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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neural transmission 80 (1990), S. 189-194 
    ISSN: 1435-1463
    Keywords: Nicotine enantiomers ; pain ; spinal analgesia ; rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Spinalized rats received an intrathecal injection of either (−)-nicotine or (+)-nicotine in order to study the stereoselectivity of antinociception. Pain threshold was measured using the tail-flick test. Both stereoisomers had antinociceptive effects, but (−)-nicotine was up to 970 times more potent, depending on test conditions. The antinociceptive action of (−)-nicotine was antagonized by mecamylamine and yohimbine but not by naloxone and atropine. The findings show that spinal mechanisms are highly stereoselective toward nicotine, and suggest that primarily nicotinergic andalpha-adrenergic receptors are involved in its central antinociceptive effects.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neural transmission 65 (1986), S. 135-145 
    ISSN: 1435-1463
    Keywords: Tranylcypromine enantiomers ; monoamine uptake ; monoamine release ; dopamine ; noradrenaline ; serotonin ; synaptosome ; imipramine binding ; blood platelet ; stereoselectivity ; rat ; rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Studies were carried outin vitro to determine effects of tranylcypromine enantiomers ([+]- and [−]-TCP) on uptake and release of 5-HT, DA and NA in rat synaptosomes and on imipramine binding to rabbit platelets. (+)-TCP was more potent than (−)-TCP as inhibitor of 5-HT uptake and imipramine binding, whereas (−)-TCP was more potent than (+)-TCP as inhibitor of DA and NA uptake. The enantiomers differed only slightly in their effects on monoamine release. The findings agree with previous reports on the stereoselectivity of monoaminergic mechanisms toward TCP enantiomers, and support the notion that the 5-HT uptake site may be associated with the imipramine binding site.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Comparative clinical pathology 1 (1991), S. 233-235 
    ISSN: 1433-2981
    Keywords: Carbon dioxide ; Euthanasia ; Leucocytes ; Mice ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Leucocyte counts obtained from Wistar rats and CD1 mice following euthanasia with carbon dioxide were compared to leucocyte values obtained using other agents for anaesthesia or euthanasia. In rats, following euthanasia with carbon dioxide, lymphocyte and neutrophil counts in samples taken from the heart were significantly raised compared with sodium barbiturate euthanasia. In mice, following carbon dioxide, total leucocyte counts from brachial plexus were significantly lower than other collection sites. Lymphocyte counts from vena cava and brachial plexus were also significantly lower than other sites.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Comparative clinical pathology 2 (1992), S. 101-102 
    ISSN: 1433-2981
    Keywords: Haemoglobinometry ; Sodium lauryl sulphate ; Rats ; Dogs ; Mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A commercially available sodium lauryl sulphate reagent was used to determine haemoglobin values in three species, and these values were compared with results obtained by a cyanmethaemoglobin method with the same haematology analyser. Correlation of the two methods was satisfactory for samples obtained from healthy rats and dogs. For mouse samples, the correlation between methods was poorer than for the other two species.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-2072
    Keywords: Electroconvulsive shock ; Corticosterone ; Muscarinic agonists ; Serotoninergic agonists ; α-Adrenoceptor agonists ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of repeated and single electroconvulsive shocks (ECS) on the corticosterone response to pharmacological stimuli has been studied in male rats. Plasma corticosterone concentrations are elevated by oxotremorine, a muscarinic agonist, and by 5-hydroxy-l-tryptophan, a precursor of serotonin. Both these agonists probably stimulate corticotrophinreleasing-factor release from the hypothalamus. The log dose-response curves of the corticosterone response to oxotremorine and to 5-hydroxy-l-tryptophan are shifted to the left after a single ECS given daily for 10 days compared with sham-shocked controls. Plasma corticosterone concentrations are elevated by treatment with α-methyl-p-tyrosine methyl ester (400 mg/kg IP). This rise is suppressed by clonidine. The log dose-response curve for the corticosterone response to clonidine after α-methyl-p-tyrosine methyl ester is also shifted to the left by repeated ECS, compared with controls. There is no difference in the corticosterone response of ECS and sham-treated groups given vasopressin, which is thought to act directly on the pituitary to release ACTH. A single ECS produces a slight enhancement of the response to 5-hydroxy-l-tryptophan, a slight decrease in the response to oxotremorine and no change in the response to clonidine after α-methyl-p-tyrosine. The disappearance of the difference in response between ECS and sham-treated animals was also studied 1,3, and 6 days after a series of ten ECS or sham procedures. Significant differences in the corticosterone responses to oxotremorine, 5-hydroxy-l-tryptophan and clonidine after α-methyl-p-tyrosine between ECS and sham-treated animas were found 24 h after the last ECS or sham shock. These differences were in decline 3 days after the last procedure and had completely disappeared by day 6. The decline was largely due to an increase in plasma corticosterone responsiveness to pharmacological stimuli of the shamshocked controls. Responses in the ECS-treated groups remained constant. It is apparent that the anaesthetic procedure suppresses the effect of oxotremorine, 5-hydroxy-l-tryptophan and clonidine after α-methyl-p-tyrosine on corticosterone concentrations in plasma. This effect is spontaneously reversible. Repeated ECS reverses the effect of the anaesthetic procedure but produces no reversible enhancement of its own.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-2072
    Keywords: Corticosterone ; Muscarinic agonists ; Serotoninergic agonists ; α-Adrenoceptor agonists ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A method is described for demonstrating the hypothalamic control of corticosterone in the intact rat. Oxotremorine 0.01–0.05 mg/kg IP and 5-hydroxy-l-tryptophan 1–50 mg/kg IP raise plasma corticosterone levels in dose-related fashion. The oxotremorine response is blocked by atropine 1 mg/kg SC and the 5-hydroxy-l-tryptophan response by mianserin 10 mg/kg IP. α-Methylparatyrosine methyl ester 400 mg/kg IP raises plasma corticosterone levels 14–16 h later. This rise can be suppressed by clonidine 0.01–0.05 mg/kg IP and this suppression is antogonized by piperoxane 5–50 mg/kg IP. Apomorphine 5 mg/kg IP does not lower plasma corticosterone levels in rats pre-treated with α-methylparatyrosine. The response to oxotremorine cannot be blocked by atropine methylbromide or by mianserin. The response to 5-hydroxy-l-tryptophan is unaffected by benserazide or atropine sulphate. These data suggest separate cholinergic and serotoninergic facilitation of corticosterone release in the intact rat. The stimulating drugs used appear to be acting centrally. The data also support the presence of a noradrenergic inhibitory system mediated by α-adrenoceptors. Dopaminergic receptors appear to play no part in the central control of corticosterone secretion after pre-treatment with α-methylparatyrosine.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-2072
    Keywords: Electroconvulsive shock ; Growth hormone ; Clonidine ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of repeated electroconvulsive shocks (ECS) on growth hormone (GH) secretion was studied in rats. Male Sprague-Dawley animals were given one ECS daily for 10 days under halothane anaesthesia. Control animals were anaesthetised only. GH secretion was studied 24 h after the last ECS or sham procedure. Background GH secretion was significantly greater in ECS-treated than in sham-treated animals (P〈0.001). The GH response to IV clonidine (0.01–0.1 mg/kg) did not differ between the two groups. The size of the GH response was not directly related to the basal GH secretion and could not be explained in terms of it.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-2048
    Keywords: N-Ethylmalemide ; Germination (seed) ; Hordeum (embryo, peptide) ; Peptide transport ; Thiol group ; Transport carrier protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Through the use of the protein reagents N-ethylmaleimide, p-chloromercuribenzenesulphonic acid and phenylarsine oxide, it is shown that in the scutellum of the germinating barley embryo, the transport of peptides, but not the transport of amino acids or glucose is specifically thiol-dependent. Furthermore, these essential thiol groups are shown to exist as redox-sensitive, vicinal-dithiols that lie at the substrate-binding sites of the peptide-transport proteins. The binding of N-ethylmaleimide to these dithiols is shown to be very fast, matching the kinetics of inhibition of peptide transport by this reagent. A technique for the specific labelling of the dithiols with N-ethyl[2,3-14C]maleimide is described, which allows the carrier proteins to be visualized at the scutellar epithelium using radioautography and permits calculation of the approximate amount of peptide-transport protein present per scutellum. In related studies, the importance of arginyl and histidyl residues to both amino-acid and peptide transport is shown, although other residues, e.g. carboxyl ligands do not seem to be critically involved.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-2048
    Keywords: Amino acid transport ; Germination (seed) ; Hordeum (peptide) ; Peptide transport ; Scutellum ; Storage protein mobilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Use of two different assays involving either radioactively labelled substrates or a fluorescent-labelling procedure, gave good agreement for the rates of transport of peptides and amino acids into the scutellum of germinating grains of barley (Hordeum vulgare cv. Maris Otter, Winter). However, evidence was obtained for the enzymic decarboxylation of transpored substrate, which can cause underestimates of transport rates when using radioactively labelled substrates. The peptide Gly-Phe, was shown to be rapidly hydrolysed after uptake, and autoradiography of transported Gly-[U-14C]Phe indicated a rapid distribution of tracer, i.e. [U-14C] phenylalanine into the epithelium and sub-epithelial layers of the scutellum. The developmental patterns of transport activity indicate that peptide transport is more important nutritionally during the early stages of germination (1–3 d) whereas amino acids become relatively more important later (4–6 d). A range of amino acids is shown to be actively transported and several compete for uptake. At physiological concentrations, e.g. 2mM, transport of peptides and amino acids is inhibited about 80% by protonophore uncouplers, but at higher concentrations (10–100 mM) passive uptake predominates.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-2048
    Keywords: Germination (seed) ; Hordeum (peptide transport) ; Peptide transport ; Protein synthesis ; Scutellum ; Seed germination ; Thiol group
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Development of peptide-transport activity in the scutella of isolated barley (Hordeum vulgare l. cv. Maris Otter, Winter) embryos is shown to increase rapidly after about 15 h of imbibition, with the bulk of the transport activity being expressed by 24 h. This development is prevented by treatment of 15 h embryos with cycloheximide. Protein synthesis is found to increase in a closely related manner and also to be abolished by cycloheximide. Measurement of the incorporation of bound [35S]methionine by 15 to 21-h embryos indicates that de-novo protein synthesis during this period is greater in the scutellum than in the embryonic axis. Previous studies have shown that the peptide-transport system possesses essential dithiol groups, probably located at the substrate-binding site (Walker-Smith and Payne 1983 b, 1984b). Treatment of 15-h embryos with the non-penetrant thiol reagent p-chloromercuribenzene sulphonic acid did not affect development of peptide-transport activity during the following 6 h, whereas with 3-d embryos identical treatment inhibited uptake almost completely during a subsequent 6-h period. Radioautography revealed that amongst the proteins synthesised during this early phase of germination and labelled in vitro with [35S]methionine some are found within the epithelial plasmalemmae of the scutellum, which is the location of the peptide-transport carrier identified previously by externally labelling with a radioactive thiol reagent. The results provide evidence that protein(s) of the peptide-transport system are synthesised and inserted into the scutellum during early germination, allowing the system to play a major role in the nitrogen nutrition of the embryo.
    Type of Medium: Electronic Resource
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