Sleep, anesthesia and norepinephrine: let's revisit

Microglial role in NE action. PREMIUM CONTENT subscriber access

Previous newsletters explored sleep and norepinephrine involvement in memory formation and retention, and also in the phenomenon of anesthesia.

Making Memories. A mashup of memorable mind level research results

“Here we show that micro-arousals are generated in a periodic pattern during NREM sleep, riding on the peak of locus-coeruleus (LC)-generated infraslow oscillations of extracellular NE, whereas descending phases of NE oscillations drive spindles. The amplitude of NE oscillations is crucial for shaping sleep micro-architecture related to memory performance: prolonged descent of NE promotes spindle-enriched intermediate state and REM sleep but also associates with awakenings, whereas shorter NE descents uphold NREM sleep and micro-arousals. - C Kjaerby et al.”

LC-NE activity provokes sensory-evoked awakenings, and when reduced during sleep, it mediates behavioral unresponsiveness.

Brain Gateways. Where are the switches located for analgesia/anesthesia?

“But where exactly is the gate of ‘conscious awareness’, if there really is one. In a new study researchers identify a key area in the cortex that appears to be that long sought-after site; the anterior insular cortex acts as a switch between low level sensory information and higher level processing, that allows only the most important information to enter conscious awareness. At the point where consciousness slips away, the anterior insular cortex deactivates and this disrupts/shifts networks in the brain that support consciousness.”

Now we have recent reports that probe the involvement of brain’s microglial cells in modulating these states of sleep/loss of consciousness and emergence from them.

Microglial processes make dynamic and transient contacts with the vasculature, astrocytes and neurons and contribute to the neurovascular coupling through P2Y12R. - https://www.mdpi.com/1422-0067/24/11/9144