bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECTS OF CHRONIC NICOTINE ADMINISTRATION ON THE DENERVATED RAT ADRENAL MEDULLA
Authors: SEIDLER F.J. , SLOTKIN T.A. 
Published: July 2012

The effects of chronic nicotine administration (1 or 10 mg/kg, s.c., twice daily) were studied in intact and denervated rat adrenal glands to determine the relative roles of central input and direct actions on catecholamines.
Catecholamine depletion was obtained in the intact glands from 1–7 days of treatment with 10 mg/kg, with recovery by 14 days of treatment; catecholamines were not decreased in denervated adrenal glands.
Catecholamine depletion was accompanied by a decline in functional storage vesicles (determined by [3H]‐adrenaline uptake per gland) in the intact side, while no change was seen in the denervated side; the proportion of newly synthesized vesicles increased markedly during 1–7 days of treatment with 10 mg/kg in the intact side, while a much smaller increase of shorter duration was seen in the denervated adrenal gland.
Chronic nicotine administration at either dose level induced tyrosine hydroxylase in both intact and denervated glands, but the increase occurred more slowly in the denervated glands.
Dopamine β‐hydroxylase levels increased similarly in both sides during treatment with nicotine (10 mg/kg).
These studies suggest that although long‐term adrenal denervation eliminates the catecholamine depletion caused by chronic administration of nicotine, the mechanisms for induction of catecholamine synthesizing enzymes are still capable of responding to the drug.
CARDIOVASCULAR EFFECTS OF DIETHYLCARBAMAZINE CITRATE
Authors: ABAITEY A.K. , PARRATT J.R. 
Published: July 2012

The cardiovascular effects of the anthelmintic drug diethylcarbamazine citrate (DECC) were examined in cats anaesthetized with pentobarbitone. There were two quite distinct haemodynamic responses, an initial transient hypotension (occurring within 10 s of an intravenous injection) and a pronounced secondary hypertension which reached a peak 30–60 s after the injection.
Within 10 s of an intravenous injection of DECC (2.5 to 10 mg/kg) there was hypotension, bradycardia and there were reductions in left ventricular and carotid artery dP/dt max. These effects were most pronounced following injections into the pulmonary artery; they were not observed after bilateral vagotomy or after injections into the lumen of the left ventricle. It is suggested that DECC, like nicotine, stimulates vagal receptors in the pulmonary vascular bed.
The secondary phase was characterized by marked systemic and pulmonary hypertension, by contractions of the nictitating membrane and by increases in left ventricular dP/dt (at fixed isovolumic pressures), in cardiac output and in myocardial blood flow. All these effects were prevented, or markedly reduced, following the administration of hexamethonium or bethanidine and the pressor response was prevented by phentolamine. It is concluded that, in doses similar to those used in therapeutics, DECC stimulates sympathetic ganglia and releases noradrenaline. The relevance of this finding to the reported side effects of the drug are discussed.
DECC (5 or 10 mg/kg) significantly inhibited prostaglandin F2α‐induced increases in peak inspiratory intra‐tracheal pressure without modifying its pulmonary hypertensive effect. The possible relevance of this finding to the use of DECC in asthma is discussed.
THE EFFECTS OF INTRA‐AMYGDALOID INJECTIONS OF 6‐HYDROXYDOPAMINE ON AVOIDANCE RESPONDING IN RATS
Authors: ASHFORD J. , JONES B.J. 
Published: July 2012

The effects of bilateral intra‐amygdaloid injections of 6‐hydroxydopamine (6‐OHDA) on shuttle box avoidance acquisition, retention, and extinction, and passive avoidance acquisition were examined in rats.
Intra‐amygdaloid 6‐OHDA injections produced catecholamine depletion in and around the amygdalae but failed to reduce striatal dopamine concentrations.
Conditioned avoidance acquisition was markedly inhibited in 6‐OHDA‐treated rats whereas retention and extinction were only slightly impaired.
Passive avoidance acquisition was slightly but significantly improved in rats with amygdaloid 6‐ OHDA lesions.
Treated rats showed no motor abnormalities, they were not hypoactive in a photocell activity cage and they performed as well as controls on a rotating rod.
It is suggested that the conditioned avoidance acquisition deficit in rats with amygdaloid 6‐OHDA lesions may be related to an impairment of associative learning rather than to perceptual or motor disturbances.
RAT UTERUS RENIN‐LIKE ACTIVITY: EFFECT OF STIMULI AND HORMONES
Authors: GUTMAN Y. , MAZUR‐RUDER M. 
Published: July 2012

The characteristics of renin‐like activity in rat uterus were studied. The optimum temperature was 50°C and optimum pH 4.0. Potassium (100 mM) enhanced this activity but sodium or calcium had no effect.
Uterine renin‐like activity was unchanged 24 h after bilateral nephrectomy.
Renin‐like activity in the uterus increased slowly from birth to 4 weeks of age and faster between the 4th and 8th week.
Ovariectomy caused a considerable fall in uterine renin‐like activity.
The following factors, known to affect renin secretion in the kidney, i.e., hypovolaemia, sodium loading, adrenalectomy, administration of desoxycorticosterone acetate and injection of isoprenaline, had no effect on uterine renin‐like activity.
Stilboestrol, an oestrogen, caused a significant increase of uterine renin‐like activity. Progesterone and testosterone had no significant effect on this activity but blocked the increase caused by stilboestrol.
During pregnancy there was a small but significant fall of renin‐like activity in the uterus in the first week and a continuous increase throughout the later period of pregnancy.
It is concluded that uterine renin‐like activity is independent of kidney renin and does not respond to stimuli affecting kidney renin. Uterine renin activity is hormone‐dependent and may be governed by the ratio, oestrogen: progesterone.
A METHOD FOR RECORDING SMOOTH MUSCLE AND VASCULAR RESPONSES OF THE BLOOD‐PERFUSED DOG TRACHEA In situ
Authors: HIMORI N. , TAIRA N. 
Published: July 2012

A method is described for measuring responses of dog tracheal musculature and vasculature in situ.
The upper two thirds of the trachea was perfused with blood through both cranial thyroid arteries at a constant pressure. The blood flow through the arteries was measured with an electromagnetic flowmeter. The response of the tracheal musculature was measured as a change in pressure in a water‐filled cuff inserted into the trachea via the mouth. Drugs were injected close‐arterially.
Acetylcholine produced dose‐dependent increases in blood flow rate (vasodilatation) and in tracheal intraluminal pressure (tracheal constriction). These responses were antagonized by atropine.
Isoprenaline produced vasodilatation which was blocked by propranolol. Adrenaline and noradrenaline caused vasoconstriction which was blocked by phentolamine.
All three catecholamines produced a decrease in tracheal intraluminal pressure (tracheal dilatation). The tracheal dilatation in response to adrenaline and noradrenaline was converted to constriction by propranolol. The tracheal constriction thus unmasked was abolished specifically by phentolamine.
From these results it is concluded that the tracheal musculature and vasculature contain muscarinic receptors, and excitatory α‐ and inhibitory β‐adrenoceptors. In the tracheal musculature β‐adrenoceptors predominate over α‐adrenoceptors; the reverse is true in the tracheal vasculature.
A CHOLINOCEPTOR ANTISERUM: ITS PHARMACOLOGICAL PROPERTIES
Authors: BERTI F. , CLEMENTI F. , CONTI‐TRONCONI B. , FOLCO G.C. 
Published: July 2012

Sera of rabbits immunized against a nicotinic receptor‐rich fraction, obtained from the electric organ of Torpedo marmorata, were tested for their pharmacological activity on different in vitro preparations.
Sera containing antibodies against the nicotinic receptor blocked neuromuscular transmission in the phrenic‐nerve hemidiaphragm preparation without affecting the muscle responses evoked by direct electrical stimulation. Complement inactivated sera were still active. Immune sera, incubated for 15 min with a receptor‐rich fraction, lost their activity.
The immune sera antagonized the responses elicited by acetylcholine on the frog rectus abdominis.
The immune sera tested in vitro decreased the compound action potential evoked in the superior cervical ganglion of the rat by electrical stimulation of the preganglionic nerve.
The sera did not show any activity on muscarinic receptors of the guinea‐pig ileum preparation.
It is concluded that in sera obtained from immunized rabbits a substance is present with curare‐like action, and that this activity is probably due to the presence of antibodies against the nicotinic receptor.
THE RELATIONSHIP BETWEEN CARDIOTOXICITY AND PLASMA DIGOXIN CONCENTRATION IN CONSCIOUS DOGS
Authors: CHAPPLE D.J. , HUGHES R. , JOHNSON B.F. 
Published: July 2012

The tendency of a given oral dose of digoxin to induce cardiac dysrhythmia was determined indirectly at various times after its administration to eight conscious dogs by measurement of the intravenous dose of acetylstrophanthidin necessary to induce toxic changes in the ECG. Acetylstrophanthidin was used because its rapid elimination from the body permitted estimates to be made 45, 180 and 360 min after digoxin administration.
Each dog underwent four studies in which doses of 0.05, 0.1, 0.2 and 0.4 mg/kg digoxin were used in a randomized sequence allowing at least ten days between each dose.
Digoxin reduced the amount of acetylstrophanthidin required to cause toxic changes in the ECG; this increase in cardiac sensitivity was dose‐dependent.
There was no correlation between plasma levels of digoxin and the tendency to dysrhythmia, since peak plasma concentrations of digoxin were reached at about 60 min after dosing whereas maximal sensitivity to acetylstrophanthidin was found 3 to 6 h after administration of digoxin.
These results suggest that there is little or no increased risk of cardiotoxicity during periods of transient increase in plasma levels of digoxin.
EFFECTS OF SOME PURINE DERIVATIVES ON THE GUINEA‐PIG TRACHEA AND THEIR INTERACTION WITH DRUGS THAT BLOCK ADENOSINE UPTAKE
Authors: COLEMAN R.A. 
Published: July 2012

Adenosine, adenosine 5′‐triphosphate (ATP), adenine, inosine and guanosine all caused concentration‐dependent relaxations of guinea‐pig tracheal smooth muscle in vitro. The relative potencies in descending order were: adenine ≥ guanosine > inosine ≥ adenosine ≥ ATP
Responses to the purine compounds were unaffected by propranolol (1 μg/ml).
The spasmolytic potencies of adenosine and ATP were greatly enhanced in the presence of the adenosine uptake blocking drugs dipyridamole, hexobendine or Dilazep, whereas responses to adenine were unaffected and those to inosine and guanosine were reduced.
The spasmolytic potencies of noradrenaline, aminophylline, prostaglandin E2 and glyceryl trinitrate were unaffected by dipyridamole, hexobendine and Dilazep.
It is suggested that an adenosine uptake process may exist in the trachea of the guinea‐pig and that this process is inhibited by dipyridamole, hexobendine and Dilazep.
CONCENTRATION OF (±)‐PROPRANOLOL IN ISOLATED, PERFUSED LUNGS OF RAT
Authors: DOLLERY C.T. , JUNOD A.F. 
Published: July 2012

The metabolism and the accumulation of (±)‐propranolol have been studied in isolated lungs of the rat, perfused with an artificial medium.
Little or no metabolism took place during the perfusion periods (up to 10 minutes).
Accumulation was observed with high tissue/medium ratios for substrate concentrations of 0.2 μm to 1 mm; there was evidence for saturability, but no real plateau could be seen. The presence of two binding sites with different affinities was established.
Cold greatly inhibited the accumulation process at low substrate concentrations, but had no effect at 1 mm propranolol.
Inhibition of accumulation was measured in the presence of imipramine, desmethylimipramine, nortryptiline, chlorpromazine and of Na+‐free medium. Cocaine, 5‐hydroxytryptamine and noradrenaline had no effect. Lidocaine enhanced the accumulation process. Release of previously bound propranolol was accelerated in the presence of propranolol and imipramine, unaffected by a Na+‐free medium and decreased by cold and by lidocaine.
Experiments on lung tissue slices yielded qualitatively similar results to those obtained with perfused lungs. Ouabain and KCN had no or little effect on propranolol accumulation.
TRYPTOPHAN METABOLISM IN THE ISOLATED PERFUSED LIVER OF THE RAT: EFFECTS OF TRYPTOPHAN CONCENTRATION, HYDROCORTISONE AND ALLOPURINOL ON TRYPTOPHAN PYRROLASE ACTIVITY AND KYNURENINE FORMATION
Authors: GREEN A.R. , WOODS H.F. , JOSEPH M.H. 
Published: July 2012

The effect of tryptophan concentration on the rate of kynurenine appearance and tryptophan disappearance in the medium perfused through the isolated liver of the rat has been investigated. The effect of pretreatment of the rat with hydrocortisone or allopurinol was also examined, together with the effects of these treatments on liver tryptophan pyrrolase activity measured in vitro at the beginning and end of perfusion.
Hydrocortisone (5 mg/kg) injection 3 h before perfusion resulted in a four‐fold increase in kynurenine production by the liver during perfusion with a medium containing either 0.1 mmol/1 or 1.0 mmol/1 tryptophan. Injection of allopurinol (20 mg/kg) together with hydrocortisone and addition of allopurinol (4 mg/100 ml) to the medium abolished the hydrocortisone‐induced rise of kynurenine in the 0.1 mmol/1 tryptophan medium but not the 1.0 mmol/1 tryptophan medium.
Injection of cycloheximide (30 mg/kg) with hydrocortisone (5 mg/kg) 3 h before perfusion inhibited the hydrocortisone‐induced rise of kynurenine production and the increase in pyrrolase activity measured in vitro both before and at the end of perfusion with 1.0 mmol/1 tryptophan. This last result suggests that protein synthesis is involved not only in hydrocortisone induction of pyrrolase but also in substrate induction.
Kynurenine production in the 1.0 mmol/1 tryptophan medium was less in both saline‐ and hydrocortisone‐treate older rats (335–450 g) compared to younger rats (180–220 g). In agreement with a previous study, pyrrolase activity in vitro was also lower in both saline‐ and hydrocortisone‐treate older rats at the beginning of the perfusion although activity had risen equally in both young and older rats at the end of perfusion.
There was little correlation between the rate of tryptophan disappearance from the medium and the activity of tryptophan pyrrolase either as measured in vitro or as indicated by the rate of kynurenine production.
In general, the production of kynurenine in the medium at the end of the 60 min perfusion was indicative of in vitro pyrrolase activity at the start of the perfusion.
It is concluded that while in vitro pyrrolase assay does not give a quantitative index of kynurenine production, it does provide a qualitative index. Furthermore, if kynurenine production in the isolated perfused liver of the rat is indicative of in vivo pyrrolase activity, then hydrocortisone must induce pyrrolase activity in vivo.
THE EFFECT OF NANDROLONE, AN ANABOLIC STEROID ON PUTRESCINE METABOLISM IN THE MOUSE
Authors: HENNINGSSON S. , ROSENGREN ELSA 
Published: July 2012

The catabolism of injected 14C‐putrescine was studied in mice treated with nandrolone phenpropionate, an anabolic steroid.
The putrescine was rapidly metabolized; almost 50% of the injected radioactivity was recovered within 2 h as 14CO2 in the expired air.
Considerable amounts of radioactive γ‐aminobutyric acid (GABA) and an unidentified compound were found in the kidney and in the urine in addition to radioactive putrescine, spermidine and spermine both in controls and nandrolone‐treated mice.
Nandrolone elevated the concentration of endogenous putrescine in the kidney and urine, eightfold and twentyfold, respectively, and the concentrations of spermidine and spermine were also increased.
After the injection of 14C‐putrescine the incorporation of 14C into spermidine was significantly increased in the kidney of mice receiving nandrolone.
FREQUENCY‐DEPENDENT CHANGES IN THE CARDIAC SARCOLEMMAL ATPASE
Authors: KHATTER J.C. , PRASAD K. 
Published: July 2012

1Effects of various frequencies (0.25, 0.5, 1.0, 1.5 or 2.0 Hz) of stimulation for various durations (2, 5, 10 or 15 min) on the contractile force of trabecular or papillary muscles of dog myocardium were investigated.2Effects of various frequencies (0, 0.25, 0.5, 1.0, 2.0 Hz) of various stimulus strengths (0.5, 1, 10 V) for various durations (2, 5, 10 or 15 min) on the Mg2+‐dependent Na+‐K+‐adenosinetriphosphatase (ATPase) of isolated sarcolemmal fraction of dog myocardium were determined.3There was a frequency‐dependent increase in the contractility and inhibition of the Na+‐K+‐ATPase within 2 minutes.4Frequency‐dependent increase in the contractility and inhibition of Na+‐K+‐ATPase decreased as the duration of stimulation was increased.5The diminution in the inhibition of ATPase was associated with a decrease in the contractility with prolonged stimulation.6These results suggest that the frequency‐dependent increase in the myocardial contractility might be mediated through an inhibition of the sarcolemmal ATPase.
EFFECTS OF THYROIDECTOMY AND l‐THYROXINE ON ADRENALINE AND NORADRENALINE CONCENTRATIONS IN THE ADRENAL GLANDS AND PLASMA OF RATS DURING THE PRO‐OESTROUS PHASE OF THE OESTROUS CYCLE AND PREGNANCY
Authors: ISMAHAN G. , PARVEZ H. , PARVEZ S. , YOUDIM M.B.H. 
Published: July 2012

1The influence of thyroidectomy upon the adrenaline and noradrenaline content of adrenal glands and plasma in mature female rats in pro‐oestrus and in pregnant rats was studied.2Adrenal adrenaline and noradrenaline declined significantly after thyroidectomy in pro‐oestrous and pregnant females but the effects were more marked in pregnant females.3Plasma adrenaline increased by 160% after thyroidectomy in pro‐oestrous females but similar treatment resulted in 85% decrease in plasma adrenaline of pregnant rats. The loss of thyroid increased plasma noradrenaline significantly in both groups of females.4The administration of l‐thyroxine to thyroidectomized females increased adrenal noradrenaline stores of both the groups. The effects of l‐thyroxine in pro‐oestrous females resulted in decreased adrenaline stores of the adrenals but the pregnant group showed an increase. Plasma noradrenaline increased after treatment of pro‐oestrous and pregnant‐thyroidectomized females with l‐thyroxine.5The thyroidectomized females in pro‐oestrous phase receiving l‐thyroxine showed a return to the control values for plasma adrenaline but in pregnant females whose plasma adrenaline had declined after thyroidectomy no such change occurred.6Considering the variations in total catecholamines in plasma and adrenals, it was observed that the loss of thyroid hormones results in an increase in total catecholamine storage and output in the blood. The results provide evidence that the thyroid‐catecholamine interrelation is significantly affected by pregnancy.
A POSSIBLE ROLE FOR CYCLIC ADENOSINE 3′,5′‐MONOPHOSPHATE IN THE REGULATION OF ACID SECRETION IN THE ISOLATED STOMACH OF GUINEA‐PIG
Authors: CANFIELD S.P. , CURWAIN B.P. , SPENCER JAN 
Published: July 2012

1The rate of acid secretion and mucosal cyclic adenosine 3′,5′‐monophosphate (cyclic AMP) content have been measured on the same guinea‐pig isolated stomach preparation in response to histamine, theophylline and ICI 63197, a potent phosphodiesterase inhibitor.2Unstimulated control tissues had a spontaneous rate of acid secretion of 74.41 ± 9.06 μmol H+/g wet wt. of mucosa per hour (s.e. mean, n=20) and a cyclic AMP content of 0.517 ± 0.058 nmol/g wet weight.3Each of the three drugs caused an increase in both the mucosal cyclic AMP content and the rate of acid secretion. These increases were linearly related to the logarithm of drug concentration for each drug.4There were no statistically significant differences between the three regression coefficients obtained for acid on drug and for cyclic AMP on drug.5There was a significant correlation between the rate of acid secretion and mucosal cyclic AMP content in stimulated preparations (P>0.001) and also in control preparations which received no drug (P<0.05).6These results are discussed in relation to the possible role of cyclic AMP in the mediation of acid secretory responses in the mammalian stomach.
MODIFICATION OF CARDIOVASCULAR RESPONSES TO HISTAMINE BY DITHIOTHREITOL
Authors: CARROLL P.R. , GLOVER W.E. 
Published: July 2012

1Histamine produced dose‐dependent contractile responses on both isolated perfused ear arteries and aortic strips of the rabbit. These responses were blocked by mepyramine and potentiated by both metiamide and dithiothreitol.2In the presence of maximum potentiation by metiamide, dithiothreitol still potentiated the contractile response to histamine of both preparations.3In the presence of mepyramine, histamine produced dose‐dependent reductions in the contractile response to noradrenaline. This vasodilator action of histamine was abolished by metiamide but was unaffected by dithiothreitol.4The vasodilator action of histamine on the human isolated perfused temporal artery and the positive inotropic effect of histamine on the isolated spontaneously beating atria of the rabbit were blocked by metiamide but unaffected by dithiothreitol.5It is concluded that the rabbit aorta, like the ear artery, contains both H1 and H2 histamine receptors and that dithiothreitol potentiates cardiovascular responses mediated by H1‐receptors but not by H2‐receptors.
THE EFFECTS OF BRADYKININ AND PROSTAGLANDIN E1 ON RAT CUTANEOUS AFFERENT NERVE ACTIVITY
Authors: CHAHL LORIS A. , IGGO A. 
Published: July 2012

1The activity produced by intra‐arterial bradykinin and prostaglandin E1 was investigated in multifibre strands dissected from the saphenous nerves of anaesthetized rats.2Bradykinin (0.5‐10 μg) alone produced little activity in nerve strands but produced considerable activity following a 10 min infusion, but not a single injection, of prostaglandin E1 (5‐100 ng).3Prostaglandin E1 alone produced a few large height spikes but following several injections of bradykinin smaller height spikes were also produced by prostaglandin E1.4It was concluded that the presence of a low concentration of prostaglandin E1 is required for bradykinin to manifest its action and that bradykinin and prostaglandin E1 are mutually potentiating in their effects on afferent nerve terminals.
INFLUENCE OF NEUROGLIAL TRANSPORT ON THE ACTION OF γ‐AMINOBUTYRIC ACID ON MAMMALIAN GANGLION CELLS
Authors: BROWN D.A. , GALVAN M. 
Published: July 2012

1The effect of inhibiting the transport of γ‐aminobutyric acid (GABA) by neuroglial cells on the depolarizing action of exogenous amino acids on isolated superior cervical ganglia of the rat was studied.2Transport (measured by uptake of [3H]‐GABA) was inhibited by (a) reducing external [Na+] from 143 to 2 mm and (b) administering alternative carrier‐substrates, 3‐amino‐n‐butyric acid (β‐amino‐butyric acid, BABA) and (±)‐nipecotic acid at a concentration of 1 mm.3All three procedures enhanced the depolarization produced by low concentrations of GABA (<10 μm) but did not alter the maximum response, nor the response to 3‐aminopropanesulphonic acid (a gabamimetic with low affinity for the neuroglial carrier).4It is concluded that the neuroglial uptake process can limit the action of exogenous GABA upon neurones, by reducing the interstitial GABA concentration.