bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of the effects of apomorphine and bulbocapnine in relation to the proposed dopamine receptor
Authors: Patil P N , Burkman A M , Yamauchi D , Hetey S 
Published: April 2011

Abstract
On rat isolated vas deferens, apomorphine was found to be l/5th as active as dopamine. Reserpine or cocaine pretreatment failed to reduce the response to apomorphine. Low concentrations of apomorphine which do not cause contraction of the tissue, antagonize the effects of dopamine. The effects of dopamine were antagonized equally by phentolamine or apomorphine. On rabbit aortic strips 4 × 10−4M apomorphine repeated at 45 min intervals induces pronounced tachyphylaxis. During the tachyphylactic period dopamine was not inhibited to a significantly greater extent than was phenylephrine. Bulbocapnine tested against dopamine and phenylephrine yielded identical pA2 values of 6. Only at 10−5M was bulbocapnine observed to produce a preferentially greater blockade of dopamine. Dopamine or isoprenaline-induced relaxations of aortic strips were not blocked by bulbocapnine. Dopamine and 3 times 10−6M bulbocapnine increased the chronotropic effects in atria. Apomorphine and higher doses of bulbocapnine produced rate decelerating effects. On atria low doses of apomorphine were equally effective in reducing the effects of dopamine or histamine. These results are discussed in light of the proposal that the effects of apomorphine and bulbocapnine involve dopamine receptor interactions. In all three tissues there was no clear cut evidence of specific dopamine receptors.
Polyphloretin phosphate temporarily potentiates prostaglandin E2 on the rat fundus, probably by inhibiting PG15-hydroxydehydrogenase
Authors: Ganesan P Adaikan , Karim S M M 
Published: April 2011

Abstract
Polyphloretin phosphate (PPP), an antagonist of some smooth muscle action of prostaglandins, potentiates the effect of prostaglandin E2 on the rat isolated stomach fundus preparation. No such potentiation could be demonstrated for prostaglandin 15(S) 15 methyl E2 methyl ester, a synthetic analogue of prostaglandin E2. PPP also stimulates the longitudinal muscle of human isolated jejunum to contract. Evidence is produced to show that the potentiation of prostaglandin E2 and the direct stimulant action of PPP are due to inhibition of prostaglandin 15-OH dehydrogenase, an enzyme which inactivates prostaglandin E2 but not 15(S) 15 methyl E2 methyl ester.
Spectrophotometric determination of microgram quantities of acetylsalicylic anhydride in acetylsalicylic acid
Authors: Bundgaard Hans , Bundgaard Charlotte 
Published: April 2011

Abstract
A rapid and convenient method for the determination of an immunogenic impurity in acetylsalicylic acid, acetylsalicylic anhydride, is described. The method is based on the spectrophotometric measurement at 362 nm of 4-benzylidene-2-phenyloxazolin-5-one, formed in quantitative yield by allowing acetylsalicylic anhydride, pre-extracted from the acetylsalicylic acid by a benzene-aqueous phosphate buffer system, to react with a mixture of pyridine and sodium α-benzamido-cinnamate in ethanol for 30 min at 20°. The method is reproducible and permits determination of 0&#x006d;̇0005% of acetylsalicylic anhydride in acetylsalicylic acid. Applying the method to nine different commercial acetylsalicylic acid preparations, acetylsalicylic anhydride was found to be present in amounts ranging from 0&#x006d;̇0012 to 0&#x006d;̇024%.
Quantitative determination of imipramine and desipramine in human blood plasma by direct densitometry of thin-layer chromatograms
Authors: Nagy Adam , Treiber Laszlo 
Published: April 2011

Abstract
Imipramine and desipramine have been estimated in the plasma of patients receiving therapeutic doses of imipramine. The compounds were extracted as bases into n-heptane, separated by thin-layer chromatography and transferred into coloured spots by an oxidative procedure. The quantification was made with a new densitometric technique of high sensitivity. The coefficient of variation was 11–16% at concentrations of 20 μg litre−1 (71&#x006d;̇2 nmol and 75&#x006d;̇0 nmol litre−1 for imipramine and desipramine respectively) and the recovery was 70–81%.
Imipramine and its metabolites in human brain
Authors: Christiansen Johs , Gram Lars F 
Published: April 2011

Abstract
A quantitative and qualitative thin-layer chromatographic study of the distribution of imipramine and its metabolites in 13 different regions of the brain in a fatal case of intoxication has been made. A quantitative thin-layer chromatographic method for in situ determination of imipramine and desipramine has been developed. The concentration of imipramine ranged from 4–36 μg g−1 and of desipramine from 0–8 μg g−1 in different parts of the brain. 8 identified and 8 unidentified metabolites were detected in the different parts of the brain. Among the identified were hydroxy-, N-oxide, and iminodibenzyl-metabolites. The metabolic pattern found corresponds closely to the pattern found in human heart tissue and in urine from patients given imipramine.
Design of agents for stimulation of neostriatal dopaminergic mechanisms
Authors: Costall B , Naylor R J , Pinder R M 
Published: April 2011

Abstract
The structure-activity requirements for stimulation of striatal dopaminergic mechanisms were investigated using a series of phenethylamine derivatives, apomorphine and isoapomorphine, and the intracerebral injection technique for direct application into the striatum. Asymmetric body posturing (unilateral injections in saline-and haloperidol-pretreated rats) and hyperactive/stereotyped be-behaviour (bilateral injections in nialamide-pretreated rats) were used as indices of dopaminergic stimulation. Of 24 phenethylamine derivatives studied, 2-(3,4-dihydroxyphenyl)ethylamine (dopamine) possessed maximum activity. Alteration in length of the ethylamine side-chain, substitution of the α-C atom (α-methyldopamine) or hydroxylation of ß-C atom (noradrenaline) markedly reduced or abolished activity. Activity was also decreased by N-methyl substitution but epinine was active. The catechol moiety appeared essential for dopaminergic stimulation since the 3- or 4-hydroxyphenethylamines (tyramine, m-tyramine) were inactive and 2-(3,4-methylenedioxyphenyl)ethylamine was only weakly active. The marked dopamine-like activity of the 2-(3,4-diacetoxyphenyl)ethylamine compounds was attributed to their non-enzymic hydrolysis to dopamine in situ. The stereoselectivity of the dopamine-induced effects was assessed using trans and cis-2-(3,4-methylenedioxyphenyl)cyclopropylamine. The trans conformer was active and the importance of this conformation was further indicated by the inactivity of isoapomorphine compared with apomorphine. It is suggested that the results provide a rational basis for the design of drugs required to stimulate striatal dopamine receptors and that the intrastriatal injection technique may be useful in the detection of potential antiparkinson agents.
Interaction of phenobarbitone and ethanol in mice studied from dose-response curves and drug concentrations in blood
Authors: Curry Stephen H , Scales Alistair H 
Published: April 2011

Abstract
The interaction of phenobarbitone and ethanol given intraperitoneally to mice has been studied. Dose-response relations were established for incidence of death, sleeping time and time of onset of sleep. Concentrations of phenobarbitone and ethanol were assayed in whole blood samples. When the two drugs were administered together, sleep occurred more rapidly than calculated as likely on the basis of the effects of the drugs given individually. On the other hand, sleep was of shorter duration and the incidence of death was less than anticipated. These modifications of the expected effects related to drug concentration changes in blood. Isobolograms indicated the need for precision in describing the interactions as potentiation, addition or antagonism, as different terms could be applied depending on the effect measured.
Effect of butriptyline on the brain uptake mechanisms for noradrenaline and 5-hydroxytryptamine
Authors: Pugsley T A , Lippmann W 
Published: April 2011

Abstract
Butriptyline, a tricyclic compound (40 mg kg−1, i.p.), in contrast to the tricyclic desipramine (20 mg kg−1, i.p.), did not alter the accumulation or metabolism in areas of the rat brain of intraventricularly-injected [3H]noradrenaline. It did not appreciably inhibit the displacement of 5-HT by α-ethyl-3-hydroxy-4-methyl phenethylamine in comparison with the tricyclic chlorimipramine. Butriptyline potentiated central 5-HTP effects only slightly whereas chlorimipramine displayed a strong potentiation. It is concluded that butriptyline differs significantly from desipramine, as no inhibitory effect on brain noradrenaline uptake was found, and from chlorimipramine, as only a weak inhibitory activity on brain 5-HT uptake was observed.
The antimicrobial efficiencies of contact lens solutions
Authors: Norton D A , Davies D J G , Richardson N E , Meakin B J , Keall A 
Published: April 2011

Abstract
The antimicrobial efficiencies of 34 commercially available contact lens solutions has been tested against Pseudomonas aeruginosa, Staphylococcus aureus, Micrococcus luteus and Candida albicans. A standard inoculum of 106 organisms ml−1 was placed in a sample of a contact lens solution and samples taken at various times up to 48 h. These were placed in a recovery medium and the presence or absence of growth noted after 48 h incubation at 37°. Of 14 solutions used to soak and disinfect lenses only 4 inactivated all four test strains within 1 h, 7 within 4 h, while 6 solutions allowed growth of one or more test organisms even after 24 h contact. Of the remaining 20 solutions, with their various functions such as cleaning and wetting of lenses, 13 failed to inhibit one or more test strains after 24 h contact. Some form of control of the manufacture and presentation together with minimum standards of antimicrobial efficiency would seem to be desirable.
Some solution properties of pentagastrin and angiotensin: aggregation of pentagastrin
Authors: Attwood D , Florence A T , Greig Rosemary , Smail G A 
Published: April 2011

Abstract
Pentagastrin and angiotensin have been studied in the presence and absence of urea by light-scattering, viscosity, dialysis, surface tension and other physicochemical techniques for evidence of peptide aggregation. Pentagastrin forms large linear, flexible aggregates (molecular weight 40 000) in phosphate buffer above a concentration of ∼0·1 g dl−1 and in solutions shows time-dependent flow behaviour. Angiotensin shows no evidence of aggregation beyond dimers. In 1m urea the pentagastrin is in the form of dimers.
An analogue computer simulation of drug dissolution
Authors: Collett J H , Rees Judith A 
Published: April 2011

Abstract
The dissolution rate of salicylic acid from non-disintegrating discs at controlled pH has been determined. A theoretical model of dissolution has been developed in terms of the diffusion layer theory. This model has been programmed on an analogue computer and theoretical dissolution curves have been obtained. Experimental dissolution curves have been compared with simulated curves and the fit of the data has allowed the estimation of drug concentration in the diffusion layer.
An ESR titration technique for the determination of accessible tyrosine and tryptophan residues in globular proteins
Authors: Cloughley J B , Hooper M , Maxwell J 
Published: April 2011

Abstract
The reaction of potassium nitrosyldisulphonate (NDS) with globular proteins has been monitored by electron spin resonance. The reaction is shown to be sufficiently sensitive and reproducible to provide a rapid new method for the estimation of exposed tyrosine and tryptophan residues in these proteins at physiological pH. Under these conditions each tyrosine residue was found to consume 2 moles, and each tryptophan residue 3 moles, of NDS. The estimation of accessible groups thus obtained are in good agreement with published data obtained using other chemical probes.
A gas chromatographic determination of carbenoxolone in human serum
Authors: Rhodes C , Wright P A 
Published: April 2011

Abstract
A gas-liquid chromatography procedure for the determination of carbenoxolone in human serum is described. The method showed a better than ± 11% coefficient of variation for all values determined. The mean determined value is accurate to ± 10% of the known value for carbenoxolone over a range of 5 to 100 μg ml−1 serum. The specificity of the method was established by combining the gas-liquid chromatography analysis with thin-layer chromatography of prepared standards and serum from treated volunteers. The method is suitable for routine pharmacokinetic and bioavailability studies of carbenoxolone in serum and other biological fluids and supersedes previous methods in specificity, sensitivity and simplicity of determination.
The binding of sulphonylureas to serum albumin
Authors: Crooks M J , Brown K F 
Published: April 2011

Abstract
The interaction of tolbutamide, glibenclamide, chlorpropamide and tolazamide with serum albumin has been examined. Glibenclamide, the most strongly bound of the four compounds, is bound to only one class of sites. The other three compounds are bound to at least two. The interaction between glibenclamide and albumin was independent of pH and increased markedly with decreasing temperature suggesting that a non-ionic mechanism is involved. In contrast, the overall interaction of tolbutamide with albumin showed little temperature dependence and, in addition, binding of both tolbutamide and chlorpropamide decreased with pH. These findings imply that the predominantly bound species is the anion. Binding parameters corrected for electrostatic effects were found to fit binding data for tolbutamide, chlorpropamide and tolazamide better than uncorrected parameters. Electrostatic correction of binding of glibenclamide is unnecessary.
The structure of nitrones derived from amphetamines
Authors: Beckett A H , Coutts R T , Ogunbona F A 
Published: April 2011

Abstract
The nitrones obtained by mercuric oxide oxidation of N-hydroxy-N-n-propylamphetamine and N-ethyl-N-hydroxyamphetamine have been identified. The major in vitro metabolic product of fenfluramine is shown by a nuclear magnetic resonance study to be α-methyl-N-[1-(m-trifluoromethylbenzyl)ethyl]nitrone and not the isomer as claimed previously (Beckett, Coutts & Ogunbona, 1973a).
Distribution of exogenous acetaldehyde in cow adrenal medulla chromaffin granules
Authors: Schneider F H 
Published: April 2011

Abstract
Release of catecholamines from the cow perfused isolated adrenal gland was induced by infusion of acetaldehyde in concentrations between 5 times 10−4 and 3·5 times 10−1m. There was a significant correlation between the concentration of acetaldehyde and catecholamine release. Analysis of homogenates of medullae from glands stimulated with [14C]acetaldehyde showed that the specific activity (14C mg−1 protein) was higher in chromaffin vesicles than in other tissue fractions. The major portion of the 14C of chromaffin vesicles was present as soluble tetrahydroisoquinoline derivatives. There was no correlation between catecholamine release and the amount of tetrahydroiso-quinolines formed. A small portion of the vesicle 14C was associated with the membrane, and there was a significant correlation between the membrane-bound 14C and catecholamine release. It is concluded that acetaldehyde can interact with the chromaffin vesicle membrane in a way that alters the ability of the vesicle to retain catecholamines which then diffuse out of the vesicle and into the circulation.
The effect of monoamine oxidase inhibitors on the rectal temperature of the rat
Authors: Summers R J 
Published: April 2011

Abstract
The monoamine oxidase (MAO) inhibitors, clorgyline, harmaline, nialamide, phenelzine and tranylcypromine, injected intraperitoneally into conscious unrestrained rats produced hypothermia. When clorgyline and tranylcypromine were compared, the latter produced a larger degree of hypothermia in spite of the fact that both drugs almost completely inhibited liver and hypothalamic MAO. Hypothermia produced by tranylcypromine, but not that produced by clorgyline, was attenuated by prior administration of haloperidol which indicated that it was partly mediated by a dopaminergic mechanism. In addition, tranylcypromine, but not clorgyline, inhibited uptake of (–)-noradrenaline into rat hearts. Hypoglycaemia was not involved in the hypothermia produced by these MAO inhibitors in rats.
Effect of serum albumin upon the response of the rat isolated superfused anococcygeus muscle to catecholamines and to nerve stimulation
Authors: Powis G 
Published: April 2011

Abstract
The presence of bovine serum albumin in the superfusing medium reduced the response of the rat isolated anococcygeus muscle to catecholamines and to nerve stimulation. It is suggested that this is a consequence of the binding of catecholamines to serum albumin. When the binding was prevented, either by decreasing the pH or by the addition of a drug such as oxytetracycline, then the inhibitory effects of serum albumin were much reduced.
Spectrophotometric determination of ampicillin sodium in the presence of its degradation and polymerization products
Authors: Bundgaard Hans 
Published: April 2011

Abstract
A spectrophotometric method is described for the quantitative determination of ampicillin sodium [sodium salt of 6-(d(–)-phenylacetamido) penicillanic acid]. The method involves acetylation of ampicillin with acetic anhydride in aqueous solution at pH 9 to yield α-acetamido benzylpenicillin and subsequent measurement at 325 nm of α-acetamidobenzylpenicillenic acid mercuric mercaptide, formed in a quantitative yield on heating for 30 min at 60° in a 1·0m imidazole and 8 times 10−4m mercuric chloride solution at pH 6·8. It has been demonstrated that degradation products do not interfere in the method whereas those di- and polymerization products of ampicillin which contain an intact β-lactam ring are capable of reacting with imidazole with the formation of penicillenic acid. A technique involving acid-catalysed opening of the β-lactam ring of these products under conditions where ampicillin is degraded to only a minor extent has been developed, and besides permitting a selective determination of ampicillin the technique permits the determination of the polymeric substances.
The influence of porosity upon the distribution of reserpine in calcium sulphate granules
Authors: Nicholson G L , Enever R P 
Published: April 2011

Abstract
Batches of calcium sulphate granules, all of the same size fraction but of widely differing porosities, were prepared from primary granules of different sizes. Each batch was coated with reserpine by spraying a solution of the drug in methylene chloride onto the granules whilst they were tumbled in a coating pan. The relation between the macroporous nature of the granules and their reserpine content was investigated. Low-pressure mercury porosimetry was used to obtain a quantitative estimate of the porosity and macropore size distribution of the granules, and their surface areas were determined by an air permeability method. Linear relations were obtained when the reserpine content was plotted against either the volume of mercury penetrating per gram of granules at 106·5 kN m−2 or their surface area.
The response of isolated cardiac muscle to acute anoxia: protective effect of adenosine triphosphate and creatine phosphate
Authors: Parratt J R , Marshall R J 
Published: April 2011

Abstract
A standardized and reproduceable preparation is described that enables the effect of drugs to be examined on the response of isolated cardiac muscle to acute anoxia. There was a linear relation (r = 0·963) between tension developed in isolated, electrically-driven guinea-pig atria and the oxygen tension of the fluid surrounding the muscle. For any one atrial preparation the time taken, from the beginning of the anoxic period, for tension to be reduced by 50 % was constant for consecutive anoxic periods. ATP and creatine phosphate significantly increased this time and protected cardiac muscle against the consequences of anoxia; in concentrations that were without direct cardiac effects, a greater degree of protection was possible with creatine phosphate.
Effect of a sea snake (Enhydrina schistosa) venom on the ganglionic nicotinic actions of acetylcholine
Authors: Yeoh Peng N , Walker M J A 
Published: April 2011

Abstract
The effects of venom from a common sea snake, Enhydrina schistosa, on the actions of acetylcholine in the superior cervical ganglion, the adrenal medulla and in the atropinized cat were investigated. The crude venom reduced nictitating membrane responses to preganglionic nerve stimulation and intra-arterial injection of acetylcholine, without lowering the responses to postganglionic nerve stimulation or intra-arterial adrenaline. In the eviscerated cat, the venom also antagonized rises in heart rate and blood pressure induced by in-injections into the coeliac artery of acetylcholine but not those of histamine. Pressor effects due to splanchnic nerve stimulation and carotid artery occlusion were blocked. In the atropinized cat, the venom depressed heart rate and pressor responses to intravenous acetylcholine, but not the responses to adrenaline. It was concluded that the venom antagonized the actions of acetylcholine at autonomic ganglia and the adrenal medulla.
Inhibition by non-steroidal anti-inflammatory agents of the release of rabbit aorta contracting substance and prostaglandins from chopped guinea-pig lungs
Authors: Fjalland B 
Published: April 2011

Abstract
The release of prostaglandins (PGs) and rabbit aorta contracting substance (RCS) was investigated using mechanical agitation of chopped lung tissue from unsensitized guinea-pigs. Manual stirring of the lung tissue for 45 s produced maximal release of prostaglandins, a release corresponding to the effect of [20–40 ng ml−1 of PGE2 x 45 s at 5 ml min−1] about 100 ng PGE2 on the rat stomach strip. Nonsteroidal anti-inflammatory agents inhibited the release of the contracting substances. Indomethacin, the most potent, was active in concentrations of about 20 ng ml−1, whereas flufenamic acid was twice, phenylbutazone about 60 times, acetylsalicylic acid 100 times and sodium salicylate about 6000 times less active than indomethacin. The method could prove to be a simple test for screening nonsteroidal anti-inflammatory agents for inhibition of prostaglandin synthesis.
Effect of some β-adrenoceptor blocking drugs on insulin secretion in the rat
Authors: Furman B L , Tayo F M 
Published: April 2011

Abstract
In pentobarbitone anaesthetized rats (±)-propranolol reduced the stimulatory effect of glucose, sulphonylureas, isoprenaline or phentolamine on insulin secretion. (+)-Propranolol produced similar effects to those produced by the racemate. Sotalol reduced only the insulin secretion stimulated by isoprenaline or phentolamine but not that stimulated by glucose or sulphonylureas. Complete inhibition of isoprenaline-induced hyperinsulinaemia was obtained with practolol, in a dose which was without effect on the plasma insulin elevations produced by glucose or glibenclamide. (±)-Propranolol inhibited glucose or tolbutamide-stimulated insulin secretion from chopped pancreas in vitro indicating a direct action of the drug on the pancreas. It is suggested that propranolol-induced inhibition of insulin secretion may not be entirely due to the β-adrenoceptor blocking activity of the drug.
The effect of 6-hydroxydopamine on the oestrus cycle and fertility of rats
Authors: MacDonald E J , Airaksinen M M 
Published: April 2011

Abstract
Increases in the numbers of foetuses resorbed and stillborn are reported in rats after treatment with 6-hydroxydopamine given before and during pregnancy. 6-Hydroxydopamine (100 mg kg−1 i.p.) given before mating had no effect on the oestrus cycle. Intrahypothalamic 6-hydroxydopamine (200 μg) produced a temporary loss of oestrus. However, after mating the injected rats had normal pregnancies despite substantially lower levels of brain noradrenaline.