Traumatic memories from social defeat stress in mice are stored in engram cells of the basolateral amygdala (BLA). A single low dose of ketamine given during, but not after, a brief re-exposure to the trauma context reduces social avoidance behavior. This effect lowers both the activity and number of reactivated BLA engram cells. Dopamine projections from the ventral tegmental area to the BLA, acting through dopamine D2 receptors, can mimic or block the therapeutic effect. Single-cell RNA sequencing shows that re-exposure with ketamine alters memory-related pathways in the BLA. The findings suggest a mechanism for how ketamine may alleviate PTSD symptoms and point to potential treatments for trauma-related disorders.
A subclinical dose of esketamine (0.25 mg/kg) given after umbilical cord clamping during elective cesarean sections did not reduce the incidence of postpartum depression at 14 days postpartum, as measured by the Edinburgh Postnatal Depression Scale. However, it did significantly lower postoperative pain scores on the Visual Analog Scale at 4 and 24 hours after surgery. The treatment group experienced temporary increases in adverse reactions and sedation scores five minutes after administration. The findings suggest esketamine may offer short-term pain relief without preventing postpartum depression.