Divalent cations as modulators of neuronal excitability: Emphasis on copper and zinc
Biol. Res
; 39(1): 173-182, 2006. ilus
Artigo
em Inglês
| LILACS
| ID: lil-430710
Biblioteca responsável:
BR1.1
RESUMO
Based on indirect evidence, a role for synaptically released copper and zinc as modulators of neuronal activity has been proposed. To test this proposal directly, we studied the effect of copper, zinc, and other divalent cations on voltage-dependent currents in dissociated toad olfactory neurons and on their firing rate induced by small depolarizing currents. Divalent cations in the nanomolar range sped up the activation kinetics and increased the amplitude of the inward sodium current. In the micromolar range, they caused a dose dependent inhibition of the inward Na+ and Ca2+ currents (INa and ICa) and reduced de amplitude of the Ca2+-dependent K+ outward current (ICa-K). On the other hand, the firing rate of olfactory neurons increased when exposed to nanomolar concentration of divalent cations and decreased when exposed to micromolar concentrations. This biphasic effect of divalent cations on neuronal excitability may be explained by the interaction of these ions with high and low affinity sites in voltage-gated channels. Our results support the idea that these ions are normal modulators of neuronal excitability.
Texto completo:
Disponível
Coleções:
Bases de dados internacionais
Base de dados:
LILACS
Assunto principal:
Zinco
/
Neurônios Receptores Olfatórios
/
Cobre
Limite:
Animais
Idioma:
Inglês
Revista:
Biol. Res
Assunto da revista:
Biologia
Ano de publicação:
2006
Tipo de documento:
Artigo
/
Documento de projeto
País de afiliação:
Chile
Instituição/País de afiliação:
Universidad de Chile/CL