Selective downregulation of an inactivating K+ conductance by analogues of cAMP in mouse Schwann cells.

AUTOR(ES)

Despeyroux, S

RESUMO

1. Voltage-dependent K+ conductances on Schwann cells in organotypic cultures of mouse dorsal root ganglia were classified as inactivating or sustained (responsible for currents IA and IK, respectively). IA is known to be much reduced on Schwann cells that contact neurites. 2. In the absence of neurones, IA and IK were present. IA, but not IK, was markedly reduced (by 80% after 105 h of treatment) by 2 mM 8-(4-chlorophenylthio)-cAMP (cpt-cAMP), a weakly hydrolysable analogue of cAMP. The effect did not appear for at least 2 h and was maximal after about 100 h. 3. The effect of 1 mM cpt-cAMP was abolished in the presence of an inhibitor of protein kinases, N-[2-bromocinnamyl(amino)ethyl]-5-isoquinolinesulphonamide (H-89, 10 microM). 4. Other analogues of cAMP, but not an analogue of cGMP (8-bromo-cGMP), also reduced IA. 5. We conclude that IA, but not IK, can be downregulated by activation of the protein kinase A pathway.

Documentos Relacionados

• Induction of megakaryocytic differentiation and modulation of protein kinase gene expression by site-selective cAMP analogs in K-562 human leukemic cells.
• Hormone secretagogues increase cytosolic calcium by increasing cAMP in corticotropin-secreting cells.
• Regulation of ATP-sensitive K+ channels in insulinoma cells: activation by somatostatin and protein kinase C and the role of cAMP.
• cAMP modulates multiple K+ currents, increasing spike duration and excitability in Aplysia sensory neurons.
• cAMP regulates P450scc gene expression by a cycloheximide-insensitive mechanism in cultured mouse Leydig MA-10 cells.