Personality Correlates of +/- Pindolol Induced Decreases in Prolactin

Abstract

The present study was conducted to investigate if personality traits can be usefully related to serotonergic vs. dopaminergic action of the 5-HT1a-antagonist +/- pindolol. Forty healthy male volunteers (aged between 20 and 30 years) were randomly assigned to a placebo or a +/- pindolol (30 mg, oral dose) group in a double blind trial. Blood samples were drawn and analyzed for PRL concentrations. In addition, the subjects completed questionnaires on personality. The results indicated that +/- pindolol decreases PRL concentrations depending on personality. While subjects high on impulsivity and related traits (aggression and disinhibition) show lower PRL decreases, well-being and personality traits frequently related to dopaminergic activity were not correlated with changes in PRL. Since reduced (blunted) PRL-responses after 5-HT challenge tests have been reported for impulsives, the present results favor the involvement of primarily serotonergic and probably only secondarily dopaminergic control of +/- pindolol induced PRL decreases.

Sensation Seeking: Behavioral Expressions and Biosocial Bases

“…Serotonin in limbic system pathways is generally associated with behavioral inhibition (Soubrie, 1986). Blunted serotonin reactivity to serotonin stimulants is characteristic in high sensation seekers (Depue, 1995;Hennig et al, 1998;Netter et al, 1996). Thus there is tentative emerging support for the biochemical/neurological theory of ImpSS.…”

Serotonergic modulation of response inhibition and re‐engagement? Results of a study in healthy human volunteers

“…There is already evidence for an involvement of 5-HT in mechanisms underlying impulsiveness and aggression. For example, studies with human volunteers found acute tryptophan depletion (ATD) to increase impulsive and aggressive behavior, although these effects seem to depend on individual differences in impulsive personality traits (Bjork et al, 2000;Marsh et al, 2002) and various studies also implicated a role of 5-HT in aggression and impulsivity (Hennig et al, 1998;Netter et al, 1999). Although 5-HT has been implicated in impulsiveness and forms of inhibitory control in rodents, the role of 5-HT in humans remains unclear till now.…”

Trait Hostility and Prolactin Response to Tryptophan Enhancement/Depletion

“…In fact, there is evidence from other studies with healthy volunteers suggesting that at least some aspects of serotonergic function may be related to hostility across a wide range of hostility scores [18]. Further, Hennig et al [19] found a blunted PRL decrease in response to pindolol in healthy volunteers. Thus, previous research has shown hostility to be associated with blunted increases and blunted decreases to serotonergic agents in different populations.…”