Precision series automated liquid handling system

Unstimulated salivary samples were collected to measure dephydroepiandrosterone (DHEA) and cortisol. DHEA and cortisol were assayed in duplicate using salivary DHEA (intra-assay precision of 5.6% with a sensitivity of 5pg/mL) and cortisol (intra-assay precision of 3.35% - 3.65% with a sensitivity of <0.003 ug/dL) enzyme immunoassay systems. PowerWave HT Microplate and Precision Series Automated Liquid Handling System (BioTek Instruments, Inc.) were used to analyze DHEA and cortisol. Samples were collected immediately prior to the TSST or no-stress condition, immediately after the TSST/prior to the drug-cue paradigm, and at 15, 30, and 60 minutes after the drug cue paradigm.

To assess cortisol response, unstimulated salivary samples were collected from participants in polypropylene vials and stored on ice at seven different time points (see ‘Laboratory Procedures’ below). Saliva samples were divided into 1.8 nunc tubes and frozen at −70°C until assayed. Using a high sensitivity salivary cortisol enzyme immunoassay kit (intra-assay precision of 3.35%–3.65%, lower sensitivity limit of <0.003 μg/dL; Salimetrics, LLC), saliva samples were assay twice. Samples were then analyzed simultaneously with a PowerWave HT Microplate Spectrophotometer and a Precision Series Automated Liquid Handling System (BioTek Instruments, Inc.).

Unstimulated salivary samples were collected by passive drool in polypropylene vials and immediately iced. Samples were aliquoted into 1.8 nunc tubes and saliva was then frozen at −70°C until assayed. Samples were assayed in duplicate using a high sensitivity salivary cortisol enzyme immunoassay system that has an intra-assay precision (coefficient of variation, CV) of 3.35% – 3.65% with a sensitivity of <0.003 ug/dL (Salimetrics LLC). Samples were analyzed using a PowerWave HT Microplate Spectrophotometer in conjunction with a Precision Series Automated Liquid Handling System (BioTek Instruments, Inc.). Salivary samples were collected immediately before the drug cue paradigm and then at 15, 30 and 60 minutes post.