Repetitive neonatal pain and reduced maternal care alter brain neurochemistry

Preterm infants are exposed to many stressors while in the neonatal intensive care unit including pain and reduced maternal care. Both stressors can have a profound negative impact on brain development, and the present study sought to investigate some of the biological mechanisms underlying this phenomenon. Rat pups underwent a series of repetitive needle pokes and/or reduced maternal care through a novel tea-ball infuser encapsulation model during the first four days of life. On postnatal day four, pups were sacrificed and serum was analyzed for corticosterone, while brains were tested for various neurotransmitters and brain metabolites through magnetic resonance spectroscopy. We found that exposure to maternal isolation and neonatal pain produced an increase in serum corticosterone but decreased glutamate levels in the hippocampus and frontal cortex. These alterations in stress responding and neurochemistry in response to the early-life stressors may help explain some of the negative outcomes seen in preterm infants.