bluuebunny/crossref_metadata_2025 huggingface dataset:
The metabolism of choline by a sympathetic ganglion
Authors: Collier B. , Lang Celia
Published: April 2011

Cat's superior cervical ganglia were perfused with Locke's solution containing choline (Ch) at physiological concentration but labelled (methyl-3H), and the radioactive products in extracts of such ganglia were identified by a combination of selective precipitation and chromatographic tests. Ch was incorporated into acetylcholine (ACh), into phosphorylcholine (PCh), and into phospholipid. The rate of formation of PCh and phospholipid from Ch was measured to be about 2 ng/min of each, and this rate was unaffected by activity or by hemicholinium. Free Ch liberated by PCh or phospholipid turnover is unlikely to be an important source of Ch for ACh synthesis under physiological conditions.
Pancreatic amylase activity from ruminants fed different rations
Authors: Clary J. J. , Mitchell Jr. G. E. , Little C. O. , Bradley N. W.
Published: April 2011

Pancreatic tissue, obtained from groups of 24 steers each fed pasture plus free-choice minerals or an all-concentrate ration for 126 days, was analyzed for amylase activity. Feeding grain resulted in a highly significant increase in pancreatic amylase activity. Pancreatic tissue from 48 steers fed grain with corn silage had intermediate amylase activity. Data from wethers with pancreatic duct or common bile duct cannulas to permit collection of pancreatic secretions during dietary change support a conclusion that ruminants adapt to increased grain intake by increasing their production of pancreatic amylase. The time required for full adaptation appeared to be longer than for monogastric animals.
A comparative study of dopamine and noradrenaline on the rabbit aorta
Authors: Kohli J. D.
Published: April 2011

α-Excitatory and β-inhibitory activities of dopamine and noradrenaline were compared on the rabbit aorta in vitro. Dopamine showed about 1/50 the excitatory activity of noradrenaline. The pA10 value of phentolamine against dopamine was 6.5 ± 0.03 as compared with the value of 6.2 ± 0.04 against noradrenaline. pA10 values of haloperidol against dopamine and noradrenaline were 6.9 ± 0.06 and 7.1 ± 0.14 respectively. The inhibitory activity of dopamine was less than 1/10 that of noradrenaline and markedly less than 1/100 that of isoprenaline. When propranolol was used to block the inhibitory action of the catecholamines, original excitatory action was unexpectedly observed, even though the strips had been treated with phenoxybenzamine 3 × 10−7 g/ml for 5 min.
Nonshivering thermogenesis in the newborn lamb
Authors: Thompson G. E. , Jenkinson D. McEwan
Published: April 2011

Microscopic examination of adipose tissue from lambs of varying ages between birth and 20 days showed that most cells were multivacuolar on the first day of life, but most were univacuolar at 10 days of age and older. The oxygen consumption of four lambs aged between 6 h and [Formula: see text] days was approximately doubled after injection with (−)noradrenaline (400 μg/kg subcutaneously) in an environment of 20 °C. Five lambs between [Formula: see text] days and 12 days showed a reduced response or no response. Three lambs between 14 days and 20 days of age showed virtually no change in oxygen consumption after noradrenaline. It is concluded that the mechanism for nonshivering heat production is present in the newborn lamb, but disappears at a relatively early age.
Effects of denervation on the sensitivity of the superior cervical ganglion of the cat to acetylcholine and McN-A-343
Authors: Vickerson Frederick H. L. , Varma D. R.
Published: April 2011

Supersensitivity of the denervated superior cervical ganglion of the cat to acetylcholine (Ach) has been reported by workers who measured contractions of the nictitating membrane, and denied by others who measured postganglionic action potentials as an index of ganglion activity. The present experiments were performed to find out the reason for this discrepancy. The increased responses of nictitating membranes to intra-arterial administration of Ach to denervated ganglia were found to be due to increased sensitivity of membranes to the adrenergic neurotransmitter rather than to an increase in the sensitivity of the ganglia. McN-A-343, a muscarinic agent, produced a greater maximal contraction of the membrane when injected to denervated than when injected to control ganglia. These results suggest that denervation causes an increase in the number and (or) sensitivity of muscarinic receptors in ganglia. Hexamethonium antagonized Ach less effectively on denervated than on control ganglia. The effect of Ach on denervated ganglia was blocked by hexamethonium plus atropine, which suggests that Ach acts both on nicotinic and muscarinic receptors in denervated ganglia. Atropine but not hexamethonium blocked the effect of McN-A-343 on both control and denervated ganglia.
Determination of glomerular filtration rate with 57Co-B12 and plasma protein binding of cyanocobalamin
Authors: Ogilvie Richard Ian , Ruedy John
Published: April 2011

A comparison was made in normal volunteers of measurements of glomerular filtration rate (G.F.R.) with 57Co-B12 and inulin. With the method of Cutler and Glatte (J. Lab. Clin. Med. 65,1041 (1965)), the mean ratio of 99 simultaneous renal clearances of 57Co-B12 and inulin was 0.43 in comparison with that of 0.88 averaged from six published reports. During clearances, the fraction of vitamin bound to plasma protein averaged 57% in our studies with a dextran–charcoal method to measure binding, compared with a 16% average in reports where exhaustive dialysis was used. Correction of clearances for unbound 57Co-B12 estimated by coated-charcoal adsorption resulted in a mean ratio of free B12 to inulin clearances of 1.0 in two patients. Because of the difference in 57Co-B12 binding in our patients compared with others, we studied three methods of determining the binding of vitamin B12 added to plasma in vitro in concentrations of 0.2 to 2000.0 ng/ml. With all three techniques, ultrafiltration, dextran-coated charcoal adsorption, and exhaustive dialysis, the percent of added 57Co-B12 bound to plasma decreased with increasing concentrations of vitamin. At concentrations above 20.0 ng/ml, binding differed with each technique. The highest binding was observed with ultrafiltration, the lowest with exhaustive dialysis. Dilution of the plasma or reduction of incubation temperatures from 37 °C to 20 °C reduced the amount bound. Studies of binding of 57Co-B12 in our patients showed a variation with time. Unless binding is measured for each clearance period by a standardized technique, 57Co-B12 should not be used as a replacement for inulin in the measurement of G.F.R.
A note on the combined effects of exercise and food restriction on plasma enzyme activities in the rat
Authors: Beaton J. R. , Oyster B.
Published: April 2011

Plasma activities of malic dehydrogenase (MDH) and glutamic–pyruvic transaminase (GPT) were measured in adult male rats made to swim for 1 h either as a single, acute exercise or in repeated exercises (training) in the presence of a 50% food restriction. Food restriction per se elevated MDH and lowered GPT activities. Food-restricted rats responded to both acute exercise and training by an elevated plasma MDH activity. The effect of exercise on plasma MDH activity in these animals was greater than in rats fed ad libitum and was greater than could be accounted for by the summation of the individual effects of training and of food restriction. Plasma GPT activity was not altered by exercise in rats fed ad libitum or in food-restricted animals. It would appear, as suggested previously, that plasma MDH activity may be a useful biochemical criterion of training.
β-Adrenergic receptors in the hepatic arterial bed of the anesthetized cat
Authors: Greenway C. V. , Lawson Anne E.
Published: April 2011

The hepatic arterial blood flow of cats anesthetized with pentobarbital was recorded with an electromagnetic flowmeter. Administration of isoprenaline by close arterial infusion caused a vasodilatation which was blocked after propranolol. Adrenaline caused a variable change but after propranolol it consistently produced vasoconstriction, and after phenoxybenzamine, vasodilatation. One hour after phenoxybenzamine, stimulation of the sympathetic nerves caused a marked vasodilatation which was blocked by propranolol. It is concluded that both α and β adrenergic receptors are present in the hepatic arterial bed. However, β receptor responses may be difficult to elicit if the basal tone of the vascular bed is already reduced by prior procedures.
The responses of rat and guinea pig vas deferens to cocaine
Authors: Vohra M. M.
Published: April 2011

Cocaine caused contractions and potentiation of motor responses to transmural stimulation of vas deferens of the rat but not of the guinea pig. Tachyphylaxis was not observed after repeated doses of cocaine to vasa deferentia from both normal and reserpine-treated rats. Pretreatment with reserpine reduced significantly (p < 0.05) the responses to cocaine but abolished completely the responses to tyramine. No catecholamines could be detected spectrophotofluorometrically in reserpine-treated preparations. Contractions following the application of cocaine to vasa deferentia from both normal and reserpine-treated rats were completely abolished by phenoxybenzamine, phentolamine, and tolazoline. Cocaine failed to protect alpha-adrenergic receptors against phenoxybenzamine blockade in reserpine-treated preparations; however, cocaine could still evoke contractions of reserpine-treated preparations protected with noradrenaline against phenoxybenzamine blockade. The evidence presented indicates that cocaine acts as a mixed sympathomimetic on the rat vas deferens preparation. The possibility that cocaine is an indirect-acting sympathomimetic amine could not be ruled out in the present study.
Quantitative electron microscopic analysis of the specific granule population of rat atrium
Authors: Chang William W. L. , Bencosme Sergio A.
Published: April 2011

The "specific granule" population of right atria of female hooded rats increased with age.
Chronic vascular cannulation in the dog
Authors: Depocas Florent , Minaire Yves
Published: April 2011

A technique for chronic implantation of cannulas into the venous and arterial circulation of the dog is described.
Interaction between the effects of pentobarbital and procaine in mice: the importance of timing in drug addition studies
Authors: Frank George B. , Jhamandas Khem H.
Published: April 2011

In agreement with a previously suggested common mechanism of action, it was found that intraperitoneal injections of convulsant doses of procaine 10 min after administration of pentobarbital produced a loss of the righting reflex in many mice not affected by the pentobarbital alone. The demonstration of this drug addition is crucially dependent upon the timing of the drug administrations.
Cold climate and cold temperature induced changes in the heat production and thermal insulation of sheep
Authors: Webster A. J. F. , Hicks A. M. , Hays F. L.
Published: April 2011

Heat production and thermal insulation were measured in three groups of sheep, control, outdoor, and indoor, which were exposed to the effects of season, cold climate, and cold temperature respectively. The experiment was for 24 weeks, from November 1967 to April 1968. Sheep in the control, outdoor, and indoor groups gained 16.2, 10.0, and 14.9 kg respectively. Average feed intake in both control and outdoor groups was 2.65 kg hay/100 kg sheep per day. Food intake was highest in the indoor group and was inversely related to ambient air temperature. Resting heat production was constant throughout in the control group but increased with time in the outdoor group. Resting heat production in indoor sheep was related to intensity of prior cold exposure. Wool growth and thermal insulation did not differ significantly between groups. Critical temperature for the outside group fell from −15 °C in week 4 to −35 °C in week 20. After these trials, all sheep were shorn. The heat production of the shorn indoor group at −30 °C was greater, and that of the outdoor group was less than that of the controls. The results suggest that, in sheep, acclimation to cold temperatures induces rapid, brief increases in resting heat production and summit metabolism. Acclimatization to cold climates slowly induces a persistent elevation in resting heat production, but appears to reduce the initial metabolic response to an intense cold stimulus.
Effects of verapamil on cardiovascular responses to lateral hypothalamic stimulation in normal and coronary-ligated dogs
Authors: Garvey H. L. , Melville K. I.
Published: April 2011

The influence of verapamil infusion on the cardiovascular responses to lateral hypothalamic stimulation was studied in mongrel dogs anesthetized with chloralose. In both normal dogs and dogs with previous (20–30 h) coronary occlusion, it was observed that hypothalamic stimulation (1 mA, 2 ms, 100 c.p.s., for 10 s) induced an initial increase in coronary flow followed by a subsequent decrease. These changes were associated with increases in blood pressure, heart rate, and contractile force and pronounced arrhythmias (multifocal ectopic beats). Infusion of verapamil (18 μg/kg per min for 15 or 30 min) produced a transient increase in coronary flow and heart rate with a slight depression of contractile force, and antagonism of all arrhythmias in dogs with coronary ligation. After verapamil infusion, hypothalamic stimulation produced only increases in coronary flow, blood pressure, heart rate, and contractile force, with no associated arrhythmias. It is suggested that verapamil can antagonize experimentally produced arrhythmias by a combination of coronary vasodilator and cardiac alpha adrenergic blocking actions, rather than by a nonspecific 'quinidine-like' effect.
Propriétés physiologiques de systèmes tétracycliques présentant le squelette des stéroïdes avec deux atonies d'azote en position 15 et 16
Authors: Bonnardeaux Jef , Lematre Jean
Published: April 2011

We have studied the physiological properties of a new family of 15,16-diazagonaheptene derivatives in rats, rabbits, cats, and dogs. It was found that only those compounds which had a free carbonyl radical in a position directly opposite to their ethylic ester were physiologically active, whereas those in which there was no substitution or those in which the acetyl or methyl radical had been substituted, did not show any evident action on the above-mentioned experimental animals. The main observed action was water retention concomitant with hypertension. At sublethal doses, cardiovascular reactions of bigeminal type were observed in the cat and rabbit. In the cat, a decrease in the resting synchronized activity was observed. In the rabbit we observed an antagonism to pentobarbital. As a result of physico-chemical studies aimed at clarifying the metabolic processes, it was found that the active compounds caused an increase in the potassium level in blood which was followed by an increase in the potassium level in urine and by acidosis. On the other hand, it can be stated that the compound injected in the blood is eliminated by means of electrostatic coupling with blood urea.
Sodium binding in the arterial wall
Authors: Palatý Vladimír , Gustafson Brigid , Friedman Sydney M.
Published: April 2011

There are two fractions of sodium in the arterial wall which can be selectively and reversibly exchanged for other ions. These fractions are believed to be bound to the acid mucopolysaccharide – protein component of the paracellular matrix. The first fraction seems to be loosely bound by weakly acidic groups, probably the carboxyl groups of the hexuronic acid moieties. It can be exchanged for hydrogen even in neutral solutions by reducing the concentration of sodium ions in the medium. In the rat tail artery, the average size of this fraction did not exceed 0.5 meq/100 g of dry fat-free tissue. The second fraction behaves as if it is more tightly bound, apparently by strongly acidic groups like the sulfo groups of the mucopolysaccharides. It amounts to 2.21 ± 0.20 meq/100 g of dry fat-free tissue if a simplified system of sodium and calcium chloride solutions is used. In the presence of normal plasma concentrations of potassium and magnesium, the sum of both sodium fractions is increased substantially and is equal to approximately 5 meq/100 g of dry fat-free tissue. This bound sodium is increased in arteries of immature animals and animals with established DOCA hypertension, both of which have a higher content of the acid mucopolysaccharides.
The medial forebrain bundle (MFB) and ascending monoaminergic pathways in the cat
Authors: Parent A. , Poirier L. J.
Published: April 2011

Unilateral lesions of the caudal hypothalamus involving the area of Tsaï result in a decreased concentration of both dopamine and serotonin (5-HT) in the ipsilateral striatum. Lesions of the rostromedial hypothalamus (medial to the fornix) and of the subthalamus do not interfere with the concentration of either amine in the corresponding striatum. Lesions of the rostrolateral hypothalamus involving the area of the medial forebrain bundle (MFB) are associated with an almost complete depletion of dopamine without any change of the 5-HT concentration in the corresponding striatum. Caudal and laterorostral hypothalamic lesions are associated with a cell loss in the ipsilateral substantia nigra, nucleus parabrachialis pigmentosus, and nucleus linearis. These results confirm previous findings suggesting that the dopamine and 5-HT ascending pathways course in the ventromedial tegmental area of the brainstem from the level of the upper pons to that of the caudal hypothalamus. Moreover they indicate that at the level of the lateral hypothalamus, the MFB contains the dopamine but not the 5-HT fibers ending in the striatum. 5-HT fibers derived from the nucleus linearis and ending in basomedial telencephalic structures apparently travel within the MFB.
Blood flow in different areas of the gastrointestinal tract in the anesthetized dog
Authors: Goodhead Bernard
Published: April 2011

Radioactive rubidium (86Rb) acts as the almost ideal tracer and gives accurate measurements of regional blood flow. In dogs weighing between 10 and 20 kg and anesthetized with sodium pentobarbital, blood was distributed to the various gastrointestinal organs as follows: esophagus 29.5 ml/min 100 g; stomach 52.3 ml/min 100 g; gall bladder 35.8 ml/min 100 g; duodenum 111.1 ml/min 100 g; pancreas 65.2 ml/min 100 g; jejunum and ileum 99.5 ml/min 100 g; and colon 123.6 ml/min 100 g.
The physical working capacity of blind and deaf school children
Authors: Cartmel J. L. , Banister E. W.
Published: April 2011

The physical working capacity of a group of 36 blind or partially sighted and 44 deaf boys and girls in the age range 10–19 years was measured by the Sjöstrand PWC170 test. A comparison of the regression of PWC170 on both weight and age between the groups of blind and deaf children showed the inferior physical fitness of blind groups within a population where extraneous influences on the performance of both groups may be considered relatively stable. In addition, comparison of the working capacity of both groups with measurements made on groups of normal Canadian children, previously reported, revealed a surprisingly high level of performance by the deaf groups. Reasons for this competitive position are advanced.
Some response characteristics of cells of the magnocellular division of the medial geniculate body of the cat
Authors: Love James A. , Scott John W.
Published: April 2011

Extracellular recordings were made from single units in the magnocellular division of the medial geniculate body of the cat. The stimuli most frequently used were auditory clicks repeated at varying rates and intensities. Somatosensory stimuli were also used to reveal the presence of polysensory units. The response characteristics for most of the cells of the magnocellular division differed from those of the principal division under similar experimental conditions. A difference was noted between the responses obtained from animals which were anesthetized with chloralose and those anesthetized with sodium pentobarbital. It is suggested that the magnocellular division of the medial geniculate body may be divided into two regions, an anterior region which is primarily somatosensory in function and a posterior region which is primarily auditory in function.
Pharmacology of EEDQ (N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline)
Authors: Martel R. R. , Berman R. , Belleau B.
Published: April 2011

EEDQ, a member of a new class of nonequilibrium alpha adrenergic blocking agents with marked central depressant activity, produced complete alpha blockade at approximately the same dose range as phenoxybenzamine (rat, cat). The effect produced on the central nervous system was similar to that of chlorpromazine (neuroleptic activity), and in the rat EEDQ was several times more potent than chlorpromazine. This compound (EEDQ) is of pharmacological interest since, in contrast to haloalkylamines, it possesses strong central depressant activity, and because the biochemical mechanism by which the compound induces irreversible changes at the alpha receptor is clearly different from that of the haloalkylamines.
The cholinesterase-inhibitory characteristics of Parpanit and its analogues in relation to their protective effectiveness in the treatment of sarin-poisoned rodents
Authors: Bannard R. A. B. , Helie J. G. , Price Joan E. , Coleman I. W.
Published: April 2011

Fifteen basic esters of 1-phenylcycloalkanecarboxylic acids were examined as reversible inhibitors of bovine erythrocyte acetylcholinesterase. All the compounds showed weak competitive or mixed inhibition of the enzyme. No correlation was found between the inhibitory potencies of the compounds and the protection which they afforded to sarin-poisoned rodents when administered together with 1-methyl-pyridinium-2-aldoxime methanesulfonate.
Removal of endogenous and exogenous toxins by a microencapsulated absorbent
Authors: Chang T. M. S.
Published: April 2011

Three types of microencapsulated activated charcoal were tested. Unlike activated charcoal in the free form, the microencapsulated form did not give off embolizing particles. Heparin-complexed or albumin-coated collodion microencapsulated activated charcoal did not lower the arterial platelet level. Albumin-coated collodion microencapsulated activated charcoal was more efficient than the heparin-complexed form in lowering the blood creatinine level.
Size and proteolytic enzyme activity of the pancreas of several species of vertebrate animals
Authors: Schingoethe D. J. , Gorrill A. D. L. , Thomas J. W. , Yang M. G.
Published: April 2011

Pancreas size and trypsin and chymotrypsin activities were determined for cattle, sheep, rats, mice, and chickens of various ages. Pancreas size per kilogram of live body weight was greater for the nonruminants than for the ruminants. Pancreas trypsin activity per milligram of pancreas dry matter was greater for ruminants than for nonruminants; however, activity per kilogram of body weight was greater for rats and mice than for chickens, which in turn was greater than for ruminants. Chymotrypsin activity was greater for rats and mice than for ruminants on the basis of both pancreas dry matter and body weight. In cattle, chymotrypsin activity per unit of pancreas dry matter was highest in the newborn calf, dropped to one-half that level within 1 week after birth, and then increased only slightly with age up to 1 year. The ratios of chymotrypsin to trypsin activities in the pancreas ranged from 0.39 to 1.20 in the ruminants, except for the newborn calf (1.60), and were greater than 2.0 for the other species. Pancreas size and trypsin and chymotrypsin activity were proportional to body weight1.0 with intraspecies comparisons, and proportional to body weight0.73–0.84 with interspecies comparisons.
Reversible effect of L-DOPA on tremor and catatonia induced by α-methyl-p-tyrosine
Authors: Bédard P. , Larochelle L. , Poirier L. J. , Sourkes T. L.
Published: April 2011

DL-α-Methyl-p-tyrosine (500 mg i.p.) induces in monkeys with unilateral lesions of the rubro–olivo–cerebello–rubral loop postural tremor in the corresponding limbs. This effect appears after a delay of 3–4 h and may last up to 12 h. The injection of the same substance (1000 to 1500 mg i.p.) into normal or lesioned monkeys induces catatonia within 24 h. Tremor and catatonia are repetitively reversible within 15 min by L-dopa (30 mg/kg, i.m.); the effects reappear, however, after 45 to 60 min.
Thermal comfort in relation to mean skin temperature
Authors: Topliff E. D. L. , Livingstone S. D.
Published: April 2011

Nude men were exposed to a range of ambient temperatures and were brought to a condition of thermal comfort by adjustment of the incident radiation. The mean skin temperature associated with comfort was found to be different for each combination of ambient temperature and incident radiation. It was evident that mean skin temperature, per se, was not a dependable criterion of thermal comfort.
Sodium compartmentalization in single muscle fibers of the giant barnacle
Authors: Allen R. D. , Hinke J. A. M.
Published: April 2011

The influx and efflux of 22Na+ was measured in single muscle fibers of the giant barnacle, Balanus nubilus. These experiments show that intracellular Na+ is divided into two compartments. A rapidly exchanging compartment, identified as myoplasmic free Na+, was evident in both influx and efflux experiments. A very slowly exchanging compartment was evident only in the influx experiments. The size of the rapidly exchanging compartment, expressed as the percentage of total intracellular Na, was estimated from the 22Na+ influx experiments and from intracellular Na+ activity measurements made with Na+-specific glass microelectrodes. Influx measurements showed 58.5% free Na+, and Na+ microelectrode measurements showed 51.6% free Na+. Both the 22Na+ flux analysis and Na+ activity measurements indicate at least two compartments for intracellular Na+.
Note on the pituitary and an anorexigenic material isolated from urine
Authors: Uehara P. S. , Beaton J. R.
Published: April 2011

The anorexigenic action and the excretion of FMSIA isolated from rat urine were investigated with intact and hypophysectomized male rats of the Wistar strain. The anorexigenic material was excreted by hypophysectomized rats in both the fasted and fed states, demonstrating that the pituitary is not required for the production of FMSIA. Further, FMSIA exhibited anorexigenic activity when administered to hypophysectomized rats. Anorexigenic activity was demonstrated in bovine posterior pituitary powder and by vasopressin in an amount equal to that contained in the powder. There was no evidence of an antidiuretic effect of FMSIA in intact and in hypophysectomized rats; it caused a reduction of both water intake and urine volume accompanying the decrease of food intake.
Induction of drug-metabolizing enzymes of rat liver by derivatives of coumarin
Authors: Feuer George
Published: April 2011

The ability of coumarin and 35 structurally related compounds to induce coumarin 3-hydroxylase was examined in the liver of the rat. After seven daily oral doses of 1 mmole/kg of the test compound, the hydroxylase activity with coumarin or 4-methylcoumarin as substrate was increased 13- to 14-fold by 8-(2″-butenyloxy-3″-methyl)-furo-(2′:3′–6:7) coumarin; 4- to 8-fold by 4-methylcoumarin; 6-fold by 6-acetyl-4,8-dimethyl-7-hydroxycoumarin; 2- to 5-fold by 7,8-dihydroxy-4-methylcoumarin; 2- to 3-fold by 6,7-dihydroxy-4-methylcoumarin, 7-hydroxy-4-methylcoumarin, 4,8-dimethyl-7-hydroxycoumarin, 3-isopropyl-7-methoxy-4-methyl coumarin, 3-chloro-7-methoxy-4-methylcoumarin, and 3-carboxycoumarin. Nearly all enzyme inducers contained the 4-methyl substituent. 4-Methylcoumarin and 6,7-dihydroxy-4-methyl coumarin elicited a greater induction on the hydroxylation of 4-methylcoumarin than on that of coumarin. The other coumarin derivatives brought about no consistently greater effect on either hydroxylase. No correlation was found between the induction effect and the lipid solubility of the inducer. 4-Methylcoumarin exerted a greater induction effect on coumarin 3-hy droxylase than on nitroanisole or codeine demethylase and hexobarbitone or butylated hydroxy toluene oxidases. Other known enzyme inducers (hexobarbitone, 17-methyltestosterone, and 20-methylcholanthrene) also increased hydroxylase activity in a manner comparable to that of 4-methylcoumarin.
Numerical versus analytical integration of hormonal disappearance data
Authors: Normand Maurice , Fortier Claude
Published: April 2011

After a single rapid injection of a hormone, evaluation of the metabolic clearance rate (MCR) and of its error is greatly facilitated when a numerical technique, such as the trapezoidal rule, is substituted for regression as a means of determining the area under the disappearance curve, which is the only parameter needed to characterize overall metabolism. Integration is achieved by summing trapezes defined through successive data points and the corresponding time intervals. The error in the resulting area, which is derived from the propagation of the independent errors of the trapezes, is proportionately related to the MCR. This method, which is applicable to any dynamic pattern of disappearance, provides the only available means of computing a realistic error for the MCR of a hormone which is distributed into several compartments. The statistical advantages of the numerical approach over regression analysis are illustrated in connection with experimental data pertaining to the disappearance from plasma, in the adult male rat, of thyrotropic hormone and of corticosterone which are respectively distributed into one and three compartments.
Cardioregulatory properties of the abdominal ganglia in Limulus
Authors: Burg R. Von , Corning W. C.
Published: April 2011

The abdominal ganglia of the Limulus central nervous system exert a net inhibitory effect on heart rate. This influence is mediated mainly by the dorsal nerves in the first three ganglia. When the dorsal nerves are sectioned, cardioacceleration results; when these nerves are stimulated, a reduction in rate is obtained. However, cardioaccelerators can be unmasked by splitting a ganglion. This selectively removes the inhibitory output, leaving only a cardioaccelerator influence. Inhibition of bioelectrical activity in the intact abdominal ganglia with GABA also resulted in an increased heart rate, confirming their net inhibitory influence on heart function. Possible models of abdominal ganglia organization are discussed.
A kinetic model of membrane repair
Authors: Prothero John W. , Bulger Jr. Randolph , Chambers James , Mack Newell
Published: April 2011

Two microelectrodes are inserted into a Xenopus laevis egg. Rectangular current pulses are injected through one microelectrode and the voltage induced across the cell membrane is measured via the second electrode. The transmembrane resistance, as deduced from the injected current and the measured voltage, is taken as a measure of membrane integrity. The cell membrane is punctured with a glass fiber. The fall and subsequent recovery of transmembrane resistance are recorded. It is confirmed that cell membranes do exhibit repair and that repair is enhanced by the presence of calcium ion. A kinetic model of membrane repair is proposed.
The organization of hemoglobin in erythrocytes containing hemoglobin A or hemoglobin C
Authors: Rand R. P. , Charache S.
Published: April 2011

Red cells containing hemoglobin C have been shown to behave as if they are more rigid than normal cells that contain hemoglobin A. Under some conditions the former cells contain inclusions that appear to be crystalline. This study shows, by X-ray scattering and diffraction, that the inclusions are crystalline. Inclusions are not seen when cells are studied in isotonic plasma; under these conditions no difference in intermolecular order could be detected between the two types of erythrocyte. X-ray scattering bands centered on 32 Å, 19 Å, and 13 Å, for both CHb and AHb solutions and cells, result from intramolecular order rather than intermolecular order.
In vitro response to oxygen of human umbilical arteries and of animal ductus arteriosus
Authors: Bor Imrich , Guntheroth Warren G.
Published: April 2011

Segments of human umbilical arteries and rings from the ductus arteriosus of lambs, rabbits, and monkeys were studied in a constant-temperature bath of Tyrode's solution. Gas mixtures of high oxygen tension produced contraction in 70% of the umbilical arteries, 90% of the lamb ductus, 67% of the monkey ductus, and only 28% of the rabbit ductus. Failure to contract was not related to the interval between delivery and study. Since no appreciable plasma or granulocytes were present in the specimens, it appeared that bradykinin was not responsible for the reversible contraction with increased [Formula: see text].
Effect of chronic intake of ethanol on pyridine nucleotide levels in rat liver and kidney
Authors: Kalant H. , Khanna J. M. , Loth Juliet
Published: April 2011

Adult male Wistar rats were given ethanol in dosage forms providing either 10–12 g/kg per day for 2 weeks or 9–10 g/kg per day for 6 weeks. Pair-fed controls received equicaloric amounts of either powdered chow or sucrose in place of the alcohol. After 2 weeks, ethanol-treated rats showed a significant increase in hepatic NADH2 concentration, a corresponding reduction in NAD concentration, and a fall in the NAD:NADH2 ratio. NADP and NADPH2 were not affected. After 6 weeks, total hepatic NAD + NADH2 in ethanol-treated rats was increased, but the NADH2 concentration remained elevated and the NAD:NADH2 ratio depressed. No similar changes were noted in the kidney. When ethanol was withheld for 16 h before sacrifice, the total NAD + NADH2 remained elevated but the NAD:NADH2 ratio returned to normal. An elevated hepatic concentration of NADPH2 and a reduced NADP: NADPH2 ratio were also found after 6 weeks of ethanol treatment, but these changes were not reversed after 16 h withdrawal of ethanol. The administration of a test dose of ethanol (1 g/kg), after a 16-h withdrawal period, was followed by very similar changes in the hepatic NAD:NADH2 ratio 1 and 4 h later, in ethanol-treated and control rats. Chronic ethanol treatment does not appear to produce adaptive changes leading to a more rapid reoxidation of NADH2.
Method for estimating rates of formation and interconversion of glucose–glycerol and glucose–lactic acid in intact animals
Authors: Depocas Florent , DeFreitas A. S. W.
Published: April 2011

The kinetic relationships between pairs of simple intermediary metabolites such as glucose–glycerol and glucose – lactic acid measured with tracers in intact animals in a physiological steady state are analogous to those previously used in the study of rates of secretion and total production of pairs of metabolically related steroid hormones. The treatment allows partitioning of each of the overall rates of formation of glucose, glycerol, and lactate into two components which can be attributed to major metabolic pathways, thus permitting quantitative investigation of these metabolic pathways in various physiological states.
A method for chronic intravenous drug administration in squirrel monkeys
Authors: Stretch Roger , Gerber Gary J.
Published: April 2011

A system for the infusion of drug solutions into the blood stream of relatively unrestrained and unanesthetized squirrel monkeys, via a chronic intravenous catheter, is described. Results pertaining to the maintenance of schedule-controlled behavior by response-contingent infusions of d-amphetamine sulfate are included to illustrate a specific application of the technique.
Sodium exchange and net movement in rat uteri at 25 °C
Authors: Daniel E. E. , Robinson Kathleen
Published: April 2011

Sodium fluxes in fresh and Na-rich uterine horns were studied. The change in efflux rate was compared with that in a theoretical model and analyzed by a curve-peeling technique. In both fresh and Na-rich tissues, the time course of efflux could be described by the sum of three exponentials. There was also a nearly inexchangeable ('bound') fraction of labelled sodium and a fraction of unlabelled sodium. Analysis of efflux led to the following equations:[Formula: see text]for fresh tissue, and[Formula: see text]for Na-rich tissues, where Y = tissue 22Na in millimoles per kilogram. The unlabelled part of the 'bound' Na amounted to 4 to 6 mmoles/kg in fresh and 6 to 8 mmoles/kg in Na-rich tissues. The amounts of 22Na in cells were calculated to be 7 and 34 mmoles/kg wet weight in fresh and Na-rich tissues. One phase of influx was similar to the fastest fraction of efflux and had a diffusion coefficient which was consistent with diffusion in the extracellular space (1/10 of that in free solution). The sodium content of this compartment was somewhat greater than sodium in the 14C-sucrose spaces (430 and 480 ml/kg in fresh and Na-rich tissue respectively). The second fastest sodium fraction (observed during efflux) was much larger in Na-rich tissues, and evidence that it contained cellular sodium was presented. Sodium efflux from cells was 5.9 pmoles cm−2 s−1 for fresh tissues and 26 pmoles cm−2 s−1 for Na-rich tissues. Comparable but less accurate values for influx were 4.2 and 7.0 pmoles cm−2 s−1. Assuming all emerging sodium was pumped against the electrochemical gradient, the energy expenditure would be 0.11 kcal/kg per h in fresh tissue and 0.22 kcal/kg per h in Na-rich tissues. It was concluded that this kind of active transport provides an unsatisfactory explanation for 22Na efflux.
The effect of local cooling upon spontaneous and evoked electrical activity of cerebral cortex
Authors: Jasper Herbert H. , Shacter David G. , Montplaisir Jacques
Published: April 2011

The effect of local cooling of the surface of the cerebral cortex by means of a metal chamber implanted in the skull was studied while recording evoked and spontaneous electrical activity from the center of a cooled area of 1 cm2. Direct cortical responses to local stimulation of the cortical surface decreased rapidly and progressively to disappear at surface temperatures of 20–22 °C. Onset and peak latencies were prolonged with a Q10 of 1.4 and 1.7 respectively. Response duration was prolonged with decreasing amplitude, having a Q10 of about 2.6. Surface cooling to 8–12 °C was necessary to abolish all postsynaptic components of somatic and auditory evoked potentials, recruiting responses, and spontaneous barbiturate spindles. Latencies of these responses were also increased with a Q10 of 1.3–1.4 while the Q10 for amplitude was consistently higher (2.0–2.6). Allowing for a gradient of increasing temperature from surface to depth it is concluded that all synaptic processes are blocked at temperatures of 20–22 °C. Synaptic mechanisms determining latency were consistently different from those determining amplitude as judged by consistent differences in the Q10 of latency and amplitude for all postsynaptic responses studied in these experiments.
Pancreas size and trypsin and chymotrypsin activities in the pancreas and intestinal contents of pigs from birth to 5 weeks of age
Authors: Gorrill A. D. L. , Friend D. W.
Published: April 2011

Pancreas size, and trypsin and chymotrypsin esterase activities were determined in the pancreas and small intestinal contents (digesta) from 84 pigs killed at 3 or at 5 weeks of age. Pancreases and digesta from 3-week-old pigs had low trypsin activity (averaging 0.33 unit/mg fresh tissue; 4.0 units/g of liquid digesta). At 5 weeks of age, trypsin activity per unit of tissue or digesta was about 3.5 times greater. Chymotrypsin activity was high at 3 weeks (0.84 unit/mg pancreatic tissue; 17.2 units/g digesta), and was only 1 to 2 times greater at 5 weeks. Digesta from three pigs killed at birth averaged 13.1 units chymotrypsin activity/g of digesta, but had no trypsin activity. The trypsin and chymotrypsin activities in the pancreases from these three pigs averaged 0.43 and 0.89 unit/mg of fresh tissue respectively. The "nonparallel" change in the rate of synthesis and secretion of pancreatic enzymes between 3 and 5 weeks of age reduced the proportion of chymotrypsin to trypsin activity (2.64 to 1.31 for pancreas; 3.39 to 1.41 for digesta). Possible mechanisms involved in this phenomenon are discussed. Increases in pancreas size and body weight were nearly proportional, but the rate of enzyme activity increased as much as 4.1 times (pancreatic trypsin) that of body weight increase. The size and enzyme activity of the pancreas were similar in male and female pigs. Three-week-old males had more trypsin activity in the digesta than did females of the same age. Body weight gains to 3 or 5 weeks of age were positively correlated with total trypsin (P < 0.05) and chymotrypsin (P < 0.01) activity in the digesta.
Lipolytic and hypocalcemic effects of sheep beta-lipotropic hormone
Authors: Chrétien M. , Davignon J. , Lis M. , Chari P. V. , Aubry F. , Gilardeau C.
Published: April 2011

Sheep beta-LPH is a hypophyseal lipolytic hormone with defined chemical structure which has been shown to be hypocalcemic when injected into rabbits. The thyroid gland seems to be essential for production of this hypocalcemic effect. Beta-LPH may be a stimulating hormone for calcitonin-secreting cells. It has no effect on plasma magnesium, cholesterol, triglycerides, and glucose, at least in short-term experiments. When intact epididymal fat pads are used for the determination of the LPH lipolytic effect in vitro, a lower minimum effective dose is found than when small pieces are used.
Relationship between acetylcholine content and release in the cat's cerebral cortex
Authors: Szerb J. C. , Malik H. , Hunter E. G.
Published: April 2011

Cortical acetylcholine (ACh) release and content were measured in non-anesthetized pretrigeminally sectioned or in Dial-anesthetized cats. In 28 pretrigerninally sectioned cats a very highly significant negative correlation between ACh content and output was found. In the same preparations, 15 mg/kg pentobarbital or electrolytic lesion in the rostral midbrain decreased ACh output and increased content. Atropine (1 mg/kg i.v. or 1 μg/ml topically) increased ACh output fourfold without significantly altering content. A larger dose of atropine (25 mg/kg i.v.) increased output ninefold and decreased ACh content. In Dial-anesthetized preparations, picrotoxin-induced ACh release was accompanied by a decrease in ACh content. Pretreatment with atropine in the same preparation resulted in an enhanced effect of picrotoxin on both output and content while atropine alone (1 mg/kg i.v.) raised ACh output without decreasing content. In pretrigerminally sectioned non-anesthetized preparations, hemicholinium-3 (HC-3) did not reduce ACh output significantly but reduced content. In the presence of atropine, HC-3 rapidly reduced the high output and decreased ACh content faster than without atropine. Cortical ACh content determined following cholinesterase inhibition (surplus ACh) did not follow changes in ACh output. It is concluded that cortical cholinergic nerve endings do not maintain constant ACh content at various output rates in contrast to peripheral cholinergic nerve endings. Atropine enhances ACh output probably both by increasing ACh synthesis and by blocking an inhibitory loop. The amount of ACh released per minute varies from 1/500 to 1/13 of the amount present depending on the activity of cholinergic fibers. ACh collected from the surface of the brain does not originate directly from surplus ACh.
Natriuretic and diuretic effects of salmon calcitonin in rats
Authors: Keeler R. , Walker Valerie , Copp D. H.
Published: April 2011

Injection of salmon calcitonin into rats caused a significant increase in the excretion of sodium and water in a dose as small as 4 × 10−9 g. There appeared to be a linear relationship between sodium excretion and the log dose of calcitonin. Potassium excretion and free-water clearance were not significantly affected. Thyroparathyroidectomized rats showed no impairment in their ability to excrete sodium either before or after saline loading.
Calcium Homeostasis and Erythropoietic Control in the Rat
Authors: Perris A. D. , Whitfield J. F.
Published: April 2011

When plasma calcium concentrations in the rat were elevated by injection of either calcium chloride or parathyroid hormone, there was an increase in mitotic activity in the bone marrow which led to an increase in reticulocyte production and radioactive iron incorporation in the peripheral blood. Thyroparathyroidectomy produced parallel decreases in plasma calcium, bone marrow mitosis, and erythropoiesis, a situation which could be reversed by the administration of parathyroid hormone or by calcium chloride injections. Since the calcium- or parathyroid hormone-induced stimulation of bone marrow mitosis also occurred in both nephrectomized and polycythemic rats, this mitogenic action was not due to a secondary release of renal erythropoietic factor or an activation of circulating plasma erythropoietin. In contrast to calcium and parathyroid hormone, (ovine) erythropoietin did not stimulate cell division in the bone marrow within 6 h of injection.
The Renin–Angiotensin System in Newborn Dogs
Authors: Granger P. , Rojo-Ortega J. M. , Pérez S. Casado , Boucher R. , Genest J.
Published: April 2011

A detailed evaluation of the rennin–angiotensin system by concurrent determinations of plasma renin activity, renal renin activity, and juxtaglomerular index in newborn dogs during the first 15 days of extrauterine life is described. Findings show that the plasma renin activity is significantly higher for the first 2 weeks of extrauterine life when compared with the values found in adult dogs, and that the renal renin activity is slightly greater despite a very low juxtaglomerular index with a few granular cells, mostly located in the juxtamedullary cortex. Stimulation (peritoneal dialysis) of renin release resulted in a marked increase in plasma renin activity. The juxtaglomerular index was not modified by the stimulation whereas the renal renin activity decreased slightly. From these results, it is suggested that the formation and secretion of renin is well developed in kidneys of newborn dogs despite the absence of demonstrable juxtaglomerular cell granules.
Time Sequence of Liver Phospholipid Alterations during Deprivation of Dietary Choline
Authors: Beare-Rogers Joyce L.
Published: April 2011

Liver phospholipids of rats fed a choline-deficient diet low in methionine were examined at 0, 1, 2, 4, 8, 16, and 24 days. The level of arachidonic acid in both the total phospholipids and in phosphatidylethanolamine was significantly lower in the choline-deficient group than in the choline-supplemented group by 4 days. In phosphatidylethanolamine the levels of docosapentaenoic and docosahexaenoic acids were elevated in the deprived group within 2 days. No significant alterations in fatty acid concentrations were detected after 1 day, but low levels of phosphatidylcholine, lysophosphatidylcholine, and sphingomyelin were evident at that time. Impaired interconversions of phospholipids may be a major effect of the diet fed.
Inhibitory Effect of Salmon and other Calcitonins on Calcium Release from Mouse Bone In Vitro
Authors: Minkin Cedric , Reynolds John J. , Copp D. Harold
Published: April 2011

Salmon calcitonin in a concentration of 0.8 ng/ml inhibited for 20 h cell-mediated release of 45Ca from cultured mouse calvaria. Porcine calcitonin in a concentration of 2500 ng/ml was much less effective. The response (percent inhibition) to salmon calcitonin was proportional to the logarithm of the dose over the range 0.012–0.20 ng/ml, and may provide a very sensitive in vitro bioassay for salmon calcitonin.