I am a
Home I AM A Search Login

Papers of the Week

Papers: 1 May 2021 - 7 May 2021

Animal Studies, Pharmacology/Drug Development

2021 Apr 29

Eur J Pharmacol

Spinal endomorphins attenuate burn-injury pain in male mice by inhibiting p38 MAPK signaling pathway through the mu-opioid receptor.


Zhang T, Zhang R, Xu B, Zhang M, Zhang Q, Li N, Qiu Y, Chen D, Xu K, Xiao J, Zhang N, Fang Q
Eur J Pharmacol. 2021 Apr 29:174139.
PMID: 33933465.


Burn injury is one of the main causes of mortality worldwide and frequently associated with severe and long-lasting pain that compromises the quality of patient life. Several studies have shown that the mu-opioid system plays an important role in burn pain relief. In this study, we investigated the spinal antinociception induced by the endogenous mu-opioid receptor (MOR) agonists endomorphins and explored their mechanisms of actions in burn injury-induced pain model. Our results showed that intrathecal injection of endomorphin-1 and -2 dose-dependently attenuated mechanical allodynia and thermal hyperalgesia via the mu-opioid receptor in mice on day 3 after burn injury, which was consistent with the data obtained from the mu-opioid receptor knockout mice. Western blot showed that the phosphorylation levels of extracellular signal-regulated kinase1/2 (ERK1/2) and p38 mitogen-activated protein kinase (p38 MAPK) in ipsilateral spinal cord tissues were significantly up-regulated after burn injury. Intrathecal injection of endomorphins selectively inhibited the activation of p38 MAPK on day 3 after burn injury via the mu-opioid receptor. Further studies found that repeated application of the specific p38 MAPK inhibitor SB203580 dose-dependently inhibited burn-injury pain, as well as the activation of spinal p38 MAPK. Taken together, our present study demonstrates that intrathecal injection of endomorphins attenuates burn-injury pain in male mice by affecting the spinal activation of p38 MAPK via the mu-opioid receptor.