Preproenkephalin mRNA expression in rat parabrachial neurons: relation to cells activated by systemic immune challenge.
By using a dual-labeling immunohistochemical/in situ hybridization technique we examined if enkephalin-expressing neurons in the pontine parabrachial nucleus, a major brain stem relay for ascending visceral and homeostatic information, were activated by systemic immune challenge. While rats subjected to intravenous injection of bacterial wall lipopolysaccharide expressed dense labeling for the immediate-early gene product FOS in parts of the parabrachial nucleus that also demonstrated dense preproenkephalin expression, only a small proportion of the enkephalin-positive neurons were FOS-positive. These data indicate that enkephalins, although implicated in a variety of autonomic responses, are not primarily involved in the transmission of immune-related information from the parabrachial nucleus to its different forebrain and brain stem targets.
Engström
L
L
Division of Cell Biology, Department of Biomedicine and Surgery, Faculty of Health Sciences, University of Linköping, S-581 85 Linköping, Sweden.
Engblom
D
D
Ortegren
U
U
Mackerlova
L
L
Paues
J
J
Blomqvist
A
A
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004745:Enkephalins / Q000235:genetics*; D007107:Immune System / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D007150:Immunohistochemistry; D007249:Inflammation / Q000139:chemically induced / Q000276:immunology / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D009474:Neurons / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D011149:Pons / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D011498:Protein Precursors / Q000235:genetics*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015854:Up-Regulation / Q000187:drug effects / Q000276:immunology; D017833:Visceral Afferents / Q000166:cytology / Q000276:immunology / Q000378:metabolism*
D004745:Enkephalins; D008070:Lipopolysaccharides; D011498:Protein Precursors; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; C033660:preproenkephalin