The effects of cyclohexyladenosine in morphine dependent mononeuropathic rats

Abstract

Opioid dependence is an important problem in the presence of chronic pain as neuropathy. The aim of present study was to determine the attenuating effect of cyclohexyladenosine (CHA) on morphine dependence and naloxone precipitated withdrawal syndrome in mononeuropathic animal model. 30 Sprague Dawley male rats weighting 185-220±15 g were included to the study. The right common sciatic nerves were ligated loosely with four 4/0 chromic gut after exploration under barbiturate anaesthesia. Animals were allocated randomly into five equal group. Drug administration and nociceptive tests were started for four days after 10 days recovery period. Saline was injected two times in a day to the control and sham operated animals. CHA 1mg/kg+saline, saline+morphine10 mg/kg and CHA 1mg/kg+morphine 10 mg/kg were administered to the other groups, respectively. Nociceptive threshold was determined during treatment period by hot plate test at 46°C. Jumping or hind limb licking of operated site was accepted as positive sign. Naloxone 1 mg/kg was administered on the 5th day, after 15 min control observation period. Escape jumping, wet dog shake or teeth chattering were determined in 15 minute period as withdrawal signs. Morphine induced analgesia was reduced by CHA. Hyperalgesia was seen on control group of rats. Anti allodynic effect was on morphine>CHA + morphine > CHA groups, respectively. CHA abolished morphine withdrawal symptoms. Adenosine agonists and morphine were effective partly on the same receptors. This study may be thought to influence further animal and clinical studies.