IL18BP and post-traumatic stress disorder: To understand how the IL-18 system in the CeA is affected by comorbid PTSD/AUD, we used ISH/RNAscope to quantify the percent of cells expressing Il18r1 (encodes the ligand binding subunit of the IL-18 receptor), Il18 (encodes IL-18), and Il18bp (encodes IL-18 binding protein) in male and female rats that experienced shock stress to a novel context (NOV) or familiar context (FAM) followed by alcohol drinking [12].