Interleukin-6 and Nitric Oxide Synthase Expression in the Vasopressin and Corticotrophin-releasing Factor Systems of the Rat Hypothalamus
Tomás González-Hernández 1*, Domingo Afonso-Oramas 1, Ignacio Cruz-Muros 1, Pedro Barroso-Chinea 1, Pedro Abreu 1, María del Mar Pérez-Delgado 1, Nélida Rancel-Torres 1 and María del Carmen González 1
1 Department of Anatomy, Pathology, and Histology (TG-H,DA-O,IC-M,PB-C,MdMP-D,NR-T) and Department of Physiology (PA,MdCG), Faculty of Medicine, University of La Laguna, Tenerife, Spain
* To whom correspondence should be addressed. E-mail: tgonhern{at}ull.es.
Submitted on September 27, 2005
Accepted on 10 November 2005
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Abstract |
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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 nonhypophysiotropic cells.
Key Words:
hypophysiotropic, suprachiasmatic nucleus, median eminence, pituitary gland