34. Neonatal immune challenge induces anxiety in adulthood and is associated with functional alterations to the autonomic nervous system

We have previously reported neonatal lipopolysaccharide (LPS; 0.05 mg/kg, i.p.) exposure produces robust increases in anxiety-like behaviour in rats in adulthood. An important physiological contributor to anxiety is considered to be sympathetic nervous system (SNS) and autonomic nervous system (ANS) activity. Here we report that neonatal LPS exposure results in immediate and persistent changes in SNS and ANS function. Programming of the ANS in Wistar rats neonatally treated with LPS was examined via assessment of tyrosine hydroxylase (TH) in neonatal and adult adrenals, and adult respiratory rate, using whole-body plethysmography assessed at baseline and in response to mild stress (acoustic and light stimuli). Anxiety-like behaviour was assessed in adulthood on the elevated plus maze (EPM) and holeboard. Neonatal LPS exposure produced an increase in TH phosphorylation and activity which persisted into adulthood ( p p p