Opioid regulation of reward in healthy humans

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We hypothesised - and found - that stimulating µ-opioid receptors in healthy humans would enhance, whereas blocking these receptors would reduce, approach to high-value rewards.
We hypothesised – and found – that stimulating µ-opioid receptors in healthy humans would enhance, whereas blocking these receptors would reduce, approach to high-value rewards.

In our first opioid psychopharmacology study, we gave healthy young men pills containing 10 mg morphine to stimulate the µ-opioid receptor; 50 mg naltrexone to block µ- and kappa opioid receptors, and placebo (cherry flavoured breath mints) on three separate days. Marie Eikemo and Guro Løseth were key investigators at all stages of this project, which established LABlab as a psychopharmacology lab, one of a handful labs worldwide which assesses opioid drug effects in the healthy human brain.

As described more fully in the ensuing manuscripts, the data was consistent with the hypothesis that in the healthy human brain, endogenous opioids modulate the reward value and approach motivation of:

  • Beautiful faces (pdf)
  • Calorie-rich foods (pdf)
  • Winning money (pdf)
  • Social exploration of faces (pdf)
  • But not caress-like touch (pdf)
This is the core team who developed the paradigm, did the recruitment and conducted all the 3 x 3-hour (ok, sometimes 4-hour) testing sessions for each participants. From left: Hedda Maurud, Marie Eikemo, Guro Løseth, Olga Chelnokova, Jeppe Riegels, Siri Leknes