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Sleep. 2010 Dec;33(12):1711-6.

Clonidine has a paradoxical effect on cyclic arousal and sleep bruxism during NREM sleep.

Author information

  • 1Faculté de Médecine Dentaire, Université de Montréal, and Centre d'étude du Sommeil et des Rythmes Biologiques, Hôpital du Sacré-Coeur de Montréal, Québec, Canada.

Abstract

STUDY OBJECTIVE:

Clonidine disrupts the NREM/REM sleep cycle and reduces the incidence of rhythmic masticatory muscle activity (RMMA) characteristic of sleep bruxism (SB). RMMA/SB is associated with brief and transient sleep arousals. This study investigates the effect of clonidine on the cyclic alternating pattern (CAP) in order to explore the role of cyclic arousal fluctuation in RMMA/SB.

DESIGN:

Polysomnographic recordings from a pharmacological study.

SETTING:

University sleep research laboratory.

PARTICIPANTS AND INTERVENTIONS:

Sixteen SB subjects received a single dose of clonidine or placebo at bedtime in a crossover design.

MEASUREMENTS AND RESULTS:

Sleep variables and RMMA/SB index were evaluated. CAP was scored to assess arousal instability between sleep-maintaining processes (phase A1) and stronger arousal processes (phases A2 and A3). Paired t-tests, ANOVAs, and cross-correlations were performed. Under clonidine, CAP time, and particularly the number of A3 phases, increased (P≤0.01). RMMA/SB onset was time correlated with phases A2 and A3 for both placebo and clonidine nights (P≤0.004). However, under clonidine, this positive correlation began up to 40 min before the RMMA/SB episode.

CONCLUSIONS:

CAP phase A3 frequency increased under clonidine, but paradoxically, RMMA/SB decreased. RMMA/SB was associated with and facilitated in CAP phase A2 and A3 rhythms. However, SB generation could be influenced by other factors besides sleep arousal pressure. NREM/REM ultradian cyclic arousal fluctuations may be required for RMMA/SB onset.

KEYWORDS:

Clonidine; cyclic alternating pattern; rhythmic masticatory muscle activity; sleep bruxism

PMID:
21120152
[PubMed - indexed for MEDLINE]
PMCID:
PMC2982742
Free PMC Article

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