نقش گيرنده هاي گرليني ناحيه سپتوم مياني در اثرات مورفينبر تثبيت حافظه در يادگيري اجتنابي غيرفعال

The Role of Middle Septal Ghrelin Receptors in theEffects of Morphine on Memory Consolidationin Passive Avoidance Learning

شواهد نشان مي دهد مورفين باعث تخريب حافظه مي شود. هم چنين هورمون گرلين در ارتباط با حافظه و يادگيري دخالت دارد و اثرات پاداشي مواد مخدر را ميانجي گري مي كند. در مطالعه حاضر نقش گيرنده هاي گرليني ناحيه سپتوم مياني در اثرات مورفين بر تثبيت حافظه در يادگيري اجتنابي غيرفعال بررسي شد. اد و روش ﻫﺎ: در اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﺗﺠﺮﺑﯽ، 91 ﺳﺮ ﻣﻮش ﺻﺤﺮاﯾﯽ ﻧﺮ ﻧﮋاد وﯾﺴﺘﺎر ﺑﻪ ﻃﻮر ﺗﺼﺎدﻓﯽ ﺑﻪ 13 ﮔﺮوه)7=n( ﺷﺎﻣﻞ ﮔﺮوه ﻫﺎي ﺳﺎﻟﯿﻦ)1ml/kg(، ﻣﻮرﻓﯿﻦ0/5 - 7/5 mg/kg و ﮔﺮﻟﯿﻦ0 - 1 nmol/µl ﺑﻪ ﻫﻤﺮاه ﻣﻮرﻓﯿﻦ)7/5mg/kg( ﯾﺎ ﺳﺎﻟﯿﻦ)1ml/kg( ﺗﻘﺴﯿﻢ ﺷﺪﻧﺪ. در ﮔﺮوه ﻫﺎي درﯾﺎﻓﺖ ﮐﻨﻨﺪه ﮔﺮﻟﯿﻦ، ﺑﻼﻓﺎﺻﻠﻪ ﭘﺲ از آﻣﻮزش ﮔﺮﻟﯿﻦ ﺑﻪ درون ﻧﺎﺣﯿﻪ ﺳﭙﺘﻮم ﻣﯿﺎﻧﯽ ﺗﺰرﯾﻖ و ﭘﺲ از ﭘﻨﺞ دﻗﯿﻘﻪ ﺳﺎﻟﯿﻦ و ﯾﺎ ﻣﻮرﻓﯿﻦ ﺑﻪ ﺻﻮرت زﯾﺮﺟﻠﺪي ﺗﺰرﯾﻖ ﺷﺪ. ﻣﺮﺣﻠﻪ آزﻣﻮن 24 ﺳﺎﻋﺖ ﺑﻌﺪ از آﻣﻮزش اﻧﺠﺎم ﺷﺪ. داده ﻫﺎ ﺑﺎ اﺳﺘﻔﺎده از آﻧﺎﻟﯿﺰ وارﯾﺎﻧﺲ و آزﻣﻮن ﺗﻌﻘﯿﺒﯽ ﺗﻮﮐﯽ ﺗﺠﺰﯾﻪ و ﺗﺤﻠﯿﻞ ﺷﺪﻧﺪ. ﯾﺎﻓﺘﻪ ﻫﺎي ﭘﮋوﻫﺶ: ﺗﺰرﯾﻖ ﭘﺲ از آﻣﻮزش ﻣﻮرﻓﯿﻦ، ﻣﺪت زﻣﺎن ورود ﺑﻪ ﻧﺎﺣﯿﻪ ﺗﺎرﯾﮏ را در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﮔﺮوه ﮐﻨﺘﺮل ﺑﻪ ﻃﻮر ﻣﻌﻨﯽ داري ﮐﺎﻫﺶ و ﻣﺪت زﻣﺎن ﻣﺎﻧﺪن در اﺗﺎق ﺗﺎرﯾﮏ را اﻓﺰاﯾﺶ ﻣﯽ دﻫﺪ)P<0.001(. ﺗﺰرﯾﻖ ﮔﺮﻟﯿﻦ ﺑﻪ داﺧﻞ ﻧﺎﺣﯿﻪ MS ﻓﺮاﻣﻮﺷﯽ ﻧﺎﺷﯽ از ﻣﻮرﻓﯿﻦ)7/5 ﻣﯿﻠﯽ ﮔﺮم ﺑﺮ ﮐﯿﻠﻮﮔﺮم وزن ﺑﺪن( را ﻣﻬﺎر ﻧﻤﻮد)P<0.001(. ﺗﺰرﯾﻖ ﮔﺮﻟﯿﻦ ﺑﻪ ﺗﻨﻬﺎﯾﯽ ﺗﺎﺛﯿﺮ ﻣﻌﻨﯽ داري ﺑﺮ ﺑﻪ ﺧﺎﻃﺮآوري ﺣﺎﻓﻈﻪ ﻧﺪاﺷﺖ)P>0.05(. گرلين قادر است از اثرات تخريبي مورفين بر حافظه و يادگيري در مدل اجتنابي مهاري جلوگيري كرده و احتمالا ناحيه سپتوم مياني در بروز اين اثر دخالت دارد.

Evidence indicates that morphine impairs memory process. Ghrelin hormone has been linked to learning and memory processes and modulates reward properties of addictive drugs. In this study we examined the role of middle septal ghrelin receptors in the effects of morphine on memory consolidation in passive avoidance learning. Materials & Methods In this experimental study, 91 male Wistar rats were randomly divided into 13 (n=7) groups: saline (1ml/kg), morphine (0.5- 7.5 mg/kg), ghrelin (0- 1 nmol/μl) plus morphine (7.5 mg/kg) or saline (1ml/kg). In ghrelin treated groups animals received intra- medial Septum injection of ghrelin immediately after training and 5 min later saline or morphine was injected subcutaneously. Testing phase was done 24 h after training. Data were analyzed using ANOVA analysis followed by Tukey multiple comparison test. Ethics code: IR.ARAKMU.REC.1397.215 Findings Post-training administration of morphine reduced step-through latency and increased Total dark chamber compared with saline group (p< 0.001). Intra- medial Septum injection of ghrelin inhibited morphine-induced amnesia (p< 0.001). Administration of ghrelin alone had no significant effect on memory retrieval (P > 0.05). Disscution & Conclusions Ghrelin is able to prevent the deleterious effects of morphine on memory and learning in the inhibitory avoidance model and the medial septal region may be involved in this effect.