Effects of single and long-term metoclopramide administration on open field and stereotyped behavior of rats.

The effects of single and long-term metoclopramide administration on rat open-field and apomorphine-induced stereotyped behavior were studied. A single dose of metoclopramide decreased dose dependently not only locomotion and rearing frequencies in the open field but also the apomorphine effects. Withdrawal from long-term metoclopramide administration induced a significant increase in all parameters of activity recorded in the open field. The responsiveness to apomorphine was also augmented in metoclopramide-withdrawn rats. These results were considered to be a consequence of the supersensitivity of central dopaminergic receptors.