Effects of Naloxone on Regional Cerebral Blood Flow in Experimentally Induced Intracerebral Hematoma in the Cat

Park, Chun Kun; Kang, Joon Ki; Song, Jin Un; Kim, Dae Jo

Abstract

In an attempt to investigate the role of endogenous opiate in the changes of regional cerebral flow(rCBF) in intracerrebral hematoma(ICH), an experimental model of ICH was induced in the cat. Forty adult cats were divided into four groups, saline-treated normal control group(10 cats), saline-treated ICH group(10 cats) and naloxone-treated ICH group(10 cats) respectively. The ICH was induced in the right frontal region stereotactically with the autogenous arterial blood(1.5ml). The rCBF measurements done by hydrogen clearance method were carried out in each cat immediately, 20 min, 40 min, 60 min, 80 min, 100 min, 120 min, 140 min, and 160 min following ICH induction, and naloxone(10 mg/kg) was intravenously administered immediately, 60 min and 120 min after ICH induction. ICH induction resulted in increases of mean arterial blood pressure(MABP) and intracranial pressure(ICP) and decrease of rCBF of the ipsilateral hemisphere. Naloxone did not modify the pattern of MABP and ICP changes, however it transiently increased rCBF, every time the drug was administered in naloxone-treated control group and from 60 min following ICH induction in naloxone-treated ICH group. The animals were sacrificed 180 min after ICH induction and the brains were sliced and prepared with Evans Blue, which revealed no significant mass effect, midline shift or perifocal brain edema. It is concluded that the decrease of rCBF in ICH could be influenced by endogenous opiates and naloxone could improve decreased rCBF in ICH without increase of MABP or decrease of ICP.