Ion mechanisms of hyperpolarizing afterpotentials accompanying epileptic discharges in neocortical neurons

Autor: G. G. Kvernadze, V. M. Okujava, T. Sh. Labakhua, L. P. Mestvirishvili, V. M. Tsomaia, S. A. Chipashvili
Rok vydání: 1999
Předmět:
Zdroj: Neurophysiology. 31:160-166
ISSN: 1573-9007
0090-2977
DOI: 10.1007/bf02515062
Popis: Hyperpolarizing afterpotentials of penicillin-induced (local application) paroxysmal depolarizing shifts (PDS) in neurons of the sensorimotor cortex of the cat were studied. The pattern of membrane conductance changes within different segments of hyperpolarization and the data on the role of various ion currents in its generation allow us to conclude that hyperpolarizing afterpotentials accompanying PDS are of a composite nature and include the following components: (i) the initial component provided by an increased membrane permeability to chloride ions (presumably a synaptic GABAA response); (ii) the second component resulting predominantly from a potassium current and representing presumably a GABAB response; and (iii) the final component comprising mainly a calcium-activated potassium current. These components are present in all neurons, are not clearly demarcated as separate waves, and partially overlap with each other, thus forming a prolonged hyperpolarizing deflection of the potential.
Databáze: OpenAIRE
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