Correlation Between Dopamine D2 Receptor in the Orbital Frontal Cortex in Rat and the Processing of Morphine Dependence

With conditional place preference (CPP) of morphine dependent rats, the study focus on the effects of the DAD2 receptor in the orbital frontal cortex (OFC) in rat associated with the processing of opioid dependence. CPP models of morphine dependent rats were established by intraperintoneal injection and combined with environmental stimulation. Rats were devided into three groups received Quinpirole or Raclopride injection (agonist or antagonist of the DAD2 receptor) in OFC by a miniminjector after the last conditioning session and CPP was assessed by the time spent in the morphine-associated environment after conditioning. All dates were analysed by statistical method. The time in drug place of Raclopride intervene group showed respectively significantly longer than the control group in the 2nd withdrawal day (P<0.05), however the time of Quinpirole intervene group didn't show significant difference compared with control group (P>0.05). The results indicated that: (1) CPP models of morphine dependent rats were established successfully by intraperintoneal injection with the proper dosage with the reference of many related papers; (2) The DA system in OFC plays an important role in the procession of morphine dependence; (3) The damnification in orbital frontal cortex of animals who addicted in drugs will increase their drugs craving behavior. Clinically, it might indicate that we must cautiously operate intervention to the patients of drug addiction.