Efeitos do eugenol sobre variáveis elétricas de neurônios do gânglio cervical superior de ratos. / Effects of eugenol on electrical parameters of neurons superior cervical ganglion of rats.

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

27/12/2008

RESUMO

Eugenol (EUG) is a fenilpropanoid obtained from the essential oils of plants such as clove and basil which has widespread use in dentistry on the sealing of the dental root cavity. EUG possesses, amongst others, an analgesic effect that may be due to a local anesthetic like inhibition of sodium currents, to a capsaicin like activation of TRPV-1 receptors or to both. Sharp microelectrode current clamp experiments were carried out in non dissociated neurons of rat superior cervical ganglia (SCG) which do not express TRPV-1 channels. EUG (0,1 2.0mM) reversibly inhibited the peak to peak amplitude of the SCG neurons action potential in a concentration and time dependent manner. EUG 0,1mM induced no significant alteration of action potential (AP) parameters in all 14 cells tested while 0,6mM and 2mM EUG induced reversible AP inhibition in 6 out of 17 and 10 out of 12 cells tested, respectively. These frequencies of occurrence of AP inhibition at 0,6 and 2mM were significantly different (p = 0,002, chi-square test). EUG 0,6mM also took longer than 2mM for both establishment end recovery of this effect. The time for establishment of EUG-induced AP inhibition, 50% recovery e maximum recovery suffered a 3, 9 and 11 fold increase respectively. EUG 0,6mM also produced a reversible decrease in membrane input resistance while 2mM did not. Those effects have lead us to propose that EUG besides acting on the voltage-dependent sodium channels of the SCG neurons, possesses a yet second mode of action that is dependent on time, responsible for the decrease in input resistance and capable of increasing the potency of EUG analgesic effect.

ASSUNTO(S)

eugenol gânglio cervical superior potencial de ação fisiologia eugenol superior cervical ganglia action potential

ACESSO AO ARTIGO

Documentos Relacionados