Analgesic effect of metoclopramide and its mechanism.

Metoclopramide produced a significant analgesic effect when tested by both acetic acid induced writhing and hot plate test. This effect was reduced by naloxone suggesting opioid involvement. Further, bromocriptine which inhibits the release of PRL attenuated the effect of metoclopramide indicating that this drug could act by releasing PRL. The unaltered analgesic effect of metoclopramide by yohimbine reveals that alpha-2 adrenoceptors may not be involved in this action.