Association of salivary-assessed oxytocin and cortisol levels with time of night and sleep stage

Abstract

There have been proposals for REM to have a function of emotional memory consolidation, and also for REM sleep to be involved in the promotion of attachment behaviour. The hormones cortisol and oxytocin, respectively, may be involved in these proposed REM sleep functions. However, there are conflicting reports on whether levels of cortisol differ between sleep stages when time since sleep onset (SSO) is controlled, and virtually no literature on whether levels of oxytocin differ between sleep stages. This study thus investigated the changes in levels of oxytocin (OT) and cortisol (CT) across the night, and whether these levels differ between REM and N2 sleep when time SSO is controlled. 20 participants (10 males, 10 females, mean age = 20.45, SD = 2.01) were awakened 10 min into REM and N2 sleep periods in the sleep laboratory and gave saliva samples which were assayed for OT and CT. Levels of OT were relatively constant across the night, whereas CT increased significantly. REM and N2 did not differ significantly neither for OT nor for CT. The study has implications for models of sleep-dependent memory consolidation that incorporate the late sleep increase in cortisol as a functional component of memory consolidation, and also for the medical diagnostic assaying of OT during sleep.

About Sleep's Role in Memory

“…Although the amounts of stage 2 sleep were comparable in the early and late sleep conditions of the studies reported above, sleep in this sleep stage may have substantially differed between the two phases, for example, with regard to spindle density (440,441,550), heart rate, or levels of neuromodulators like catecholamines and cortisol (95,124,131,313,554,960). There is consistent evidence for an involvement of stage 2 sleep and sleep spindles in motor learning (139,396,822,862,921), and memory for a simple motor task is impaired after selective stage 2 sleep deprivation (1112,1117).…”

Transcriptome Analysis Reveals Altered Expression of Memory and Neurotransmission Associated Genes in the REM Sleep Deprived Rat Brain

“…LNPEP is also involved in the final step of conversion of angiotensinogen to angiotensin IV and enhance acquisition, consolidation and recall in animal models of learning and memory (Stragier et al, 2008); it may have bearing with REMSD-associated hypertension. OXT is associated with cognition, tolerance, adaptation as well as complex sexual and maternal behaviors (Argiolas and Gessa, 1991) and its level elevated during active REMS (Blagrove et al, 2012). Interestingly, while dysregulated OXT levels are implicated in autism-spectrum disorders and OXT supplementation may help patients with autism; children with autism also show reduced REMS (Tanguay et al, 1976).…”

Meaning of becoming mother and son/daughter through massage

“…This is confirmed from the postulation that a secure attachment between mother and child contributes to a healthy and non-violent interaction (22) . This type of link promotes a contact of deep love, which allows children to grow and develop in the safety of their mothers' love (4,10) . Therefore, encouraging practices of health promotion (23) such as the massage could help to reduce violence and child abuse, a fact which is especially important in Chile, considering that violence towards children in all its forms reaches more than 70% in all socioeconomic levels (24) .…”

“…Finally, the massage helps to improve the patterns of sleep and relaxation, due to the muscle relaxation produced, plus the adjustment and regulation of the circadian rhythm (9)(10) . Another important effect of the massage is reducing the level of the 'stress hormone' (cortisol), and increasing the serotonin levels, which allows the release of the growth hormone and is responsible for the feelings of pleasure and happiness (11) .…”

“…Another important effect of the massage is reducing the level of the 'stress hormone' (cortisol), and increasing the serotonin levels, which allows the release of the growth hormone and is responsible for the feelings of pleasure and happiness (11) . Also, longer periods of alert are recorded without manifestations of stress (10) , and a lower stress reaction in face of painful stimuli (12) .…”