Kinetics, Pharmacology, and Autoradiographic Distribution of l-[3H]Nitroarginine Binding Sites in Rat Cerebellum
| Autor: | Roger F. Butterworth, V. L. Raghavendra Rao |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Male
Arginine Calmodulin Stereochemistry Nerve Tissue Proteins Granular layer Pharmacology Tritium Nitroarginine Biochemistry Rats Sprague-Dawley Cellular and Molecular Neuroscience chemistry.chemical_compound Cerebellum Animals Tissue Distribution Binding site chemistry.chemical_classification Binding Sites biology Hydrogen-Ion Concentration Rats Nitric oxide synthase Kinetics Enzyme chemistry Enzyme inhibitor cardiovascular system biology.protein Autoradiography Calcium Nitric Oxide Synthase |
| Zdroj: | Journal of Neurochemistry. 66:701-709 |
| ISSN: | 1471-4159 0022-3042 |
| DOI: | 10.1046/j.1471-4159.1996.66020701.x |
| Popis: | The kinetics and pharmacology of N G -nitro-L-[2,3,4,5- 3 H]arginine (L-[ 3 H]NOARG) binding to rat cerebellum were investigated using in vitro radioligand binding. Specific L-[ 3 H]NOARG binding in cerebellum was of nanomolar affinity, reversible, saturable, and best fit to a single-site model. Specific binding was Ca 2+ dependent and sensitive to pH (with an optimum of 5.5-7.0). Added calmodulin (1.5-40 μg/ml) had no influence on specific L-[ 3 H]NOARG binding. However, the calmodulin antagonists W-5, W-13, and calmidazolium inhibited L-[ 3 H]-NOARG binding with IC 50 values in the micromolar range, and calmodulin (10 μg/ml) competitively reversed this inhibition. Nitric oxide synthase (NOS) inhibitors (N G -nitro-L-arginine methyl ester and N G -monomethyl-L-arginine acetate) and L-arginine displaced L-[ 3 H]NOARG binding with IC 50 values in the nanomolar range, whereas D-arginine and basic amino acids (L-lysine and L-histidine) displaced L-[ 3 H]NOARG binding with IC 50 values in the millimolar range. A comparison of the NOS functional assay with L-[ 3 H]NOARG binding in rat cerebellum showed similar profiles of Ca 2+ dependency and inhibitory kinetics. Quantitative autoradiographic distribution of L-[ 3 H]NOARG binding sites was significantly higher in the molecular layer than in the granular layer of cerebellum. These studies confirm the potential use of L-[ 3 H]NOARG binding to study the regional distribution and functional properties of NOS. |
| Databáze: | OpenAIRE |
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