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Inhibiting cortisol response accelerates recovery from a photic phase shift
Jennifer A Mohawk1, Katherine Cashen, Theresa M Lee
1Department of Psychology, University of Michigan, Ann Arbor, MI, USA.
Summary
Altering cortisol levels impacts circadian rhythm reentrainment after light-dark cycle shifts. Decreasing cortisol accelerated recovery, while increasing it showed no significant effect.
Area of Science:
- Chronobiology
- Neuroendocrinology
- Circadian Rhythms
Background:
- Jetlag disrupts internal rhythms and external synchrony.
- The hypothalamic-pituitary-adrenal (HPA) axis may influence reentrainment speed after light-dark cycle shifts.
Purpose of the Study:
- To investigate the effect of cortisol level alterations on circadian locomotor rhythm reentrainment rates in Octodon degus following a phase advance.
Main Methods:
- Experiment 1: Administered metyrapone to decrease cortisol and assessed reentrainment time.
- Experiment 2: Increased plasma cortisol levels and measured reentrainment duration.
- Experiment 3: Used dexamethasone to suppress HPA activity and evaluated reentrainment acceleration.
Main Results:
- Metyrapone significantly accelerated reentrainment by 11.5%.
- Increased cortisol levels showed a non-significant trend towards slower reentrainment (8% increase).
- Dexamethasone significantly accelerated reentrainment by approximately 33%.
Conclusions:
- Cortisol levels play a role in the rate of circadian rhythm reentrainment after phase shifts.
- Modulating the HPA axis can influence the speed of recovery from circadian disruption.