HTR5A and major depressive disorder: If the mechanism by which wheel running prevents sensitized 5-HT activity in the dorsal striatum is through decreasing the activity of 5-HT neurons across the DRN, it could have broader implications for several behavioral correlates of depression and anxiety related to or dependent upon excessive DRN 5-HT activity including exaggerated fear, reduced social interaction, decreased sucrose preference, and enhanced drug seeking [24, 30, 50, 51].