The rol of central serotoninergic system in neurocardiogenic syncope etiology.

The implementation of the tilt test in 1986 as a diagnostic tool forunexplained syncope, established to the neurocardiogenic syncopeas the most common cause of recurrent fainting in the general population.Despite its prevalence, the pathophysiology and treatmentof the neurocardiogenic syncope remains to be elucidated. It wasformerly believed that the Bezold-Jarisch refl ex was the triggeringfactor for neurocardiogenic syncope. However, the evidenceagainst this as a mechanism is now overwhelming. Nowadays, itis suggested that the etiology of the neurocardiogenic syncope isrelated with hormonal alterations in the central nervous system. Manymechanisms have been implicated involving central and peripheralparticipation. Recent studies suggest that the central serotonergicsystem may play an important role in eliciting the vasovagal reactionof the neurocardiogenic syncope by inhibiting sympathetic nervoussystem. In this article we attempt to review some basic aspectsof the central serotonergic system and it role in the regulation ofcardiovascular function, present data suggesting its potential role in neurocardiogenic syncope.