THE IMPORTANT ROLE OF MPFC ELECTRICAL STIMULATION IN MORPHINE ADDICTION BY CHANGING GLUTAMATE CONCENTRATION IN THE VENTRAL TEGMENTAL AREA (VTA)

Background and Aim : Morphine addiction is known as a serious social problem. Medial prefrontal cortex (mPFC) and ventral tegmental area (VTA) are two important sites of the brain that contribute to this addiction and there is a complicated relation in between. In addition, neurotransmitters like glutamate and GABA play an important role in the formation of these relations. Thus, the present study was undertaken to investigate these relations via measurement of the indicated neurotransmitter changes in the VTAMethods : A total of 32 rats were used in this study, male wistar rats were selected randomly and divided into four groups. The rats anesthetized with chororal hydrate and electrode was implanted into the mPFC and animals except control group were made addicted by chronic administration of morphine intraperitoneally during 9 days in Incremental dose. In stimulation group rats were receiving mPFC electrical stimulation of 100 um every day and after 15 minute received morphine. In lesion group rats at fist day rats mPFC were destroyed with using intensity of 0.4mA for a period of 64s.At the end of the experiment the rats were decapitated and levels of GABA and Glutamate was measured into the VTA via using HPLC methodResults : Our results showed that intra-peritoneal administration of morphine and electrical stimulation (100 A) of mPFC in addicted rats, caused an increase in glutamate release in the VTA, while --Amino Butyric Acid (GABA) release was decreasing. Our findings also showed that electrical lesion (0.4mA) of caused decreased glutamate concentration in the VTAConclusion : , it can be concluded that mPFC electrical stimulation changes glutamate level in the VTA and plays an important role in reward system

Keywords:

mPFC , Lesion , GABA , Glutamate , Stimulation , VTA