P = 0.08 Preliminary Characterization of Sleep-Wake Behavior and Locomotor Activity in the VMAT2-Deficient Mouse Model of Parkinson’s Disease Introduction C.H. Vaughan 1, G.L. Keating 2,4, T.S. Guillot 3, A. Rogers 1, P.S. Garcia 4, G.W. Miller 3, D.B. Rye 2, & J.T. Willie 1,2 Departments of Neurological Surgery 1, Neurology 2, Environmental Health 3 & Anesthesiology 4, Emory University, Atlanta, GA, o Patients with Parkinson’s Disease (PD) experience motor and nonmotor impairments o PD patients report excessive daytime sleepiness and/or disturbed nocturnal sleep. Their sleep physiology exhibits sleep fragmentation, excessive phasic muscle activity during sleep and REM sleep during naps 1,2 o Mice with deficiency of vesicular monoamine transporter 2 (VMAT2LO) have pathological and behavioral features of Parkinsonism 3 o progressive loss of striatal & nigral dopamine and α - synucleinopathy 3 o L-DOPA responsive motor deficits 3 o Nonmotor impairments in olfaction, gastric emptying, sleepiness 4 o VMAT2-deficient mice (VMAT2LO) and WT mice (4 – 6 months old) were acclimated to testing room followed by 48h recording of baseline locomotor activity (infrared beam breaks). o Mice were surgically implanted with EEG & EMG electrodes and allowed to recover for 1 week o Experimental timeline: The authors would like to thank Minzheng Wang for providing and genotyping mice. Baseline behavior of VMAT2LO mice: o Nonsignificant trend toward increased total locomotor activity. o EEG/EMG traces show excess phasic muscle activity and associated arousals suggesting sleep fragmentation. o No significant difference in total times spent in sleep/wake states during light/dark phases compared with WT. o Nonsignificant trends suggesting wake fragmentation (more frequent episodes, shorter durations) during light and dark phases. o Significantly prolonged REM sleep mean episode duration during light phase Test 1 – 4h Sleep Deprivation: o VMAT2LOs had reduced latency to sleep, consistent with excessive sleepiness. o VMAT2LOs showed increased sleep/wake transitions and reduced wake/NREM episode durations consistent with sleep/wake fragmentation. Test 2 – MSLT: o VMAT2LOs slept more during stimulus presentation and nap opportunities. o When naps occurred, VMAT2LOs spent less time in NREM and relatively more time in REM. Test 2 – 6h Sleep Deprivation + MSLT: o Preliminary results show VMAT2LOs have reduced latency to sleep and increased sleep/wake transitions consistent with sleep/wake fragmentation. Additional data collection underway. o Verify findings with larger numbers of subjects and quantify EMG disturbances during NREM and REM. o Test novel interventions for sleep/wake disturbances in PD. Figure 7: VMAT2LOs have more sleep/wake transitions following a 4h sleep deprivation (beginning at lights on). Bars represent average transition # during 8 h of recovery. N = 7 WTs; N = 7 VMAT2LOs DARK Figure 3: VMAT2LO total time in sleep / wake during dark period is similar to total time during light. Average total time spent in Wake, REM & NREM during lights off / active period. N = 7 WTs; N = 7 VMAT2LOs Figure 5: VMAT2LOs showed a trend toward short wake & NREM episodes and longer REM episodes. Average episode duration of bouts of wake, REM & NREM during lights off period. N = 7 WTs; N = 7 VMAT2LOs WT VMAT2LO 2 days – Acclimation to chamber 1 day – Baseline Test 1: 4 h – Sleep deprivation Test 2: 2 h – Murine multiple sleep latency test (MSLT) 5 10 min = wake; 20 min = opportunity to nap Test 3: 6 h – Sleep deprivation & 2 h – Murine MSLT Testing week with 1 day between tests 1.Zesiewicz et al. (2006). Expert Rev Neurother, 6(12): Taylor et al. (2010). Behav Brain Res, 211: Caudle et al. (2007). J Neurosci, 27(30): Taylor et al. (2009). J Neurosci, 29(25): Veasey et al. (2004). Sleep, 27(3): o Hypothesis: VMAT2-deficient mice will exhibit disturbances comparable to that in PD. Figure 2: VMAT2LOs showed a trend toward more time spent in wake and less time in NREM. Average total minutes spent in Wake, REM & NREM during lights on / rest period. N = 7 WTs; N = 7 VMAT2LOs Figure 4: VMAT2LOs have longer REM episodes than WTs. Average episode duration of bouts of wake, REM & NREM during lights on period. *VMAT2LO spent more time in REM during their rest phase. N = 7 WTs; N = 7 VMAT2LOs LIGHT WT VMAT2LO Figure 6: VMAT2LOs trend towards shorter latency to 1 st sleep episode after 4h sleep deprivation (beginning at lights on). N = 7 WTs; N = 7 VMAT2LOs Figure 8: VMAT2LOs had short wake & NREM episodes and long REM episodes. N = 3 WTs; N = 6 VMAT2LOs Conclusions Results Future Directions Acknowledgements References Methods VMAT2 LO Figures above modified from Caudle et al., Cells in substantia nigra, pars compacta Synuclein neuropathology in 22 mo. old mice Figure 1: VMAT2LOs showed a trend toward increased activity. Average total distance traveled over 2 days as detected by Versamax system. N = 6 WTs; N = 7 VMAT2LOs Locomotor Activity EEG EMG WT example of normal sleep (NREM) EEG EMG VMAT2LO example of normal sleep (NREM) WT VMAT2LO WT VMAT2LO