bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in sodium pool and kinetics of sodium transport in frog skin produced by amiloride
Authors: SALAKO L. A. , SMITH A. J. 
Published: July 2012

Summary
. Amiloride produces a decrease in size of the active sodium transport pool of isolated frog skin.
. Rate coefficients for sodium movement into and out of the transporting cells across the outside membrane are decreased by amiloride. The rate coefficient for sodium extrusion across the inside membrane is not significantly affected.
. In the presence and in the absence of amiloride, the relation of sodium transport to outside sodium concentration exhibits similar saturation kinetics but amiloride reduces sodium transport rate at every sodium concentration of the outside solution.
. Labelling of skin with 14C‐amiloride from the outside solution is significantly greater than labelling with 14C‐inulin.
. The results of these studies suggest that amiloride reacts with sites on the outside membrane of the transporting cells as a result of which the rate of sodium movement across this membrane is diminished.
Prejunctional actions of some β‐adrenoceptor antagonists in the vas deferens preparation of the guinea‐pig
Authors: MYLECHARANE E. J. , RAPER C. 
Published: July 2012

Summary
. The β‐adrenoceptor antagonists propranolol, pronethalol, MJ 1999 and Ciba 39089‐Ba reduced responses to field stimulation of the guinea‐pig isolated vas deferens preparation without significantly affecting responses to exogenously added noradrenaline.
. This prejunctional blocking action of the drugs cannot be correlated with their action as β‐adrenoceptor antagonists or non‐specific depressants.
. The blockade produced was more pronounced at low (520 Hz) than at high (50 Hz) frequencies of stimulation.
. The blockade was slow in onset, and once established was poorly reversed by washing the preparation over a period of 1 to 2 h.
. The blockade produced could be reversed by dexamphetamine and cocaine.
. These experiments suggest that the β‐adrenoceptor antagonists may have some actions which closely resemble those of the adrenergic neurone blocking agent guanethidine.
A method for the estimation of the catecholamines and their metabolites in brain tissue
Authors: CRAWFORD T. B. B. , YATES CELIA M. 
Published: July 2012

A method is described whereby the catecholamines, their precursors and metabolites may be estimated in the same brain sample. The method, outlined below, was rigorously tested in pure solution before being applied to the estimation of the catechol and methoxyamines in extracts of rat brain. (i) The brain tissue was homogenized in perchloric acid and the perchloric acid removed as its insoluble potassium salt. (ii) The acid metabolites of the amines were extracted from the acidified extract into ethyl acetate. (iii) After extraction with ethyl acetate, the aqueous extract was treated with acetic anhydride and sodium hydrogen carbonate and the acetylated derivatives of the amines extracted into dichloromethane. (iv) The aqueous solution remaining after extraction with dichloromethane contains the acetylated amino‐acids. Acetyl‐dopa could be extracted into dichloromethane only after acidification of this aqueous solution. The acetyl‐dopa in this dichloromethane extract could be estimated fluorimetrically. (v) The dichloromethane extract containing the acetylated amines was chromatographed on paper in the organic phase of a mixture of toluene: ethyl acetate: methanol: water, 10: 1: 5: 5. (vi) The acetylated amines were eluted and estimated fluorimetrically. A new method was developed for the estimation of 3‐methoxytyramine and its acetylated derivative.
The reproducibility of the method was demonstrated by the consistent estimates obtained for the concentrations of noradrenaline, dopamine and 3‐methoxytyramine in whole rat brain. Adrenaline and metanephrine were not detected. The concentration of normetanephrine in rat brain was at the limit of detection of the method.
Although the estimation for the levels of endogenous amines in whole rat brain were consistent, the recoveries of exogenous amines taken through the procedure were low and very variable. Control experiments demonstrated that the exogenous amines were lost at the perchloric acid extraction stage of the procedure.
Cholinergic mechanisms on the heart and coronary circulation
Authors: BLESA MARTA I. , ROSS G. 
Published: July 2012

The effects of rapid intracoronary injection of acetylcholine (ACh) were studied in anaesthetized open chest dogs. Changes in phasic coronary blood flow were followed with non‐cannulating electromagnetic flow probes and in contractile force with isometric strain gauges.
Increasing doses of ACh from 0.01 to 100 μg produced progressively larger increases in systolic and diastolic coronary blood flow and progressive decreases in end‐diastolic vascular resistance which were blocked by atropine but not by propranolol.
Contractile force showed both negative and positive responses. The negative inotropic effect was small and was blocked by atropine but not by propranolol. The threshold for the negative inotropic response was higher than for the coronary vasodilator effect and the dose response curve was flatter. The positive inotropic response usually showed two components. One component reached its maximum 13 to 18 s after injection, had a high threshold (over 1 μg), was potentiated by atropine and blocked by propranolol. The other reached its maximum 25 to 60 s after the injection, had a threshold between 0.01 and 0.1 μg, and was blocked by atropine but not by propranolol.
These results suggest that the coronary dilator response, the negative inotropic response and part of the positive inotropic response are mediated through “muscarinic” receptors. The remaining component of the positive inotropic response appears to involve catecholamine release.
Effects of monoamine oxidase inhibitors and amphetamine on hypothermia produced by halothane
Authors: FELDBERG W. , LANG W. J. 
Published: July 2012

In cats, the effects of tranylcypromine and pheniprazine, two monoamine oxidase (MAO) inhibitors with strong amphetamine‐like actions, of pargyline, an inhibitor without amphetamine‐like actions, and of amphetamine itself, were examined on the hypothermia produced by a 2 hr period of halothane inhalation.
The hypothermia was prevented by intraperitoneal injections of the three MAO inhibitors. Tranylcypromine and pheniprazine acted in doses of a few milligrams, pargyline in doses of over 100 mg.
The hypothermia was prevented by injections into the cerebral ventricles of tranylcypromine and pheniprazine, in doses which were effective also on intraperitoneal injection; intraperitoneal injections were sometimes more effective. The large doses of pargyline needed to prevent the hypothermia when injected intraperitoneally were not tested by the intraventricular route, as the injections had to be made in a volume of 0.1 ml. In smaller doses intraventricular pargyline was not effective.
The hypothermia was prevented by an intraperitoneal or intraventricular injection of amphetamine in a dose as little as 1 mg; intraperitoneal injections were sometimes more effective.
The effects of tranylcypromine and pargyline given intraperitoneally, and of amphetamine given intraventricularly as well, were also examined on the hypothermia produced by an intraventricular injection of 200 μg noradrenaline. The two MAO inhibitors and amphetamine prevented the hypothermia, or greatly reduced it.
It is concluded (a) that even on intraventricular injection the MAO inhibitors must first be absorbed into the blood stream before they can prevent the hypothermia of a halothane anaesthesia; (b) that their action may not be solely on the anterior hypothalamus; and (c) that they may not act only through MAO inhibition.
Some pharmacodynamic properties of carrageenin in the rat
Authors: DI ROSA M. , SORRENTINO L. 
Published: July 2012

Carrageenin oedema is suppressed by pre‐treating the rats with cellulose sulphate, a kininogen depleting agent. This inhibition is closely related to the dose of cellulose sulphate and to the time course of kininogen depletion.
Oedema induced by egg white or by dextran, in which the mediators are histamine and 5‐hydroxytryptamine, is quite unaffected by cellulose sulphate treatment.
Carrageenin injected intravenously lowers the arterial blood pressure of rats. This hypotensive effect is unaffected by histamine antagonists and is abolished by protease inhibitors and thus seems to be due to kinin release from plasma substrates.
Like cellulose sulphate, carrageenin enhances the esterolytic activity of the blood from treated rats when incubated with benzoyl‐arginine ethyl ester.
The ability of carrageenin to activate the kinin‐forming system could account for both its inflammatory and hypotensive effects.
The mechanism of the paralysing action of tetramisole on Ascaris somatic muscle
Authors: ACEVES J. , ERLIJ D. , MARTÍNEZ‐MARAÑÓN R. 
Published: July 2012

Summary
. Tetramisole (100 μg/ml) paralysed live Ascaris in 3 min.
. Tetramisole (10 μg/ml) caused a sustained contraction of the isolated somatic muscles of the worm. This contraction was not blocked by curare nor by piperazine.
. Tetramisole reduced the resting potential of Ascaris muscle from 34 ± 4 to 10 ± 1 mV.
. Tetramisole caused contraction of Ascaris muscle previously depolarized with high K+ solutions. This observation suggests that tetramisole can induce a contracture that is independent of membrane depolarization.
A comparison between the blocking actions of 2‐(4‐phenylpiperidino) cyclohexanol (AH 5183) and its N‐methyl quaternary analogue (AH 5954)
Authors: MARSHALL I. G. 
Published: July 2012

Summary
. The neuromuscular blocking activities of AH 5183 (2‐(4‐phenylpiperidino) cyclohexanol) and its N‐methyl quaternary analogue (AH 5954) were compared in rapidly stimulated nerve‐skeletal muscle preparations of the rat, chicken and cat.
. The evidence indicated that in isolated preparations the neuromuscular block produced by both AH 5183 and AH 5954 was primarily pre‐junctional in origin. That produced by AH 5954 was readily reversible either by washing the tissue or by reducing the stimulation frequency, whereas that produced by AH 5183 was difficult to reverse in these ways.
. Low doses of AH 5954 sensitized the rat hemidiaphragm preparation to the neuromuscular blocking action of choline. The neuromuscular block produced by choline was reversible by tetraethylammonium but not by neostigmine. This suggested that the blocking action of choline is at least partly pre‐junctional in nature.
. In anaesthetized cats AH 5954 possessed a biphasic neuromuscular blocking action. The initial phase was rapid in onset, suggestive of a postjunctional action, whereas the second phase was prolonged and reversible by choline, suggestive of a prejunctional inhibitory action on the choline transport mechanism. AH 5183 produced no initial blocking action and was irreversible by choline.
. Both AH 5183 and AH 5954 possessed local anaesthetic and α‐adrenoceptor blocking actions. These actions and the neuromuscular blocking action were affected to different degrees by quaternization, suggesting that the three main actions of the two drugs are independent.
. It was concluded that AH 5954 and AH 5183 act at different pre‐junctional sites at the neuromuscular junction, AH 5954 acting extraneuronally by inhibiting choline transport and AH 5183 intraneuronally at the level of the synaptic vesicle membrane.
A comparison of the antinociceptive actions of cholinomimetic and morphine‐like drugs
Authors: IRESON J. D. 
Published: July 2012

Summary
. The antinociceptive activity of morphine, nalorphine, oxotremorine and eserine has been examined in mice in electroshock and phenylbenzoquinone writhing tests.
. The effectiveness of these drugs alone, in combination with each other, and in combination with the muscarinic antagonist atropine sulphate, and with the narcotic antagonist naloxone has also been investigated.
. In both tests morphine was effective and antagonized by naloxone.
. Nalorphine was active in the phenylbenzoquinone test but only slightly active in the electroshock test: it was antagonized by naloxone in both tests.
. Morphine was potentiated by nalorphine in the phenylbenzoquinone test. but antagonized by it in the electroshock test.
. Oxotremorine was effective in both tests, and was antagonized by atropine sulphate.
. Eserine was active only in the phenylbenzoquinone test, and was antagonized by atropine sulphate.
. Oxotremorine was potentiated by eserine in the phenylbenzoquinone test. but antagonized by it in the electroshock test.
. Crossed agonist and partial agonist experiments produced enhancement.
. No antagonism was seen in the crossed antagonist experiments.
. The similarities between the effects of the two classes of drugs are discussed, and the conclusion drawn that they act by separate mechanisms.
Central effects of 6‐hydroxydopamine on the body temperature of the rat
Authors: SIMMONDS M. A. , URETSKY N. J. 
Published: July 2012

Summary
. Rats which had been pretreated with intraventricular injections of 6‐hydroxydopamine (6‐OHDA) to cause a selective depletion of brain noradrenaline (NA) to 20.7% of control brain NA and brain dopamine (DA) to 34.6% of control brain DA retained an unimpaired ability to regulate their body temperatures on exposure to heat or cold. This is discussed in relation to the possible role of brain NA in the central control of body temperature.
. Intraventricular injections of 6‐OHDA in normal rats at room temperature caused an acute, dose dependent hypothermia of up to 4.5° C which lasted for 4–5 hours. Depletion of brain NA and DA by prior treatment with 6‐OHDA markedly reduced the hypothermic response to a subsequent dose of 6‐OHDA. Selective depletion of brain NA without affecting brain DA did not reduce the response to 6‐OHDA. The acute hypothermic response to 6‐OHDA, may therefore, be related to a release of DA in the brain.
Evidence that adenosine triphosphate or a related nucleotide is the transmitter substance released by non‐adrenergic inhibitory nerves in the gut
Authors: BURNSTOCK G. , CAMPBELL G. , SATCHELL D. , SMYTHE ANNE 
Published: July 2012

Summary
. Stimulation of the vagal non‐adrenergic inhibitory innervation caused the release of adenosine and inosine into vascular perfusates from the stomachs of guinea‐pigs and toads.
. Stimulation of portions of Auerbach's plexus isolated from turkey gizzard caused the release of adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP).
. ATP, added to solutions perfused through the toad stomach vasculature, was broken down to adenosine, inosine and adenine.
. Of a series of purine and pyrimidine derivatives tested for inhibitory activity on the guinea‐pig isolated taenia coli, ATP and ADP were the most potent.
. ATP caused inhibition of twelve other gut preparations previously shown to contain non‐adrenergic inhibitory nerves. The inhibitory action of ATP was not prevented by tetrodotoxin.
. Quinidine antagonized relaxations of the guinea‐pig taenia coli caused by catecholamines or adrenergic nerve stimulation. Higher concentrations of quinidine antagonized relaxations caused by ATP or non‐adrenergic inhibitory nerve stimulation.
. When tachyphylaxis to ATP had been produced in the rabbit ileum, there was a consistent depression of the responses to non‐adrenergic inhibitory nerve stimulation but not of responses to adrenergic nerve stimulation.
. It is suggested that ATP or a related nucleotide is the transmitter substance released by the non‐adrenergic inhibitory innervation of the gut.
Cardiovascular actions of substituted adenosine analogues
Authors: ANGUS J. A. , COBBIN L. B. , EINSTEIN ROSEMARIE , MAGUIRE M. H. 
Published: July 2012

Summary
The effects of adenosine on systemic blood pressure, coronary blood flow and cardiac contractility and rate were studied in anaesthetized open‐thorax dogs.
The potency and duration of action of substituted adenosine analogues were compared with that of adenosine.
With the exception of 2‐chloroadenosine, in which coronary dilator activity was enhanced, substitution in the 2‐position of the adenosine molecule reduced activity.
In all cases 2‐substitution prolonged the duration of the coronary dilator activity of adenosine.
N6‐Methylation of adenosine and 2‐chloroadenosine reduced their coronary dilator activities, but had no effect on the duration of the response.
Comparison of the coronary dilator potencies and hypotensive activities of 2‐ethylaminoadenosine and 2‐methoxyadenosine indicates that these analogues have some specificity for the coronary bed.
Effects of ranatensin, a polypeptide from frog skin, on isolated smooth muscle
Authors: CLINESCHMIDT B. V. , GELLER R. G. , GOVIER W. C. , PISANO J. J. , TANIMURA T. 
Published: July 2012

Summary
The actions of bretylium tosylate on neuromuscular transmission in the rat phrenic nerve diaphragm preparation have been investigated by electro‐
On the guinea‐pig ileum, threshold doses elicit repeated maximal spike contractions which are blocked by atropine. In the presence of atropine, higher concentrations of ranatensin elicit small contraction spikes superimposed on a relatively weak sustained contraction. These latter two actions are not blocked by increasing the concentration of atropine.
Other smooth muscle preparations respond as follows: rat uterus, rhythmic contractions; rat duodenum, relaxation; rabbit aortic strip, contraction. Atropine has no effect on the above responses. The rat aortic strip does not respond to ranatensin. Ranatensin is four times as active as bradykinin on the rat uterus.
Ranatensin can be readily distinguished from other known peptides such as angiotensin, bradykinin and the eledoisin‐like peptides, by bioassay.
Comparative study of antral gastrin activity in some mammals
Authors: AMURE B. O. , OMOLE A. 
Published: July 2012

Summary
The amounts of crude gastrin extract and the gastrin activities of extracts from antral mucosa of several mammalian species have been determined.
The yield of crude gastrin powder per gramme wet weight of antral mucosa was greater in goats and rabbits than in cat, dog, man or pig.
Statistical differences do not appear to exist between the potencies of gastrin from the various species. The potencies of the powders were within the ranges 1·2–1·8 μg porcine gastrin II/mg with the exception of the extract from frozen dog antra (0·8 μg/mg).
During prolonged freezing of animal antra and consequent thawing before extraction, significant losses in gastrin activity occurred in the dog.
The amounts of gastrin activity per gramme wet weight of antral mucosa from herbivores (goat, rabbit and cattle) were greater than those from non‐herbivores (cat, dog, man and pig).
Responses of mean arterial pressure to pressor agents and diuretics in renal hypertensive and salt hypertensive rats
Authors: NICHOLAS T. E. 
Published: July 2012

Summary
The responses of the mean arterial pressure to (—)‐noradrenaline, tyramine, angiotensin II‐val5‐amide, vasopressin and rat renin have been contrasted in renal hypertensive and in salt plus desoxycorticosterone hypertensive rats. The responses were measured in rats both unanaesthetized and rats anaesthetized with pentobarbitone.
Responses of unanaesthetized, ganglion blocked renal hypertensive rats to noradrenaline, tyramine and vasopressin markedly exceeded, and to angiotensin II and renin were markedly smaller than, those of unanaesthetized ganglion blocked salt + DOC hypertensive animals. Responses to angiotensin and to renin were apparently enhanced in the latter animals.
Hydrochlorothiazide and frusemide markedly reduced mean arterial pressure in salt + DOC hypertensive rats before and after ganglionic blockade.
Neither diuretic caused significant reduction in the mean arterial pressures of unanaesthetized, renal hypertensive rats in the absence of ganglionic blockade: frusemide did so in anaesthetized and unanaesthetized rats after ganglionic blockade.
Whereas the diuretics did not affect the responses of the renal hypertensive rats to pressor agents, frusemide and to a lesser extent hydrochlorothiazide tended to depress the responses to pressor agents in salt induced hypertension.
Hydrochlorothiazide did not influence mean arterial pressure in unanaesthetized rats with neurogenic hypertension.
Evidence for inhibition of the reuptake of 5‐hydroxytryptamine and noradrenaline by tetrahydronaphthylamine in rat brain
Authors: BRUINVELS J. 
Published: July 2012

Summary
The concentrations of 5‐hydroxytryptamine (5‐HT), 5‐hydroxyindolacetic acid (5‐HIAA) and noradrenaline (NA) in homogenized rat brains were determined after intraperitoneal injection of 1,2,3,4‐tetrahydro‐2‐naphthylamine (THN).
THN caused a decrease in the concentration of brain 5‐HIAA without altering its 5‐HT content, but the percentage of ‘free 5‐HT’ in the supernatant increased. The decrease in 5‐HIAA and the increase in free 5‐HT were negatively correlated, suggesting inhibition of the reuptake of 5‐HT.
THN decreased brain NA content without changing free NA. The fact that no increase in free NA occurred is ascribed to the action of catechol‐O‐methyl‐transferase.
Inhibition of the reuptake of NA and of 5‐HT was further studied by using the compounds 5‐methyl‐α‐ethyl‐meta‐tyramine (H 75/12) and 4,α‐dimethyl‐meta‐tyramine (H 77/77). The results of these studies also suggested inhibition by THN of the reuptake of 5‐HT as well as of NA.
The action of THN is explained by inhibition of the reuptake of NA and of 5‐HT and by release of NA from its stores. However, the possibility is not excluded that, instead of releasing NA from its stores, THN inhibits the enzyme dopamine‐β‐hydroxylase.
Comparison of the effects of morphine, pethidine and pentazocine in rabbits pretreated with a monoamine oxidase inhibitor
Authors: PENN R. G. , ROGERS K. J. 
Published: July 2012

Summary
Rabbits were premedicated with pargyline and the changes in rectal temperature measured after the intravenous infusion of morphine, pentazocine and pethidine.
Pethidine produced pronounced rises in rectal temperature which were dose dependent. One out of the four rabbits given 1 mg/kg died in hyperthermia. Four out of the four rabbits given 5 mg/kg died in hyperthermia. Doses of 10 mg/kg of pethidine caused no significant change in the rectal temperature of rabbits not pretreated with pargyline.
Morphine and pentazocine in doses of 1 mg and 10 mg/kg did not significantly alter the rectal temperature of rabbits pretreated with pargyline except for one rabbit which developed a delayed hyperthermia following the injection of morphine 1 mg/kg.