Urinary cortisol and endogenous monoamine oxidase inhibitor(s), but not isatin, are raised in anticipation of stress and/or arousal in normal individuals

Cortisol, isatin and monoamine oxidase (MAO) inhibitory activity (tribulin) distinguished by its A and B components were measured in spot-urine samples provided by 20 students prior to an assessed oral seminar presentation. Stress arousal checklists (SACL) were completed on five occasions at timed intervals before and after the presentation over a 3 1/2-hour period, Significant changes in stress and arousal (p<0.000) were reported during this period; levels reached their peak at the time of presentation and fell to their lowest 30 minutes after the presentation. Urinary cortisol concentration was found to correlate with MAO-A inhibitory activity (r=0.444, p=0.05) and with the elevation in perceived stress (but not arousal) in terms of peak levels compared to post-presentation base levels (r=0.478, p<0.05), Both MAO-A and B inhibitory activities correlated with the elevation in arousal (but not stress) in terms of peak levels, experienced during the presentation, compared to post-presentation base levels (respectively: r=0.6477, p<0.005; r=0.6068, p<0.01). Additionally, there was a difference between absolute peak arousal (but not stress) experienced by those subjects who had previously exhibited high levels of MAO-B inhibitory activity compared to those with low levels (p<0.05, two-tailed). Isatin did not correlate with any of the measured parameters.