QnAs with Nicholas C. Spitzer

Abstract

The developing human brain is known for its remarkable plasticity, whereas the adult brain has been considered relatively unchanging. However, learning and memory continue throughout adult life, as do changes in synapse strength and synapse number. Adding to these facets of adult brain plasticity is the phenomenon of neurotransmitter switching, discovered by National Academy of Sciences member Nicholas C. Spitzer, of the University of California, San Diego, and colleagues. According to Spitzer, neurotransmitter switching refers to the down-regulation of one neurotransmitter and up-regulation of another within the same neurons. Such switching usually converts the neurons from excitatory to inhibitory or vice versa, with the receptors of connecting neurons undergoing corresponding changes. Neurotransmitter switching typically occurs in response to sustained stimulation and can cause changes in behavior. For example, nocturnal rats experience neurotransmitter switching from dopamine to somatostatin when exposed to long-day photoperiods for a week, which causes anxious and depressed behavior. In his Inaugural Article, Spitzer and his colleagues explore the mechanism of neurotransmitter switching, which may have relevance to human mental illness (1). Spitzer recently spoke with PNAS about his findings.