0032 ADA Functional Polymorphism Modulates REM Sleep Following Total Sleep Deprivation

Abstract

Abstract Introduction Adenosine Deaminase (ADA) regulates extracellular levels of adenosine, a brain correlate of sleep homeostasis. A single nucleotide polymorphism (SNP) of the ADA gene (rs73598374) is known to be associated with increased homeostatic pressure for NREM sleep after total sleep deprivation (TSD). Whether this genotype effect also impacts REM sleep after TSD has not been systematically investigated. The limit cycle reciprocal interaction model posits that NREM/REM cycles are regulated by cholinergic and GABAergic neurotransmitter systems. While NREM/REM regulation is also thought to be mediated by sleep homeostatic state, evidence of an association with adenosine levels has not been reported. Here we investigate the influence of ADA on REM sleep at baseline and following TSD. Methods N=48 healthy, normal sleepers (ages 27.7 + 5.3, 23 females) participated in one of three in-laboratory TSD studies. Following 10h baseline sleep (22:00–08:00), participants underwent 38h TSD, with subsequent 10h recovery sleep (22:00–08:00). Sleep periods were recorded polysomnographically and scored visually according to AASM criteria. Genomic DNA was extracted from whole blood, and the ADA SNP was assayed using real-time PCR. Sleep stages were analyzed using mixed-effect ANOVA with fixed effects of ADA genotype, night (baseline vs. recovery), and their interaction, controlling for study, with a random effect over subject on the intercept. Results The frequency of genotypes (G/G: 42, A/G: 6) did not vary from Hardy-Weinberg equilibrium. There was no genotype effect on total sleep time and no genotype by night interaction (p>0.7). However, A allele carriers spent more time in REM during baseline and less during recovery compared to G/G homozygotes (genotype by night interaction: F[1,46]=8.13, p=0.007). Conversely, while not statistically significant (p>0.1), A allele carriers spent less time in NREM during baseline and more during recovery compared to G/G homozygotes. Conclusion ADA genotype was associated with a shift in balance between REM and NREM at baseline, as well as changes therein after TSD, without concomitant effect on total sleep time. This suggests a role for adenosine in mediating REM sleep regulation, possibly through a sleep homeostatic effect on the reciprocal interaction between NREM and REM. Support (if any) CDMRP W81XWH-05-1-0099; ONR N00014-13-C-0063; NIH R21CA16769; ARO W911NF2210223.