The synergetic modulation of the excitability of central gray matter by a neuropeptide: two protocols using excitation waves in chick retina

Anais da Academia Brasileira de Ciências

Vera M.f. De Lima²  José R.c. Piqueira¹  Wolfgang Hanke¹ 

[1] ,Universidade Federal de São João del Rei Departamento de Medicina Divinópolis MG ,Brasil

关键词: extra-cellular potassium;    migraine;    neuronal-glial dynamics;    somatostatin;    spread depression;    potássio extra-celular;    enxaqueca;    dinâmica neuronal;    dinâmica glial;    somatostatina;    depressão alastrante;   

DOI  :  10.1590/S0001-37652009000100006

来源: SciELO

【 摘 要 】

The isolated chick retina provides an in vitro tissue model, in which two protocols were developed to verify the efficacy of a peptide in the excitability control of the central gray matter. In the first, extra-cellular potassium homeostasis is challenged at long intervals and in the second, a wave is trapped in a ring of tissue causing the system to be under self-sustained challenge. Within the neuropil, the extra-cellular potassium transient observed in the first protocol was affected from the initial rising phase to the final concentration at the end of the five-minute pulse. There was no change in the concomitants of excitation waves elicited by the extra-cellular rise of potassium. However, there was an increase on the elicited waves latency and/or a rise in the threshold potassium concentration for these waves to appear. In the second protocol, the wave concomitants and the propagation velocity were affected by the peptide. The results suggest a synergetic action of the peptide on glial and synaptic membranes: by accelerating the glial Na/KATPase and changing the kinetics of the glial potassium channels, with glia tending to accumulate KCl. At the same time, there is an increase in potassium currents through nerve terminals.

【 授权许可】

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