Adult Attachment System Links With Brain Mu Opioid Receptor Availability In Vivo

Mu-opioid receptor system modulates responses to vocal bonding and distress signals in humans

“…This accords with prior fusion imaging studies showing that high MOR tone may downregulate acute haemodynamic responses to both distressing and arousing socioemotional events [37,57]. Yet, studies linking opioid receptor signalling with trait measures of sociability have typically observed a positive association between sociability and MORs [19,20]. One way to reconcile these lines of evidence is that while heightened MOR availability is linked with increased trait-level sociability, it is simultaneously associated with weaker responses to transient bonding and distress signals, and opioid system may thus modulate social perception and behaviour at multiple timescales.…”

“…At molecular level, human and animal studies converge in showing that the endogenous mu-opioid receptor (MOR) system modulating pleasurable and calm sensations [16] is an important mechanism for modulating social motivation [17]. In vivo molecular imaging studies in humans have shown that prosocial cues including social laughter trigger central endogenous opioid release [18], and that individual differences in MOR tone are associated with stable patterns of socioemotional behaviour such as childhood and adult romantic attachment styles [19,20]. Pharmacological studies in primates have further found that opioid receptor antagonists increase grooming and social behaviour [21,22].…”

μ-opioid receptor availability is associated with sex drive in human males

“…Similarly as for sex drive, exogenous opioid use is associated with lower affiliative social motivation in humans (Ross et al, 2005; Schindler et al, 2009). Paralleling the pharmacological and clinical studies, molecular imaging experiments have consistently shown that MOR expression is consistently and positively associated with secure romantic and affiliative bonding (Manninen et al, 2017; Nummenmaa et al, 2015; Nummenmaa et al, 2016b; Turtonen et al, 2021). It has also been established that the more OR individuals have in the striatum, the higher pain threshold they have (Hagelberg et al, 2012).…”

Mapping neurotransmitter systems to the structural and functional organization of the human neocortex

“…We show the comparisons between tracers in Fig. S2b for the following neurotransmitter receptors/transporters: 5-HT1 A [12,105], 5-HT1 B [12,39,105], 5-HT2 A [12,105,124], 5-HTT [12,105], CB 1 [64,79], D 2 [2,55,101,117], DAT [29,104], GABA A [29,78], MOR [57,126], and NET [27,48]. Here we make some specific notes: (1) 5-HTT and GABA A involve comparisons between the same tracers (DASB and flumazenil, respectively) but one map is autoradiography-informed (see [12] and [78]) and the other is not [29,30,105]; (2) raclopride is a popular D 2 tracer but has unreliable binding in the cortex, and is therefore an inappropriate tracer to use for mapping D 2 densities in the cortex, but we show its comparison to FLB457 and another D 2 tracer, fallypride, for completeness [2,22,55]; (3) the chosen carfentanil (MOR) map was collated across carfentanil images in the PET Turku Centre database-since our alternative map is a partly overlapping subset of participants, we did not combine the tracers into a single mean map [57,126].…”