Effects of Naloxone on Stress-Induced Analgesia After Hemorrhagic Shock

Abstract

Naloxone did not reverse the hemorrhagic shock-induced analgesia, which suggests that endogenous opioids might not be a major factor that governs stress-induced analgesia (SIA) after hemorrhagic shock.

Unilateral adrenalectomy attenuates hemorrhagic shock-induced analgesia in rats

“…It has been found that the anesthetic requirement decreased during hypovolemic shock, but our study was the fi rst to report the SIA phenomenon under a normotensive condition after hemorrhagic shock. In our next study, we found that naloxone pretreatment did not reverse the SIA [5]. Endogenous opioids may not be the main factor governing SIA after hemorrhagic shock.…”

“…In their study, the SIA was reversed by naloxone, which means that endogenous opioids, such as β-endorphin, were an important factor in regulating the SIA. However, our previous study showed that naloxone did not reverse hemorrhagic shock-induced analgesia [5]. Because β-endorphin and adrenocorticotropic hormone (ACTH) are produced from the same precursor [14], we speculated that a high concentration of β-endorphin induced by their chemical adrenalectomy may have been promoted after cold-swim stress and may have potentiated the analgesia.…”