bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prejunctional inhibition mediated via α2-adrenoceptors in excitatory transmission of canine small intestine
Authors: NAKAHATA NORIMICHI , NAKANISHI HIRONORI , SUZUKI TAKEHIKO 
Published: April 2011

Abstract
Noradrenaline(NA) inhibited the contractile responses of longitudinal and circular muscles of canine small intestine to field stimulation (20 Hz, 1 ms, supramaximal voltage for 5 s). The purpose of this study was to see if NA-induced inhibitory action is mediated via α1- or α2-receptors and whether the inhibitory action involved prostaglandins. In both muscle layers the α2-agonist, clonidine inhibited the contractile response to field stimulation more potently than did the α1-agonists phenylephrine or methoxamine. It is suggested that NA-mediated prejunctional inhibition is mediated via α2-receptors. Yohimbine, an α2-adrenoceptor blocking drug antagonized NA-induced prejunctional inhibition, while E-643, an α1-blocker, did not affect the inhibition. These results suggest that the inhibitory action of NA is mediated via α2-receptors in both muscle layers. Indomethacin, an inhibitor of prostaglandin synthesis, did not affect NA-induced prejunctional inhibition in circular muscle, while augmenting it in longitudinal muscle. It is thought that NA-induced prejunctional inhibition is not mediated via prostaglandin release.
Disulfiram-like effect of diethyl maleate on barbiturate-induced hypnosis and 5-hydroxytryptamine metabolism
Authors: MINEGISHI AKEMI , FUKUMORI RYUJI , SATOH TETSUO , KITAGAWA HARUO 
Published: April 2011

Abstract
Diethyl maleate (DEM, 600 mg kg−1 i.p.) significantly potentiated hexobarbitone hypnosis and lowered plasma hexobarbitone level on awakening. Sleeping time following intra-cerebroventricular (i.c.v.) injection of phenobarbitone was also prolonged by DEM treatment. When administered to DEM-treated rats, L-tryptophan (50 mg kg−1 i.p.) significantly potentiated hexobarbitone hypnosis, although alone it had no effect in control rats. DEM markedly diminished the activity of brain low-Km aldehyde dehydrogenase (AlDH) and the formation of 5-hydroxyindoleacetic acid from 5-hydroxytryptamine (5-HT) without affecting MAO activity in various areas of the brain. Conversely, the protein-bound radioactivity derived from i.c.v. [14C]-5-HT was increased by DEM treatment. These results showed that DEM is comparable with disulfiram, a brain AlDH inhibitor, in terms of its effect on 5-HT metabolism and barbiturate hypnosis.
A study of the effects of nabumetone (BRL 14777), a novel anti-inflammatory drug, on cell infiltration into sterile cotton pellets implanted in rats
Authors: FREEMAN P C , MANGAN F R , WATKINS D K 
Published: April 2011

Abstract
Nabumetone a new non-steroidal anti-inflammatory drug is active in reducing the DNA content of implanted cotton pellets in rats on various dosing regimens. The effect of nabumetone can be seen during the early and late phases of the cellular reaction to the implant implicating effects upon polymorphonuclear leucocytes and monocytes. The levels of two lysosomal enzymes are reduced in the exudate by the drug treatment.
Conformationally restricted dopamine congeners—a molecular mechanics-based study
Authors: Kocjan D , Hadži D 
Published: April 2011

Abstract
Potential energies of several systems containing the phenylethylamine fragment were computed by the QCFF/PI method and some of them also by the PCILO method. The systems considered are: octahydrobenzo [f]- and [g]-quinolines, aporphine, 1-phenyl-benzazepine, 4-phenyltetrahydroisoquinoline, 3-phenylpiperidine and 9-aminodihydrophenanthrene. No common set of torsion angles defining the stereostructure around the amine head is apparent if only the lowest energy conformations are considered. Leaving out the orientation of the N-CH3 group, and considering also some higher energy conformations, two groups of systems may be formed, A and B, the members of which are congruent amongst themselves in parameters defining the spatial relations of the amine site and the catechol ring, and in the orientation of the N+-H bond. The stereostructure of the rigid representatives of group A is postulated to be the one required by the brain and cardioaccelerator nerve receptor. A corresponding postulate for the vascular bed DA receptors cannot be made since systems forming group B, the derivatives of which are active both on brain and vascular bed receptors, have more conformation space and, moreover, they carry additional potential anchoring groups.
Acenocoumarol and its amino and acetamido metabolites. Comparative pharmacokinetics and pharmacodynamics in the rat
Authors: Thijssen H H W , Baars L G , Reijnders M J 
Published: April 2011

Abstract
The elimination, distribution and anticoagulant activity of racemic acenocoumarol, its amino (AM) and acetamido (AA) derivative were determined in male Wistar rats after subcutaneous injection of a single dose of 2 mg kg−1. The effect of daily administration of acenocoumarol on the prothrombin complex activity (PCA) was also investigated. A rapid onset of the hypothrombogenic effect was observed for all three derivatives with the half-life of decline of PCA=3˙6 h. The duration of the hypothrombogenic effect was short for the drug and its AA derivative and long for the AM compound (normalization at about 24 and 70 h, respectively), parallelling the half-life of elimination of the compounds of, 3˙3, 4, and 8 h respectively. Daily administration of acenocoumarol for 8 days showed no change in the kinetics of the anticoagulant effect. Elimination of the drug is solely by metabolism. Reduction of the 4′-nitro group was not a metabolic route of importance; the amount of its two derivatives cumulatively excreted in urine over 5 days accounted for 2–3% of the dose only. Elimination of AM derivative is mainly by acetylation to AA, the compound which itself is eliminated by renal excretion. The distribution of acenocoumarol between liver and plasma was determined. The liver to plasma ratio was higher than 1 beyond 10 min after administration. The elimination rate of the drug from liver was slower than from plasma giving an increase in liver to plasma ratio in time. Plasma protein binding was extensive, being the highest for the drug; 1˙81, 2˙84 and 3˙89% free for drug, AM, and AA derivative, respectively.
β2-Adrenoceptors in guinea-pig atria
Authors: Johansson Lars-Håkan , Persson Henry 
Published: April 2011

Abstract
The occurrence of β2-adrenoceptors in the isolated, spontaneously beating right atrium and the electrically driven left atrium of the guinea-pig was studied. Isoprenaline was used as reference compound and procaterol as selective β2-agonist. Cumulative concentration response (C/R) curves were obtained with the agonists. The C/R curve of procaterol was biphasic in both preparations. Compared with isoprenaline, procaterol was a partial agonist, with a mean maximum response of 0˙78 ± 0˙04 in the right atrium and 0˙29 ± 0˙05 in the left atrium. The β2-selective antagonist ICI 118,551, 10−7 mol litre−1, caused a small but significant shift of the C/R curve of isoprenaline to a higher concentration range in both preparations. The same concentration of the β2-blocker changed the shape of the C/R curve of procaterol from biphasic to monophasic by blocking the responses to low concentrations of procaterol. Practolol, a β1-selective antagonist, 10−6 mol litre−1, gave a highly significant shift of the C/R curve of isoprenaline to a higher concentration range in both preparations but had no effect on the responses to low concentrations of procaterol. The effect of practolol on the responses to high concentrations of procaterol is discussed. We conclude that the guinea-pig atria may contain β2-adrenoceptors mediating positive chronotropic and inotropic effects.
The pharmacokinetic assessment of sodium cromoglycate
Authors: Fuller R W , Collier J G 
Published: April 2011

Abstract
The plasma concentration of sodium cromoglycate (SCG) was measured in four healthy subjects by radioimmunoassay after a 4 mg intravenous dose and after inhaling from 20 mg capsules, and from 10 and 30 mg ml−1 nebulizer solutions. The mean absorption constant (K1) after inhalation was 0·43 h−1. The mean elimination constant from the plasma (Kelim) after intravenous administration was 11·5 h−1, and that after inhalation was similar. The apparent volume of distribution of SCG (Vdβ) was 0·2 litre kg−1 and the mean plasma clearance was 0·35 litre h−1kg−1. The amount of SCG absorbed after inhalation varied according to the method of inhalation and dose. After the inhalation of powder from 20 mg capsules, 1·30–3·96 mg reached the plasma, after inhalation of SCG produced by nebulizing a 10 mg ml−1 solution for 5 min at 10 psi using a Minineb nebulizer 0·19—0·31 mg reached the plasma and when the solution was increased to 30 mg ml−1 the figure was 0·33—0·45 mg.
An assessment of indomethacin-induced gastrointestinal mucosal damage in-vivo: enhancement of urinary recovery after oral administration of phenolsulfonphthalein in rats
Authors: Nakamura Junzo , Takada Shigeyuki , Ohtsuka Noboru , Heya Toshiro , Yamamoto Akira , Kimura Toshikiro , Sezaki Hitoshi 
Published: April 2011

Abstract
The permeability of phenolsulfonphthalein(phenol red), a poorly absorbed drug, was examined as an index of an assessment of gastrointestinal mucosal damage in-vivo. The urinary recovery after oral administration of phenol red was significantly increased in rats with indomethacin-induced ulcers. However, the urinary recovery of phenol red after its intravenous administration was not affected by the ulcers. Gastric absorption of phenol red from the stomach was examined by means of the in-situ loop technique. A significant increase in disappearance of phenol red from the luminal solution was observed in rats orally pretreated with indomethacin. These findings suggest that the increase in urinary recovery of phenol red is due to increased gastrointestinal absorption. This method may be utilized as a simple, useful and non-invasive screening test for an assessment of gastrointestinal mucosal damage in-vivo.
Stereoselectivity of catecholamines: differential effects of cocaine and desipramine on catecholamine-induced contractions of the rat isolated vas deferens
Authors: Park B K , Haynes B P , Sheridan S A , Nowell P T 
Published: April 2011

Abstract
The effect of uptake1 inhibitors, cocaine and desipramine, on the contractile response of the rat isolated vas deferens to the enantiomers of noradrenaline and adrenaline and to the corresponding deoxy-derivatives, dopamine and epinene, was investigated. Cocaine (10−6 M) significantly potentiated all six agonists; the effect was most marked for the laevo-isomers (-)-noradrenaline and (-)-adrenaline. Desipramine (10−7 M) also potentiated (-)-noradrenaline, (+)-noradrenaline, (-)-adrenaline, (+)-adrenaline and epinene but, in contrast, antagonized dopamine. This selective antagonism of dopamine by desipramine was also observed for the separated epididymal and prostatic ends of the rat vas deferens.
On the substrate specificities of the two forms of monoamine oxidase
Authors: Fowler Christopher J , Tipton Keith F 
Published: April 2011

Abstract
By use of the selective irreversible inhibitors clorgyline and selegiline [(-)-deprenyl], it is possible to determine the Km and Vmax values of the two forms of monoamine oxidase towards a variety of substrates. The validity of this procedure is demonstrated for the deamination of dopamine by rat liver monoamine oxidase -A and -B, and the specificities of the two forms are analysed in terms of their kinetic parameters towards different substrates.
Evidence for the intrusion of polyoxyethylene into the hydrocarbon core of non-ionic surfactant micelles
Authors: Elworthy P H , Patel M S 
Published: April 2011

Abstract
The intrinsic viscosities, [η], of non-ionic surfactants of structure, CH3[CH2]m-1[OCH2OCH2]1·25mOH, were measured in water at 298 K. [η] increased linearly with hydrocarbon chain length from m = 3 to m = 15, and between m = 17 and m = 31. There was a discontinuity between m = 15 and m = 17, which was attributed to intrusion of some polyoxyethylene into part of the hydrocarbon core for surfactants in which m &gt; 15. This effect gave a micellar hydration which was lower than expected for the higher members of the series. Other factors relevant to the intrusion of polyoxyethylene into hydrocarbon are discussed.
Benzodiazepine receptor antagonists reverse the effect of diazepam on plasma corticosterone in stressed rats
Authors: Bizzi A , Ricci M R , Veneroni E , Amato M , Garattini S 
Published: April 2011

Abstract
The aim of this work has been to investigate the mechanism by which diazepam counteracts the plasma corticosterone rise induced by stress in rats. This effect is reversed by pretreatment with RO151788 and CGS8216. This observation suggests that the effect is mediated by benzodiazepine-specific receptors in brain.
Simultaneous measurement of gastric emptying of the soluble and insoluble components of a formulation using a dual isotope, gamma scintigraphic technique
Authors: Kaus Lydia , Sharma H , Fell J T 
Published: April 2011

Abstract
The gastric emptying of a soluble and an insoluble component of a capsule formulation has been monitored by gamma scintigraphy using a dual isotope technique. There was no significant difference between the emptying rates for the two components or between fasting and non-fasting conditions (P &gt; 001).
The action of R51619 on transport processes in the rat small intestine
Authors: Hardcastle Jacqueline , Hardcastle P T , Kelleher Debra K 
Published: April 2011

Abstract
R51619, an agent reported to release endogenous acetylcholine, increased the potential difference and short-circuit current across non-stripped, but not stripped sheets of rat mid-intestine. The response was abolished by both hexamethonium and atropine. R51619 stimulated fluid accumulation by intestinal loops in-vivo suggesting its predominant effect is to stimulate anion secretion. These results are consistent with R51619 releasing endogenous acetylcholine within the myenteric plexus to activate postganglionic cholinergic fibres which stimulate intestinal secretion via muscarinic cholinoreceptors.
Development of a sensitive radioreceptor assay for oxyphenonium in plasma and urine
Authors: Ensing K , Kluivingh F , Gerding T K , De Zeeuw R A 
Published: April 2011

Abstract
A radioreceptor assay (RRA) for oxyphenonium has been developed. It is based on competition between [3H]dexetimide and oxyphenonium for binding to muscarinic receptors from calf striata. The RRA is optimized towards incubation medium and to extraction by ion pair formation with sodium picrate. At least 4 times 10−10 m of oxyphenonium is necessary to permit a reliable assay. This corresponds to a detection limit of drug of 2 ng ml−1 urine. After extraction, drug at 100 pg ml−1 of plasma can be estimated using 4 ml samples. The method is applicable to monitoring the drug and to the determination of its pharmacokinetics after therapeutic dosing. Urine levels can also be monitored.
Mechanism of the indirect adrenergic effect of histamine in cat cerebral arteries
Authors: Balfagón Gloria , Galván Rosa , Marco Emilio J 
Published: April 2011

Abstract
KCl (50 mm), tyramine (10−7 m), and histamine (10−4 m) induced an increase in tritium release from cat cerebral arteries preincubated with [3H]noradrenaline, this increase being due in part to noradrenaline. When calcium was absent from the superfusion medium, only tyramine (10−7 m) enhanced the tritium outflow. Colchicine (10−3 m) partially inhibited the increase in radioactivity brought about by 10−4 m histamine. KCl (50 mm) also evoked release of radioactivity from cerebral arteries preloaded with [3H]histamine; this release was unafffected by reserpine pretreatment or removal of both superior cervical sympathetic ganglia. Neither tyramine (10−7 m) nor compound 48/80 (300 μg ml−1) altered the spontaneous tritium outflow from cerebral blood vessels preincubated with [3H]histamine. These results suggest that histamine is not accumulated by sympathetic nerve endings and elicits its noradrenaline-releasing effect by means of an exocytotic process.
Relationship between sine random vibrations, resonance and drug content uniformity
Authors: Staniforth John N 
Published: April 2011

Abstract
The effect of sine random vibrations on the segregation tendency of 3 ordered powder mixes was studied. Ordered mixes containing either Emdex, Dipac or recrystallized lactose carrier particles mixed with 0·5% fine-particle potassium chloride were prepared. It was found that the coefficients of variation of drug content in samples removed from the ordered mixes following random vibration were, in general, lower than those derived from vibration at equivalent single frequencies. Ordered mixes vibrated at low centre-frequencies were found to be most prone to slight demixing and under these conditions, a vibration bandwidth of 30 Hz produced more de-mixing than a 10 Hz bandwidth. Most ordered mixes were considered to be segregation free following random vibration.
The influence of α1- and α2-adrenoceptor agonists on cardiac output in rats and cats
Authors: Kalkman Hans O , Thoolen Martin J M C , Timmermans Pieter B M W M , Van Zwieten Pieter A 
Published: April 2011

Abstract
In pithed rats, but not in pithed cats, the α2-/dopamine agonist B-HT 920 (10–300 μg kg−1) increased cardiac output. The increase was inhibited by yohimbine (1 mg kg−1), but not by sulpiride (0·3 mg kg−1) and nifedipine (1 mg kg−1). Both in pithed rats and cats, the α1−adrenoceptor agonist methoxamine (30–300 μg kg−1 and 30–1000 μg kg−1, respectively) increased cardiac output. This increase (rats) was inhibited by prazosin (0·1 mg kg−1). The results indicate the existence of functional venous α2−adrenoceptors in pithed rats, and their absence in pithed cats. Furthermore, α2−adrenoceptor−mediated venoconstriction appears independent of extracellular calcium.
The effect of garlic extracts on contractions of rat gastric fundus and human platelet aggregation
Authors: Gaffen J D , Tavares I A , Bennett A 
Published: April 2011

Abstract
Garlic has been extracted and separated chromatographically into various fractions which show different degrees of activity as inhibitors of platelet aggregation and smooth muscle. The most potent smooth muscle inhibitor fraction had little activity on platelet aggregation, but μg ml−1 concentrations greatly reduced the contractions of rat gastric fundus to prostaglandin E2 and acetylcholine. Material in this fraction may contribute to some of the claimed therapeutic effects of garlic involving smooth muscle. Its identity is not known, but is different from allyl sulphide, dimethyl sulphide and diallyl disulphide. These compounds eluted earlier on liquid chromatography than the most active fraction, and they showed only modest inhibitory activity against prostaglandin E2 and acetylcholine on rat fundus.
Possible prostaglandin―mediated effect of diethylcarbamazine on rat uterine contractility
Authors: Joseph C A , Dixon P A F 
Published: April 2011

Abstract
The effect of diethylcarbamazine pretreatment on uterine contractility was investigated in both pregnant and nonpregnant rats. The pretreatment potentiated the uterine responses to oxytocin and acetylcholine, and enhanced the spontaneous uterine contraction of rats in oestrus or 17–20 days pregnant. This enhanced contraction was antagonized both in−vivo and in−vitro by indomethacin, suggesting the involvement of prostaglandins.
In―vitro evaluation of the anticandidiasis activity of honey distillate (HY−1) compared with that of some antimycotic agents
Authors: Obaseiki―Ebor E E , Afonya T C A 
Published: April 2011

Abstract
The susceptibility of 72 isolates of Candida albicans to the antimicrobial honey distillate fraction (HY−1) and several antimycotic agents is presented. All the isolates were sensitive to HY−1, H−115 and Jadit, while about 10% of the isolates were variably resistant to nystatin, miconazole nitrate and clotrimazole. The nystatin, miconazole nitrate and clotrimazole resistant isolates were inhibited by HY−1.
Preparation and release kinetics of microencapsulated cisplatin with ethylcellulose
Authors: Hecquet B , Fournier C , Depadt G , Cappelaere P 
Published: April 2011

Abstract
Several kinds of microcapsules containing cisplatin were prepared by the ethylcellulose coacervation process in an attempt to administer cisplatin with chemoembolization. Microcapsules made either with mechanical stirring or with sonication showed similar properties; the chemical structure of cisplatin was not affected by the micro-encapsulation process. The release kinetics of cisplatin from ethylcellulose-walled microcapsules followed different patterns, according to the wall thickness. In each case, the release kinetics did not depend on the stirring rate of the surrounding medium. Only microcapsules with a cisplatin release ratio from 80 to 100% within 24 h were selected for later clinical use.
The effect of ergot alkaloids ergosinine, dihydroergosine and dihydroergotamine on neurotransmission and contractility of the isolated ileum of the guinea-pig
Authors: Radulović S , Djordjević N , Kažić T 
Published: April 2011

Abstract
The effects of ergosinine (ESNN), dihydroergosine (DHESN) and dihydroergotamine (DHE) on contractions of the isolated terminal and middle segments of the guinea-pig ileum were studied in-vitro. Responses to cholinergic (3 Hz) and adrenergic stimulation (30 Hz in the presence of atropine) were inhibited, albeit at high concentrations of all three alkaloids (1–30 μg ml−1). Cholinergic neurotransmission was surprisingly more affected than adrenergic transmission. Noradrenaline (NA) contractions, however, were inhibited at very low concentrations (1–30 ng ml−1) with the following order of potency: DHESN = DHE &gt; ESNN. Prazosin was equally as potent as DHESN in inhibiting NA contractions and similarly potent in inhibiting responses to adrenergic stimulation. ESNN, DHESN and DHE when used at concentrations from 1–30 μg ml−1 were also found to inhibit 5-hydroxytryptamine &gt; histamine &gt; acetylcholine &gt; KCl contractions. The results suggest that the principal pharmacological action of ESNN, DHESN and DHE on the guinea-pig isolated ileum is the antagonism to NA on the postsynaptic and extrajunctional population of α-adrenoceptors. The neurotransmission, adrenergic as well as cholinergic, appeared to be inhibited via a non-specific presynaptic mechanism presumably regulating the transmitter release. Anti-5-hydroxytryptamine, anti-acetylcholine and antihistamine actions were obtained at similar and relatively high concentrations, thus pointing to a non-specific depressant action upon a common mechanism regulating the contractility of the smooth muscle. Finally, ESNN although a derivative of (+)-isolysergic acid (derivatives of which are generally regarded as inactive) was shown to possess a pharmacological activity comparable to DHESN, i.e. to the drug representing active derivatives of (+)-lysergic acid.