Neuroendocrine correlates of temperamental traits in humans

Studies investigating temperament traits in humans and their biological cor relates have found high levels of novelty seeking (NS) linked with dopamine rgic system changes, and particularly a deficit of dopamine transporter. Ha rm avoidance and reward dependence, on the other hand, appeared to be assoc iated, respectively with serotonin and noradrenaline changes. In the presen t study, we have investigated the dopaminergic (DA), serotonergic (5-HT), a nd noradrenergic (NE) functions in healthy volunteers by challenging the mo noamine systems with the DA agonist bromocriptine, the 5-HT agonist D-fenfl uramine, and the NE agonist clonidine, respectively. Parallel to this inves tigation, we examined the temperament traits of our subjects by measuring N S, harm avoidance (HA) and reward dependence (RD) using the 'Three-dimensio nal Personality Questionnaire' (TPQ). The aims of the study were to see whe ther or not the monoamine functions were correlated with temperament traits . Bromocriptine challenge induced a significant GH increase and a significa nt suppression of PRL. D-fenfluramine test significantly increased PRL and cortisol plasma levels and Clonidine test induced a significant rise in GH values. NS scores showed a significant direct correlation with brom-stimula ted GH values (r=0.426, P<0.05) and a significant inverse correlation with brom-inhibited PRL values (r=-0.498, P<0.01). HA scores correlated signific antly with D-fen-stimulated PRL and CORT AUCs, (PRL: r=0.424, P<0.05; CORT: r=0.595, P<0.005). RD scores correlated positively with cion-stimulated GH values (r=0.55; F=8.6; P<0.01) and negatively with brom-inhibited-PRL AUCs (r=0.439, P<0.05). Our data support Cloninger theory concerning the biolog ical correlates of temperamental traits, and evidence the link between the neuroendocrine responses to dynamic challenges and stable temperament featu res. (C) 2000 Elsevier Science Ltd. All rights reserved.