title: The protective effect of hydromorphone to ischemia in rat glial cells.
abstract: BACKGROUND
  Ischemic insults during operation can cause ischemic-reperfusion injuries in brain as well as memory impairments. Total intravenous anesthesia (TIVA) is the preferred anesthetic method in brain surgery, as it utilizes motor evoked potential monitoring. And the use of opioids is common in TIVA. However there are few studies about ischemic protective effect of opioids to glial cells.
  
  
  METHODS
  We used mixed cultures of rat glial cells, which were harvested from the brain of 1-day old rat. We divided the experimental groups according to their hydromorphone conditioning period: (a) pre-culture, (b) per-culture, or (c) pre- and per-culture. We measured the levels of the reactive oxygen species (ROS) induced by tert-butyl hydroperoxide (TBH) using flow cytometry. The ROS levels in the glial cells were also measured after the administration of 100 nM hydromorphone and selective opioid receptor antagonists.
  
  
  RESULTS
  The ROS levels were reduced in the hydromorphone-treated group, as compared to the control group (only TBH treated). There were no differences between pre-conditioned and per-conditioned groups. However, the ROS levels were more reduced in pre- and per-conditioned group compared to pre-conditioned or per-conditioned only groups. Furthermore, selective antagonists for the delta, kappa, or mu opioid receptor partially negated the hydromorphone effect.
  
  
  CONCLUSIONS
  This study demonstrated that hydromorphone can have additional protective effects on oxidative stress when pre- and per-conditioning is combined. Furthermore we proved that μ, δ, κ opioid receptors participate in protective mechanism of hydromorphone to glial cells.
authors.affiliation: Department of Anesthesiology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Young Sung
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Department of Anesthesiology and Pain Medicine, Korea University Ansan Hospital, 123, Jeokgeum-ro, Danwon-gu, Ansan-si, Gyeonggi-do 15355 Korea.
authors.forename: Woon Young
authors.initials: WY
authors.lastname: Kim
authors.affiliation: Institute of Medical Science, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Korea.
authors.forename: Yeon-Hwa
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine and Institute of Gerontology, University of Nevada, School of Medicine, Las Vegas, NV USA.
authors.forename: Ji Won
authors.initials: JW
authors.lastname: Yoo
authors.affiliation: Department of Anesthesiology and Pain Medicine, Korea University Ansan Hospital, 123, Jeokgeum-ro, Danwon-gu, Ansan-si, Gyeonggi-do 15355 Korea.
authors.forename: Too Jae
authors.initials: TJ
authors.lastname: Min
keywords: Hydromorphone; Neuroglia; Reactive oxygen species