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  • 1
    Electronic Resource
    Electronic Resource
    Pharmacological characterization of muscarine receptors of PC 12 (rat phaeochromocytoma) cells (1990)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 341 (1990), S. 158-164 
    Details
    ISSN: 1432-1912
    Keywords: PC 12 cells ; Muscarnne receptors ; 3H-Noradrenaline release ; 3H-Telenzepine binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The muscarinereceptors of PC12 (rat phaeochromocytoma) cells were studied in functional and binding experiments. The catecholamine stores of PC 12 cells were labelled by incubation of the cells with tritiated noradrenaline. Muscarinic agonists elicited concentration-dependent release of tritium which consisted overwhelmingly of unchanged 3H-noradrenaline. The rank order of potency was: oxotremorine 〉 acetylcholine 〉 muscarine = methacholine 〉 carbachol 〉 bethanechol. The release evoked by carbachol (0.1 mmol/l) was inhibited with high potency by the M1-selective antagonist telenzepine (pK i = 8.82), with intermediate potency by pirenzepine (pK i = 7.00) and with low potency by the M2-selective antagonist AF-DX 116 (pK i = 5.74). The binding of 3H-N-methylscopolamine to PC 12 membranes was inhibited by various non-selective and subtype-selective muscarinic antagonists with the following rank order of potency: telenzepine = atropine 〉 4-DAMP 〉 dicyclomine 〉 pirenzepine 〉 HHSiD 〉 AF-DX 116. A similar rank order was obtained for the inhibition by these compounds of 3H-telenzepine binding to Mi-receptors in membranes of the cerebral cortex of the guinea pig. The Hill coefficients for inhibition of 3H-N-methylscopolamine binding (to PC 12 membranes) by pirenzepine, telenzepine and AF-DX 116 were below unity. Specific binding of both 3H-telenzepine and 3H-N-methylscopolamine to muscarine receptors of PC 12 membranes was saturable and of high affinity; the maximal number of binding sites was higher for 3H-N-methylscopolamine than for 3H-telenzepine (calculated for the active (+)enantiomer). PC 12 cells are presumably endowed with more than one subtype of muscarine receptors. The predominant receptor is an “atypical” receptor; it is neither a M2- nor a M3-receptor, and in spite of the high affinity of telenzepine for this receptor it is probably also not an M1-receptor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169725
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of the [3H]-desipramine binding site of the bovine adrenomedullary plasma membrane (1992)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 346 (1992), S. 203-207 
    Details
    ISSN: 1432-1912
    Keywords: Neuronal noradrenaline transporter ; Uptake1 ; [3H]Desipramine binding ; Bovine adrenal medulla ; Membrane solubilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The specific (i.e. nisoxetine-sensitive) binding of [3H]desipramine was studied in membranes prepared from bovine adrenal medullae. (1) [3H]desipramine bound reversibly and with high affinity (K D = 2.8 nmol/l) to a single class of non-interacting binding sites (Hill coefficient = 0.96); the maximal number of binding sites (Bmax) was 2.1 pmol/mg protein. (2) Binding of [3H]desipramine was dependent on [Na+] and [Cl−]. Increasing the concentrations of these ions increased binding. (3) Substrates and inhibitors of the neuronal noradrenaline transport system (uptake,) inhibited binding of [3H]desipramine with a rank order of potency typical for an interaction with the uptake, carrier. The characteristics of [3H]desipramine binding remained essentially unchanged after solubilization of adrenomedullary membranes with the non-ionic detergent digitonin. The results indicate that the plasma membrane of bovine adreno-medulary cells is endowed with the neuronal uptake1 transporter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00165302
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  • 3
    Electronic Resource
    Electronic Resource
    Preferential location of N-methyl-D-aspartate (NMDA) receptors on postsynaptic membranes and on non-noradrenergic nerve terminals of the rat brain cortex (1992)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 345 (1992), S. 633-638 
    Details
    ISSN: 1432-1912
    Keywords: NMDA receptor ; 3H-CPP binding ; 3H-Desipramine binding ; DSP4 ; Rat brain cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of DSP4-induced destruction of noradrenergic neurones on 3H-3-(2-carboxypiperazine-4-yl)propyl-1-phosphonic acid (3H-CPP) binding to N-methyl-D-aspartate (NMDA) receptors and on 3H-desipramine (3H-DMI) binding to the neuronal noradrenaline carrier was investigated in rat brain cortex buffy coat membranes. 3H-DMI bound with high affinity to a single site at the neuronal noradrenaline carrier (KD = 5.26 ± 1.67 nmol/l) whereas the binding of 3H-CPP to the NMDA receptor was of intermediate affinity (KD = 274 ± 45 nmol/l). Fourteen days after a single-dose treatment with DSP4 (1) the Bmax value for 3H-DMI binding was reduced by 74%, (2) the Bmax value for 3H-CPP binding only tended to be decreased (by 24%; not statistically significant), (3) the endogenous noradrenaline content was reduced by 70% compared to untreated controls and, (4) the absolute amount of the NMDA-evoked 3H-noradrenaline overflow but not the fractional release was reduced by 55%. It is concluded that in the rat cerebral cortex presynaptic NMDA-receptors on noradrenergic nerve endings, which have previously been detected in release experiments with NMDA on cortical synaptosomes preincubated with 3H-noradrenaline, cannot be identified in radioligand binding experiments. Obviously, the cerebral cortical NMDA receptors are predominantly located on postsynaptic neuronal membranes and potentially on non-noradrenergic nerve terminals as well.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00164576
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    Paper (German National Licenses)
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