At the Sharp End of Spines

Abstract

Once considered unthinkable, the alarming possibility that general anesthetics might have lasting effects on the developing brain has gained traction with anesthesiologists, the Food and Drug Administration, the popular media, and parents. The basis for concern comes mainly from animal studies showing that exposure to a variety of commonly used intravenous and volatile anesthetics produces cognitive and social behavioral deficits that last into adulthood.1,2 Although cause:effect relationships have not been established, these cognitive and behavioral dysfunctions have been attributed to the transient suppression of neurogenesis or widespread neuroapoptosis that are well documented in animals following anesthetic exposure in the early postnatal period.1,3 At least in the case of neuroapoptosis, the developing brain is most vulnerable during the period of rapid synaptogenesis (i.e., the brain growth spurt)1,4 putting synapse development at center stage in the story of anesthetic neurotoxicity. In this issue of the Journal, Briner and colleagues5 take research in this area a step further. In a series of elegant in vitro and in vivo experiments, they demonstrate in rodents that synapse development itself is altered by exposure to volatile anesthetics during the early stage of postnatal brain development. As such, this work adds synaptic remodeling to the list of potential mechanisms by which anesthetics might produce long-lasting changes in the developing rodent brain.