Linear differences of neuronal NO-synthase expression pattern in locus coeruleus in rats

Abstract

The aim of the research was to establish linear differences of nNOS expression pattern, peculiarities of its distribution in vascular and cellular compartment of locus coeruleus in the brainstem of Wistar and SHR rats. Methods and results . The research was carried out on 10 Wistar male rats and 10 male SHR rats with body mass 250-270 g. Decapitation was done under anesthesia (sodium ethaminalum 40 mg/kg intraperitoneally). Identification of locus coeruleus neurons was done with the help of stereotactic atlas of rat’s brain. nNOS expression in the serial brainstem histological sections was studied with immunocytofluorescent method. Histological sections were incubated with primary rabbit IgG to rats’ nNOS (Sigma Chemical, USA). Then secondary mice IgG to rabbit IgG conjugated with FITC (Sigma Chemical, USA). 1:64 dilution were applied. Package of statistical programs VIDAS-2.5 (Kontron Elektronik, Germany) іn EXCEL‑7.0 (Microsoft Corp., USA) was used for analysis. Data with p<0,05 were taken as reliable. Conclusion. The results of the research demonstrated heterogeneity of nNOS distribution in rat’s brain stem locus coeruleus. Expression pattern of nNOS in locus coeruleus is characterized by compartmentalisation into two sections: cellular (neurons and glial cells) and vascular (endothelial cells and erythrocytes). Wistar and SHR rats have linear differences in nNOS expression. It is characterized by increased concentration of the enzyme in cellular compartment in two times more (р<0,05) in SHR rats. At the same time in vascular compartment in SHR rats the increase immunoreactive area in 1,8 times more (р<0,05), and by 7% (р<0,05) concentration in comparison with appropriate indices in Wistar rats.