en Behavioral Neuroscience Behavioral Neuroscience Original Original <p style="text-align: justify;"><strong>Introduction</strong>: Methamphetamine (Meth) and Buprenorphine (BUP) modulate pain perception. However, the antinociceptive effects of their interactions, which affect through different systems, are unclear in rats. This study aimed to compare the analgesic effects of Meth, BUP, and their coadministration, as well as the effect of withdrawal from these substances on nociception in male rats.<br> <strong>Methods</strong>: In this experiment, 40 male Wistar rats (weight: 250-300 g) were categorized into four groups: control, Meth, BUP, or BUP+Meth. After seven days of treatments, the antinociceptive effects were assessed using the hot plate and the tail flick tests. The differences among the groups were analyzed with ANOVA and Tukey&rsquo;s post hoc tests. P values less than 0.05 were considered significant.<br> <strong>Results</strong>: Meth and BUP increased the reaction times during the hot plate and tail flick tests. The combination of Meth and BUP increased reaction time more than Meth or BUP alone.&nbsp;<br> <strong>Conclusion</strong>: The significantly high reaction times in rats treated with Meth and BUP indicate that these substances have antinociceptive effects. In addition, Meth enhanced the antinociceptive effects of BUP. These synergistic effects might occur through the dopaminergic, serotonergic, and or adrenergic systems.</p> Methamphetamine, Buprenorphine, Pain, Hot plate, Tail flick, Interactions 313 322 http://bcn.iums.ac.ir/browse.php?a_code=A-10-290-5&slc_lang=en&sid=1 Farshid Etaee Dr.farshid.etaee@gmail.com 13700319475328460030378 13700319475328460030378 No Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.; Urogenital Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran Arezoo Rezvani-Kamran a.rezvani862@yahoo.com 13700319475328460030379 13700319475328460030379 No Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran. Mohammad Taheri mohammad.taheri@sbmu.ac.ir 13700319475328460030380 13700319475328460030380 No Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran. Ghazaleh Omidi gh_omidi07@yahoo.com 13700319475328460030381 13700319475328460030381 No Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran. Parisa Hasanein p.hasanein@uoz.ac.ir 13700319475328460030382 13700319475328460030382 No Department of Biology, School of Sciences, University of Zabol, Zabol, Iran. Alireza Komaki alirezakomaki@gmail.com 13700319475328460030383 13700319475328460030383 Yes Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.