Effect of 8-bromo-cAMP on the tetrodotoxin-resistant sodium (Nav 1.8) current in small-diameter nodose ganglion neurons
| Autor: | Yukio Shima, Chikako Saiki, Shinki Yoshida, Mizuho Ikeda, Hidehiko Ohta, Mamoru Takeda, Shigeji Matsumoto, Takeshi Tanimoto |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
medicine.medical_specialty
Bisindolylmaleimide Patch-Clamp Techniques medicine.drug_class 8-Bromo Cyclic Adenosine Monophosphate Gene Expression Nerve Tissue Proteins Tetrodotoxin Sodium Channels Membrane Potentials NAV1.8 Voltage-Gated Sodium Channel Cellular and Molecular Neuroscience chemistry.chemical_compound Internal medicine medicine Animals Drug Interactions Patch clamp RNA Messenger Enzyme Inhibitors Protein kinase A Protein kinase C Cells Cultured Pharmacology Neurons Forskolin Dose-Response Relationship Drug Reverse Transcriptase Polymerase Chain Reaction Colforsin Nodose Ganglion Neural Inhibition Protein kinase inhibitor Rats Endocrinology chemistry Animals Newborn Phorbol Sodium Channel Blockers |
| Zdroj: | Neuropharmacology. 52(3) |
| ISSN: | 0028-3908 |
| Popis: | We examined whether 8-bromo-cAMP (8-Br-cAMP)-induced modification of tetrodotoxin-resistant (TTX-R) sodium current in neonatal rat nodose ganglion neurons is mediated by the activation of protein kinase A (PKA) and/or protein kinase C (PKC). In 8-Br-cAMP applications ranging from 0.001 to 1.0mM, 8-Br-cAMP at 0.1mM showed a maximal increase in the peak TTX-R Na(+) (Nav1.8) current and produced a hyperpolarizing shift in the conductance-voltage (G-V) curve. The PKC inhibitor bisindolylmaleimide Ro-31-8425 (Ro-31-8425, 0.5microM) decreased the peak Nav 1.8 current. The Ro-31-8425-induced modulation of the G(V)(1/2) baseline (a percent change in G at baseline V1/2) was not affected by additional 8-Br-cAMP application (0.1mM). The maximal increase in Nav 1.8 currents was seen at 0.1microM after the application of a PKC activator, phorbol 12-myristate 13-acetate (PMA) and forskolin. The PMA-induced increase in Nav 1.8 currents was not significantly affected by additional 0.1mM 8-Br-cAMP application. Intracellular application of a PKA inhibitor, protein kinase inhibitor (PKI, 0.01mM), inhibited the baseline Nav 1.8 current, significantly attenuated the 8-Br-cAMP-and PMA-induced increase in the peak Nav 1.8 current, and caused a significant increase in the slope factor of the inactivation curve. The PKI application at a higher concentration (0.5mM) greatly inhibited the PMA (0.1microM)-induced increase in the peak Nav 1.8 current amplitude and further enhanced the Ro-31-8425-induced decrease in the current. These results suggest that the 8-Br-cAMP-induced increase in Nav 1.8 currents may be mediated by activation of both PKA and PKC. |
| Databáze: | OpenAIRE |
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