Mitogen-Activated Protein Kinase Signaling Mediates Morphine Induced-Delayed Hyperalgesia.

ABSTRACT: The use of morphine, the standard opioid drug, is limited by its undesirable effects, such as tolerance, physical dependence, and hyperalgesia (increased pain sensitivity). Clinical and preclinical studies have reported development of hyperalgesia after prolonged opioid administration or after a single dose of intrathecal (i.t.) morphine in uninjured rats. However, whether a single standard systemic morphine dose is sufficient to decrease the nociceptive threshold in rats is unknown. Here, we showed that a single morphine subcutaneous injection induces analgesia followed by a long-lasting delayed hyperalgesia in uninjured and PGE2 sensitized rats. The i.t injection of extracellular signal-regulated kinase (ERK) inhibitor blocked morphine-induced analgesia, without interfering with the morp

SUBMITTER: de Freitas BG 

PROVIDER: S-EPMC6763729 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature