Effects of ACTH-(1–24) on dopamine and noradrenaline release, B-50 phosphorylation and calmodulin binding to B-50 in vitro
| Autor: | Wouter J. Florijn, Jacques J. H. Hens, P.N.E. de Graan, W.H. Gispen, Dirk H.G. Versteeg |
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| Rok vydání: | 1993 |
| Předmět: |
Male
endocrine system medicine.medical_specialty Calmodulin Dopamine chemistry.chemical_element Calcium Biology Tritium General Biochemistry Genetics and Molecular Biology Phosphates Norepinephrine chemistry.chemical_compound Adenosine Triphosphate Bacterial Proteins Internal medicine medicine Animals Phosphorylation Rats Wistar General Pharmacology Toxicology and Pharmaceutics Neurotransmitter Protein Kinase C Protein kinase C Cerebral Cortex Synaptosome Brain General Medicine Rats Kinetics Endocrinology chemistry Streptolysins biology.protein Cosyntropin Liberation Phosphorus Radioisotopes Adenosine triphosphate Synaptosomes medicine.drug |
| Zdroj: | Life Sciences. 52:1013-1022 |
| ISSN: | 0024-3205 |
| Popis: | ACTH-(1-24), 1 microM, enhanced the Ca(2+)-dependent release of [3H]dopamine ([3H]DA) from intact septal synaptosomes by approximately 30%, but had no effect on the release of [3H]noradrenaline ([3H]NA) from intact cortical synaptosomes. Since a strong correlation has been reported between B-50 (phosphorylation) and [3H]NA release from intact or streptolysin-O- (SL-O-) permeated cortical synaptosomes, we investigated whether the effects of ACTH-(1-24) on the release of radiolabelled transmitters are mediated by B-50. We observed that the increment in the release of [3H]DA from SL-O-permeated septal synaptosomes as a result of exposure to a high Ca2+ concentration was much less pronounced than that of the release of [3H]NA from SL-O permeated septal and cortical synaptosomes. ACTH-(1-24) concentration-dependently inhibited [3H]NA release from SL-O-permeated cortical synaptosomes (IC50 value of approximately 10 microM) when ACTH-(1-24) was added 150 s prior to the Ca2+ trigger. Simultaneous addition of ACTH-(1-24), SL-O and Ca(2+)-buffers to cortical synaptosomes did not lead to a change in [3H]NA release at any of the ACTH-(1-24) concentrations tested. ACTH-(1-24) had no effect on B-50 phosphorylation in intact synaptosomes, whereas it concentration-dependently inhibited B-50 phosphorylation in permeated cortical synaptosomes (IC50 value of 100 microM). ACTH-(1-24) inhibited (IC50 value of 10 microM) B-50/calmodulin binding in vitro. We conclude that the effects of high concentrations of ACTH-(1-24) on various biochemical B-50 related parameters are not likely to represent the mechanisms underlying the action of ACTH-(1-24) on neurotransmitter release. |
| Databáze: | OpenAIRE |
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