Pain　is　a　complex　and　subjective　experience　that　involves　not　only　the　transduction　of　noxious　stimuli　by　nociceptive　fibers,　but　also　the　cognitive　and　emotional　processing　by　the　brain.　Previous　studies　on　the　transmission　of　nociception　suggest　that　the　activation　of　mesolimbic　dopamine　(DA)　system　plays　an　important　role　in　mediating　the　suppression　of　tonic　pain.　The　aim　of　the　current　study　was　to　examine　the　role　of　DA　D3　receptor　in　modulating　basal　and　amphetamine-induced　changes　in　pain　sensitivity　in　mice.　We　used　wild-type　and　D3　receptor　mutant　mice　and　determined　allodynia　induced　by　both　noxious　heat　(radiant　heat)　and　mechanical　(von　Frey　hair)　stimuli.　We　show　that　D3　receptor　mutant　mice　exhibit　hypoalgesia　in　both　the　tail-flick　test　and　von　Frey　hair　test　compared　to　wild-type　mice.　Amphetamine-induced　hyperalgesia　in　both　D3　receptor　mutant　and　wild-type　mice　in　the　tail-flick　test　and　von　Frey　hair　test.　There　was　no　significantly　difference　in　the　relative　change　in　pain　sensitivity　between　wild-type　and　D3　receptor　mutant　mice　in　both　the　tail-flick　test　and　von　Frey　hair　test　following　amphetamine　administration.　These　results　suggest　that　the　D3　receptor　regulates　the　transmission　of　nociception.　Moreover,　amphetamine　can　lower　pain　threshold　in　mice.　(C)　2010　Elsevier　Ireland　Ltd.　All　rights　reserved.