THE CONDITION OF C-FOS GENE IN THE NEUROSECRETORY NUCLEI OF THE HYPOTHALAMUS IN RATS STRESSED BY LIGHT AND THE EFFECTS OF MELATONIN AND EPITHALON

Abstract

The aim was to study the effect of melatonin and a synthetic bioregulator – epthalon for the purpose of correction stress-induced changes of the activity of the gene of “ultraearly response” c-fos in the lateral large cell subnuclei of the paraventricular nucleus (llPVN) of the rat hypothalamus at different intervals of 24- hour period (in the daytime and at night). The expression of the product of this gene – protein c-Fos – in animals kept under normal conditions of alternating illumination and darkness demonstrated a clear-cut circadian pattern (with a higher level by day). The diurnal index of the c-Fos content in the animal’s llPVN is lower by 33,0%, under conditions of light stress, whereas the nocturnal one approximated to the control values. An injection of melatonin (0,5 mg/kg) to light-stressed animals refl ected at 02.00 p.m. hundred by exceeding the index of the c-Fos protein in the animal’s llPVN almost twofold compared to the experimental fi ndings on stressed animals without hormone introduction, as well as by a normalization of the circadian dynamics of the expression of the gene under study. An augmentation of the index of the c-Fos protein concentration was disclosed in the structure upon using tetrapeptide epithalon (0,5 μg/kg) at night in relation to individuals with epiphysial hypofunction without undergoing experimental therapy with epithalon. No such effect was fi xed at night.

Keywords

• melatonin, epthalon, gene – protein c-fos, epiphysial hypofunction