The Role of Opioidergic Systems in Breathing Based Analgesia

A well-validated brief mindfulness-based mental training regimen \[four sessions; 20 min/session\] was used to teach patients to independently practice mindfulness meditation.

A well-validated brief meditation-based mental training regimen \[four sessions; 20 min/session\] was used to teach patients to independently practice closing their eyes and take a deep breath every few minutes.

Study volunteers practiced lowering their breathing rate, across four, 20 minute training sessions, in response to a fluctuating light with the guidance of a trained facilitator.

A 0.15 mg/kg bolus dose of naloxone (Naloxone Hydrichloride, Amphastar Pharmaceuticals, Inc., Rancho Cucamonga, California) in 25ml normal saline was administered over 10 minutes. We also administered a supplementary IV infusion dose of 0.1mg/kg/hour naloxone immediately after bolus infusion ceased till the end of the experiment.

A 0.15 mg/kg bolus dose of saline in 25ml normal saline was administered over 10 minutes. We also administered a supplementary IV infusion dose of 0.1mg/kg/hour saline immediately after bolus infusion ceased till the end of the experiment.