M1 muscarinic acetylcholine receptor agonism alters sleep without affecting memory consolidation

Area of Science:

• Neuroscience
• Sleep Science
• Pharmacology

Background:

• Cholinergic neurotransmission, particularly M1 muscarinic acetylcholine receptor (mAChR) activation, is suggested by preclinical research to play a role in memory consolidation during sleep.
• Understanding the precise mechanisms of memory consolidation is crucial for developing interventions for cognitive disorders.

Purpose of the Study:

• To investigate the impact of a direct M1 mAChR agonist, RS-86, on the consolidation of declarative and procedural memories following sleep in healthy human participants.
• To determine if M1 mAChR activation influences sleep architecture, specifically rapid eye movement (REM) sleep latency and slow wave sleep (SWS) duration.

Main Methods:

• A double-blind, placebo-controlled study involving 20 healthy participants.
• Participants completed a declarative word-list task and a procedural mirror-tracing task.
• RS-86 or placebo was administered, and sleep parameters (REM latency, SWS duration) and memory recall were assessed.

Main Results:

• Administration of RS-86 significantly reduced REM sleep latency and SWS duration compared to placebo.
• Memory recall rates for both declarative and procedural tasks were nearly identical between the RS-86 and placebo groups.
• Presleep memory acquisition and postsleep recall were within expected ranges for both conditions.

Conclusions:

• Selective M1 mAChR activation with RS-86 in healthy humans does not produce a clinically significant effect on the post-sleep consolidation of declarative or procedural memories.
• While RS-86 alters sleep architecture by reducing REM sleep latency and SWS duration, this modulation does not translate to enhanced memory consolidation at the tested dose.