Changes Of G₁₂ Protein In The Neuron With Morphine Treament And Its Mechanisms In Rats

Objective: The molecular basis for opiate tolerance and dependence remains poorly understood despite widespread investigation in several preparations, including the hippocampus.Although chronic application of opiates is expected to produce changes in all neurons expressing the appropriate receptors, recent studies have implicated the hippocampus is playing a central role in opiate tolerance, dependence, and withdrawal. In the present study, we have investigated the change of G protein in primary cultured hippocampal neurons with morphine treament by using immunofluorscence and laser scanning confocal microscope(LSCM) techniques.Material and methods: The hippocampi were dissected from newbron Sprague-Dawley rats. Primary hippocampal neuronal cultures of 7 days in vitro were used and were divided randomly into six Groups(n=6): morphine treament 4h group(M4),8h group(M8),16h group(M16),24h group(M24), 48h group(M48),and control group(C).All morphine treament groups were treated with morphine (10mol/L).C group was treated with saline.The G protein levels were detected with immunofluorscence and laser scanning confocal microscope(LSCM) imaging techniques.Result:We found that (1) In the M16,M24,and M48 groups,Gi2 protein levels were significantly decrease than the C group(p<0.01);(2) compared with the C group ,in the M4 and M8 groups ,Gi2 protein did not change (p>0.05); (3)among the M16,M24 and M4g groups,Gi2 protein levels in the M48 group were the lowest;(4)between the M16 and M24groups,the 612 protein levels were lower in M24 group than those in M16group but there were not significant difference.CoDclusion:Our research indicates that the Gi2 protein levels weresignificantly decrease in primary cultured hippocampal neurons withmorphine treament that is a potential molecular mechanism of oipioidtolerance and dependence.