Interleukin-6 and Nitric Oxide Synthase Expression in the Vasopressin and Corticotrophin-releasing Factor Systems of the Rat Hypothalamus

• Published in: The journal of histochemistry and cytochemistry Vol. 54; no. 4; pp. 427 - 441
• Main Authors: Gonzalez-Hernandez, Tomas, Afonso-Oramas, Domingo, Cruz-Muros, Ignacio, Barroso-Chinea, Pedro, Abreu, Pedro, del Mar Perez-Delgado, Maria, Rancel-Torres, Nelida, del Carmen Gonzalez, Maria
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA Histochemical Soc 01.04.2006; SAGE Publications
• Subjects: Animals; Arginine Vasopressin - metabolism; Colchicine - administration & dosage; Colchicine - pharmacology; Corticotropin-Releasing Hormone - metabolism; Hypothalamus - anatomy & histology; Hypothalamus - metabolism; Immunohistochemistry; Injections, Intraventricular; Interleukin-6 - biosynthesis; Male; Median Eminence - metabolism; Nitric Oxide Synthase Type I - biosynthesis; Paraventricular Hypothalamic Nucleus - metabolism; Rats; Rats, Sprague-Dawley; Suprachiasmatic Nucleus - metabolism; Supraoptic Nucleus - metabolism; hypophysiotropic; median eminence; suprachiasmatic nucleus; pituitary gland
• ISSN: 0022-1554; 1551-5044
• DOI: 10.1369/jhc.5A6845.2005

Nitric oxide synthase (NOS) and interleukin-6 (IL-6) are constitutively expressed in hypothalamic cells. However, phenotypic and functional aspects of these cells remain unknown. We have studied the expression pattern of these two molecules in hypothalamic cells expressing corticotropin-releasing factor (CRF) and arginin-vasopressin (AVP), two major regulatory peptides in the hypothalamus-pituitary system, using immunofluorescence, intracerebroventricular injection of colchicine, and the study in parallel of the labeling pattern of axons in the median eminence. Within AVP cells, we distinguished two different populations: large, intensely stained AVP cells coexpressing IL-6; and large, intensely stained AVP cells coexpressing IL-6 and NOS. Within the CRF cells, we distinguished three different populations: large, intensely stained CRF cells immunonegative for AVP, NOS, and IL-6; large cells weakly stained for CRF and AVP, immunopositive for NOS and immunonegative for IL-6; and small cells intensely stained for CRF and AVP and immunonegative for IL-6 and NOS. In addition, we also found AVP cells containing IL-6 in the suprachiasmatic nucleus. These results suggest that neuronal NOS and IL-6 may be involved in different modulatory processes in hypophysiotropic and non-hypophysiotropic cells.