Mechanism of dopamine mediated inhibition of neuropeptide Y release from pheochromocytoma cells (PC12 cells)
| Autor: | Alice Gardner, Guihua Cao, Thomas C. Westfall |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
medicine.medical_specialty
Apomorphine Dopamine Adrenal Gland Neoplasms Pheochromocytoma Pharmacology PC12 Cells Biochemistry Dopamine agonist Article chemistry.chemical_compound Eticlopride Ca2+/calmodulin-dependent protein kinase Internal medicine medicine Animals Drug Interactions Neuropeptide Y Protein kinase A Protein Kinase C Protein kinase C Chemistry Cyclic AMP-Dependent Protein Kinases Rats Endocrinology Chelerythrine Calcium-Calmodulin-Dependent Protein Kinase Type 1 Pertussis Toxin Dopamine receptor Calcium-Calmodulin-Dependent Protein Kinases Dopamine Antagonists Cattle Calcium Channels Rabbits Adenylyl Cyclases medicine.drug |
| Zdroj: | Biochemical Pharmacology. 73:1446-1454 |
| ISSN: | 0006-2952 |
| DOI: | 10.1016/j.bcp.2007.01.003 |
| Popis: | In rat pheochromocytoma (PC12) cells the dopamine D(2) receptor agonists apomorphine (APO) and n-propylnorapomorphine (NPA) produced a concentration dependent inhibition of K(+)-evoked neuropeptide Y release (NPY-ir). The effect of APO was blocked by the dopamine D(2)-receptor antagonist, eticlopride, but not the D(1)/D(3) or the D(4)/D(2) antagonists, SCH23390 or clozapine, respectively. The D(1)/D(5) receptor agonist, SKF38393 or the D(3) agonists PD128907 and 7-OH DPAT had no effect. Selective N and L-type voltage gated Ca(2+) channel blockers, omega-conotoxin GVIa (Ctx-GVIa) and nifedipine, respectively, produced a concentration dependent inhibition of NPY-ir release but were not additive with APO. The Ca(2+)/calmodulin-dependent protein kinase (CaM kinase) II inhibitor KN-62 produced a concentration-dependent inhibition of NPY-ir release but the combination of KN-62 and APO produced no further inhibition. PMA-mediated protein kinase C stimulation significantly increased both basal and K(+)-evoked release of NPY-ir, and in the presence of PMA APO had no inhibitory effect. The PKC antagonist, chelerythrine, inhibited K(+)-evoked NPY-ir release but was not additive with APO. Neither forskolin-mediated adenylate cyclase activation and the active cAMP analog Sp-cAMPS, nor the adenylate cyclase inhibitor SQ 22536, and the competitive inhibitor of cAMP-dependent protein kinases Rp-cAMPS, had any significant effect on K(+)-evoked NPY-ir release. This suggests the inhibitory effect of APO on K(+)-evoked release of NPY-ir from PC12 cells is most likely mediated through activation of dopamine D(2) receptors leading to direct inhibition of N and L-type voltage gated Ca(2+) channels, or indirect inhibition of PKC, both of which would reduce [Ca(2+)](i) and inactivate CaM kinase. |
| Databáze: | OpenAIRE |
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