bluuebunny/crossref_metadata_2025_split huggingface dataset:
ACUTE MYOCARDIAL ISCHAEMIA IN ANAESTHETIZED CATS: EFFECTS OF PAPAVERINE
Authors: KISIN I. 
Published: July 2012

The effects of papaverine on coronary blood flow, myocardial oxygen consumption, myocardial oxygen tension and the ischaemic ECG pattern were studied in anaesthetized open‐chest cats representing three models of acute coronary insufficiency: ligation, spasm, and perfusion of the coronary artery at a stabilized insufficient level.
Despite the increase in myocardial oxygen consumption reflecting elevation of oxygen demand, papaverine improved the signs of myocardial ischaemia (the myocardial oxygen tension and ECG pattern), as long as there was a possibility of an increase in blood supply to the affected zone. Where this was excluded, the symptoms were actually aggravated.
The results suggest that there is no basis for dividing coronary dilators into ‘benign’ and ‘malignant’ according to their ability to increase myocardial oxygen requirements. A coronary dilator enhancing oxygen demand may prove beneficial even following complete coronary artery occlusion.
E. col/ ENDOTOXIN SHOCK IN THE DOG; TREATMENT WITH LIDOCAINE OR INDOMETHACIN
Authors: FLETCHER J.R. , RAMWELL P.W. 
Published: July 2012

Dogs treated with lidocaine (1 mg kg−1 h−1) or indomethacin (1.5 mg/kg) before and after an LD60 dose (1 mg/kg) of E. coli endotoxin survived for at least 72 h.
Although all dogs in both treated groups survived, only those treated with indomethacin were significantly protected against the fall in the arterial blood pressure 1 to 2 min following endotoxin administration.
Endotoxin increased the plasma prostaglandin F2α (PGF2α) concentration in the control and lidocaine‐treated groups, however, no increase was observed with indomethacin treatment.
Neither lidocaine nor indomethacin alone had any significant effect on the parameters measured in this model.
Following the administration of endotoxin, lidocaine‐treated animals had significantly decreased plasma fibrinogen concentrations when compared to the other groups.
This study suggests that lidocaine, a local anaesthetic and a drug widely used for cardiac arrhythmias, might offer protection in endotoxin shock.
THE EFFECTS OF PUTATIVE 5‐HYDROXYTRYPTAMINE ANTAGONISTS ON THE BEHAVIOUR PRODUCED BY ADMINISTRATION OF TRANYLCYPROMINE AND L‐TRYPTOPHAN OR TRANYLCYPROMINE AND L‐DOPA TO RATS
Authors: DEAKIN J.F.W. , GREEN A.R. 
Published: July 2012

The putative 5‐hydroxytryptamine (5‐HT) receptor blocking drugs methysergide (10 mg/kg) and methergoline (5 mg/kg) were found to abolish some components of the hyperactivity syndrome, including head weaving and forepaw treading, which follow administration to rats of tranylcypromine (20 mg/kg) and L‐tryptophan (100 mg/kg). Hyperactivity and hyper‐reactivity were potentiated with a resultant increase in automated locomotor activity counts. In contrast (—)‐propranolol (20 mg/kg) inhibited all features of the syndrome. The same results were obtained with these drugs when the behaviour was elicited by p‐chloroamphetamine (10 mg/kg) or by tranylcypromine and tryptamine (10 mg/kg).
Methysergide and methergoline had similar effects on the syndrome produced by tranylcypromine and l‐DOPA (50 mg/kg) whereas propranolol was without effect.
None of the putative 5‐HT receptor antagonists affected brain 5‐HT turnover as assessed by rate of accumulation of 5‐HT following monoamine oxidase inhibition with tranylcypromine.
Microinjections of 5,7‐dihydroxytryptamine into the spinal cord resulted in a 70% fall in cord 5‐HT concentrations without an effect on brain 5‐HT concentrations. The behavioural response to the putative 5‐HT receptor agonist, 5‐methoxy JV, N‐dimethyltryptamine (2 mg/kg), was potentiated in these animals suggesting that 5‐HT receptors become supersensitive on denervation, and that some components of the behavioural syndrome are mediated by spinal cord 5‐HT receptors.
Pretreatment with α‐methyl p‐tyrosine (2 × 200 mg/kg) delayed the onset of all components of the behaviour elicited by tranylcypromine/L‐tryptophan by 60 min, indicating an involvement of catecholamines in the syndrome.
p‐Chloroamphetamine‐induced 5‐HT depletion had no effect on any component of the tranylcypromine‐L‐DOPA behaviour.
ADRENOCORTICOTROPHIC HORMONE FRAGMENTS MIMIC THE EFFECT OF MORPHINE in vitro
Authors: PLOMP GERDA J.J. , VAN REE JAN M. 
Published: July 2012

Fragments of the N terminal part of adrenocorticotrophic hormone (ACTH) inhibited the electrically evoked contractions of the mouse vas deferens. This inhibition could be antagonized by naloxone.
The same fragments displaced radiolabelled morphine from morphine antiserum.
Structure‐activity relationship studies showed that in both assay systems the active core is located within the sequence ACTH 7–10.
It is postulated that the Trp9 residue and the peptide bond between Trp9 and Gly10 are particularly important for interaction of ACTH fragments with morphine receptors.
CHANGES IN PLASMA NORADRENALINE CONCENTRATION AS A MEASURE OF RELEASE RATE
Authors: BENEDICT C.R. , FILLENZ M. , STANFORD CLARE 
Published: July 2012

A method is described for repeated sampling of plasma noradrenaline (NA) in freely moving rats. Na concentration does not change during the day or after adrenalectomy.
Exogenous NA has a half‐life of 1.5 min; drugs which block neuronal and extra‐neuronal uptake lengthen this to 6.3 min.
Swim‐stress leads to a steep rise followed by a rapid decline in plasma NA concentration.
This method of plasma NA sampling can serve as a measure of both steady and rapid changes in release rate over long periods of time.
EFFECTS OF CIGARETTE SMOKE ON THE METABOLISM OF VASOACTIVE HORMONES IN RAT ISOLATED LUNGS
Authors: BAKHLE Y.S. , HARTIALA J. , TOIVONEN H. , UOTILA P. 
Published: July 2012

The effects of exposure of rats to cigarette smoke have been studied on the metabolism of vasoactive hormones in isolated lungs from these animals.
Rats were exposed for 1 h per day to cigarette smoke for 1 day or for 10 days.
Angiotensin I conversion was increased after 1 day's exposure but after 10 days' exposure conversion returned to normal.
Inactivation of prostaglandin E2 was decreased after 1 day's exposure. After 10 days' exposure there was a further decrease which could not be attributed to smoke alone.
The inactivation of 5‐hydroxytryptamine and bradykinin remained unchanged after both short and longer exposures to smoke.
The metabolic activity of the lung towards some vasoactive hormones in the pulmonary circulation is affected by exposure of the animal to cigarette smoke and such changes may be relevant to the initiation of cardiovascular changes consequent upon cigarette smoking.
EFFECTS OF MORPHINE, PHYSOSTIGMINE AND RAPHE NUCLEI STIMULATION ON 5‐HYDROXYTRYPTAMINE RELEASE FROM THE CEREBRAL CORTEX OF THE CAT
Authors: AIELLO‐MALMBERG PETRA , BARTOLINI A. , BARTOLINI ROSALIA , GALLI A. 
Published: July 2012

The release of 5‐hydroxytryptamine (5‐HT) from the cerebral cortex and caudate nucleus of brainstem‐transected cats and from the cerebral cortex of rats anaesthetized with urethane was determined by radioenzymatic and biological assay.
The stimulation of nucleus linearis intermedius of raphe doubles the basal 5‐HT release in the caudate nucleus and increases it 3 fold in the cerebral cortex. The effects of the electrical stimulation of the raphe are potentiated by chlorimipramine.
Brain 5‐HT release is greatly increased by morphine hydrochloride (6 mg/kg i.v.) and by physostigmine (100 μg/kg i.v.), but not by dl‐DOPA (50 mg/kg i.v.).
It is suggested that the 5‐HT releasing action of physostigmine can contribute to some of its pharmacological effects such as the analgesic effect so far attributed exclusively to its indirect cholinomimetic activity.
The 5‐HT releasing action of physostigmine seems unrelated to its anticholinesterase activity.
THE ROLE OF HISTAMINE Hr AND H2‐RECEPTORS IN THE GENERATION OF THROMBOXANE A2 IN PERFUSED GUINEA‐PIG LUNGS
Authors: BERTI F. , FOLCO G. C. , NICOSIA SIMONETTA , OMINI C. , PASARGIKLIAN R. 
Published: July 2012

When isolated perfused lungs from normal and ovalbumin sensitized guinea‐pigs were challenged with histamine and 2‐methylhistamine (agonists for Hj‐receptor), a release of thromboxane A2‐like substance was observed. The effect of histamine on production of thromboxane A2 (TXA2) in sensitized lungs, was more pronounced than in normal lungs (P < 0.01).
Specific activation of histamine H2‐receptors in normal lungs with large doses (100 jag) of dimaprit and 4‐methylhistamine, does not produce thromboxane‐like or prostaglandin‐like substances.
Perfusion of the lungs with pyrilamine (10 μg/ml) inhibited the release of arachidonate metabolites induced by histamine H1‐receptor stimulation, whereas cimetidine (5 μg/ml) was ineffective.
It is concluded that only the stimulation of histamine H1‐receptors appears to be responsible for generation of thromboxane A2 and other prostaglandin‐like substances in normal guinea‐pig lungs. In sensitized lungs, an increased ability of histamine to release TXA2 could be due to a possible interconversion of H2 into Hj‐receptors.
CONTENT AND SUBCELLULAR LOCALIZATION OF CATECHOLAMINES AND 5‐HYDROXYTRYPTAMINE IN HUMAN AND ANIMAL BLOOD PLATELETS: MONOAMINE DISTRIBUTION BETWEEN PLATELETS AND PLASMA
Authors: DA PRADA M. , PICOTTI G.B. 
Published: July 2012

The content of adrenaline (Ad), noradrenaline (NA) and dopamine was measured in human, guinea‐pig, cat, rabbit and rat blood platelets by a highly sensitive and specific radioenzymatic method.
In all platelet specimens analyzed, the content of the three catecholamines (CA) was several thousand times lower than that of 5‐hydroxytryptamine (5‐HT).
In basal conditions, the NA concentration in platelets and plasma always exceeded that of Ad and dopamine.
In rat and rabbit platelets, Ad, NA and dopamine were present only in the free (unconjugated) form.
Platelets of rats with storage pool deficiency (Fawn‐hooded) contained much less 5‐HT and CA than normal rat platelets.
Following restraint stress, platelets of Fawn‐hooded rats, in contrast to normal rat platelets, did not accumulate CA in spite of a dramatic rise in plasma CA.
Reserpine, a monoamine depletor, released CA as well as 5‐HT from rabbit platelets in vivo.
Subcellular fractionation experiments with rabbit platelets indicate that both CA and 5‐HT are most concentrated in the fraction consisting of pure 5‐HT organelles.
Both in humans and rabbits the concentration gradient between platelets and plasma was much lower for CA than for 5‐HT, indicating that a high affinity transport mechanism operates in vivo for 5‐HT but not for CA.
In conclusion, the present data show that both human and animal platelets contain Ad, NA and dopamine. The bulk of the CA seems to be stored as unconjugated amines together with 5‐HT, histamine and p‐octopamine in a multitransmitter storage site, namely the 5‐HT organelle.
CONCOMITANT DEVELOPMENT OF [3H]‐DOPAMINE AND [3H]‐5‐HYDROXYTRYPTAMINE UPTAKE SYSTEMS IN RAT BRAIN REGIONS
Authors: KIRKSEY D.F. , SLOTKIN T.A. 
Published: July 2012

Synaptosomal uptake mechanisms of 5‐hydroxytryptamine and dopamine were examined in cerebral cortex, corpus striatum and midbrain plus brainstem of developing rats.
In all regions, there was generally a parallel biphasic development of both uptake systems; the most rapid increases occurred in the first two weeks postpartum, followed by a slower rate of increase.
Kinetic studies with dopamine indicated that the maturation involved increases in maximal uptake without a change in the substrate Km, suggesting that there is a change in the number of terminals but not in the uptake system per se.
GLUTAMATE AS THE NEUROTRANSMITTER OF CEREBELLAR GRANULE CELLS IN THE RAT: ELECTROPHYSIOLOGICAL EVIDENCE
Authors: STONE TREVOR W. 
Published: July 2012

Glutamate and the excitatory aminoacid antagonist, α‐aminoadipic acid (αAA), have been applied by microiontophoresis to Purkinje cells in the rat cerebellum.
Glutamate produced excitation of Purkinje cells and αAA selectively reduced that excitation without affecting responses to acetylcholine or hydrogen ions.
Monosynaptic spikes were evoked in Purkinje cells by stimulating the parallel fibres. αAA had little effect on these spikes when applied alone.
When the Purkinje cell excitability was reduced by the iontophoresis of γ‐aminobutyric acid, αAA then produced failure of the monosynaptic spike on 10 of 13 Purkinje cells, in doses shown to be selectively antagonistic towards aminoacids.
These results support neurochemical evidence that glutamic acid may be the neurotransmitter released by granule cell parallel fibres.
A STUDY OF THE MUSCARINIC RECEPTOR BY GEL ELECTROPHORESIS
Authors: BIRDSALL N.J.M. , BURGEN A.S.V. , HULME E.C. 
Published: July 2012

Muscarinic receptors from the brain of rat, guinea‐pig and frog have been labelled with tritiated propylbenzilylcholine mustard ([3H]‐PrBCM).
After solubilisation and sodium dodecyl sulphate (SDS)‐polyacrylamide gel electrophoresis a single radiolabeled peak was seen which was completely suppressed when labelling was carried out in the presence of 10−6 m atropine. The results suggest the presence of a single polypeptide chain with a molecular weight of ∼80,000.
In the case of intestinal smooth muscle multiple labelled peaks were found. Precautions against proteolysis led to the identification of a major peak with a molecular weight in the region of 80,000.
SINGLE PULSE STIMULATION OF GUINEA‐PIG VAS DEFERENS AND THE PRESYNAPTIC RECEPTOR HYPOTHESIS
Authors: KALSNER STANLEY 
Published: July 2012

The effect of phenoxybenzamine on the efflux of [3H]‐noradrenaline and the mechanical response to single pulse excitation of superfused guinea‐pig vas deferens was determined to examine the validity of the currently accepted hypothesis of a presynaptic negative feedback system on adrenergic nerve terminals.
The adrenoceptor antagonist enhanced both the outflow of tritium and the mechanical response to single pulse stimulation. The efflux of labelled material and the responses to 4 pulses were also enhanced, as expected.
Blockade of neuronal and extraneuronal uptake did not by itself increase nerve‐induced outflow or the mechanical response nor did it prevent phenoxybenzamine from doing so.
The present observations cannot be accommodated within the framework of a hypothesis that proposes that the enhancement of response and tritium efflux by phenoxybenzamine results from blockade of a feedback system whereby noradrenaline released by previous impulses inhibits its own subsequent release.
TEMPERATURE COEFFICIENTS OF AFFINITY CONSTANTS FOR THE BINDING OF ANTAGONISTS TO MUSCARINIC RECEPTORS IN THE RAT CEREBRAL CORTEX
Authors: BARLOW R.B. , BIRDSALL N.J.M. , HULME E.C. 
Published: July 2012

The temperature coefficients of binding of a series of muscarinic antagonists to their receptors in membrane preparations from the rat cerebral cortex has been examined.
At 37°C the affinity constants agree with those determined by antagonism of acetylcholine‐induced contractions of the guinea‐pig ileum.
The temperature‐dependence of the affinity constants is low; for the antagonists examined, the affinity constants at 0°C differ by less than a factor of 3 from those measured at 37°C.
There are qualitative similarities between the estimates of the temperature coefficient of binding of the antagonists to receptors in ileum strips and in the cerebral cortex.
EFFECTS OF METHOXYVERAPAMIL ON THE STIMULATION BY Ca2+, Sr2+ AND Ba2+ AND ON THE INHIBITION BY Mg2+ OF CATECHOLAMINE RELEASE FROM THE ADRENAL MEDULLA
Authors: AGUIRRE J. , FALUTZ J. , PINTO J.E.B. , TRIFARÓ J.M. 
Published: July 2012

Bovine adrenal glands were perfused with Ca2+‐free Locke solution and catecholamine release was induced either by the introduction of Ca2+, Sr2+ or Ba2+ into the perfusion fluid or by the substitution of Na+ by an osmotically equivalent amount of sucrose.
Methoxyverapamil (D600) at a concentration of 3 × 10−4 m blocked the release of catecholamines in response to Ca2+, Sr2+ or Ba2+ stimulation but failed to block the release evoked by the omission of Na+.
Mg2+ (10 to 20 mm) blocked the release induced by Na+‐deprivation; however, this inhibitory effect of Mg2+ was not modified by D600.
D600 blocked the increase in the efflux of 45Ca from the perfused gland induced by the introduction of Ca2+ into the perfusion fluid and blocked the uptake of 45Ca into adrenal medullary slices induced by K+ depolarization.
The results suggest that Ca2+, Sr2+ and Ba2+ may enter the chromaffin cell through the same channel and that this channel is blocked by D600. Mg2+ may enter the cell through the same Ca2+ channel but with a high rate of permeation or it may enter through a channel which is resistant to D600. Alternatively, Mg2+ may exert its inhibitory effect at an extracellular site.
FUNCTIONAL ACTIVITY OF THE NORADRENERGIC INNERVATION OF LARGE CEREBRAL ARTERIES
Authors: DUCKLES SUE PIPER 
Published: July 2012

The role of the sympathetic innervation of cerebral arteries remains controversial. Therefore, the functional activity of the adrenergic innervation of the rabbit basilar artery was characterized and compared to that of a peripheral artery, the ear artery.
Both the ear artery and basilar artery have similar endogenous noradrenaline (NA) contents but accumulation of [3H]‐NA was considerably greater in the basilar artery.
Studies of tritium efflux after loading with [3H]‐NA demonstrated a considerable non‐neuronal component since neither guanethidine nor tetrodotoxin completely blocked tritium efflux during nerve stimulation. Pretreatment with blockers of uptake2 did not eliminate this problem.
Comparison of methods for estimating the functional activity of adrenergic nerves showed that, for the vessels studied, NA content and [3H]‐NA accumulation gave markedly different answers. Fractional release of [3H]‐NA did not correspond to fractional release of endogenous NA.
Adrenergic nerves innervating cerebral arteries are shown to have a high activity relative to a peripheral artery. While cerebrovascular sympathetic innervation may not play an important role in normal circumstances, its influence may be seen in pathological conditions.
ANTICOAGULANT EFFECTS OF SULPHATED POLYSACCHARIDES IN NORMAL AND ANTITHROMBIN III‐DEFICIENT PLASMAS
Authors: KINDNESS G. , LONG W.F. , WILLIAMSON F.B. 
Published: July 2012

Comparison of the effects of sulphated polysaccharides on thrombin‐induced clotting of normal and antithrombin III‐deficient plasmas suggests the involvement of antithrombin III (AT III) in the anticoagulant activities of cellulose, dextran and xylan sulphates.
AT III appears to play little or no role in the anticoagulant activity of carrageenans.
THE EFFECTS OF ACUTE AND CHRONIC ETHANOL ADMINISTRATION AND ITS WITHDRAWAL ON γ‐AMINOBUTYRIC ACID RECEPTOR BINDING IN RAT BRAIN
Authors: TICKU MAHARAJ K. 
Published: July 2012

The effects of acute and chronic ethanol administration, and withdrawal on the binding of the inhibitory neurotransmitter, γ‐aminobutyric acid (GABA), was investigated in rat brain.
Acute ethanol (2 to 4 g/kg i.p. 30 min before removal of brain) produced an increase in the binding capacity of the low affinity GABA receptor binding site.
Following chronic ethanol administration (1 to 21 days), the GABA receptor binding characteristics were not altered. These results suggest a possible adaptation of GABA receptors to the continuous presence of ethanol at the GABA synapse.
During ethanol withdrawal, the affinity of the low affinity GABA receptor binding site was significantly lower than pair‐fed controls at 8 and 16 h withdrawal.
These results suggest that GABA receptor sensitivity may play a role in some of the neuropharmacological effects of ethanol and in its withdrawal symptoms.
EFFECTS OF VASODILATOR DRUGS, ALKALINE PHOSPHTASE, AND CYCLIC AMP‐DEPENDENT PROTEIN KINASE ON THE 45CALCIUM UPTAKE OF SARCOLEMMAL MICROSOMES FROM HUMAN UMBILICAL ARTERIES
Authors: KREYE VOLKER A.W. , SCHLICKER EBERHARD 
Published: July 2012

A microsomal fraction was prepared from human umbilical arteries by differential centrifugation. The preparation was capable of an oxalate‐stimulated Ca2+ uptake at a mean rate of 0.74 nmol Ca2+ mg−1 protein min−1 which could be inhibited by a Ca2+ ionophore, A 23 187, and by Tween 80.
The rate of Ca2+ uptake in the fractions obtained by density gradient fractionation paralleled 5′‐nucleotidase activity suggesting that vesicles of predominantly sarcolemmal origin were responsible for the microsomal Ca2+ uptake.
Cyclic adenosine 3′,5′‐monophosphate‐dependent protein kinase enhanced membrane phosphorylation but did not affect Ca2+ uptake. Preincubation with alkaline phosphatase reduced membrane phosphorylation to a greater extent than Ca2+ uptake. These data are not in favour of a close correlation between Ca2+ uptake and phosphorylation.
None of 15 vasodilator drugs (bencyclane, carbocromen, diazoxide, dilazep, hydralazine, indapamide, isosorbide dinitrate, methyl‐isobutyl‐xanthine, minoxidil, naftidrofuryl, nitroglycerine, prenylamine, sodium nitroprusside, tetracaine, and verapamil) had any effect on Ca2+ uptake at 10−5 m. This suggests that vasodilator drugs do not act by a direct influence on the Ca2+ pumps of vascular smooth muscle cells.
SOME EFFECTS OF SODIUM NITROPRUSSIDE, METHOXYVERAPAMIL (D600) AND NIFEDIPINE ON RAT PORTAL VEIN
Authors: JETLEY MRIDULA , WESTON A.H. 
Published: July 2012

The effects of methoxyverapamil (D600), nifedipine and sodium nitroprusside on noradrenaline‐induced electrical and mechanical activity in rat portal vein have been examined.
D600 and nifedipine produced a concentration‐dependent reduction in mechanical responses to noradrenaline whilst sodium nitroprusside had no effect. The effects of D600 and nifedipine were reversed by increasing the extracellular calcium concentration.
The mechano‐inhibitory effects of D600 were accompanied by a marked reduction in electrical activity with some evidence of electromechanical uncoupling.
The mechano‐inhibitory effects of nifedipine were associated with considerable electromechanical uncoupling.
It is concluded that in the concentrations used, D600 acts primarily by inhibiting calcium influx with some effect on electromechanical coupling whilst nifedipine interferes mainly with the coupling process. The inactivity of sodium nitroprusside suggests that the excitation‐contraction coupling process in rat portal vein is relatively simple and further studies with this tissue seem indicated.
INFLUENCE OF β‐ADRENOCEPTOR BLOCKING AGENTS ON THE TURNOVER RATE OF CARDIAC AND SPLENIC NORADRENALINE IN RATS
Authors: ALEXANDRE J.M. , CHEVILLARD C. 
Published: July 2012

The effects of (+) and (±)‐propranolol, pindolol, alprenolol, practolol, acebutolol and bretylium were studied on the turnover rate of noradrenaline in heart and spleen of rats.Bretylium (8 mg/kg) greatly reduced the turnover rate of noradrenaline in both organs.(+)‐Propranolol (4 and 10 mg/kg) also diminished the turnover rate of noradrenaline, but its effects were smaller than those of (±)‐propranolol (4 and 10 mg/kg).Pindolol (300 μg/kg) greatly increased the turnover rate of noradrenaline; this effect was especially important in the spleen.Alprenolol (4 and 10 mg/kg) acebutolol (20 and 40 mg/kg) practolol (10 mg/kg) did not produce any significant change.These effects are compatible with the view that β‐adrenoceptor blocking agents may affect noradrenaline release in different manners: anaesthetic properties of some of these drugs and blockade of β2prejunctional adrenoceptors produce a diminished release of transmitter, whereas the intrinsic sympathomimetic action of pindolol causes the opposite effect.