Acute augmentation of serotonin suppresses cardiovascular responses to emotional valence.

A key component in visceral reactivity to emotional states is heart rate (HR), however little is known about how HR response to emotional stimuli is modulated by neurochemicals. The present study investigated the way in which acute enhancement of serotonin (5-HT) function with a selective serotonin reuptake inhibitor (SSRI) modulates the HR associated with differently valent images (pleasant, neutral, unpleasant). Sixteen healthy participants viewed 75 images whilst HR was recorded. Participants were tested under two single-dose treatment conditions: placebo and citalopram (20 mg). Our findings suggest: (1) HR is able to differentiate differently valent images during placebo treatment and, (2) administration of citalopram suppresses the differences in HR between differently valent images. These results suggest that 5-HT may modulate the cardiovascular HR response to visual emotional stimuli and indicate that 5-HT may have a protective effect on the cardiovascular responses to emotional stimuli.