The effects of combining serotonin reuptake inhibition and 5-HT7 receptor blockade on circadian rhythm regulation in rodents

► Inhibition of serotonin transporter and 5-HT7 receptor lengthens circadian period. ► Serotonin transporter and 5-HT7 receptor blockade delay phase of circadian activity. ► 5-HT7 receptor activation modulates circadian period length.