bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stimulation by atropine of acetylcholine release and synthesis in cortical slices from rat brain
Authors: MOLENAAR P. C. , POLAK R. L. 
Published: July 2012

. Cortical slices from rat brain were incubated in media containing the irreversible Cholinesterase inhibitor soman and a high KCl concentration, and the release and synthesis of acetylcholine (ACh) were determined.
. Atropine enhanced the release and synthesis of ACh.
. Tetrodotoxin, a substance which blocks nervous conduction, did not influence the release and synthesis of ACh, in the absence or in the presence of atropine. Therefore the nerve endings are probably the site at which atropine acts when stimulating the release and synthesis of ACh.
. Pretreatment of the slices with botulinum type A toxin partially blocked the release and synthesis of ACh and reduced the extra amounts of ACh released and synthesized under the influence of atropine.
. Lowering the calcium or raising the magnesium concentration in the incubation medium reduced the release and synthesis of ACh and their enhancement by atropine.
. Physostigmine decreased the total extractable ACh content of the slices during incubation in a 25 mm KCl containing medium. This decrease was nearly prevented when the release and synthesis of ACh were inhibited by omission of the calcium ions from the medium, but was enhanced by atropine.
. The observations made with pretreatment by botulinum type A toxin, with changes in the calcium and magnesium concentration as well as with physostigmine, all support the theory that it is primarily the release of ACh which is enhanced by atropine and that its stimulating action on the synthesis results from the increased release.
Inhibition of catecholamine Uptake2 by steroids in the isolated rat heart
Authors: Iversen L. L. , Salt P. J. 
Published: July 2012

Various steroids (1 7‐fl‐oestradiol, cortico‐sterone, deoxycorticosterone, progesterone, testosterone and androsterone) produced a dose‐dependent inhibition of the uptake of 3H‐noradrenaline by the Uptake2 mechanism in the isolated perfused heart. It is suggestedthat these results may explain the potentiating effects of such steroids on the responses of vascular smooth muscle to catecholamines.
Function of smooth muscle of the rat renal pelvis—response of the isolated pelvis muscle to angiotensin and some other substances
Authors: FINBERG J. P. M. , PEART W. S. 
Published: July 2012

Summary
The circular component of the renal pelvis muscle of the rat appears as an intact band around the tip of the papilla.
The isolated pelvis muscle strip showed spontaneous rhythmic contractions in Locke solution at 38° C. The rate of contractions corresponded with the rate of pressure fluctuations recorded during free‐flow from a ureteral catheter inserted up to the renal hilum of anaesthetized rats.
Angiotensin and adrenaline (13 ng/ml) produced a rise in tone of the isolated pelvis muscle, and an increase in the rate of spontaneous contractions; noradrenaline produced mainly an increase in the amplitude and rate of spontaneous contractions. Angiotensin and noradrenaline injected intravenously also produced an increased rate of pressure fluctuations recorded from the ureteral catheter.
Acetylcholine, nicotine and 5‐hydroxytryptamine had no effect on the isolated tissue, but isoprenaline was capable of causing a decrease, and tyramine an increase, in the rate of spontaneous contractions in high dose (0.33 μg/ml).
An increase in the tone of the circular pelvis muscle could lead to a reversible obstruction of urine outflow from the kidney.
Specificity of some ganglion stimulants
Authors: BARLOW R. B. , FRANKS FIONA 
Published: July 2012

Summary
The specificity of several ganglion stimulants has been tested on the isolated guinea‐pig ileum by measuring the dose ratios produced by concentrations of hexamethonium.
Most ganglion stimulants are also active at postganglionic receptors, some as blocking agents (for example, lobeline and dimethylphenylpiperazinium), others as agonists (for example, o‐aminophenethyltrimethylammonium and, to a lesser extent, nicotine). The most specific ganglion stimulant, with the least activity at postganglionic receptors, was p‐aminophenethyltrimethylammonium.
The affinity constants of lobeline and dimethylphenylpiperazinium for the muscarine sensitive receptors in the guinea‐pig ileum are 1·05 × 106 and 3·71 × 104, respectively.
The antagonism of p‐aminophenethyltrimethylammonium by hexamethonium gave results consistent with competition up to dose ratios of about 20. Such results could also be obtained if the antagonism were non‐competitive, however, provided large responses could be obtained with less than about 5% of the receptors in the ganglia activated. The affinity constant of hexamethonium is about 2·6 × 105.
It is suggested that the affinity of hexamethonium can largely be ascribed to hydrophobic bonding.
In vivo production of steroids with central depressant actions by the ovary of the rat
Authors: HOLZBAUER MARGARETHE 
Published: July 2012

Summary
In addition to progesterone and 20‐dihydroprogesterone, the following unconjugated steroids were isolated from ovarian tissue and ovarian venous blood of mature, non‐pregnant rats: pregnenolone, 3βOH‐5α‐pregnan‐20‐one, 3αOH‐5α‐pregnan‐20‐one, 20αOH‐5α‐pregnan‐3‐one and 5α‐pregnane‐3α, 20α‐diol.
Their concentration in the ovarian tissue and their secretion rates into the ovarian venous blood was of the same order of magnitude as that of progesterone.
In the evening of the day of pro‐oestrus significant increases in the ovarian contents of the following steroids were observed: progesterone,+ 140%; 3αOH‐5α‐pregnan‐20‐one, +320%; 20αOH‐5α‐pregnan‐3‐one, +195%; sum of pregnenolone and 3βOH‐5α‐pregnan‐20‐one, +275%.
At the same time the ovarian progesterone secretion rate was increased by 365%, that of 3αOH‐5α‐pregnan‐20‐one by 190%.
A possible physiological role of the ovarian allopregnane derivatives as central depressant agents is discussed.
Actions of quazodine (MJ1988) on smooth muscle
Authors: PARRATT J. R. , WINSLOW EILEEN 
Published: July 2012

Summary
Quazodine (MJ1988; 6,7‐dimethoxy‐4‐ethyl‐quinazoline) relaxed a variety of vascular and extravascular smooth muscle preparations and antagonized, non‐competitively, several substances which contract smooth muscle.
This activity was not due to β‐adrenoceptor stimulation or to α‐adrenoceptor blockade.
On the rabbit duodenum, the inhibitory effect was qualitatively similar to that of theophylline and was antagonized by the phosphodiesterase potentiator, imidazole.
The activity of quazodine was similar to, but up to 18 times greater than, that of theophylline and it is suggested that at least part of its activity on vascular and extravascular smooth muscle is due to inhibition of phosphodiesterase.
Effect of pretreatment with 6‐hydroxydopamine on the uptake and metabolism of catecholamines by the isolated perfused rat heart
Authors: HELLMANN G. , HERTTING G. , PESKAR B. 
Published: July 2012

Summary
Isolated rat hearts from control and 6‐hydroxydopamine pretreated animals were perfused with 3H‐noradrenaline or 3H‐dopamine, either at a low perfusion concentration (1.50 × 10−10 mol/ml 3H‐dopamine; 1.18 × 10−10 mol/ml 3H‐noradrenaline) or a high perfusion concentration (296.69 × 10−10 mol/ml 3H‐noradrenaline, 327.45 × 10−10 mol/ml 3H‐dopamine) for 8 minutes.
At the low perfusion concentration, the total activity, the radioactivity in the alumina eluates (sum of 3H‐dopamine, 3H‐noradrenaline and deaminated catechol metabolites) and the concentration of 3H‐dopamine, 3H‐noradrenaline and the deaminated catechol metabolites were decreased in the hearts of the pretreated rats as compared with the controls. The O‐methylated amine metabolites were increased. The deaminated O‐methylated metabolites were increased in the experiments with 3H‐noradrenaline and decreased in the 3H‐dopamine experiments.
Uptake of 3H‐dopamine and 3H‐noradrenaline by the hearts of 6‐hydroxydopamine pretreated rats was decreased to a much smaller extent when perfused with the high concentration than with the low concentration.
At the high perfusion concentration there was a significant difference between control and pretreated animals with regard to the total radioactivity and the radioactivity in the alumina eluates only. The absolute and relative amounts of metabolites were not significantly changed by pretreatment with the exception of the deaminated catechol metabolites in the 3H‐dopamine experiments.
It is concluded that neuronal Uptake 1 is greatly impaired in the hearts from rats pretreated with 6‐hydroxydopamine, but extraneuronal Uptake 2 remains intact.
Stimulating action of catecholamines on isolated preparations of the rat colon and human and rabbit taeniae coli
Authors: BELISLE S. , GAGNON D. J. 
Published: July 2012

Summary
Adrenaline and noradrenaline induced dose related relaxations of the superfused rat colon. The relaxations were progressively transformed into contractions when β‐adrenoceptors were blocked with increasing doses of oxprenolol.
Since phentolamine or phenoxybenzamine inhibited the contractions induced by adrenaline or noradrenaline in the presence of oxprenolol, it is assumed that the contractions are caused by stimulation of excitatory α‐adrenoceptors.
Human and rabbit taeniae coli showed responses that were qualitatively similar to those observed with the rat colon.
Myocardial and haemodynamic effects of phentolamine
Authors: DAS P. K. , PARRATT J. R. 
Published: July 2012

Summary
In cats anaesthetized with pentobarbitone, intravenous infusions of phentolamine ((10–50 μg/kg)/min for 5 min) increased heart rate, left ventricular dp/dt max (without increasing end‐diastolic pressure), aortic dp/dt, cardiac output, myocardial blood flow and metabolic heat production.
Phentolamine‐induced increases in myocardial contractility occurred irrespective of the direction or magnitude of the blood pressure change and were maintained well beyond the actual infusion period.
In cats treated with alprenolol, bretylium or reserpine there was no evidence of increased cardiac contractility following phentolamine administration.
It is concluded that phentolamine, in doses less than those required to produce significant α‐adrenoceptor blockade, increased myocardial contractility through an effect on the sympathetic nervous system.
Spasmolytic effects of cadmium and zinc ions upon the guinea‐pig isolated ileum preparation
Authors: SCHNIEDEN H. , SMALL R. C. 
Published: July 2012

Summary
An investigation has been made of the effects of cadmium and zinc ions upon the contractile response of the guinea‐pig isolated ileum to methacholine, histamine, potassium ion and a.c. field stimulation. The metal ions depress the response to all of these agents.
Radioisotope studies showed that cadmium and zinc ions have very much larger apparent volumes of distribution than sorbitol, both within whole ileum and within strips of the longitudinal smooth muscle layer. The results of these studies were indicative of surface binding and/or intracellular accumulation of these ions.
It is suggested that cadmium and zinc ions directly depress smooth muscle contractility in a non‐specific manner. This action may result from their binding to or accumulation within the muscle cells.
Estimation of urinary 5‐hydroxytryptamine‐O‐glucuronide, a metabolite of endogenous 5‐hydroxytryptamine in sheep
Authors: BARTLET A. L. , GILBERT FRANCES M. 
Published: July 2012

Summary
5‐Hydroxytryptamine‐O‐glucuronide has been extracted from sheep urine and characterized by its chemical reactions and RF values on paper chromatograms.
5‐Hydroxytryptamine‐O‐glucuronide in urine was separated from an inhibitor of β‐glucuronidase using an anion exchange resin, and then estimated by measurement of the 5‐hydroxytryptamine (5‐HT) liberated on incubation with β‐glucuronidase.
About 20% of the 5‐hydroxyindoles found in sheep urine was 5‐HT conjugated with glucuronic acid (1.18 ± 0.08 mg 5‐HT/24 h, thirty experiments).
Sheep urine also contained free 5‐HT (0.35 ± 0.04 mg/24 h, thirty experiments) and 5‐hydroxyindolylacetic acid (4.43 ± 0.33 mg/24 h, thirty experiments).
5‐Hydroxytryptamine‐O‐sulphate was not found in sheep urine.
Effects of the diuretics, triamterene and mersalyl on active sodium transport mechanisms in isolated frog skin
Authors: SALAKO L. A. , SMITH A. J. 
Published: July 2012

Summary
Triamterene reduces the rate coefficients for sodium movement into the transporting system of the isolated frog skin. The isotopically measured ‘active sodium transport pool’ is also reduced.
Mersalyl reduces the rate coefficient for sodium and the calculated sodium flux from the transporting system to the inner bathing solution. The ‘active sodium transport pool’ is increased by this diuretic.
The action of triamterene closely resembles that of amiloride and both reduce the entry of sodium into the system. In contrast, mersalyl limits the exit of sodium ions from the skin.
Effect of morphine on the cerebral contents of metabolites of dopamine in normal and tolerant mice: its possible relation to analgesic action
Authors: FUKUI K. , TAKAGI H. 
Published: July 2012

Summary
The administration of an analgesic dose (10 mg/kg, s.c.) of morphine increased the concentrations of the dopamine metabolites, 3,4‐dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the brains of normal mice, and the time course of the change in the DOPAC concentration corresponded approximately to that of morphine analgesia. The increase in the concentration of the DOPAC induced by morphine (20 mg/kg, s.c.) was completely suppressed by nalorphine (2 mg/kg, s.c.) given 5 min after the morphine administration.
In morphine‐tolerant mice the concentrations of DOPAC and HVA in the brain did not differ from those observed in normal mice, and the increase in the concentrations of DOPAC and HVA in brain after the acute administration of morphine no longer occurred.
Nalorphine (2 mg/kg) given alone did not cause any change in brain DOPAC and HVA concentrations in normal mice.
The morphine‐induced increase in DOPAC and HVA concentrations in the brain are discussed in the light of the hypothesis that dopamine might participate not only in the extrapyramidal motor system but also in the sensory mechanisms of the brain.
Anterograde amnesic effects of pethidine, hyoscine and diazepam in adults
Authors: DUNDEE J. W. , PANDIT S. K. 
Published: July 2012

Summary
The intravenous administration of 5 and 10 mg of diazepam caused anterograde amnesia in 50 and 90% of adults, the peak effect occurring in 2–3 min and action persisting for 20–30 minutes.
Hyoscine (0·4 and 0·6 mg) caused amnesia in 35 and 50% of patients with peak effect not occurring until 50–80 min after injection and action persisting for at least 120 minutes.
With neither drug was there any relationship between the incidence of amnesia and the degree of drowsiness.
Amnesia was not observed after saline or after 50 mg pethidine.
On questioning 6 h after a short operation many patients had no memory of an object which they clearly recognized and described 1 h after surgery.
Berberine in toxin‐induced experimental cholera
Authors: DUTTA N. K. , MARKER P. H. , RAO N. R. 
Published: July 2012

Appendix on berberine in toxin‐induced experimental choleraSummary
Oral administration of berberine to infant rabbits 18–24 h before the intraintestinal administration of choleragenic toxins, arrests diarrhoea or significantly prolongs the survival time.
The use of berberine in the treatment of clinical cholera is further justified.
Berberine is an antidiarrhoeal drug and the host tissues play a major part in the control of diarrhoeal symptoms.
Distribution of Δ9‐tetrahydrocannabinol in the mouse
Authors: FREUDENTHAL R. I. , MARTIN J. , WALL M. E. 
Published: July 2012

Summary
The distribution of Δ9‐tetrahydrocannabinol‐14C in the pregnant and nonpregnant mouse is very similar. High concentrations of radiolabel can be seen in the maternal liver, spleen, lungs, brown fat, adrenal glands, mammary glands, yolk sac placenta and corpora lutea. In the pregnant mouse Δ9‐THC crosses the placenta and enters the foetuses in very low concentrations, with no apparent selective intrafoetal radiolabel accumulation sites. Autoradiograms showing the distribution of 14C‐cannabinoid 2 h after dosing are presented.
A small amount of maternal liver and foetal tissue was removed from the mice, used for autoradiography and extracted with ethyl acetate. Most of the radiolabel in these tissues was solvent extractable and was separated by thin layer chromatography into two fractions, THC and metabolites.
It appears that most of the cannabinoid is present in a free rather than conjugated form.
Uptake of desipramine by the rat vas deferens
Authors: BININI R. , BONACCORSI A. , GARATTINI S. , MORSELLI P. L. , MUSCETTOLA G. 
Published: July 2012

Summary
Determinations of desipramine in the isolated rat vas deferens were carried out in order to study the uptake of the drug and to evaluate how this may correlate with the effect on noradrenaline (NA)‐induced contraction.
Vasa deferentia, in contact with concentrations of desipramine of 1 ng—25 μg/ml for 10 min accumulated the drug about 6‐fold in respect to the medium. When the time of contact was prolonged to 4 h, desipramine (200 ng/ml) was concentrated about 100‐fold. The uptake was not saturable and it was not affected by the presence of imipramine, cocaine, ouabain, dinitrophenol and iodoacetate.
No metabolic process is involved although the accumulation of desipramine is temperature dependent. The release of desipramine from the vas deferens is exponential and it is not affected by the presence of plasma in the medium.
No clear correlation was found between tissue concentration of the drug and the potentiation of noradrenaline responses, probably because of the high non‐specific binding of the drug to tissue components which may mask specific binding sites for NA resulting in potentiation. However, the concentration of desipramine seems to correlate with the inhibition of NA effect which occurs at high doses of desipramine.
Atropine resistant excitation of the urinary bladder: the possibility of transmission via nerves releasing a purine nucleotide
Authors: BURNSTOCK G. , DUMSDAY B. , SMYTHE A. 
Published: July 2012

Summary
The possibility that a purine nucleotide is involved in excitatory transmission to the urinary bladder has been tested. All the purine compounds tested which contained a pyrophosphate bond produced contraction, adenosine triphosphate (ATP) being the most potent. Adenosine and adenosine monophosphate caused relaxation.
The response to ATP closely mimicked the nerve‐mediated contraction, both being characterized by a rapid contraction which was not maintained. A lack of sensitivity to ATP was noted in some preparations of the rat urinary bladder.
Both nerve‐mediated contractions and contractions caused by ATP were blocked by quinidine, while the response to acetylcholine persisted.
Nerve‐mediated responses were depressed during tachyphylaxis produced by high concentrations of ATP. Tachyphylaxis did not occur when low concentrations were used. Possible explanations for these results are discussed.
The results are consistent with the hypothesis that non‐cholinergic excitatory nerves to the guinea‐pig bladder release a purine nucleotide, but do not provide critical evidence for it.
Alterations of histamine metabolism after injections of sex hormones in mice
Authors: HENNINGSSON S. S. G. , ROSENGREN ELSA 
Published: July 2012

Summary
Urinary excretion of histamine in female mice was determined after the injection of oestradiol, progesterone or testosterone. Histamine excretion was increased by oestradiol but was not affected by progesterone. Testosterone administration, by contrast, effected a striking reduction of histamine excretion.
After injection of oestradiol, the kidney histamine forming capacity was greatly elevated, but in the other tissues investigated no significant change occurred.
Testosterone administered in vivo but not in vitro reduced the histidine decarboxylase activity of female mouse kidney to a small fraction of normal.
On thin‐layer chromatography, after extraction and coupling of the amines to 2,4‐dinitrofluorobenzene, the amount of histamine and to a lesser extent, methyl histamine in urine was reduced after testosterone administration. On the chromatogram of urine from untreated mice, an unidentified yellow spot appeared and the quantity of this spot was increased during testosterone treatment.
Excretion of 14C‐edrophonium and its metabolites in bile: role of the liver cell and the peribiliary vascular plexus
Authors: BACK D. J. , CALVEY T. N. 
Published: July 2012

Summary
The metabolism and biliary excretion of 14C‐edrophonium chloride was studied in Wistar rats.
Approximately 5% of the dose was recovered from bile in 6 hours. Most of the radioactivity was eliminated as 14C‐edrophonium glucuronide. Small amounts of the unchanged drug were also detected in bile, particularly during the first hour after administration of the drug.
The concentration of 14C‐edrophonium glucuronide in bile was approximately 15–20 times its concentration in plasma.
In contrast, the concentration of unchanged 14C‐edrophonium was similar in bile and plasma.
Evidence is presented that unchanged 14C‐edrophonium is transferred from plasma to bile via the peribiliary vascular plexus.
Effect of cigarette smoking on human precapillary sphincters
Authors: MATSUBARA ICHIRO , SANO TOYOMI 
Published: July 2012

Summary
. Capillary filtration coefficient of human calf was measured by pressure plethysmography before and after cigarette smoking, which is known to release noradrenaline from nerve terminals of sympathetic vasoconstrictors. Calf blood flow and venous pressure‐volume curves of the calf were also obtained before and after smoking.
. Capillary filtration coefficient decreased by 19% when cigarette smoke was inhaled deeply at 30 s intervals for 12–15 min, indicating the closure of precapillary sphincters.
. Calf blood flow decreased by 31% after smoking, indicating that arterioles were constricted. The degree of arteriolar constriction, however, was not strong enough to lessen the capillary hydrostatic pressure, since the absorption of tissue fluid into capillary blood vessels did not occur.
. The venous system seemed little affected by cigarette smoking, since venous pressure‐volume curves were unaltered.
The presence of β‐adrenoceptors in the guinea‐pig seminal vesicle
Authors: SPEDDING M. , WEETMAN D. F. 
Published: July 2012

Summary
. The preparation of longitudinal smooth muscle strips from guinea‐pig seminal vesicles is described.
. Isoprenaline and salbutamol inhibited contractions produced by parasympathomimetic agents.
. The inhibitory action of isoprenaline was blocked by low concentrations of propranolol and butoxamine. It was concluded that β2‐adrenoceptors were present in the tissue.
. The inhibitory action of isoprenaline was not apparent when adrenaline, noradrenaline, hypogastric nerve or transmural stimulation were used to contract the tissue.