Sedation-Analgesia with Propofol and Remifentanil: Concentrations Required to Avoid Gag Reflex in Upper Gastrointestinal Endoscopy

The work presented by Borrat et al wants to define safe sedation and analgesia guidelines in this case for upper gastrointestinal endoscopy. One of the most stressful moments for the patient is introduction of the endoscopy tube through the mouth and pharynx. Using a sequential statistical approach the concetrations associated with a probability of 0.5 or 0.9 of avoding gag response are estimated and could be used as a starting point for any combination of sedation and analgesia in this situation.

A Framework for Quantitative Modeling of Neural Circuits Involved in Sleep-to-Wake Transition

Optogenetics has transformed research in the understanding on how neural circuits work. The ability to estimulate single neurons enables the investigators to learn how can influence a predetermined behavior or response. In the present paper Luis de Lecea and his research group proposes a framework to investigate all the circuitry involved in the sleep-wake transitions using the stimulation of single neurons. It is through the knowledge of these mechanisms that we might be able to know how similar or different sedation techniques could be as compared to physiologic sleep and to test if the use of specific drugs to induce sedation might have the same beneficial effects as physiologic sleep.

Oxalic Acid and Diacylglycerol 36:3 are Cross-Species Markers of Sleep Debt

This work compares metabolic serum profiles from human subjects and experimental rats subjects to similar sleep restriction protocols. They identified numerous significant changes in lipid metabolism between experimental and control groups in both species. Interestingly amongst all changes, a reduction in the metabolites oxalic acid and diacylglycerol 36:3 strongly correlated with sleep restriction across both species. This work provides an overview of the dysfunctional metabolic profile associated with reduced sleep duration and provides potential biomarkers for sleep loss.

Neuronal Ensembles Sufficient for Recovery Sleep and the Sedative Actions of a2 Adrenergic Agonists

This paper outlines brain regions involved in α-2 adrenergic (α2A) mediated sleep pathways in a mouse model.   By using targeted acute genetic knockdowns of α2A receptors in the locus coeruleus the authors were able to show that the loss of righting reflex and sedation are mediated by α2A agonists but likely involved distinct pathways, and suggesting that LORR is not loss of consciousness but rather a spinal cord inhibitory process. Looking at activated neurons in the hypothalamus they showed a similar pattern of activation between dexmedetomidine-sedated animals and animals in normal recovery sleep.   Targeted reactivation of lateral preoptic neu­rons was sufficient to induce sedation and that GABA inhibition in the same region delayed the sedation caused by dexmedetomidine implying in the involvement of other neuronal subsets in this process.