Changes Of CREB Protein In Morphine Dependent Or Abstinent Rats Studies On Bupivacaine Loaded Sustained-Release Microspheres

Objective: To investigate the different changes of CREB proteins in three brain regions of acute or chronic morphine addiction and withdrawl rats with the technique of western-blot . Methods:Thirty six adult male Sprague-Dawley rats were divided randomly into six groups(n=6):acute morphine dependent group,acute abstinent group,acute control group,chronic morphine dependent group,chronic abstinent group and chronic control group. Dependent groups and abstinent group were administered with morphine by intraperitoneal injection till morphine dependent models were founded.The rats in abstinent groups were induced withdrawal sydromes with naloxone 5mg/kg for 30min.The rats in control group were injected with Saline. All rats were sacrificed by decapitation.The brain region of nucleus accumbens, prefrontal cortex and hippocampus were separated .The relative concentrations of CREB protein were detected by the technique of western-blot. Results: l)In acute morphine dependent group and acute abstinent group, CREB protein didn't change significantly in prefrontal cortex, nucleus accumbens and hippocampus compared with control group(p>0.05);2)In chronic morphine dependent group and chronic abstinent group, CREB protein increased significantly in cortex and hippocampus (p<0.01,p<0.05) more than the chronic control group. But CREB protein decrease significantly in nucleus accumbens compared with the chronic control group (/?>0.05). Conclusion: The acute morphine dependence did not change the CREB level. It maybemeans that mophine dependence was a long-term biological effect. It maybe took some time to change the transcription factor.