Serotonergic-1a activity and contingent negative variation.

While cholinergic, dopaminergic, noradrenergic, and gabaergic effects on contingent negative variation (CNV) have been largely described, little is known about serotonergic influence. Therefore, the relationship between CNV and serotonergic activity as reflected by prolactin (PRL) response to flesinoxan, a 5-HT(1A) full agonist, has been investigated in 28 healthy volunteers. To investigate the clinical implications of the relationship between CNV and serotonergic-1a activity, a group of 43 depressed patients was included in the study. Results among healthy volunteers showed a significant negative relationship between PRL response to flesinoxan and CNV amplitude at Fz, but no relationship for the other electrodes (Cz and Pz). In depressed patients, the relationships were not significant. Overall, this study does not support serotonergic effects on CNV. However, this information is indirect (correlations) and is limited to 5-HT(1A) activity.