en Behavioral Neuroscience Behavioral Neuroscience Original Original <div style="text-align: justify;"><strong>Introduction</strong>: The mesolimbic dopamine system is important in the modulation of pain and is activated under stress. Various types of stress can induce analgesia through the release of neurotransmitters and neuropeptides, such as dopamine. Accordingly, the present study investigated the role of dopamine receptors in the dentate gyrus (DG) of the hippocampus in two stress models of analgesia.&nbsp;<br> <strong>Methods</strong>: One hundred and thirty-three adult male rats underwent stereotaxic surgery to place a unilateral cannula into the DG. After a one-week recovery period, separate groups of animals received different doses of the D1 receptor antagonist SCH-23390 (0.25, 1 and 4 &mu;g/0.5 &mu;L) or D2 receptor antagonist sulpiride (0.25, 1, and 4 &mu;g/0.5 &mu;L) or vehicle (0.5 &mu;L DMSO or saline) into the DG, respectively. Animals were then exposed to forced swim stress (FSS) for 6 min or restraint stress (RS) for 3 hours, and then, pain thresholds were assessed in the tail-flick test over a 60-min period.<br> <strong>Results</strong>: Exposure to RS and FSS reduced pain responses in the tail-flick test, which was reduced by the inhibition of dopamine receptors. Intra-DG administration of SCH-23390 significantly reduced antinociceptive behaviors in the RS compared to the FSS.&nbsp;<br> <strong>Conclusion</strong>: On the other hand, the effect of D2-like dopamine receptors in reducing FSS-induced analgesia was more prominent than RS.&nbsp;</div> Restraint stress (RS), Force swimming stress, Dentate gyrus (DG), Dopamine receptors, Tail-flick test, Rat 323 336 http://bcn.iums.ac.ir/browse.php?a_code=A-10-8558-1&slc_lang=en&sid=1 Homayoon Golmohammadi homayoongolmohammadi@yahoo.com 13700319475328460058690 0009-0002-1748-0461 No Neuroscience Research Center, Institute of Neuroscience and Cognition, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Mohadeseh Ghalandari-Shamami ghalandari.m@iau.ac.ir 13700319475328460058691 13700319475328460058691 Yes Department of Physiology, TeMS.C., Islamic Azad University, Tehran, Iran. Abbas Haghparast haghparast@yahoo.com 13700319475328460058692 13700319475328460058692 No Neuroscience Research Center, Institute of Neuroscience and Cognition, Shahid Beheshti University of Medical Sciences, Tehran, Iran.