bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hormonal regulation of rat seminal vesicle sensitivity to adrenaline, noradrenaline, acetylcholine and acetyl‐β‐methylcholine
Authors: PICARELLI ZULEIKA P. , VALLE J. R. 
Published: July 2012

The influence of the hormonal condition of rats on the responsiveness of their seminal vesicles to drugs was investigated by determining pD2 and α values for adrenaline, for noradrenaline, for acetylcholine and for acetyl‐β‐methyl‐choline on isolated vesicles of normal, of castrated, and of oestradiol‐treated castrated rats.
pD2 values of adrenaline, of noradrenaline, of acetylcholine and of acetyl‐β‐methylcholine acting on seminal vesicles of castrated or of oestradiol‐treated castrated rats were greater than the corresponding values obtained on the organs of normal rats. The differences were significant at the level P < 0.001.
Similar results were obtained for the relative intrinsic activity of noradrenaline and acetyl‐β‐methylcholine.
Consequently affinity of adrenaline, noradrenaline, acetylcholine and of acetyl‐β‐methylcholine for their corresponding receptors and the stimulus produced by each unit of the noradrenaline‐receptor or acetyl‐β‐methylcholine‐receptor complex were enhanced.
The data indicate that an increase in the sensitivity of the smooth musculature of seminal vesicles to adrenaline and noradrenaline as well as to acetylcholine and acetyl‐β‐methylcholine is obtained by castration, or by treatment with oestradiol following castration.
The pharmacological nature of the response of the reserpinized guinea‐pig vas deferens to postganglionic nerve stimulation
Authors: BELL C. 
Published: July 2012

. Intracellular recordings from single smooth muscle cells of the guinea‐pig vas deferens have been made after depletion of neuronal stores of noradrenaline by chronic reserpine treatment.
. Junctional responses to postganglionic hypogastric nerve stimulation were depressed, but large excitatory junction potentials (EJPs) and action potentials could still be evoked by stimulation at 1–2 c/s.
. These junctional responses were not reduced by the presence of hyoscine (5 × 10−7g/ml.), but were greatly depressed by the presence of bretylium (2 × 10−6g/ml.).
. Even in the presence of bretylium, junctional responses leading to action potentials could still be evoked by using high voltages of stimulation.
. It is concluded that when neuronal noradrenaline stores have been depleted by reserpine some noradrenaline is still available for release by nerve stimulation.
. It is further concluded that if the non‐adrenergic component of the response of the guinea‐pig vas deferens to nerve stimulation is cholinergic, this component is resistant to blockade by hyoscine.
Blockade of biogenic amine synthesis: its effect on the responses to leptazol and dexamphetamine in rats
Authors: SPENCER P. S. J. , TURNER T. A. R. 
Published: July 2012

. The convulsive effects of leptazol in the rat are potentiated by prior treatment with dexamphetamine.. An intact dopamine synthesis is necessary for the potentiation of the convulsive action of leptazol.. An intact noradrenaline synthesis is not necessary for this action of amphetamine, as long as the dopamine synthesis is intact.. An intact 5‐hydroxytryptamine synthesis is not necessary for the potentiation to be shown.. Blockade of either noradrenaline, dopamine or 5‐hydroxytryptamine synthesis has no direct effect on leptazol convulsions.. It is possible that it is an intact 3–4 dihydroxyphenylalanine (dopa) synthesis rather than an intact dopamine synthesis that is involved.
Secretion from the cortex‐free bovine adrenal medulla
Authors: SCHNEIDER F. H. 
Published: July 2012

. The isolated bovine adrenal medulla was prepared from whole glands by careful removal of the cortex. The tissue was perfused with physiological salt solution and stimulated with a variety of secretogogues.
. Catecholamines were secreted from the tissue upon stimulation with carbamylcholine, nicotine sulphate, acetylcholine bromide, histamine dihydrochloride, (+)‐amphetamine sulphate and potassium chloride.
. Carbachol‐induced secretion of catecholamines was reduced in the presence of either hexamethonium bromide or tetracaine hydrochloride, during perfusion with calcium‐free perfusion fluid, or during perfusion at low temperature.
. Stimulation of the medulla with carbachol also led to secretion of chromaffin granule protein and acid deoxyribonuclease. The relationships between catecholamines secreted and the amounts of these proteins secreted were similar to the corresponding values for the perfused whole bovine adrenal gland. Perfusate lactate dehydrogenase activity and perfusate haemoglobin content were unchanged after carbachol stimulation.
. It is concluded that there are no differences in the mechanisms for catecholamine secretion from the cortex‐free perfused medulla and the perfused whole gland.
The possible role of adenosine in the coronary dilator action of some pyrimidopyrimidines and pteridines
Authors: NOTT M. W. 
Published: July 2012

Summary
The abilities of some pyrimidopyrimidines (including dipyridamole) and pteridine derivatives to potentiate heart block produced by adenosine in the guinea‐pig and to produce coronary dilatation in kitten hearts were investigated.
The results demonstrated a correlation between adenosine potentiating and coronary dilating activities of the compounds studied, and are therefore compatible with the concept that compounds of the dipyridamole type owe their coronary dilator activity to potentiation of endogenous adenosine.
A pharmacological analysis of the peristaltic reflex in the isolated colon of the guinea‐pig or cat
Authors: CREMA A. , FRIGO G. M. , LECCHINI S. 
Published: July 2012

Summary
The peristaltic reflex in the colon was elicited by a localized intraluminal stimulus. The contractile response of the longitudinal coat, which consists of two phases, begins before the start of propulsion. Although the contractions of the longitudinal and circular musculature are usually associated, they may be independent of each other. In particular, the longitudinal contraction does not seem to be necessary for propulsion.
Both the longitudinal reflex contraction and the segmental responses of the circular muscle to distension, namely a contraction above and a relaxation below the bolus, are abolished by tetrodotoxin and ganglion blocking agents.
In the guinea‐pig, longitudinal and circular reflex contractions are usually resistant to antimuscarine, antihistamine and antitryptamine drugs but in the cat they are abolished by antimuscarine drugs. In both species, however, atropine and hyoscine can impair propulsion by blocking selectively the descending inhibition. In the cat, it is possible to find doses which abolish the descending inhibition without affecting the contractile responses of the longitudinal and circular muscle.
Sympathetic denervation and pretreatment with reserpine do not affect the propulsive activity. The maintenance of the descending inhibition in denervated organs suggests that the inhibitory neurones to the circular muscle are not adrenergic.
On the basis of the effects of drugs, the possible nervous mechanism subserving the polarity of propulsion has been examined. Such a mechanism seems to require an inhibitory pathway involving muscarinic receptors at some point.
Pelvic nerve stimulation facilitates propulsive activity. The effect of transmural stimulation is different at low and at high frequencies of stimulation. The inhibitory effect of sympathetic stimulation on the reflex responses seems to be due mainly to an action on intrinsic nervous structures.
Renal tubular flow dynamics during angiotensin diuresis in the rat
Authors: FINBERG J. P. M. , PEART W. S. 
Published: July 2012

Summary
Tubular size and lissamine green transit times were measured in rat kidneys undergoing a diuretic response to angiotensin II (05 μg/kg per min), and compared with the changes observed during diuresis induced by osmotic diuretics, noradrenaline and chlorothiazide.
Angiotensin always caused a marked prolongation in proximal and distal tubular transit times; individual distal convolutions were coloured for prolonged periods, and lissamine green appeared in high concentration in distal tubules.
Marked changes were observed in superficial tubular calibre during a stable diuretic response to angiotensin. Where distal tubular diameter was normal for the rate of urine flow, proximal tubular volume was generally reduced. In a number of experiments, however, distal tubules were markedly dilated, and in these cases proximal tubular volume was also often increased. Angiotensin may therefore be capable of causing a degree of internal hydronephrosis in the rat kidney.
Prolongation of dye transit times, and the appearance of a concentrated lissamine green bolus in distal tubules, was suggestive of a decreased superficial nephron flow rate, indicating that the diuretic effect of angiotensin may take place only through deeper nephrons.
Comparison of the bronchodilator and cardiovascular actions of salbutamol, isoprenaline and orciprenaline in guinea‐pigs and dogs
Authors: DALY M. J. , FARMER J. B. , LEVY G. P. 
Published: July 2012

Summary
Bronchodilator and cardiovascular actions of salbutamol and isoprenaline have been compared in guinea‐pigs and dogs. Orciprenaline was also included in some experiments.
All three drugs antagonized acetylcholine‐induced increases in pulmonary resistance. In addition they increased heart rate and decreased arterial blood pressure.
Compared with isoprenaline, salbutamol has relatively stronger actions on bronchial and vascular β‐adrenoceptors than on cardiac β‐adrenoceptors, on which its action is very weak. In contrast, orciprenaline has similar potencies on β‐adrenoceptors in these three tissues.
The positive chronotropic potency of intravenously or orally administered salbutamol was increased in conscious dogs. These heart rate responses to salbutamol were probably mainly reflex in origin.
Salbutamol and orciprenaline were both longer acting than isoprenaline.
The results support the idea of two distinct groups of β‐adrenoceptors. Salbutamol differentiates between bronchial and vascular β2‐adrenoceptors on the one hand and cardiac β1‐adrenoceptors on the other. Isoprenaline and orciprenaline do not differentiate between β1‐ and β2‐adrenoceptors.
Pharmacological properties of amino‐oxyacetic acid in the chicken
Authors: OSUIDE G. 
Published: July 2012

Summary
The effects of amino‐oxyacetic acid (AOAA) on the central nervous system and on skeletal muscle have been examined in the chicken.
AOAA had both anticonvulsant and convulsant effects, depending on the dose, as in other species.
The convulsant effect, accompanied by EEG spiking, decreased rapidly with increase in age of young chicks.
The convulsant effect was exerted primarily through supraspinal centres.
Of control depressants tested, only troxidone and small doses of AOAA afforded significant protection against AOAA seizures.
Analysis of the inhibition of pethidine N‐demethylation by monoamine oxidase inhibitors and some other drugs with special reference to drug interactions in man
Authors: CLARK B. , THOMPSON J. W. , WIDDRINGTON G. 
Published: July 2012

Summary
N‐Demethylation of pethidine was studied in microsomal suspensions from unstarved male rat liver and the N‐demethylase identified as belonging to the class of hepatic microsomal mixed function oxidases.
A study of the structure/action relationships of compounds inhibiting pethidine N‐demethylase revealed that hydrazine derivatives including phenylhydrazine, methylphenylhydrazine and mebanazine were all potent competitive inhibitors.
Pethidine N‐demethylase was only slightly inhibited by histamine and amphetamine but not by adrenaline and ephedrine nor by several miscellaneous compounds including piperidine, N‐ethylpiperidine, N‐methylpiperidine, N‐methylammonium, hydrallazine or pethidinic acid.
Several psychotropic drugs were all found to be potent competitive inhibitors of pethidine N‐demethylase. These included monoaminoxidase inhibitors (the most active being nialamide and phenoxypropazine [Ki = 0·01 mm]; the least active iproniazid [Ki = 1·05 mm]); the tranquillizers promazine, propiomazine and chlorpromazine and tricyclic antidepressants (opipramol [Ki = 0·01 mm], imipramine [Ki = 0·03 mm], desipramine [Ki = 0·03 mm] and amitryptyline [Ki = 0·03 mm]). Hydrocortisone [Ki = 0·3 mm], prednisolone [2·8 mm] and nalorphine [0·07 mm] were also inhibitors, whilst SKF 525A was the most active of all [Ki = 0·002 mm].
These results are discussed in relation to the clinically observed drug interactions which may occur between monoamineoxidase inhibitors and pethidine. It is concluded that since many different groups of drugs, including monoamineoxidase inhibitors, tranquillizers, tricyclic antidepressants, steroids, nalorphine, SKF 525A and barbiturates compete for cytochrome P450 reductase, it is possible that this mechanism may account, at least in part, for the observed interactions of these various drugs in man.
Effects of 5‐hydroxytryptamine on isolated strips of the guinea‐pig stomach
Authors: YAMAGUCHI T. 
Published: July 2012

Summary
The effects of 5‐hydroxytryptamine (5‐HT) on isolated strips of the longitudinal and circular muscles of the guinea‐pig stomach were investigated.
5‐HT (0·1–1 μg/ml) increased the resting tension of the longitudinal muscle while it decreased that of the circular muscle. These effects were blocked by lysergic acid diethylamide (LSD), but were not affected by tetrodotoxin, hyoscine or morphine.
Electrical stimulation caused contraction in the longitudinal muscle, and contraction followed by relaxation in the circular muscle. In both the longitudinal and circular muscles, the evoked contractions were potentiated by 5‐HT. This effect was blocked by tetrodotoxin, hyoscine and morphine, but was not affected by LSD.
It is concluded that, in the stomach as well as the intestine of the guinea‐pig, there are two kinds of 5‐HT receptors: the morphine‐sensitive M receptor is situated on the intramural nerves and the D‐receptor on the smooth muscle cells.
Measurement of inflammation in man and animals by radiometry
Authors: COLLINS A. J. , RING E. F. J. 
Published: July 2012

Summary
A radiometer is described, which is sensitive to infrared radiation in the range 0–25 μm, and which, after calibration with a black body standard can be used as a non‐contact, fast reading thermometer.
An example of acute joint inflammation in a patient with rheumatoid arthritis is described. The temperatures over the joint measured by radiometry, followed inflammatory changes in the joint effusion.
Using rats, the method of measuring inflammation by radiometry was compared with measurements of increase in joint size. Changes measured by radiometry preceded changes shown by increase in joint size.
The radiometer method was able to demonstrate the effect of an anti‐inflammatory drug, given orally, against carrageenin inflammation.
The procedure was found to be an accurate means of measuring inflammation and the anti‐inflammatory effects of drugs. It was faster and less tedious than the other methods for the quantitative measurement of inflammation in man and animals.
Effects of adrenaline, isoprenaline and histamine on transsinusoidal fluid filtration in the cat liver
Authors: GREENWAY C. V. , LAUTT W. W. 
Published: July 2012

Summary
Hepatic volume was recorded by a plethysmographic technique in cats anaesthetized with pentobarbitone. It has been shown previously that during an increase of hepatic venous pressure in this preparation, there is a maintained filtration of fluid from the sinusoids into the plethysmograph. The rate of this filtration is directly proportional to the increase in hepatic venous pressure. Infusions of drugs during this period of steady filtration provide a sensitive measure of the effects of the drugs on transsinusoidal fluid transfer.
Infusions of adrenaline, isoprenaline and histamine had no effect on the steady transsinusoidal filtration produced by an increased hepatic venous pressure. It is concluded that these agents do not change sinusoidal hydrostatic pressure by more than 1·5 mmHg (1 mmHg ≡ 1·333 mbar) even though they alter hepatic arterial and portal flows. They do not change sinusoidal surface area by more than 20% and histamine does not change sinusoidal permeability.
The data are discussed in the light of current theories on the application of Starling's hypothesis to the liver sinusoids and to muscle capillaries. The postsinusoidal resistance appears to be very low in the liver and it does not increase during contraction of the capacitance vessels. The liver does not have presinusoidal sphincters, and closed sinusoids analogous to closed capillaries in skeletal muscle do not occur. The major factor controlling hepatic transsinusoidal fluid movements in the anaesthetized cat is hepatic venous pressure.
Some aspects of the inhibition of the action of antidiuretic hormone by lithium ions in the rat kidney and bladder of the toad Bufo marinus
Authors: HARRIS CAROL A. , JENNER F. A. 
Published: July 2012

Summary
The effect of intravenous infusions of various ions on the antidiuretic action of antidiuretic hormone has been studied in rats.
Lithium (13 mmol/l.) reversibly inhibits the antidiuretic responses. Similar concentrations of potassium, rubidium, strontium, magnesium, choline and calcium do not. Lithium has a similar effect on the antidiuretic activity of oxytocin.
The inhibition is not simply related to blood nor whole body lithium concentrations.
Lithium (2 mmol/1.) in contact with the serosal surface also inhibits the transport of water facilitated by either 0·5 u/l. antidiuretic hormone or 1·1 mmol/l. cyclic adenosine monophosphate in the isolated toad bladder.
Choline (2 mmol/l.) on the serosal surface also inhibits the transport of water facilitated by vasopressin in the toad bladder.
Comparison of blockade at α‐adrenoceptors by thymoxamine and phentolamine in peripheral arteries and veins of man
Authors: COLLIER J. G. , NACHEV CH. , ROBINSON B. F. 
Published: July 2012

Summary
The antagonism at α‐adrenoceptors by thymoxamine and phentolamine of the response to noradrenaline was investigated in the limb veins and arteries of man.
Brachial artery infusions of thymoxamine (40 μg/min) produced rises in resting arterial flow of up to 100%. When infused mixed with noradrenaline, thymoxamine (40 μg/min) attenuated the blood flow response to noradrenaline. Blockade was of a similar degree to that which occurred following a 10 min infusion of phentolamine (40 μg/min).
Local intravenous infusion of thymoxamine (400–2,000 ng/min) mixed with noradrenaline attenuated the venoconstrictor response to noradrenaline. The degree of attenuation was similar to that seen after a 10 min infusion of phentolamine (500 ng/min). Blockade after thymoxamine did not last longer than 16 minutes. Neither thymoxamine nor phentolamine altered resting venous compliance.
Local intravenous infusions of thymoxamine (500 ng/min) and phentolamine (500 ng/min) abolished the sympathetically mediated venoconstriction produced by overbreathing.
Systemic injection of thymoxamine (0·1 mg/kg) did not block the reduction in forearm arterial flow produced by locally infused noradrenaline. In two out of three experiments, however, it produced some antagonism of noradrenaline induced venoconstriction. Systemic phentolamine (5 mg) blocked the effect of noradrenaline in the arterial bed, but antagonized its actions in the veins in only one out of three experiments.
Effects of dopamine on the conductance of perfused vascular beds of the chloralosed cat
Authors: HAMILTON T. C. 
Published: July 2012

Summary
Dopamine produced vasoconstriction followed by secondary vasodilatation in the perfused cat hindquarters and splanchnic region. Low doses produced only vasodilatation in the splanchnic region.
Phenoxybenzamine abolished, while desipramine and cocaine potentiated, the vasoconstrictor and secondary dilator actions of dopamine.
After phenoxybenzamine, dopamine produced only vasodilatation in both the hindquarters and splanchnic region, being more effective in the latter.
Haloperidol, but not propranolol, atropine or mepyramine, antagonized dopamine‐induced vasodilatation.
Dopamine differs from other catecholamines in that, while its cardiac effects are mediated by a β‐adrenoceptive mechanism, its vasodilator effects are not.
The results support the concept of a specific receptor mediating dopamine vasodilatation.
Studies on the possible role of brain histamine in behaviour
Authors: GERALD M. C. , MAICKEL R. P. 
Published: July 2012

Summary
The possible role of brain histamine in behavioural performance was studied in rats using thirst‐induced water consumption, continuous (Sidman) avoidance, and reinforcement withdrawal test systems.
Parenteral administration of a variety of antihistamines to rats decreased thirst‐induced water consumption; this effect could be antagonized by administration of histamine directly into the brain by a ventricular cannula.
When intraventricular doses of histamine were administered to rats at weekly intervals, an adaptation was seen in the effects of the amine on continuous avoidance behaviour. With succeeding doses, the initial period of depression of avoidance responding was shortened and the subsequent rebound stimulation disappeared.
The results support the hypothesis that histamine in the brain is involved in several behavioural phenomena.
Salivation induced by prostaglandin F2α and modification of the response by atropine and physostigmine
Authors: HAHN R. A. , PATIL P. N. 
Published: July 2012

Summary
Administration of PGF2α to the anaesthetized dog produced dose‐related salivation accompanied by weak pressor and negative cardiac chronotropic effects. Injection of PGE1 did not produce salivation.
Electrical stimulation of the chorda tympani nerve or injection of PGF2α produced salivary responses which were not affected by pretreatment with phentolamine, but were abolished by pretreatment with atropine. Treatment with hexamethonium reduced the response to nerve stimulation but did not alter the response to PGF2α.
Pretreatment with physostigmine augmented the salivary response to both nerve stimulation and PGF2α.
These experiments suggest that salivation produced by PGF2α is probably due in part, to liberation of acetylcholine from cholinergic nerve terminals. These results are consistent with previously proposed modulatory functions of prostaglandins on neurotransmission.
Nerve‐mediated inhibition of mechanical activity in rabbit duodenum and the effects of desensitization to adenosine and several of its derivatives
Authors: WESTON A. H. 
Published: July 2012

Summary
. Inhibition of mechanical activity in longitudinal muscle strips of rabbit duodenum was induced by perivascular and intramural nerve stimulation.
. The effects of perivascular stimulation were abolished by phentolamine + propranolol, guanethidine, reserpine and by tetrodotoxin. The effects of intramural stimulation were abolished only by tetrodotoxin.
. Noradrenaline, phenylephrine, isoprenaline, adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP) and adenosine each produced an inhibition of mechanical activity. The relative potencies of these agonists were noradrenaline>isoprenaline>phenylephrine>ATP>ADP>adenosine>AMP.
. Exposure of tissues to high concentrations of either ATP or adenosine desensitized the tissue to further exposure to ATP, ADP, AMP and adenosine, whilst the inhibitory effects of noradrenaline, phenylephrine and isoprenaline and of perivascular and intramural stimulation were unaffected. The effects of desensitization were reversible.
. It was concluded that the effects of intramural stimulation were mediated neither by noradrenaline nor by adenosine or its derivatives.