs systemic blood pressure was significantly decreased and arterial plasma renin concentration increased by infusions of PGI2 (300 and 1200 ng/min) and PGE2 (300 ng/min). Both compounds stimulated urine flow and renal blood flow but PGE2 induced a much larger increase in sodium excretion than PGI2. PGI2 exerts its actions on renal function by inducing vasodilatation whereas PGE2 also has a direct action on tubular function.
A HORSERADISH PEROXIDASE STUDY OF VAGAL MOTONEURONES WITH AXONS IN CARDIAC AND PULMONARY BRANCHES OF THE CAT AND DOG
Authors: Bennett J. A. , Kidd C. , Latif A. B. , McWilliam P. N.
Published: December 2014

The location, within the brain stem, of vagal efferent neurones with axons in the cardiac and pulmonary branches of the cat, and the cardiac branch of the dog, have been defined. Horseradish peroxidase was applied to the cut central ends of these vagal branches and, after an appropriate time, sections of the brain stem were examined for labelled cell bodies. Labelled cell bodies were found ipsilaterally in the dorsal motor vagal nucleus, the nucleus ambiguus and in the reticular formation between these two nuclei. We suggest that the dual location for cell bodies of vagal axons may represent a separation of somata with myelinated and non‐myelinated vagal axons to the nucleus ambiguus and the dorsal motor vagal nucleus respectively.
ROLE OF DOPAMINE IN THE DIURESIS CAUSED BY STIMULATION OF ATRIAL RECEPTORS
Authors: Linden R. J. , Mary D. A. S. G.
Published: December 2014

The diuretic response to stimulation of left atrial receptors, by distending balloons located either at the pulmonary vein‐left atrial junctions or in the body of the left atrium was studied during blockade of dopamine receptors using a continuous infusion of sulpiride in doses ranging from 0·632 to 5·153 µmol.kg‐1.min‐1, in anaesthetized dogs. A diuretic response was obtained in each experiment of distension of the balloons: the response was similar to that observed in dogs without blockade of dopamine receptors and was not significantly related to the dose of sulpiride used. It is concluded that the diuretic response to stimulation of atrial receptors, known to be mediated by a blood‐borne agent, is unlikely to be caused by dopamine.
THE UTILIZATION OF LACTIC ACID BY SHEEP IN LATE PREGNANCY
Authors: Faichney G. J. , Barker P. J. , Setchell B. P. , Lindsay D. B.
Published: December 2014

The irreversible loss of lactate and the respiratory exchange in four conscious ewes that were about 138 days pregnant were measured at least seven days after surgery. In addition, the uptake and net output of lactate and the net uptake of glucose and alanine by the gravid uterus and an upper hind limb (primarily skeletal muscle) were measured. Calculated heat production of the ewes was 496 kJ/d.kg¾; irreversible loss of lactate was 9·5 µmol/min.kg of which 73% was oxidized to CO2, contributing 9% to the ewes' CO2 production. About 2% of the glucose and 65% of the alanine was derived from lactate. Lactate was taken up by both the gravid uterus and the upper hind limb; output of lactate could have accounted for from 8–12% of glucose uptake by the gravid uterus but from 35–50% of that by the upper hind limb. The carbohydrate/O2 quotient was 1·07 for the gravid uterus and 0·35 for the upper hind limb.
IONTOPHORETIC STUDIES ON PALLIDAL NEURONES AND THE PROJECTION FROM THE SUBTHALAMIC NUCLEUS
Authors: Perkins M. N. , Stone T. W.
Published: December 2014

The predominant response of pallidal neurones to γ‐aminobutyric acid (GABA), glycine and dopamine when applied iontophoretically, was inhibition of firing rate. With dopamine some excitatory responses were observed, this never being the case with GABA or glycine. Picrotoxin reversibly blocked neuronal responses to GABA but not glycine in fourteen cases. Strychnine abolished glycine evoked inhibitions in seventeen cells while not affecting GABA responses. A number of cells were responsive to a stimulus delivered to the subthalamic nucleus (s.t.n.), an electrode array being used to establish the specificity of response to s.t.n. stimulation. In eight out of fourteen cases there was a reduction of 40% or more in the inhibitory responses following stimulation, with picrotoxin applied iontophoretically. Strychnine, conversely, had no effect on the synaptically evoked inhibition at doses that exceeded those required to antagonize iontophoretically applied glycine. Similarly, fluphenazine and naloxone administered iontophoretically or intraperitoneally (I.P.) had no effect on eight cells. The results indicate the existence of a ‘GABA‐ergic’ link in the projection from the subthalamic nucleus to the globus pallidus, though other transmitters, but not glycine or dopamine, may contribute to the observed synaptic responses.
EFFECT OF INTESTINAL RESECTION IN DOGS ON DIFFERENT DIGESTIVE PARAMETERS
Authors: Murillo M. L. , Campos M. S. , Mataix F. J. , Varela G.
Published: December 2014

Some aspects of the digestive secretions in intact dogs (Control group) and the same dogs after resections of either 50 or 80% of the small intestine starting from the ileocaecal valve have been studied. In all of the animals the duodenal content flow, duodenal content pH, bile salts and amylase production have been determined; under fasting conditions, response to food (4% fat) and response to cholecystokinin‐pancreozymin (CCK‐PZ) injection (2 i.u./kg). Our results showed a decrease of pH and amylase production in resected animals, but duodenal content flow and bile salt production were not affected. The increase in duodenal content flow in response to feeding was delayed at onset in resected dogs. The pH and bile salts production were unchanged in response to food and to CCK‐PZ injection in all animals, but amylase production decreased in response to food and particularly to CCK‐PZ administration in resected animals.
BILIARY RESPONSE TO FOOD IN RABBITS: ROLE OF THE GALL BLADDER AND THE ENTEROHEPATIC CIRCULATION OF BILE SALTS
Authors: Esteller A. , Jiminez R. , Lopez M. A.
Published: December 2014

The biliary response to feeding has been investigated in intact and cholecystectomized rabbits, with and without interruption of the enterohepatic circulation of bile salts. The relative contribution of the different secretory mechanisms involved in this process has been examined. Feeding induced an increase in the flow and bicarbonate concentration of the bile and a slight decrease in the bile salt content in rabbits with gall bladders and the enterohepatic circulation intact. Feeding with the enterohepatic circulation interrupted elicited a drop in bile flow and the bile salt concentration, but an increase in bicarbonate concentration. Interruption of the enterohepatic circulation thus dramatically modifies the feeding response: a response to food is still detectable after interruption, but is masked by the negative effects of drainage of the bile away from the duodenum.
THE DISTRIBUTION IN THE CAT BRAIN STEM OF NEURONES ACTIVATED BY VAGAL NON‐MYELINATED FIBRES FROM THE HEART AND LUNGS
Authors: Donoghue S. , Fox R. E. , Kidd C. , Koley B. N.
Published: December 2014

In anaesthetized cats, right cardiac vagal branches were electrically stimulated and recordings of evoked ‘slow wave’ and single neurone activity were made in the brain stem. Short‐latency ‘slow wave’ and multi‐neuronal activity evoked by excitation of myelinated vagal afferent fibres were recorded in the medial and lateral subnuclei of the nucleus tractus solitarius, the area postrema, the dorsal vagal motor nucleus, the lateral reticular formation and the nucleus ambiguus. Long‐latency responses evoked by vagal non‐myelinated fibres were recorded in the medial subnucleus of the nucleus tractus solitarius, the area postrema, dorsal vagal motor nucleus, the parahypoglossal area and the lateral reticular formation dorsal to the nucleus ambiguus. A specific study was made of seventy‐two single neurones activated by non‐myelinated afferent fibres in the cardiac branch. Thirty‐four were shown to be synaptically activated, twenty‐one were activated nonsynaptically and seventeen could not be classified. One neurone was also activated by myelinated cardiac afferent fibres, and two by thoracic vagal (including pulmonary) afferent fibres. Neurones were not spontaneously active. Indirect evidence suggests that the majority of the recordings of nonsynaptically activated neurones were likely to be from cell bodies. Neurones were located from the level of the obex to 3·0 mm rostral to it in the medial subnucleus of the nucleus tractus solitarius (45), and in the lateral subnucleus (2), the area postrema and its border with the medial subnucleus of the nucleus tractus solitarius (13), the dorsal vagal motor nucleus (9), the parahypoglossal area (1) and the lateral reticular formation dorsal to nucleus ambiguus (2). Recordings were made from fifteen neurones activated by myelinated fibres in the cardiac vagal branches, and twelve were excited synaptically. The neurones were located in the medial (8) and lateral (3) subnuclei of the nucleus tractus solitarius, the dorsal vagal motor nucleus (1) and the lateral reticular formation (1). Four neurones were also excited by vagal afferent fibres in the thoracic vagal nerve immediately caudal to the caudal cardiac branch.
AN EXPERIMENTAL APPROACH FOR EVALUATION OF THE O2 BALANCE IN LOCAL MYOCARDIAL REGIONS IN VIVO
Authors: Kedem Joseph , Mayevsky Avraham , Sonn Judith , Acad Bat-Ami
Published: December 2014

Quantitative evaluation of myocardial oxygen balance can be accomplished by measurement of oxygen supply, demand, and intracellular oxygen concentration. Experimentally, these parameters are often related to coronary blood flow, cardiac contractility, and mitochondrial NADH redox level, respectively. Methods were developed to measure these three parameters in a local region on the myocardial surface in open‐chest dogs. Local coronary blood supply was measured with the aid of a small surface thermistor, and cardiac work with a miniature strain gauge arch. NADH oxidation‐reduction state was recorded using surface fluorometry through a fibre optic light guide. Transient anoxia produced by nitrogen breathing caused a rapid but reversible elevation in NADH levels, which was not always accompanied by a concomitant change in contractile force. Elevation of heart rate resulted in a rise in intramitochondrial NADH followed by an increase in coronary flow. In spite of the increased flow, NADH levels remained elevated, indicating a change in the O2 balance; this may indicate that autoregulation does not necessarily result in total compensation.
DEGENERATION AND REGENERATION OF THE OLFACTORY EPITHELIUM AFTER OLFACTORY BULB ABLATION IN THE PIG: A MORPHOLOGICAL AND ELECTROPHYSIOLOGICAL STUDY
Authors: Booth W. D. , Baldwin B. A. , Poynder T. M. , Bannister L. H. , Gower D. B.
Published: December 2014

The olfactory bulbs were removed surgically from Large White male and female pigs, 10–12 weeks of age. At intervals of 3, 7, 14, 42 and 84 d after bulbectomy, the pigs were sacrificed and portions of olfactory mucosa were removed from the ethmoturbinate and septum regions of the nasal cavity; olfactory mucosa was also removed from unoperated pigs. A piece of each tissue sample was processed for light microscopy. The remaining tissue was placed in Ringer‐Locke solution, saturated with O2/CO2 at room temperture, and the electrical activity of the olfactory epithelium was investigated in vitro by passing a stimulus of butyl acetate vapour over the epithelium. Slow negative potential changes (electro‐olfactogram, e.o.g.) induced by butyl acetate were recorded. During the first two weeks after bulbectomy there was a rapid decrease in the height of the olfactory epithelium associated with the disappearance of the e.o.g. response. However by 42 and 84 d after bulbectomy, partial recovery of the height and some electrical activity of the olfactory mucosa had occurred. In some pigs, the insertion of a stainless steel lining over the cribriform plate to prevent any association of regenerating axons with forebrain tissue had no effect on the regenerative characteristics studied.
RENAL PROSTAGLANDINS AND SODIUM EXCRETION
Authors: Lote C. J.
Published: December 2014

In conclusion, it can be said that renal prostaglandins undoubtedly influence sodium excretion, but they cannot really be said to regulate sodium excretion. The primary purpose of cortical prostaglandin synthesis seems to be to modulate renin release, and to guard the renal blood supply and glomerular filtration rate against potential reductions. The primary purpose of medullary prostaglandin synthesis appears to be to regulate the papillary osmolality, and some of the effects of the renal prostaglandins on sodium and water excretion are probably secondary to changes in the papillary osmolality. In addition medullary prostaglandin synthesis modulates the actions of vasopressin, though this action may be of little physiological importance (Padfield & Grekin, 1981).
CHICKEN INTRAPULMONARY CHEMORECEPTOR DISCHARGE FREQUENCY REDUCED BY INCREASING RATE OF REPETITIVE PCO2 CHANGES
Authors: Nye Piers C. G. , Barker Margaret R. , Burger Ray E.
Published: December 2014

We have recently reported that repetitive changes of PCO2 given to innervated non‐perfused chicken lungs reflexly inhibit respiratory efforts. The degree of respiratory inhibition is rate‐dependent, decreasing as repetition rate is increased to 3·2 Hz (Barker, Burger & Nye, 1981) to nearly that expected from the average PCO2 of the two levels given. Intrapulmonary chemoreceptors (i.p.c.s), whose discharge frequencies are inversely related to PCO2, are presumably responsible for these effects. Here we report the activity of twenty single i.p.c.s in the left, non‐perfused lungs of twelve thoractomized cockerels as PCO2 of the gas ventilating those lungs was repetively changed between 7 and 27 or 7 and 40 torr. Maximal discharge rates of individual receptors after a PCO2 decrease were related to the location of receptors within the gas exchange region. From 0·2 to 1·6 Hz both average and maximal discharge frequencies decreased. The inhibition of discharge in this range was greater than that predicted by the steady‐state relationship between reflex responses and receptor discharge, suggesting that the reflex effects of i.p.c. discharge are not a simple function of the mean discharge frequency of all i.p.c.s. Either average i.p.c. discharge frequency per PCO2, cycle over‐estimates their respiratory reflex inhibition or only the less rate‐sensitive i.p.c.s, those in the middle of the gas exchange region, may dominate this rate‐dependent respiratory reflex.
THE INFLUENCE OF CALCIUM ON THE CONTROL OF FLUID SECRETION IN THE COCKROACH SALIVARY GLAND
Authors: Gray D. C. , House C. R.
Published: December 2014

When cockroach salivary glands are bathed in calcium‐free medium the basal rate of fluid secretion increases from about 1 nl/min to about 10 nl/min; maintained dopamine stimulation elicits a further rise in secretory rate which gradually declines. Evidence is presented which indicates that magnesium is unable to substitute for calcium in this system. When calcium is returned to the bathing solution after a period of calcium deprivation there is a transient increase in secretory rate. Stimulation of the glands in certain conditions which inhibit the secretory response leads to some kind of calcium‐dependent active state in the secretory cells which can outlast the interaction of the agonist with its receptors. It is concluded that stimulus‐secretion coupling in this gland involves a calcium‐dependent second messenger system.
REPRODUCTIVE BEHAVIOUR IN THE PIG AFTER AUTOTRANSPLANTATION OF THE OVARY BY VASCULAR ANASTOMOSES
Authors: Harrison F. A.
Published: December 2014

Orthotopic autotransplantation of the left ovary with vascular anastomoses to the aorta and vena cava on the right side of the abdomen of a gilt, in which the right ovary had been removed, was followed by normal cyclic activity ofthe transplanted ovary and the successful establishment, maintenance and completion of pregnancies of normal gestational length, with apparently normal lactation.

Heterotopic autotransplantation of the left ovary with vascular anastomoses to major vessels in the neck in two sows, in which the other ovary had been removed, was also followed by cyclic ovarian activity of normal length with normal sexual behaviour. The observations suggest that, in the pig, the uterine luteolysin is capable of acting by a vascular route independent of local connexions.
STIMULUS‐SECRETION COUPLING IN ISOLATED BOVINE ADRENAL MEDULLARY CELLS
Authors: Knight D. E. , Baker P. F.
Published: December 2014

Adrenal medullary cells can be obtained in high yield by protease digestion of slices of bovine adrenal medulla. The properties of catecholamine release from these isolated cells have been determined and compared with the intact perfused gland. Exposure to carbamylcholine, veratridine or high K evokes a transient increase in the rate of catecholamine release in association with dopamine β hydroxylase but not lactate dehydrogenase. Exposure to A23187 releases catecholamine together with lactate dehydrogenase. In all cases release requires extracellular Ca. A comparison is made of the sensitivities of catecholamine release evoked by various agonists and the effects of nicotinic antagonists, D 600, Na‐free media, TTX, Mg and trifluoperazine. Resting and carbamylcholine‐evoked catecholamine release is relatively insensitive to the nature of the major extracellular anion and to the external pH over the range 6·4 to 7·8. Measurements with the dye 3 3'‐Diethylthiadicarbocyanine iodide (di S‐C2−(5)) show that release evoked by carbamylcholine or low concentrations of veratridine is associated‐on average‐with a small steady depolarization of the cells. Catecholamine release in response to nicotinic agonists, but not the other secretagogues, is greater at 20 °C than at 37 °C, possibly because of a slower rate of receptor desensitization at this temperature. Transmission electron microscopy of stimulated cells reveals a marked increase in the proportion of large membrane bounded vesicles that lack electron‐dense cores. After stimulating secretion in the presence of horseradish peroxidase, the vesicles contain reaction product suggesting that they are generated by endocytosis.
ADRENAL CORTEX OF FETAL LAMB: CHANGES AFTER HYPOPHYSECTOMY AND EFFECTS OF SYNACTHEN ON CYTOARCHITECTURE AND SECRETORY ACTIVITY
Authors: Robinson P. M. , Comline R. S. , Fowden Abigail L. , Silver Marian
Published: December 2014

The effects of hypophysectomy on the cell population of the adrenal cortex has been examined with light and electron microscopy. The sensitivity of the adrenal cortical cells to exogenous ACTH in both normal and hypophysectomized fetuses has been investigated by comparing plasma cortisol concentrations with structural changes in the adrenal cortex. Hypophysectomy was carried out at about 100 d and the subsequent analysis was made at about 135 d on fetuses catheterized at least 6 d earlier. The zona fasciculata of intact fetuses contained about 25% mature and 75% immature cells at 130–136 d. After hypophysectomy this zone contained a uniform population of immature cells and no mature cells; there was a significant reduction in both adrenal weight and cortical thickness. The zona glomerulosa was unaffected by hypophysectomy. The infusion of Synacthen 0·25 mg/d I.V. for 48 h did not affect the zona glomerulosa but resulted in a 2‐fold increase in the thickness of the zona fasciculata in hypophysectomized and intact fetuses. This cortical growth was due to both hypertrophy and hyperplasia. All the cells in the zona fasciculata were mature following Synacthen treatment in both groups. The most striking difference between the secretory response of the adrenal cortex to Synacthen in the two groups was found within 3–6 h of the onset of infusion. Within this period there was a significant increment in the plasma cortisol concentration in the intact fetuses while no response was observed in the hypophysectomized animals. After 12 h infusion by contrast, a steadily rising response was observed in both groups. There was a significant correlation between the final plasma cortisol concentration and both the adrenal weight and cortical thickness after 48 h treatment. The increased sensitivity of the adrenal cortex to exogenous ACTH as term approaches in the sheep is considered to be dependent upon the increasing proportion of mature zona fasciculata cells within the adrenal cortex.
EFFECT OF DIETARY LINOLEIC AND LINOLENIC ACIDS ON TESTICULAR DEVELOPMENT IN THE RAT
Authors: Leat W. M. F. , Northrop Christine A. , Harrison F. A. , Cox R. W.
Published: December 2014

In two experiments a total of twelve male rats were reared from weaning for up to 63 weeks on an essential fatty acid (EFA)‐deficient diet alone (2 x two animals) or supplemented with the methyl esters of linoleic acid (18:2ω6) (2 x two animals) or linolenic acid (18:3ω3) (2 x two animals). Testicular development was normal in rats given 18:2ω6, but in rats fed the FEA‐deficient diet alone, and in those supplemented with 18:3ω3 the testes were reduced in size. Histologically, a degeneration of the seminiferous tubules was noted, with progressive loss of the germinal cells, and with an absence of spermatozoa in the lumina of the seminiferous tubules and epididymides. Leydig cells appeared unaffected, and were prominent. The six rats in Experiment 1 were capable of mating with females reared on commercial diets, but only the two 18:2ω6 supplemented animals were fertile. There was a marked reduction in the percentage of arachidonic acid (20:4ω6) and docosapentaenoic acid (22:5ω6) in the total fatty acids of the atrophic testes. There was no compensatory increase in long‐chain derivatives of 18:3ω3 in the 18:3ω3 fed rats and it is concluded that linolenic acid cannot replace linoleic acid in the development of the rat testis.
THE MECHANISM OF RUMINAL STASIS IN LANTANA‐POISONED SHEEP
Authors: McSweeney Christopher S. , Pass Michael A.
Published: December 2014

The effect of poisoning by the plant Lantana camara L. on reticulo‐ruminal motility was investigated in sheep. There was a marked decrease in forestomach motility 4–6 h after dosing with the plant and motility continued to be depressed throughout the course of the disease. The effect of lantana on motility was characterized by a decrease in the number and median amplitude of forestomach movements. This was in contrast to the effect of starvation which caused a decrease in only the number of forestomach movements and even this effect was less severe than in lantana‐poisoned animals. The effects of lantana on the components of the reflex which controls rumen motility were examined. No evidence was found for a direct effect of lantana toxins on the stretch and tactile receptors in the reticulum; on the vagus nerves; on the gastric centre or on the muscle of the forestomach. However, evidence was found to support an hypothesis that stasis of the rumen in lantana poisoning is due to inhibitory influences arising from the damaged liver. The evidence included a correlation between the onset of ruminal stasis and liver injury; a relationship between the severity of liver injury and ruminal stasis and the finding that denervation of the liver converted the pattern of forestomach movements in intoxicated animals to that seen in starved animals. It is concluded that stasis of the rumen in lantana‐poisoned animals is due at least initially, to inhibitory neural impulses arising from the damaged liver and to the effects of anorexia.
A NEW OPEN AND CLOSED RESPIRATION CHAMBER
Authors: Aulick L. Howard , Arnhold H. , Hander E. H. , Mason A. D.
Published: December 2014

A new, fully automated, open and closed respiration chamber has been constructed, which is large enough to accommodate man or comparable sized animals. Metabolic rate is calculated from measured changes in respiratory gas volumes while the system is hermetically sealed. When CO2 concentration reaches a prescribed level, large ports are opened and the chamber is ventilated. By repeating this process, a series of metabolic determinations can be conducted over an extended period. Temperature, humidity and air velocity are fixed, but chamber volume and pressure vary with changes in the respiratory exchange of the animal and/or barometric pressure. Small, rapid changes in gas volumes are monitored by a low‐resistance spirometer and large changes accommodated in a second, high‐volume, motorized spirometer. Chamber operations, data aquisition and metabolic calculations are performed by a small computer. System calibration with methanol combustion indicates that estimates of respiratory gas exchange are highly accurate over a temperature range from 10‐40°C.