CCK mRNA expression in neuroendocrine CRH neurons is increased in rats subjected to an immune challenge

The expression of cholecystokinin (CCK) mRNA in neuroendocrine corticotropi n-releasing hormone (CRH) neurons of the hypothalamic paraventricular nucle us (PVN) of male rats was examined 8 h following an acute immune challenge by intraperitoneal lipopolysaccharide (LPS, 250 mug/kg). Both quantitative, macroautoradiographic. single-label radioactive in situ hybridization hist ochemistry (ISHH) and qualitative dual-label ISHH were performed. Compared to controls. LPS-injected rats displayed increased (185%) parvicellular CCK mRNA expression levels, occurring in a majority (70%) of CRH neurons as re vealed by dual-label ISHH. (C) 2001 Elsevier Science B.V. All rights reserv ed.