AU - Yaghmaei, Parichehr AU - Oryan, Shahrbanoo AU - Hojati, Zahra AU - Javadi, Hamid Reza TI - Interaction of α2-adrenergic system and caffeine on passive avoidance learning in male wistar rats PT - JOURNAL ARTICLE TA - iau-tmuj JN - iau-tmuj VO - 18 VI - 1 IP - 1 4099 - http://tmuj.iautmu.ac.ir/article-1-302-en.html 4100 - http://tmuj.iautmu.ac.ir/article-1-302-en.pdf SO - iau-tmuj 1 AB  - Background: There are numerous studies on the effects of caffeine on memory and learning. The activation of &alpha;2-adrenoreceptors has been reported to impair memory functions in both rats and humans. In this study, interaction of &alpha;2-adrenergic system and caffeine on memory and learning was evaluated. Materials and methods: In this experimental study, 90 wistar rats assigned into six groups of fifteen. Rats received yohimbine (4, 6, 8, 10 &mu;g), as a &alpha;2-adrenergic antagonist, clonidine (2, 4, 6 &mu;g), as a &alpha;2-adrenergic agonist, and caffeine (10, 20, 30 &mu;g). The cannula was implanted into the right lateral ventricle of all rats with steriotaxi method. Then, they were trained in shuttlebox. Post-training intracerebroventricular (ICV) injection was carried out in all experiments and optimum doses were identified. Results: Caffeine and yohimbine fostered memory and learning (p<0.001), while clonidine diminished these abilities compared to saline injection (p<0.05). Co-administration of the optimum doses of clonidine and yohimbine showed statistically significant reduction in the time of step-through latency (p<0.05). Instead, co-administration of clonidine and caffeine revealed no significant increase in the time of step-through latency (NS). Conclusion: It is concluded that yohimbine and caffeine, unlike clonidine, increase memory. CP - IRAN IN - Assistant Professor, PhD of Physiology, Department of Biology, Islamic Azad University, Science and Research Campus, Tehran, Iran LG - eng PB - iau-tmuj PG - 7 PT - YR - 2008