Messenger RNA for neuropeptide Y in the arcuate nucleus increases in parallel with plasma adrenocorticotropin during sepsis in the rat

Loss of appetite occurs in the cecal ligation and puncture (CLP) model of sepsis in conjunction with the activation of central neural stress pathways. Neuropeptide Y (NPY) in the arcuate nucleus of the hypothalamus is upregulated by several stressors and is stimulatory to feeding. To examine the response of NPY messenger RNA in the arcuate nucleus to sepsis, we used biotinylated RNA probes and a quantitative non-isotopic in situ hybridization approach in cryo-preserved sections from rats made septic by CLP. The mRNA in arcuate neurons was upregulated from the first day after CLP. By the afternoon of the third day through the morning of the fourth day, the average grey level of NPY mRNA clusters was 30% greater after CLP than after sham surgery (P