1. 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, 30322 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):1811-22. 2.Taylor et al. (2010). Behav Brain Res, 211:1-10. 3.Caudle et al. (2007). J Neurosci, 27(30): 8138-48. 4.Taylor et al. (2009). J Neurosci, 29(25): 8103-13. 5.Veasey et al. (2004). Sleep, 27(3):388-93. 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., 2007 3 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