Efeito do 1,8-cineol sobre os parâmetros eletrofisiológicos das células nervosas do gânglio cervical superior de ratos / Effect of 1,8-cineol on electrophysiological parameters of nerve cells in the rat superior cervical ganglion

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

18/07/2007

RESUMO

1,8-cineol is a terpene that constitutes many essential oils from medicinal folk plants. This compound presents many pharmacological activities as anti-inflammatory, antitumoral and gastroprotective. However it is difficult to find studies that relate the effects of both essential oils and its compounds in nervous system tissues. Since many of these oils and its constitutes are reported to be anesthetics drugs, the study of the effects of 1,8-cineol in electrophysiological parameters, as well as nervous excitability, in rats intact Superior Cervical Ganglion (SCG) nervous cells was performed. For this, Wistar rats were sacrificed by cerebral concussion and its SCG dissected and mounted in a chamber for superfusion in Locke solution and 1,8-cineol. It was used the intracellular microelectrode technique and protocols in current clamp mode for determination of these parameters under 1,8-cineol chalenge, being the data continuously monitored and recorded in computer. In the concentration of 6 mM, all cells (n=12) had inhibition of Action Potential (AP) and showed modifications in the electrophysiological parameters studied (AP amplitude, maximum inclinations, duration, input membrane resistance and rest potential). The effects of 1,8-cineol were reversible until 45 min after passage of the compound to the tissue in the concentration of 6 mM. In the concentration of 1 mM it had two types of cells: with AP inhibition and similar features to the cells treated with 1,8-cineol in the concentration of 6 mM (n=7) and cells with no inhibition (n=8). However this last group of cells was weakly affected in the AP amplitude and AP maximum ascendant inclination and showed no alteration of rest potential. For the concentration of 0,1 mM there was no significant alteration in the parameters associated to the AP, neither in the input membrane resistance, or in rest potential (n=14). There was a membrane depolarization when the tissue was treated with the concentration of 6 mM and the excitability in the final of this depolarization was investigated. For this, we injected current continuously in the cell to return the transmembrane potential to its value in the stabilization and we found alterations in some electrophysiological parameters, as well as, modification in the AP generation threshold current. Therefore, in conclusion, the 1,8-cineol blocked the AP in the concentration of 6mM and 1mM and its effects were reversible. This blockade could be, possibly, by the action of the compound directly in the sodium channels or by indirect mechanism of cellular membrane depolarization, through the activation of calcium-activated chloride channel. Besides, the data showed yet that 1,8-cineol blocked the neuronal excitability in the rats SCG cells.

ASSUNTO(S)

células nervosas glânglio cervical 1,8-cineol parâmetros eletrofisiológicos fisiologia nerve cells, cervical ganglia, 1.8-cineole electrophysiological parameters

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