Abstract

It was recently demonstrated that acute administration of 3,4-methylenedioxymethamphet-amine (MDMA, "Ecstasy") is capable of counteracting haloperidol-induced catalepsy in rats. The present study was done with another psychostimulant, S-(-)-cathinone. In these experiments, 32 male Sprague-Dawley rats, 225 +/- 25 g, were used. They were divided into three groups. All groups received 0.5 mg/kg haloperidol in normal saline (s.c.) as a first injection. Then 30 min later each group received either isotonic phosphate-buffered saline, 1 mg/kg S-(-)-cathinone, or 2.5 mg/kg (RS)-MDMA (s.c.) as a second injection. The results of descent latency on both the horizontal bar and vertical grid showed that S-(-)-cathinone or (RS)-MDMA upon acute administration induces a strong anticataleptic activity (P < 0.0001) compared to rats treated with haloperidol plus vehicle. The effect of both drugs was later masked upon subchronic administration (days 2-7, 26-29). This is probably due to sensitization of cataleptic behavior. However, when the same groups of rats were tested on day 8 in a different task, i.e., open-field, they showed a significant difference (P < 0.05). The detailed mechanism of the observed strong anticataleptic activity of S-(-)-cathinone (which is considered a potent dopamine releaser) requires further investigation.

Copyright 2003 Wiley-Liss, Inc.