bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Inorganic Ions on the Uptake and Retention of Tritiated Noradrenaline by Isolated Perfused Rat Hearts
Authors: Nash C. W. , Tu T. , Martin M. J.
Published: October 2017

The influence of a variety of modified Krebs media on the cumulative uptake of 3H-noradrenaline (3HNA) by perfused rat hearts was tested, and followed immediately by a determination of the effects of those altered media on the efflux of the tritiated compounds retained in the hearts. The efflux data were analyzed with the aid of a computer-assisted program for curve stripping and compartmental analysis, to indicate the distribution of 3HNA in the hearts. By this program the tritiated material in the heart was divided into four fractions: the nonspecific bound, the neuronal bound, the extraneuronal bound, and the free and loosely bound fractions. The results obtained from these experiments are summarized below. (1) Cocaine and desmethylimipramine reduced binding and passage of 3HNA into all cells, and in their presence the infused 3HNA was largely confined to the extra cellular space without uptake into tissue cells. (2) Reserpine prevented neuronal binding but the extraneuronal, the nonspecific, and the free and loosely bound fractions were also reduced, suggesting that reserpine may have some cocaine-like action. (3) Low calcium conditions increased uptake into the extraneuronal and the free and loosely bound fractions but reduced nonspecific binding. (4) EDTA reduced neuronal and extraneuronal binding but increased nonspecific binding and the amount in the free and loosely bound fraction. The effects of EDTA were similar to those of reserpine but had no cocaine-like action. (5) A high sodium concentration in the perfusion fluid increased binding in all fractions but under sodium-free conditions the neuronal and extraneuronal bound fractions were decreased while the nonspecific bound and the free and loosely bound fractions were increased. Neuronal binding required sodium but was not proportional to the concentration of sodium in the extracellular fluid. (6) Anions in the perfusion fluid influenced the uptake and distribution of 3HNA. Na2SO4 substituted for NaCl increased neuronal binding. NO3 and sodium cyanide substitution decreased neuronal binding but increased extraneuronal binding and the free and loosely bound fraction. The observations are consistent with the hypothesis that free Ca ions may inhibit transport and binding systems for noradrenaline in both nerve and extraneuronal tissues, probably largely muscle, and that alterations in the ionic environment which influence the availability of free Ca ions may influence the distribution of noradrenaline in perfused rat hearts.
Preparation of Degradation Products of Fibrinogen Free of Plasmin, and Their Effect on Thrombin Activity
Authors: Chandra S. , Triantaphyllgpoulos D. C.
Published: October 2017

Sepharose 4B, a beaded agarose gel, was first activated with cyanogen bromide and then covalently coupled with pancreatic or soybean trypsin inhibitor. The degradation products of plasmin-lysed fibrinogen (DPF) were filtered through the coupled gel and the contaminating plasmin was removed by binding with the coupled inhibitor.The plasmin-free DPF thus obtained were used to study their effect on the clotting activity of thrombin. Chromatographed human thrombin was incubated in siliconized and nonsiliconized glass tubes with: (a) plasmin-free DPF, (b) albumin, (c) ceruloplasmin, and (d) saline. The activity of thrombin declined rapidly in the saline control, less so in the presence of albumin and ceruloplasmin (especially in siliconized glass tubes), and remained unchanged in the presence of DPF both in siliconized and nonsiliconized tubes. In order to study the effect of plasmin-free DPF on the inactivation of thrombin by antithrombin III, thrombin was first mixed with saline or DPF and then added to heat-defibrinated plasma (supplier of antithrombin III). The residual thrombin activity was subsequently determined at frequent intervals and was found to decline at the same rate both in the presence and in the absence of DPF. These findings demonstrate that DPF protect thrombin from spontaneous inactivation but fail to protect it against inactivation by antithrombin III.
The Effect of Papillectomy on Renal Function in the Rat during Hydropenia and after an Acute Saline Load
Authors: Wilson D. R.
Published: October 2017

The effect of unilateral papillectomy on renal function in the rat was compared with the effect of partial nephrectomy which produced a similar decrease in glomerular filtration rate (G.F.R.) in the presence of an intact papilla. Under hydropenic conditions the kidney with papillectomy had a higher urine flow rate, sodium excretion rate, fractional sodium excretion, and osmolar clearance, while urine osmolality was lower. After an acute saline load the differences in sodium and water excretion disappeared, and fractional excretion of sodium and water were significantly higher in both types of kidney damage than in the contralateral control kidney. Free water reabsorption was lower in the papillectomized kidney after saline loading. Thus removal of the papilla resulted in abnormalities in the renal handling of salt and water which varied with the state of hydration of the animal and which were distinct from the effects of a reduction in G.F.R. by partial nephrectomy. It was concluded that the site of nephron loss, whether mainly in the renal medulla or in the cortex, may be another factor, in addition to G.F.R. and tubular reabsorption, which influences sodium and water excretion by the moderately damaged kidney.
The Sympathoadrenergic System in the Cardiovascular Responses to Hypoxia in the Dog
Authors: Chiong Miguel A. , Hatcher J. Donald
Published: October 2017

The role of the sympathoadrenergic system in the cardiovascular responses during the steady state of acute severe hypoxia (6% O2 in N2 for 15 min) was studied in 49 anesthetized dogs divided into five groups: sham-operated, sympathectomized (stellate to T5), intact untreated, and pronethalol-treated (2.5 and 5.0 mg/kg i.v.). In a separate group of animals, the steady state as to O2 consumption, arterial and venous O2 saturation, blood respiratory quotient, and ventilation was investigated and found to be present between 10–15 min after the onset of acute hypoxia. Under these experimental conditions cardiac output rose significantly in the sham-operated, sympathectomized, and intact groups. This increase occurred on the basis of tachycardia in the intact untreated group and a combination of increased heart rate and stroke volume in the operated groups. In contrast, beta adrenergic blockade with pronethalol prevented the rise in cardiac output through a combination of reduced tachycardia and a fall in stroke volume at the end of the 15 min of hypoxia. It is concluded that during the steady state of acute hypoxia, stimulation of cardiac beta adrenergic receptors by a humoral mechanism plays an important role in the cardiovascular responses observed in anesthetized dogs, and that the cardiac sympathetic nerves are not essential for these responses to occur.
Effects of Cytochalasin B on Osmotic Fragility and Deformability of Human Erythrocytes
Authors: Beck James S. , Jay Alfred W. L. , Saari Jack T.
Published: October 2017

The presence of cytochalasin B is associated with an increase in the osmotic fragility of human erythrocytes as determined by measuring the extent of hemolysis in solutions of various osmolarities. Erythrocytes exposed to cytochalasin and subsequently washed displayed the same osmotic fragility as controls. Cytochalasin similarly increased deformability as indicated by measurement of pressure differences required to draw single cells into a micropipette of 2.0–2.5 μm diameter. The required pressure, reduced in the presence of cytochalasin, was the same as for controls after the cells treated with cytochalasin were washed.The reversible increases in osmotic fragility and deformability are interpreted as indicative of a reduction in tensile strength of the plasma membrane, perhaps associated with a loss of microfilaments.
Development, Cellular Growth, and Function of the Avian Oviduct. II. A Comparative Study on the Changes of Cellular Components in each Region of the Domestic Fow1 (Gallus domesticus) Oviduct during a Reproductive Cycle
Authors: Yu John Y.-L. , Marquardt R. R. , Hodgson G. C.
Published: October 2017

The levels of cellular components in each region of the domestic fowl (Gallus domesticus) oviduct at various stages of a reproductive cycle (developing, laying, and regressing) were compared. There were differential growth patterns in each region of the oviduct (infundibulum, magnum, isthmus, uterus, and vagina) during a reproductive cycle. The magnum weight, relative to other regions of the oviduct, increased most rapidly during development and growth, and decreased in a similar manner during regression of the oviduct. Development and growth of the oviduct were primarily associated with hyperplasia (increase in total DNA), and to a lesser extent with cellular hypertrophy (dry matter/DNA). Regression of the oviduct was essentially a reversal of the developing oviduct: both total DNA and ratios of dry matter/DNA decreased.The highest ratios of RNA/DNA and protein/DNA were found in the laying-hen oviduct, particularly in the magnum and isthmus. The magnum and isthmus of the laying hen, being actively involved with the formation of secretory soluble and insoluble proteins, respectively, also had the highest respective ratios of soluble protein/DNA and insoluble protein/DNA. The infundibulum, uterus, and vagina, consisting mainly of connective tissue and musculature, are not actively involved in the formation of secretory proteins. These regions of the laying-hen oviduct had low ratios of RNA/DNA and protein/DNA. All regions of the functionally quiescent developing and regressing oviducts had similar and low ratios of RNA/DNA and protein/DNA.The levels of soluble nonprotein nitrogen, when expressed on a cell unit basis, also tended to parallel those of protein while lipid levels remained relatively constant for all regions of the oviduct throughout the various stages of the reproductive cycle.
Catecholamines in Turkeys with High or Low Blood Pressure: Effects of Tyrosine Hydroxylase Inhibitor and Ganglionic Blocker
Authors: El-Halawani M. E. , Waibel P. E. , Appel R. , Good A. L. , Duke G. E.
Published: October 2017

Following six generations of genetic selection for hyper- or hypotensive turkeys, tissues were assayed for catecholamines. The concentrations of norepinephrine and epinephrine were essentially the same in both groups except for the posterior aorta and the left ventricle. The latter tissues showed higher concentration of norepinephrine in the hypertensive birds.The administration of α-methyl-L-tyrosine or mecamylamine reduced norepinephrine to a greater extent in hyper- than in hypotensive turkeys. The results suggest that hypertension may be caused by increased rate of norepinephrine release.
Angiotensin II: Local Renal Effects of Physiological Increments in Concentration
Authors: Waugh William H.
Published: October 2017

Infusion of low dosage of angiotensin II into the main artery of acutely denervated kidneys of volume-expanded dogs resulted in ipsilateral renal vasoconstriction, antinatriuresis, and antikaliuresis. The infused angiotensin raised the concentration of angiotensin II in the blood flowing into the kidneys by a physiological amount, which averaged 8.5 ± 1.5 ng/100 ml (mean ± S.D.). The findings suggest that angiotensin II, by direct intrarenal effects, may act in the regulation of salt homeostasis, through renal conservation of electrolyte.
Serum and Tissue Enzymes and Adrenocortical Responses in Rats Exercised at Intervals after Cold Acclimation
Authors: Dieter M. P. , Altland P. D. , Parker M. G.
Published: October 2017

Tolerance of rats to exercise at room temperature was studied at various intervals after cold acclimation. Survival was reduced when rats were exercised immediately after removal from the cold, but improved as time out of the cold was extended, attaining 100% survival after 24 h. The levels of serum enzymes, white muscle enzymes, and plasma corticosterone were greater in cold-acclimated rats exercised at 0 h or 6 h after removal from the cold than in unacclimated exercised rats. By 12–24 h after removal from the cold differences between the two groups of rats were less marked or absent. It is apparent that the greater response of cold-acclimated rats to exercise is lessened within 12 h and that a normal response is present within 24 h.
Inhibition of Hepatic Microsomal Drug Metabolism by the Hydrazines Ro 4-4602, MK 486, and Procarbazine Hydrochloride
Authors: Bade Norman R. , MacLeod Stuart M. , Renton Kenneth W.
Published: October 2017

Preliminary experiments were undertaken to examine the effect of three hydrazine derivatives, viz. Ro 4-4602, MK 486, and procarbazine hydrochloride, on hepatic microsomal drug metabolism in rats. All three compounds when given as pretreatment significantly prolonged pentobarbital sleeping time. In vitro, the hepatic microsomal N-demethylation of aminopyrine was inhibited. It is concluded that all three drugs are possible sources of clinically significant drug interaction when administered in combination with other agents which undergo hepatic biotransformation.
The Effects of Excitatory Drugs on Potassium Fluxes in Uterine Smooth Muscle
Authors: Hodgson Barrie J. , Daniel Edwin E.
Published: October 2017

Exchange of 42K and 86Rb has been studied in pregnant rat uterine muscle. Efflux of these ions could be represented as the sum of three exponential processes, but discrimination between potassium and rubidium was observed. Acetylcholine, but not oxytocin, increased the passive permeability of the cell membrane to potassium or rubidium, as indicated by drug-induced movements of 42K or 86Rb in normal tissues and in tissues depolarized by potassium chloride medium. The implications of this difference for the excitation mechanisms of these drugs and for the possibility that spike repolarization was caused by increased potassium permeability were discussed.
Uptake of Lanthanum by Smooth Muscle
Authors: Hodgson B. J. , Kidwai A. M. , Daniel E. E.
Published: October 2017

140La3+ was taken up and tightly bound by rat myometrium. Its calculated volume of distribution was much greater than tissue water, and it was associated after cell fractionation with cellular particulates. The highest amounts were found in mitochondria. These results invalidate assumptions that La3+ is confined to the extracellular space and limited in its action to the cell surface.
Maintenance of glomerulotubular balance for bicarbonate during carbonic anhydrase inhibition in the dog
Authors: Gougoux André , Duran Maria-Angelica , Lemieux Guy , Vinay Patrick
Published: October 2017

Studies were performed to examine the possible effects of carbonic anhydrase (CA) inhibition on the glomerulotubular balance for bicarbonate in anesthetized dogs. Maximal CA inhibition was achieved by acetazolamide infusion and glomerular filtration rate (GFR) was reduced in a stepwise fashion by progressive clamping of the left renal artery. A close relationship (R = 0.973) was maintained between the amount of filtered and reabsorbed bicarbonate in normal dogs with CA inhibition. A similar relationship was observed between GFR and bicarbonate reabsorption during CA inhibition in normal dogs (R = 0.957) as well as in sodium bicarbonate loaded dogs (R = 0.867). In these two groups, GFR in the clamped kidney was reduced to values ranging respectively from 99 to 5% and from 96 to 3%. Distal tubular blockade with ethacrynic acid and chlorothiazide, performed in normal dogs and in sodium bicarbonate loaded dogs, did not abolish glomerulotubular balance for bicarbonate during CA inhibition. This study demonstrates that the glomerulotubular balance for bicarbonate is maintained during CA inhibition whether or not distal tubular blockade is superimposed. A proportionate decrease in both fractions of bicarbonate reabsorption, either CA dependent or not mediated by CA, or an adaptive increase in the fraction of bicarbonate reabsorption not mediated by CA can explain the maintenance of glomerulotubular balance for bicarbonate.
Effect of mineralocorticoids on collecting duct hydrogen ion secretion in the rabbit
Authors: Robson W. L. M. , Halperin M. L. , Stinebaugh B.J. , Goldstein M. B.
Published: October 2017

The purpose of this study was to elucidate the mechanism whereby a potassium infusion led to an elevation in the urine minus blood (U – B) [Formula: see text] difference in alkaline urine of the rabbit. Rabbits given 9α-flurohydrocortisone 16 h prior to study had a significantly higher U – B [Formula: see text] than control rabbits. However, the U – B [Formula: see text] was increased further after potassium infusion. These results suggest that the increased collecting duet hydrogen ion secretion in the rabbit may in part have been induced by mineralocorticoids and in addition been influenced by increasing the potassium concentration.
The postexcitatory effects of acidic amino acids on spinal neurones
Authors: McLennan H. , Liu Jin-Rong
Published: October 2017

The excitation of some neurones in the spinal cord of rats by L-glutamate and L-aspartate is followed by a period of reduced excitability. This effect is not observed after excitation by D-glutamate nor, in the case of Renshaw cells, by acetylcholine. The depressions following L-glutamate were reduced by bicuculline and those after aspartate by strychnine, suggesting that they may have been caused through decarboxylation of the excitatory amino acids to yield the inhibitory compounds γ-aminobutyric acid and β-alanine, respectively.
Baclofen modifies via the release of monoamines the synaptic depression, frequency facilitation, and posttetanic potentiation observed at an identified cholinergic synapse of Aplysia californica
Authors: Philippe E. , Grenon G. , Tremblay J. P.
Published: October 2017

1. The mechanism of action of baclofen was studied at a cholinergic synapse of Aplysia. This synapse, called RCl – R15, can be activated by a minimal stimulation of the right pleurovisceral connective and is recorded in cell R15 of Aplysia californica. Repeated stimulation of synapse RCl – R15 produces depression, followed by frequency facilitation and by posttetanic potentiation (PTP).2. Perfusion with baclofen (3 × 10)−5 or 5 × 10−5 M) reduces the size of all excitatory postsynaptic potentials (EPSPs) of synapse RCl – R15 produced by a train of 100 stimuli at 1.5 Hz. It also reduces the synaptic depression and PTP but increases the frequency facilitation. These effects are similar to those produced by γ-aminobutyric acid (GABA), serotonin, and dopamine on this synapse.3. When the preparation is perfused with bicuculline or picrotoxin, two antagonists of GABA, the effects of baclofen are not antagonized. However, when baclofen is perfused in the presence of SQ10,631 (an antagonist of serotonin) or butaclamol (an antagonist of dopamine), its effects are partially blocked.4. To determine if baclofen produces its action by direct interaction with aminergic receptors or by liberating the amines from some nerve endings, a few animals were treated with reserpine to deplete the aminergic pool. Following this treatment no effects were obtained with baclofen suggesting that it acts by liberating dopamine and serotonin or some other amines.5. In animals treated with reserpine, GABA still produces its normal effects (reduction of EPSP size, synaptic depression, posttetanic potentiation, and increase of facilitation), indicating that baclofen does not act directly on the GABA receptor located on the presynaptic terminal.
Prostaglandin involvement in contractions evoked in rabbit detrusor by field stimulation and by adenosine 5′-triphosphate
Authors: Downie J. W. , Larsson C.
Published: October 2017

Previous reports suggest that in rabbit urinary bladder both noncholinergic nonadrenergic excitatory responses and the contraction produced by adenosine 5′-triphosphate (ATP) are antagonized by indomethacin. We have attempted by further indirect testing on isolated detrusor strips to determine what role prostaglandins (PGs) might play in these processes. The second part of the biphasic contractile response to ATP was reduced to about 30% of control by PG synthesis inhibitors but the initial phase of the ATP response and the contraction produced by the β, γ-methylene analogue of ATP were unaffected. At concentrations that did not affect the response to acetylcholine but greatly suppressed the response to arachidonic acid, indomethacin antagonized the contraction evoked by field stimulation by about 30% at 1–2 Hz (largely noncholinergic and nonadrenergic). SC 19220, a putative PG receptor blocker, also produced about 25% reduction in the response to field stimulation but with only about 50% reduction in the response to arachidonic acid, PGE2, or PGF2α. SC 19220 also antagonized the frequency – response curve in atropine-treated strips. These findings lead us to suggest that besides maintaining tone and spontaneous activity in the bladder PGs mediate the slow tonic phase of the ATP response and may contribute to facilitatory modulation of noncholinergic nonadrenergic excitatory transmission.
Short-term fluctuations in the concentration of cortisol and progesterone in fetal plasma, maternal plasma, and amniotic and allantoic fluids from sheep during late pregnancy
Authors: Challis J. R. G. , Patrick J. E. , Cross Jill , Workewych J. , Manchester E. , Power S.
Published: October 2017

Fluctuations in the concentrations of cortisol and progesterone in fetal plasma, maternal plasma, and amniotic and allantoic fluids were measured in samples taken at 10-min intervals over a 90-min period from three groups of sheep sampled at different times during late pregnancy. During the last 30 days of gestation there was a significant rise in the mean concentration of cortisol in fetal plasma and amniotic fluid and a significant correlation between the cortisol concentration in these two fluids. The concentration of cortisol in allantoic fluid exceeded that in amniotic fluid. The concentration of cortisol in fetal plasma varied in a pulsatile manner; however the coefficient of variation (CV) within animals was greater (36%) on days −11 to −20, relative to the day of parturition (day 0), than on days −21 to −30 or days −5 to 0 (15–19%). The CV values for cortisol in amniotic fluid and maternal plasma during the last 30 days of pregnancy were 20–50% and two to five times greater than the intraassay CV. The concentration of progesterone in amniotic fluid increased after day −20 but was not correlated with that in maternal plasma or fetal plasma. The concentrations of progesterone in paired samples of amniotic fluid and allantoic fluid were similar. The CV values for progesterone (18–34%) were similar in fetal and maternal plasma and amniotic fluid and did not change significantly during late pregnancy. Changes in the concentration of progesterone were unrelated to changes in cortisol. Interpretation of steroid profiles in fetal plasma and fluids through late pregnancy should take into account these short-term fluctuations in hormone concentrations.
The effect of prolonged physical training and high fat diet on heart size and body weight in rats
Authors: O'Brien Darryl W.
Published: October 2017

White male Woodlyn Wistar rats (aged 9–10 weeks) were subjected to prolonged physical training on a treadmill for 10 weeks. After 4 weeks half of the rats received a high fat test diet (45%) (Nutritional Biochemical Corporation) while the control group was fed standard lab chow (Purina lab chow). The body weights, heart weights, and heart weight per 100 g body weight were compared in a two by two factorial analysis, the independent variables being condition (exercise or sedentary) and diet (balanced or high fat). After 10 weeks the difference in body weight between the sedentary rats (body weight (BW) = 514.4 ± 76.4 g) and the exercise rats (BW = 389 ± 44 g) was significant (p < 0.05). The difference in body weight between the high fat diet rats (BW = 479 ± 80 g, n = 10) and the balanced diet group (BW = 424 ± 76 g, n = 10) was also significant (p < 0.05). No significant differences were observed in heart weights among any of the groups whereas a significant difference was noted between the sedentary group and the exercise group with respect to heart weight: body weight ratio. Thus the exercise rats had relatively larger hearts than the sedentary group (p < 0.05) but no evidence for cardiac hypertrophy in the exercise group compared with the sedentary group was observed. The difference with regard to heart ratios between the balanced diet and high fat diet groups was not significant and no interaction was present (p = 0.065). It was concluded that cardiac hypertrophy is not necessarily a consequence of prolonged physical training but is a product of the type of training, the intensity and duration, and the emotional stress involved. Prolonged physical exercise was a powerful deterrent to weight gain even in rats on a high fat diet. In the absence of the development of cardiac hypertrophy in response to prolonged training, further work is needed to quantify the factors that result in cardiac hypertrophy and to identify other changes that may be occurring in the cardiovascular system in response to prolonged physical training.
Renal acidification in the hypothyroid rat. Evaluation by urinary CO2 tension
Authors: Michael Ulrich F. , Kelley Jan , Meeks Laurence A. , Vaamonde Carlos A.
Published: October 2017

We have previously demonstrated an abnormal renal response to chronic acid loading in the hypothyroid rat. The present study was designed to characterize further this defect by examining the renal response to bicarbonate loading. Hypothyroidism was induced by the intraperitoneal injection of Na131I and animals were studied 10 or more weeks thereafter under anesthesia and compared with their age-matched littermates. Inulin clearance of hypothyroid animals was lower and fractional urine flow and sodium excretion rates were higher than in the control rats. At the time of maximal urinary bicarbonate levels, the urine [Formula: see text] exceeded blood values [Formula: see text] by 41 ± 2 (mean ± SE) mmHg (1 mmHg = 133.322 Pa) in the controls and 25 ± 3 mmHg in the hypothyroid rats (p < 0.001). Although maximal urinary bicarbonate concentrations achieved during bicarbonate loading were lower in the hypothyroid animals, [Formula: see text] was consistently less than in controls when compared at similar urine bicarbonate concentrations. Thus, the difference in [Formula: see text] was not explained by lower urinary bicarbonate concentrations in the hypothyroid animals. Maximal [Formula: see text] during neutral phosphate loading was significantly less in the hypothyroid rats (38 ± 2 mmHg) than in the controls (68 ± 5 mmHg), p < 0.001, arguing against a gradient defect of distal hydrogen ion handling. These data indicate that hypothyroid rats exhibit an impairment of distal hydrogen ion secretion.
Migration of Hymenolepis diminuta (Cestoda) and changes in 5-HT (serotonin) levels in the rat host following parenteral and oral 5-HT administration
Authors: Mettrick D. F. , Cho C. H.
Published: October 2017

Changes in the distribution of the tapeworm Hymenolepis diminuta in the rat small intestine were studied for up to 3 h following intraperitoneal, intramuscular, subcutaneous, and oral administration of 5-HT. Changes in 5-HT levels in the arterial circulation, intestinal lumen, and in worm tissue were also monitored.In all cases following 5-HT administration there was an anteriad migration by H. diminuta. The extent of the migration was dose dependent, the higher the dose the more marked the migration response.Normal 5-HT levels in the parasitized gut are higher than those in uninfected animals. The pattern of increasing levels of 5-HT in worm tissue directly followed the increases in the intestinal lumen, suggesting that worm 5-HT was of host origin. Blood 5-HT levels similarly followed luminal increases.It is suggested that the pharmacological action of 5-HT on H. diminuta resulting in worm migration is implemented through the regulation of helminth neuromuscular activity and carbohydrate metabolism, as has been demonstrated in other parasitic worms.
Segmental ventricular adjustments to brief periods of ischemia in the dog
Authors: Bosnjak Z. J. , Seacard J. L. , Zuperku E. J. , Coon R. L. , Singh H. M. , Bamrah V. S. , Kampine J. P.
Published: October 2017

The changes in left ventricular segmental contractile force induced by brief periods of ischemia (15 – 90 s) and subsequent reperfusions were analyzed in anesthetized dogs. Segmental coronary artery occlusion (left anterior descending or left circumflex) produced a decrease in segmental ventricular function in the occluded area and an increase in contractile force in the myocardial segment away from the occluded area. With reperfusion, a transient overshoot in contractile force above preischemic control levels was observed in the occluded segment. This overshoot was shown not to be dependent on adrenergic mechanisms but appears to indicate changes in calcium permeability.
Cyclic nucleotide phosphodiesterase in rat parotid gland
Authors: Yokoyama Noriko , Abe Mayumi , Furuyama Shunsuke
Published: October 2017

Cyclic nucleotide phosphodiesterase was investigated in rat parotid gland to elucidate the regulatory mechanisms of this enzyme. Cyclic nucleotide phosphodiesterase activities for both cAMP and cGMP were present in the supernatant fraction of adult rat parotid gland. The elution profile of the enzyme activities from DEAE-cellulose column chromatography showed two main peaks. One of them was eluted with 0.15 M KCl and was fairly specific for cGMP. This enzyme was activated by calmodulin with an increase in Vmax and with no effect on Km. The other one was eluted with 0.25 M KCl and showed a higher specificity for cAMP than for cGMP. This enzyme, however, was not activated by Ca2+ and calmodulin. The presence of calmodulin and an inhibitor substance was confirmed by DEAE-cellulose column chromatography. The inhibitor substance was protein in nature and did not inhibit cAMP phosphodiesterase. These results may indicate that cGMP in rat parotid gland, which is supposed to correlate with secretion, is regulated also by phosphodiesterase through calmodulin and an inhibitor substance.
Platelet phenolsulfotransferase and catecholamines: physiological and pathological variations in humans
Authors: Abenhaim L. , Romain Y. , Kuchel O.
Published: October 2017

The phenolsulfotransferase (PST) is the main sulfoconjugating enzyme of catecholamines. We have described a standardized, sensitive, and reproducible method of measurement of PST activity from human blood platelets. The affinity of PST was, in descending order, towards dopamine (DA) > norepinephrine (NE) > epinephrine (E) (Km (DA) = 17.6 μM, Km (NE) = 66.6 μM, Km (E) = 330 μM). The optimum pH was found to be 5.9.Platelet PST measurements in 26 subjects led to the following observations. (i) The individual PST activity remains relatively stable during manipulations such as direct venous puncture, upright posture, physical exercise, and consumption of a copious meal. (ii) The mean platelet PST activity was 67 ± 34 (mean ± SD) U/mg protein in men and 43 ± 19 U/mg protein in women. (iii) The platelet PST activity varies during the menstrual cycle with a marked decrease 7–10 days before menstruation. (iv) Essential hypertensive patients, appearing clinically as a syndrome imitating pheochromocytoma, had absent or low conjugated catecholamines. In one of them, no PST activity could be detected in platelets using catecholamines as substrates whereas a considerable activity was present with P-nitrophenol.The potential usefulness of the platelet PST measurements is discussed.
Opiatelike actions of eseroline, an eserine derivative
Authors: Jhamandas K. , Elliott J. , Sutak M.
Published: October 2017

Eseroline, an eserine derivative without anticholinesterase activity, was tested in several systems for opiatelike activity. Eseroline depressed the twitch of the field-stimulated guinea pig ileum myenteric plexus longitudinal muscle preparation but failed to depress the twitch of the rat vas deferens. Intraperitoneal injections of eseroline in rats induced naloxone-antagonizable analgesia and catalepsy. Eseroline failed to influence the release of acetylcholine from the cortex of anesthetized rats. These observations have implications for studies in which eserine is used as a pharmacological tool.
Endorphines: structure, rôles et biogénèse
Authors: Chrétien M. , Seidah N. G. , Scherrer H.
Published: October 2017

The knowledge of the amino acid sequence of both β-lipotropin (β-LPH) and γ-LPH was the starting point that led to the hypothesis, considered revolutionary in 1967, that hormonal precursors exist. This concept was simultaneously proposed for proinsulin and applied later to other polypeptide hormones. The discovery of endorphins brought together two fields of research that were not related: the opiates and the so-called pituitary lipotropic hormones. The demonstration of specific brain opiate receptors led to the hypothesis of the existence of endogenous opiate ligands which could act as neurotransmittors. The isolation of such substances in the brain, first named enkephalins, revealed through their amino acid sequence their structural homology with the pituitary lipolytic hormones. The finding of a more potent opioid substance in the pituitary (β-endorphin) that comprises the last 31 amino acids of β-LPH shed a new light on the hypothesis proposed earlier which gave to β-LPH a role as a precursor molecule. Finally, the addition of ACTH completed a putative multipotent precursor model that has been recently named pro-opiomelanocortin. Pulse–chase experiments have definitely proven that β-endorphin is a maturation product of a large precursor also containing ACTH and MSH. In other studies, many groups have suggested that endorphins play important roles as possible neuromodulators in pain transmission, in analgesia, in tolerance and dependance, as well as on behavior and endocrine regulations, mainly those related to the hypothalamo–pituitary axes. The elucidation of the biosynthetic process or processes of cerebral endorphins (either enkephalins or β-endorphin) is of primary importance in order to understand better their biological as well as regulatory functions. These studies should also be applicable to the biosynthesis of all the other neuronal peptide hormones. It is hoped that they will provide new tools for the study of some important central nervous system functions, such as pain and endocrine control and the physiopathology of behavioral diseases.
Explanted cardiac cells: a model to study drug actions?
Authors: Schanne O. F. , Bkaily G.
Published: October 2017

Results from drug action studies are reviewed together with techniques to produce preparations of explanted cardiac cells and parameters that can be measured in these preparations. Results from drug action studies on explanted cells are poorly integrated into our present knowledge of drug effects derived from investigations of more conventional models. Recent reports indicate that most explanted cardiac cells change their electrophysiological properties after explantation and this may be responsible for the difficulties in interpreting results obtained from this preparation. To exploit the potential of explanted cardiac cells as a model to study drug actions it is recommended that (a) the preparation be characterized with electrophysiological methods and (b) the preparation of explanted cardiac cells be selected so that it facilitates the solution of a well-defined pharmacological problem.
Gastric inhibitory polypeptide stimulated secretion of somatostatinlike immunoreactivity from the stomach: inhibition by acetylcholine or vagal stimulation
Authors: McIntosh C. H. S. , Pederson R. A. , Koop H. , Brown J. C.
Published: October 2017

The possible involvement of gastric somatostatinlike immunoreactivity (SLI) in the acid inhibitory action of gastric inhibitory polypeptide (GIP) was studied in an isolated perfused rat stomach.GIP, in a dose of 5 or 50 ng/mL, caused a 4- and 12-fold increase in SLI secretion, respectively. At the higher dose level the stimulated secretory rate declined throughout the perfusion suggesting that secretion exceeded the capacity to synthesize SLI under excessive GIP stimulation. Acetylcholine (10 μM) or vagal stimulation (7 V, 10 Hz, 5 ms) completely inhibited GIP-stimulated SLI secretion. It is therefore proposed that the acid inhibitory activity of GIP is probably mediated via release of gastric SLI and this action is under cholinergic control.
Cardiac effects of prostaglandins E1 and F1α
Authors: Vadlamudi Rao V. S. V. , McNheill John H.
Published: October 2017

The effects of prostaglandin E1 (PGE1) and prostaglandin F1α (PGF1α) were studied on perfused rat hearts and isolated rat atria. Both PGE1 and PGF1α produced dose-dependent increases in right atrial rate but had no effect on left atrial tension development. PGE1 (10−4 M) increased right atrial cyclic AMP content without changing phosphorylase a activity. PGF1α (10−4 M) did not change right atrial cyclic AMP or cyclic GMP content. Both prostaglandins had no effect on left atrial cyclic nucleotide content. When infused at a rate of 1 μg/min, PGE1 produced a time-dependent increase in cyclic AMP content in the Langendorff perfused hearts but did not alter contractile force development or phosphorylase a activity. An infusion of PGF1α produced a dose-dependent increase in tension development which was secondary to a negative chronotropic effect. PGF1α (1 μg/min) did not produce any changes in cyclic nucleotide levels or phosphorylase a activity in the Langendorff perfused hearts. These results show that PGE1 can selectively increase myocardial cyclic AMP content without altering contractile force or phosphorylase activity and that PGF1α does not increase rat cardiac AMP levels.
Intracellular Cl activity, Cl binding, and 36Cl efflux in rabbit papillary muscle
Authors: Fong C. N. , Hinke J. A. M.
Published: October 2017

Chloride liquid ion-exchange microelectrodes were used to measure intracellular chloride activity (aCl)i of rabbit papillary muscle in vitro. In HCO3−–CO2 buffered Ringer (aCl)i was 15.2 ± 0.6 mM (n = 40) at pH 7.3 and 15.4 ± 0.3 mM (n = 29) at pH 6.8. In HEPES-buffered Ringer (aCl)i was 24.1 ± 0.6 mM (n = 21) at pH 7.3 and 20.0 ± 0.3 mM (n = 17) at pH 6.9. If Cl was distributed passively across the membrane (aCl)i should be about 3 mM. From total muscle Cl analysis and [14C]sorbitol extracellular space measurements we calculate an apparent intracellular Cl concentration of 71 mM. As this estimate is three times larger than the measured free Cl in the cytoplasm we conclude that a significant fraction of muscle Cl must be bound or compartmentalized. Analysis of 36Cl efflux from the papillary muscle indicates the presence of two compartments. The compartment with the slower efflux rate (2.0 × 10−2 min−1) contains about 25% of the intracellular Cl, which compares with the estimation (21%) of the free intracellular Cl fraction obtained from the Cl microelectrode measurements. Our data permit us to conclude that about 37% of the muscle Cl is bound and that it is probably located extracellularly.
Pressor responses and adrenomedullary catecholamine release during brain stimulation in the rat
Authors: Gauthier Pierre
Published: October 2017

Electrical stimulation of the diencephalon and rostral mesencephalon produced a biphasic pressor response consisting of an initial sharp rise followed by a more prolonged elevation in blood pressure. Active sites from which comparable responses could be evoked were found in the ventral medial and lateral hypothalamus, in the region of the parafascicularis nucleus, and in the central gray matter and the tegmentum of the mesencephalon. Together with the biphasic pressor response brain stimulation also increased plasma catecholamine (CA) concentrations 10-fold. Either bilateral adrenalectomy or demedullation selectively abolished the secondary phase of the pressor response and greatly reduced the plasma CA response to stimulation. After chemical destruction of the terminals of the sympathetic neurones by intravenous administration of 6-hydroxydopamine (6-OHDA), the primary pressor phase was eliminated whereas the secondary phase as well as plasma CA concentration reached higher levels than in normal rats. 6-OHDA treatment combined with adrenalectomy completely abolished both pressor and CA responses. The results demonstrate that adrenomedullary mechanisms capable of increasing blood pressure significantly can be activiated by electrical stimulation of different sites in the diencephalon and mesencephalon.
Respiratory and cardiovascular responses to temperature changes in the perfused pulmonary arteries of the dog
Authors: Ledsome J. R. , Kan W. O. , Bolter C. P.
Published: October 2017

In chloralose-anaesthetized dogs a right heart bypass was established and the isolated main pulmonary arteries were perfused at controlled pressure and temperature. Increasing pulmonary arterial pressure by 20–60 mmHg (1 mmHg = 133.322 Pa) increased systemic vascular resistance and respiratory activity. Decreasing the temperature of the pulmonary arterial perfusate over the range 37 – 31 °C decreased systemic arterial pressure and respiratory activity. Increasing the temperature over the range 37–41 °C had the opposite effects. The decreases in systemic arterial pressure and respiratory activity in response to a decrease in temperature of the pulmonary arterial perfusate were present at low (20 mmHg) or high (80 mmHg) pulmonary arterial pressures. All responses to changing the pressure or temperature of the pulmonary arterial perfusate were prevented by cutting the vagosympathetic nerves in the neck. It is concluded that there are receptors, lying in or close to the pulmonary arterial walls, that in this preparation are tonically active. Their discharge is affected by changes of ± 2 degrees in pulmonary arterial temperature.
Effect of changes in the red cell volume on the carbon dioxide titration curve in vivo in the rat
Authors: Kaufman S. , Kappagoda C. T.
Published: October 2017

Acute in vivo CO2 titration curves were performed on rats anaesthetized with pentobarbitone. The slope of the in vivo CO2 titration curve in the rat was found to be similar to that previously reported in the dog and in man. Removal of approximately 30% of the haemoglobin of the body did not influence significantly the slope of the in vivo CO2 titration curve in the rat.
A simple, inexpensive filtration device suitable for neurotransmitter receptor binding studies in brain tissue
Authors: Wilkinson M. , Grovestine Dale
Published: October 2017

We describe the construction and use of an inexpensive filtration manifold suitable for radioligand binding assays. Experiments with [3H]flunitrazepam indicate that the binding data for benzodiazepine receptors in rat brain homogenate are almost indistinguishable from those obtained with a commercially available manifold.
Relaxin inhibition of KCl-induced uterine contractions in vitro: an alternative bioassay
Authors: St-Louis Jean
Published: October 2017

The effect on the rat uterus of the ovarian peptide hormone, relaxin, has been studied in vitro. Partial (20%) replacement of the NaCl in physiological saline by KCl resulted in a strong contraction of the uterus which was reversed by relaxin. The preparation contracted by this level of KCl substitution was shown to be very sensitive to the action of extracts of pregnant sow ovaries containing relaxin in comparison with the ones contracted by higher and lower degrees of KCl substitution. The ovarian extracts induced a concentration-dependent reversal of the contraction of the uterus; this activity of relaxin increased with the degree of purification of the hormone. Relaxin induced a slowly developing relaxation whereas epinephrine relaxed the same preparation very rapidly until a plateau relaxation was reached. The concentration–response curves to relaxin at different states of purification were parallel and were also parallel and comparable in potency to the ones measured for similar preparations from other laboratories. These results suggest that rat uterus contracted in vitro by KCl-substituted saline should be a valuable and reproducible bioassy for relaxin.
AN EXPERIMENTAL STUDY ON THE EFFECT OF THE SWIMBLADDER ON HEARING SENSITIVITY IN AMEIURUS NEBULOSUS NEBULOSUS (LESUEUR)
Authors: Kleerekoper H. , Roggenkamp Petronella A.
Published: October 2017

Hearing sensitivity was observed in Ameiurus nebulosus nebulosus (LeSueur). A threshold curve over the frequency range from 210 to 1840 c.p.s. was established for normal fish as well as for fish in which the swimbladder had been mutilated. A comparison of both threshold curves indicates that the sensitivity in operated fish was decreased in the whole frequency range: for the frequencies from 330 to 750 c.p.s. by about 13 db; for the frequencies of 1000, 1300, and 1500 c.p.s. by respectively 23, 27, and 30 db. The stronger decrease at the higher frequencies was attributed to the loss or modification of the resonance of the opened swimbladder. The sensitivity of the operated fish increased in the frequency range from 330 to 210 c.p.s. This increase in sensitivity is abolished when the lateralis branch of the vagus is cut and must therefore be attributed to perception of low frequency vibrations by the lateral line.
The National Rural Drinking Water Security Pilot Project in India: A Cost–Benefit Analysis
Authors: Weis David , Hutton Guy , Kumar Manish
Published: October 2017

India categorizes the water situation of more than one-quarter of its governmental units as over-exploited, critical, or semi-critical. Unsustainable water extraction, inefficient use of resources, and the large water demand of the agricultural sector (more than 90%) are among the causes of the worsening state of water resources. In order to assure the access to clean drinking water, the Indian Ministry of Drinking Water and Sanitation initiated the National Rural Drinking Water Security Pilot Project in 2011. To analyze the costs and benefits of this pilot project, we follow the pretest–posttest control group study design comparing two points in time and two groups (study group and control group). In total, 12 sample villages (consisting of 3,265 households and 20,767 individuals) in two different areas were included. Costs and benefits were captured if they were directly and causally linked with the project. This includes financial and economic costs for individuals and the government, as well as benefits in four major fields: health, economy, environment, and time savings. We found total benefits ranging between USD 420,000 in low performing sites and USD 480,000 in high performing sites. Corresponding costs were between USD 40,000 and 45,000. Adjusted to per capita values, benefits vary between USD 54 and USD 300 and costs between USD 5 and USD 28. Adjusting a 99% confidence interval, the net benefits will vary between approximately USD 150 and USD 400 in the high performing sites and between USD 30 and USD 70 in the low performing sites. The expected benefit-to-cost ratios are 11 in high performing sites and 10 in the low performing sites. Due to the large social return in high as well as in low performing study sites, this paper recommends prolonging and upscaling the interventions evaluated in the pilot project sites.
Global Structure of Positive Solutions for Some Second-Order Multipoint Boundary Value Problems
Authors: Li Hongyu , Zhang Junting
Published: October 2017

We investigate in this paper the following second-order multipoint boundary value problem:-(Lφ)(t)=λf(t,φ(t)),0≤t≤1,φ′0=0,φ1=∑i=1m-2βiφηi. Under some conditions, we obtain global structure of positive solution set of this boundary value problem and the behavior of positive solutions with respect to parameterλby using global bifurcation method. We also obtain the infinite interval of parameterλabout the existence of positive solution.