bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prostanoids and adrenaline release: a study of [3 H]adrenaline efflux from the rabbit isolated, perfused, adrenal gland
Authors: Collett A R , Dusting G J , Story D F , Purchase M 
Published: April 2011

Abstract
[3 H]Adrenaline was incorporated in an isolated perfused preparation of the rabbit adrenal gland and the effects of indomethacin, PGE2 and PGI2 on its release were investigated. Efflux of [3 H]adrenaline was elicited by electrical stimulation of the splanchnic nerve (60 s at 5 Hz). Indomethacin (3 and 30 μM) had no effect on stimulation-induced efflux. PGE2 (30, 90 and 300 nM) reduced the efflux; with 90 nM PGE2 the inhibition amounted to approximately 30%. PGI2, in concentrations from 90 to 600 nM, was without effect. These findings indicate that release of [3 H]adrenaline from the rabbit adrenal gland is not subject to modulation by endogenous adrenal prostaglandins; however, PGE2 may play a role in some pathological situations.
Effect of valproic acid on 5−hydroxytryptamine turnover in mouse brain
Authors: Whitton Peter S , Oreŝković Darko , Jernej Branko , Bulat Marin 
Published: April 2011

Abstract
The effect of the antiepileptic drug valproic acid (di-n-propylacetic acid, 200 mgkg−1) on brain 5−hydroxytryptamine (5−HT) synthesis during monoamine oxidase inhibition by pargyline hydrochloride (120 mg kg −1) was studied in mice. Valproic acid increased 5−HT synthesis and elevated 5−hydroxyindoleacetic acid level in brain indicating that turnover of 5−HT is increased. The possible significance of this effect in relation to anticonvulsant action of valproic acid is discussed.
Pharmacological characterization of postsynaptic α-adrenoceptor subtypes in five different dog arteries in-vitro
Authors: Polónia J J , Paiva M Q , Guimarāes S 
Published: April 2011

Abstract
The responses of helically cut strips of arteries isolated from five different sites in the body of dogs to relatively selective α1- and α2-adrenoceptor agonists and the antagonism exerted on these responses by relatively selective α1 - and α2-adrenoceptor blockers have been studied. On all arteries (renal, splenic, cranial mesenteric, jejunal and femoral) phenylephrine was a full agonist whereas UK−14, 304 was a partial agonist causing maximal contractions of 49, 30, 27, 27 and 10% of the maximum, respectively. Phenylephrine was more potent than UK−14, 304, being 9 times more potent in the renal artery and up to 42 times more potent in the cranial mesenteric artery. In the dog saphenous vein, where there are both α1- and α2-adrenoceptors, it has been previously shown that UK−14, 304 is 530 times more potent than phenylephrine. Prazosin in low concentrations displaced concentration-response curves for both phenylephrine and UK−14, 304 (pA2 values of 8.16−8.43 and 8.13−8.79, respectively) whereas yohimbine was much less potent (pA2 values of 6.53−6.88 and 6.50−7.20, respectively). The results suggest that the α-adrenoceptors of all arteries studied are predominantly, if not exclusively, of the α1-subtype.
The effect of non-ionic surfactant vesicle (niosome) entrapment on the absorption and distribution of methotrexate in mice
Authors: Azmin M N , Florence A T , Handjani-Vila R M , Stuart J F B , Vanlerberghe G , Whittaker J S 
Published: April 2011

Abstract
Non-ionic surfactant vesicles (niosomes) prepared from a non-ionic surfactant, cholesterol and dicetyl phosphate and containing methotrexate (MTX) have been administered to mice. Given intravenously the niosomes prolong the levels of MTX in the blood, large amounts of the drug being taken up by the liver. There was also an increased uptake of MTX into the brain, perhaps due to an effect of the niosome components on the permeability of the blood brain barrier. Absorption of the drug from the gastrointestinal tract following oral ingestion, appeared to be increased at some doses; most of the entrapped MTX was taken up by the liver, but uptake of MTX into the brain was also increased. The metabolic profile of the drug is altered by the niosomes which appear to prevent the rapid formation of 7-hydroxy methotrexate.
A new method for studying cell growth in suspension, and its use to show that indomethacin enhances cell killing by methotrexate
Authors: Gaffen John D , Bennett Alan , Barer Michael R 
Published: April 2011

Abstract
Microturbidimetry has been used to measure the growth of cells in suspension. Disaggregated mouse NC carcinoma cells in culture medium were added to the wells of a microtitre test plate and incubated. Absorbance of 600 nm light was measured daily for 4 days using a microplate reader. As the cells grew, light absorbance increased. Methotrexate 2–40 ng ml−1 reduced cell growth; this effect was increased by indomethacin 1 μg ml−1, possibly by displacing methotrexate from its binding by serum protein or by enhancing cell uptake of methotrexate. Similar results were obtained by conventional clonogenic assays. The new technique offers simplicity, better reproducibility, and substantial savings in time and cost.
Pergolide elevation of MHPG sulphate concentration in rat hypothalamus blocked by spiperone and mimicked by other dopamine agonists
Authors: Fuller Ray W , Hemrick-Luecke Susan K , Perry Kenneth W , Toomey Richard E 
Published: April 2011

Abstract
Pergolide increased the concentration of MHPG sulphate (3-methoxy-4-hydroxy-phenylethylene glycol sulphate) in rat hypothalamus, and the increase was prevented by pretreatment with spiperone, a dopamine antagonist. An increase in hypothalamic MHPG sulphate concentration similar to that caused by pergolide was found after injection of quinpirole, a ‘partial ergoline’ that is a selective D2 agonist not affecting α-adrenoceptors, and by (-)- N-propylnorapomorphine, a dopamine agonist not related to the ergolines. Although the increase in MHPG sulphate concentration produced by pergolide had earlier been assumed to result from blockage of α-adrenoceptors, the present data indicate that it is an effect produced by dopamine D2 receptor stimulation.
Ethanol diuresis in rats: Possible modifying factors
Authors: Pohorecky L A 
Published: April 2011

Abstract
Ethanol has been shown to produce a biphasic dose-dependent effect on urine output in rats. Experiments were carried out to examine factors which may influence ethanol diuresis. Immobilization stress (30 min) decreased and ethanol (2.5 g kg−1) increased urine output of intragastrically hydrated rats. In stressed rats, ethanol had a more pronounced diuretic effect compared with home cage control rats. This increased sensitivity to ethanol disappeared when rats were immobilized daily for four days, indicating development of tolerance. The diuretic action of ethanol was not influenced by adrenalectomy.
Effect of prostaglandin F2α on brain and stomach 5 -hydroxytryptamine
Authors: Sanyal A K , Chakrabarti A , Goel R K 
Published: April 2011

Abstract
PGF2α initially inhibits the rate of 5-HT synthesis in both rat brain and stomach and subsequently stimulates it. The results suggest that PGs of E and F series modulate tryptaminergic neuronal activity which in its turn variously affects 5-HT mediated responses.
Optimization of bioavailability of topical steroids: non-occluded penetration enhancers under thermodynamic control
Authors: Bennett Susan L , Barry Brian W , Woodford Roger 
Published: April 2011

Abstract
The non-occluded vasoconstrictor test under thermodynamic control assessed the effect of penetration enhancers on the topical bioavailability of a model steroid betamethasone 17-benzoate, using aqueous dimethylisosorbide (DMI) as a standard solvent. The aqueous potential penetration enhancers used were at 10% steroid saturation i.e. ideally at identical steroid thermodynamic activity. In the vasoconstrictor test, 2-pyrrolidone, N-methyl-2-pyrrolidone, propylene glycol with oleic acid, propylene glycol with azone and dimethylformamide (DMF) increased the steroid bioavailability compared with that from DMI, while propylene glycol alone produced borderline improvement. Azone and oleic acid in combination with DMI or Betnovate cream did not increase the steroid bioavailability indicating the importance of the correct cosolvent. The pyrrolidones established superior stratum corneum reservoirs compared with DMI, the other vehicles being similar to DMI. It was concluded that excepting DMI, the solvents tested were penetration enhancers for the model steroid betamethasone 17-benzoate and are worthy of further study. However, irritant effects may make some of them unacceptable for clinical use.
Properties of rat striatal D-2 dopamine receptors solubilized with the zwitterionic detergent CHAPS
Authors: Kilpatrick G J , Jenner P , Marsden C D 
Published: April 2011

Abstract
The specific binding of [3 H]spiperone was determined in membrane preparations of rat striatum and following solubilization treatment with the zwitterionic detergent CHAPS. Membrane protein solubilization was confirmed by ultrafiltration, gel filtration and increased heat sensitivity. Specific binding of [3 H]spiperone to the solubilized preparation was saturable and of high affinity, although solubilization led to an approximate 10 fold decrease in receptor affinity for [3 H]spiperone. The drug displacement profile of binding to the CHAPS solubilized preparation corresponded to that of the dopamine D-2 receptor; binding was stereoselectively displaced by the isomers of butaclamol. The sodium dependence of sulpiride displacement of specific [3 H]spiperone binding was retained in the CHAPS solubilized preparation. GTP (100 μM) only altered the ability of dopamine to displace [3 H]spiperone binding to the solubilized preparation in the presence of 120 mM sodium chloride. The GTP effect was small compared with that observed in the membranes. Specific [3 H]spiperone binding sites in the solubilized preparation were preferentially retained by a wheat germ agglutinin affinity column and subsequently eluted with N-acetyl-D-glucosamine. Gel filtration of the solubilized preparation using a Sepharose column resulted in two peaks of specific [3 H]spiperone binding, the larger component had a Stokes radius of 7.7 nm. CHAPS treatment of rat striatal membranes results in solubilization of the D-2 receptor in an active form. The D-2 site appears to be a glycoprotein of high molecular weight.
Intrinsic dissolution of lithium carbonate in aqueous solutions
Authors: Wall B P , Parkin J E , Sunderland V B 
Published: April 2011

Abstract
Intrinsic dissolution rate studies were carried out on lithium carbonate discs that were prepared with the disc in a component on the final support. This overcame the problem of further handling of the fragile discs. Dissolution media employed were similar to those used for the routine evaluation of lithium carbonate dosage forms. Linear dissolution rate profiles were found in simulated gastric fluid (SGF), Tris buffer and water. Data in SGF and water showed positive intercepts with the Levich model. The dissolution process of lithium carbonate was considered to be complex. Dissolution profiles in simulated intestinal fluid (SIF) containing phosphate showed a marked initial curvature and a subsequent reduced dissolution rate. This was due to the precipitation of trilithium phosphate onto the disc. Dissolution rate studies on lithium carbonate dosage forms could be invalidated where a phosphate buffer system has been used.
Age-related changes in monoamine oxidase and semicarbazide-sensitive amine oxidase activities of rat aorta
Authors: Danh H Cao , Benedetti M Strolin , Dostert P , Mousset A 
Published: April 2011

Abstract
Aorta MAO-A and SSAO activities were measured on young (3 months) and old (23–26 months) rats. A significant decrease (30–40%) in SSAO activity was found with benzylamine as substrate and the decrease was due to a reduction in Vmax. No significant changes in MAO-A activity were found in the aorta of old rats. β-PEA is oxidized mainly by SSAO in rat aorta. However, the significance of this is unclear since the physiological role of that enzyme remains unknown.
Evidence against putrescine and polyamines as endogenous mediators of fever
Authors: Dascombe M J , Haegele K D 
Published: April 2011

Abstract
Endogenous concentrations of putrescine, spermidine, spermine and related biosynthetic enzymes were not affected by the administration of bacterial endotoxin and the subsequent development of fever in rabbits. In addition, the febrile response to endotoxin was unaffected either by the ornithine decarboxylase inhibitor, DL-α-difluoromethylornithine or by putrescine. These data indicate polyamines are not involved in the development of fever.
Comparison of the affinity constant of some muscarinic receptor antagonists with their displacement of [3 H]quinuclidinyl benzilate binding in atrial and ileal longitudinal muscle of the guinea-pig
Authors: Choo L K , Mitchelson F J 
Published: April 2011

Abstract
The ability of the muscarinic receptor antagonists fenipramide, 4-diphenylacetoxy-N-methyl piperidine methiodide (4-DAMP) and secoverine to displace [3 H]QNB binding was correlated with the inhibition of responses of cholinomimetics at muscarinic receptors in the atria and ileal longitudinal muscle of the guinea-pig. Fenipramide and 4-DAMP exhibited a 2–4 fold higher affinity for muscarinic receptors in ileal longitudinal muscle in both types of experiments. Secoverine exhibited no difference in affinity in the two tissues.
A selective potentiation by naloxone of L-dopa but not atropine suppression of oxotremorine-induced tremor in mice
Authors: Quock Raymond M , Scott Lucas T 
Published: April 2011

Abstract
Oxotremorine-induced tremor activity in mice was suppressed by pretreatment with either L-dopa or atropine. Additional pretreatment with the opiate receptor blocker naloxone significantly potentiated the antitremor effect of L-dopa but not that of atropine. These findings indicate a selectivity of drug interaction between naloxone and L-dopa.
Relations between gastric irritancy/ulcerogenicity and anti-oedemic activity of non-steroidal anti-inflammatory drugs
Authors: Rainsford K D 
Published: April 2011

Abstract
Recently, Dearden & Nicholson (1984) reported a study of the relation between gastric irritancy and anti-inflammatory activity for some 25 non-steroidal anti-inflammatory (NSAI) drugs in which they made statements concerning work by Rainsford that require clarification because there appears to be some misinterpretation—viz:
In-vitro cytotoxic activity of cross-linked protein microcapsules
Authors: Desoize B , Jardillier J C , Kanoun K , Guerin D , Levy M C 
Published: April 2011

Abstract
Microcapsules (5-100 μm) were prepared through interfacial cross-linking of various proteins (human serum albumin, lysozyme, haemoglobin, casein, pepsin) with glutaraldehyde or terephthaloylchloride. Surprisingly they all snowed an inhibitory effect on cultured cells in a concentration range of 100 μg ml−1 to 10 mg ml−1. This effect seemed non-specific, reversible and to depend on contact with the cell plasma membrane. The electric charges of microcapsules could be involved in the inhibition phenomenon.
Concentration-response relations for apomorphine effects on heart rate in conscious rats
Authors: Paalzow Lennart K , Paalzow Gudrun H M 
Published: April 2011

Abstract
The pharmacokinetics of apomorphine in plasma and brain tissue have been studied in relation to the time courses of effects on heart rate in conscious rats. The kinetic behaviour was investigated after 2 mg kg−1 i.v. and 5 mg kg−1 s.c., respectively. Apomorphine showed a high total plasma clearance (165–207 ml min−1 kg−1) and, despite a relatively large volume of distribution (3.4–4.1 litre kg−1), a biological half-life of about 14 min was obtained irrespective of route of administration. The kinetics in whole brain were identical with those in plasma. Apomorphine produced biphasic effects on the heart rate during the time courses of subcutaneous single doses: a low dose (50 μg kg−1) induced pure bradycardia while the doses of 100 μg kg−1 and 5 mg kg−1 produced responses oscillating between bradycardia and tachycardia. When we evaluated the relation between apomorphine concentrations and effects on the heart frequency with a composed sigmoid Emax model, apomorphine exhibited a U-shaped steady-state plasma concentration-response curve. Bradycardia appeared after low concentrations, reached a maximum and then decreased with increasing concentrations. A further augmentation of apomorphine concentration resulted in the opposite effect, i.e. tachycardia. Separate concentration-response curves for bradycardia and tachycardia were calculated. The changes in biophase concentration that occur during the absorption and disposition may thus cause the fluctuations between contrasting effects seen during the time course of a single dose.
The effect of an aqueous extract of Tanacetum parthenium L. on arachidonic acid metabolism by rat peritoneal leucocytes
Authors: Capasso Francesco 
Published: April 2011

Abstract
The effect of feverfew (Tanacetum parthenium L., Schultz Bip.) as a whole plant on an aqueous extract equivalent to 20 mg dried plant per ml, has been examined on both cyclo-oxygenase and lipoxygenase activity in rat leucocytes in-vitro. At 1–25 μg ml−1 feverfew had no effect on the formation of arachidonate metabolites while at highest concentrations (51–200 μg ml−1) it inhibited both cyclo-oxygenase and lipoxygenase metabolic products.
The degradation of temocillin, a 6α-methoxypenicillin, and identification of the major degradation products
Authors: Burton George , Dobson Christopher R , Everett Jeremy R 
Published: April 2011

Abstract
Temocillin, 6β-(R,S-2′-carboxy-2′-thien-3-ylacetamido)-6α-methoxypenicillanic acid, shows good stability in mild aqueous acid or base; in stronger acid the methoxypenillic acid is formed whereas alkaline or enzyme hydrolysis results in the formation of the methoxypenicilloic acid and the C-5‡ epimer.
Antiarrhythmic effect of acute and chronic amiodarone treatment in conscious rats
Authors: Varró András , Rabloczky George 
Published: April 2011

Abstract
The effect of amiodarone after acute and chronic pretreatment was studied in the early phase of arrhythmias induced by coronary artery ligation in conscious rats. Both acute and chronic amiodarone pretreatments improved survival during the first 20 min after coronary ligation. Only chronic amiodarone pretreatment reduced significantly the incidence of ventricular fibrillation. It was concluded that chronic amiodarone pretreatment seemed to be more effective than the acute one.
Effects of sulphonylureas on spontaneous motility and induced contractions in rat isolated uterus
Authors: Villar A , Ivora M D , D'Ocon M P , Anselmi E 
Published: April 2011

Abstract
To clarify the action of sulphonylureas on calcium, the effect of tolbutamide and ghbenclamide has been investigated on a Ca-dependent process, the contractile activity of uterine smooth muscle. Both sulphonylureas antagonized the contractions evoked by CaCl2 in a non-competitive manner when the uterus was maintained in depolarizing solution and did not affect the spontaneous contractions of rat uterus. The capacity of tolbutamide and ghbenclamide to relax vanadate-induced contraction of rat uterus in Ca-free medium suggests that sulphonylureas may have an intracellular site of action related to cytosolic free Ca levels, or effect a reduction in Ca action.
The metabolism or atropine in man
Authors: van der Meer M J , Hundt H K L , Müller F O 
Published: April 2011

Abstract
A metabolic pattern of atropine in man, based on the detection of radiolabelled products in urine by high performance liquid chromatography after administration of [3H]atropine sulphate to a normal volunteer is proposed. Noratropine (24%), atropine-N-oxide (equatorial isomer) (15%), tropine (2%) and tropic acid (3%) appear to be the major metabolites, while 50% of the administered dose is excreted as apparently unchanged atropine. No conjugates were detectable. Evidence that atropine is present as (+)-hyoscyamine was found, suggesting that stereoselective metabolism of atropine probably occurs.
The pharmacokinetics of pyrimethamine in the rat: effect of mefloquine
Authors: Coleman M D , Thompson A J , Edwards G , Braithwaite I M , Breckenridge A M 
Published: April 2011

Abstract
The pharmacokinetics and tissue distribution of pyrimethamine have been determined in the rat. Following administration of pyrimethamine alone, drug concentrations declined biexponentially. By contrast, in the presence of mefloquine, the decline in pyrimethamine concentration more closely fitted a monoexponential pattern and the AUC0-6h, for pyrimethamine was significantly reduced. Significantly more pyrimethamine was recovered from the livers but less from the lungs of the mefloquine-dosed rats compared with control. This study outlines a potentially clinically relevant drug interaction.
The adenosine receptor antagonist, 8-phenyltheophylline, causes diuresis and saliuresis in the rat
Authors: Collis M G , Baxter G S , Keddie J R 
Published: April 2011

Abstract
The diuretic and adenosine antagonist actions of two alkylxanthines have been compared in the conscious rat. 8-Phenyltheophylline (10 mg kg−1) antagonized adenosine-induced bradycardia in the rat for at least 3 h whereas enprofylline (10 mg kg−1) had no effect on this response. 8-Phenyltheophylline (10 mg kg−1) evoked diuresis and saliuresis in the rat whereas enprofylline (10 mg kg−1) had no effect on excretory parameters. These results indicate that the diuretic action of some alkylxanthines may be related to adenosine antagonism.
Concentration and pH dependency of α-methyldopa absorption in rat intestine
Authors: Amidon G L , Merfeld A E , Dressman J B 
Published: April 2011

Abstract
The intestinal absorption of α-methyldopa from perfused segments of rat intestine was determined. Jejunal and ileal segments were studied at pH 4.5, 6.0 and 7.4 at an α-methyldopa concentration of 0.01 mM, and at pH 6.0 at concentrations of 0.01, 0.10 and 10 mM. Intestinal absorption was found to depend on both concentration and pH but not on segment. A weak positive correlation (r = 0.5) was observed between net water absorption and α-methyldopa absorption, similar to that observed for amino acids. The low intestinal wall permeability of α-methyldopa under normal intestinal pH conditions (pH 7.4) is consistent with the incomplete oral bioavailability of this drug.
Protein binding of nifedipine
Authors: Otto J , Lesko L J 
Published: April 2011

Abstract
The protein binding of nifedipine in concentrations up to 1200 ng ml−1 has been measured in serum, pure human albumin solution and pure human α1-acid glycoprotein (AAG) solutions by ultrafiltration. The drug was extensively bound in serum from four healthy volunteers with a mean (±s.d.) fraction bound of 0.992 ± 0.008. In albumin solution (40 g litre−1) the mean (±s.d.) fraction bound 0.970 ± 0.012, was not significantly different (P &gt; 0.05) from that in serum, suggesting that albumin is the major, but not necessarily the only, binding protein for nifedipine in serum. The binding of nifedipine in solutions of A AG was proportional to the AAG concentration and ranged from 0.514 ± 0.059 to 0.755 ± 0.035 in solutions containing 50 and 150 mg% AAG, respectively. Binding of nifedipine in all protein solutions was linear.
A comparison of the effect of viscosity on the precorneal residence of solutions in rabbit and man
Authors: Zaki I , Fitzgerald P , Hardy J G , Wilson C G 
Published: April 2011

Abstract
The precorneal drainage of radiolabeled solutions containing polyvinyl alcohol (PVA) or hydroxypropyl methylcellulose (HPMC) have been measured in rabbit and man by gamma scintigraphy. Concentration of the polymers was varied to produce solutions with a viscosity range between 10.2 and 102 mPas. Solution drainage was faster in man than in the rabbit with a more pronounced effect of viscosity. Significant retardation of drainage in man was noted at the higher polymer concentrations (0.9% HPMC or 5.85% PVA).