Supraspinal antinociceptive effect of apelin-13 in a mouse visceral pain model

► Supraspinal apelin-13 induced antinociceptive effect in the visceral pain model. ► I.t. (not i.p.) injected apelin-13 produced antinociception in the writhing test. ► The antinociception of i.c.v. apelin-13 was mediated by APJ and μ-opioid receptor. ► Apelin-13 could significantly potentiate the antinociceptive effect of morphine. ► This potentiated analgesic response was fully blocked by naloxone.