Control of hippocampal theta rhythm by serotonin: Role of 5-HT2c receptors

► 5-HT2cR agonist suppresses limbic theta rhythm in waking and REM sleep (by 20%, 57%). ► mCPP also suppressed brainstem stimulation-elicited theta rhythm under anesthesia (62%). ► The effect was dose-dependent and was antagonized with 5-HT2cR antagonist, SB-242084. ► Thus, serotonin modulation of theta activity involves 5-ht2c receptor mechanism. ► Drugs acting on 5-HT2cR may affect theta-associated pathological processes of cognition.