Synthesis of IL-2 mRNA in cells of rat hypothalamic structures after injection of short peptides.

In situ hybridization on paraffin sections of the rat brain showed that synthetic peptides Vilon, Epithalon, and Cortagen modulated the expression of IL-2 gene in vivo in cells of some hypothalamic structures depending on the terms and routes of administration.

Antigen-induced activation of hypothalamic cells (assessed by expression of the c-fos gene).

The aim of the present work was to study the activation of the expression of the c-fos gene (by in situ hybridization) in cells from rat (Sprague Dawley) hypothalamic structures 0.5, 2, 6, and 16 h after i.v. injections of tetanus toxoid (200 microg/kg). Tetanus toxoid was selected as the antigen because it does not induce any general non-specific body reactions. Control animals received i.v. doses of apyrogenic physiological saline. The number of c-fos mRNA-positive cells in all the hypothalamic structures studied was insignificant 30 min after injections of tetanus toxoid. c-fos mRNA-positive cells were seen in the posterior, lateral, and anterior hypothalamic fields and in the dorsomedial and ventromedial hypothalamic nuclei 2 h after injections of tetanus toxoid. The intensity of c-fos mRNA expression decreased in the posterior, lateral, and anterior hypothalamic fields 6 h after injections of tetanus toxoid. The maximum number of c-fos mRNA-positive cells in the anterior field and the paraventricular nucleus of the hypothalamic induced by tetanus toxoid, as compared with reactions to administration of physiological saline, were seen at 6 h. Administration of tetanus toxoid and physiological saline did not active the synthesis of c-fos mRNA in the arcuate or supraoptic nuclei at any time point. The number of c-fos mRNA-positive cells returned to baseline by 16 h after tetanus toxoid injections. Thus, this study revealed the temporospatial pattern of activation of hypothalamic structures in response to exposure to an antigen.

[Cell activation in the hypothalamus after exposure to an antigen (based on c-fos gene expression)]. / Aktivatsiia kletok gipotalamusa posle antigennogo vozdeistviia (po ékspressii gena c-fos).

Increase of the c-fos mRNA positive cells number was insignificant in 30 min. following activation of the rat hypothalamic structures with the tetanus toxoid (TT). Elevation of the c-fos mRNA positive cells number occurred in the hypothalamic' posterior (PHA), lateral (LHA), anterior (AHA), areas dorsomedial (DMH), and ventromedial (VMH) nuclei within 2 hours of the TT administration. In 6 hours the c-fos mRNA positive cells number decreased in PHA, LHA, DMH. The c-fos mRNA expression was stable in arquate and supraoptic hypothalamic nuclei following either the TT or saline administration.