The effects of transcranial electrical stimulation (TCES) on droperidol-treated rats were evaluated using the righting reflex latency (RRL) test. TCES (high frequency (HF)-166 kHz, intermittent-100 Hz current) delivered through three electrodes (a negative electrode placed between the eyebrows and positive electrodes located in the retro-mastoid region) was shown to potentiate the inhibition of righting reflex induced by droperidol. This potentiation was found to depend on the dose of the drug, the characteristics of the current delivered and the duration of stimulation. We also observed that TCES-induced potentiation of inhibition of righting reflex produced by droperidol injection was not reversed: (i) after naltrexone administration, (ii) when measures were performed on p-chlorophenylalanine (pCPA)-treated animals. These results suggest that, under the experimental conditions: (i) TCES does not interact with opioid endogenous to potentiate droperidol effects, (ii) the effect of TCES on dopaminergic system prevails against TCES action on serotonergic system. Though these findings enlarge the comprehension of TCES effects on the central nervous system, further investigations are necessary to elucidate TCES mechanisms.
Copyright 1999 Elsevier Science B.V.