Effects of personality on the opioidergic modulation of the emotion warmth-liking

Neurobiological research suggests there are discrete emotion systems, which are based on separate neural pathways with specific neurotransmitters (i.e., oxytocin, opioids). So far, autonomic regulation patterns of different positive emotions could not be unambiguously characterized. Warmth-liking, as an emotion system, is activated during interpersonal interactions and close relationships. We postulated that warmth-liking has a specific somatovisceral signature, which is, however, qualified by individual differences in personality and attachment style. Individual differences in personality and attachment style are postulated to contribute to -opiate functioning. Forty-eight females in a heterosexual relationship, selected on the basis of attachment reports, took part in a virtual ball-tossing game with their partners and two confederates. Participants received either the competitive -opioid antagonist naltrexone (25 mg) or a placebo in a randomized double-blind design. Social exclusion during the game reduced feelings of warmth, increased feelings of anger, and increased blood pressure and left-ventricular contractibility, whereas social inclusion was characterized by physiological quiescence. Further analyses revealed differential effects in self-reported feelings as well as in cardiovascular parameters as a function of attachment style. Secure attachment predicted higher levels of warmth-liking, physiological quiescence, and less negative feelings even during social exclusion. These findings can be interpreted as evidence for psychophysiological resilience. Furthermore, naltrexone reduced feelings of warmth and increased vasoconstriction during social inclusion, especially for securely bonded participants. These findings are remarkable hints for an opioidergic modulation of the interaction between emotion and personality. J. Comp. Neurol. 524:1712-1726, 2016. (c) 2015 Wiley Periodicals, Inc.