ETHANOL-WITHDRAWAL AND DIAZEPAM-WITHDRAWAL HYPERLOCOMOTION IS NOT DUETO 5-HT(3) RECEPTOR STIMULATION

The effect of 5-HT3 receptor antagonists such as ondansetron, ICS 205- 930, MDL 72222, metoclopramide, and zacopride was investigated on the ethanol as well as diazepam withdrawal phenomena in the present study. There was a significant increase in locomotor activity in the ethanol - as well as diazepam-withdrawn rats. The treatment of rats with 5-HT3 receptor antagonists during withdrawal phase did not modify the effec t. The ethanol-withdrawn rats were more sensitive to pentylenetetrazol e (PTZ)-induced convulsions as compared to control animals. 5-HT3 rece ptor antagonists did not attenuate the increased sensitivity of ethano l-withdrawn rats to PTZ. These observations indicated that 5-HT3 recep tor antagonists are ineffective in attenuating hyperlocomotor activity following abrupt termination of chronic administration of ethanol or diazepam, and increased sensitivity to PTZ in the ethanol-withdrawn ra ts.