Submitted on June 24, 2008
Revised on September 1, 2008
Accepted on September 26, 2008
PER3 Polymorphism and Cardiac Autonomic Control: Effects of Sleep Debt and Circadian Phase
Antoine U Viola1, Lynette M James1, Simon N Archer2, and Derk-Jan Dijk1*
1 University of Surrey
2 University of surrey
* To whom correspondence should be addressed. E-mail: d.j.dijk{at}surrey.ac.uk.
Aims- A variable number tandem repeat polymorphism in the coding region of the circadian clock gene PER3 gene has been shown to affect sleep. Because circadian rhythms and sleep and are known to modulate sympatho-vagal balance, we investigated whether homozygosity for this PER3 polymorphism is associated with changes in autonomic nervous system (ANS) activity during sleep and wakefulness at baseline and following sleep deprivation. Methods and results- 22 healthy participants were selected according to their PER3 genotype. ANS activity, evaluated by heart rate (HR) and HR variability (HRV) indices was quantified during baseline sleep, a 40 hour period of wakefulness and recovery sleep. Sleep deprivation induced an increase in Slow-Wave-Sleep (SWS), a decrease in the global variability and an unbalance of the ANS with a loss of parasympathetic predominance and an increase in sympathetic activity. Individuals homozygous for the longer allele (PER35/5) had more SWS, an elevated sympathetic predominance and a reduction of parasympathetic activity compared to PER34/4, in particular during baseline sleep. The effects of genotype were strongest during non-REM (NREM) sleep, and absent or much smaller during REM sleep. The NREM-REM cycle-dependent modulation of the LF/(LF+HF) ratio was diminished in PER35/5 individuals. Circadian phase modulated HR and HRV but no interaction with genotype was observed. Conclusion- The PER3 polymorphism affects sympatho-vagal balance in the cardiac control in NREM sleep similar to the effect of sleep deprivation.
