CATECHOLAMINERGIC FUNCTION AND P300 AMPLITUDE IN MAJOR DEPRESSIVE DISORDER (P300 AND CATECHOLAMINES)

The neurobiology of P300 is still a subject of controversy. P300 ampli tude appears to be modulated by multiple neurotransmitter systems, esp ecially dopaminergic, noradrenergic as well as cholinergic and GABAerg ic. In this study, we investigated the relationship between P300 ampli tude and catecholaminergic neurotransmission as assessed by the growth hormone (GH) response to clonidine and apomorphine challenges in 20 m ajor depressive patients. Results showed a correlation of P300 amplitu de with the apomorphine test (r = 0.54; P = 0.01), but not with the cl onidine test (r = 0.22; NS). This study supports a role for dopamine i n the neurobiological modulation of P300 amplitude.