Immunophenotypic Characteristics of the Expression of Inducible NO Synthase in the Dentate Gyrus in Mature Rats and Its Pharmacological Correction

Objective. To identify the characteristics of the expression of inducible NO synthase (iNOS) in the dentate gyrus in rats of mature age with a model of depression and to establish the potential for pharmacological correction of changes with phenibut and compounds with laboratory designations RGPU-189 and RGPU-135. Materials and methods. Depression-like behavior in animals was modeled by combining stressors such as loud noise, flashing bright light, and vibration, which acted on the background of constant movement restriction and fluctuation in environmental temperature for seven days (daily for 30 min). Changes in iNOS expression levels in the dentate gyrus were assessed by determining the relative area of immunoreactive material (IRM) and staining intensity on a scale of 0–3 points. Results. Rats with experimental depression, as compared with the control group, showed increases in the level of expression of iNOS-IRM in cytoplasm of the perikaryon of neurons in the granular layer of the dentate gyrus and an increase in the relative area of iNOS–IRM in the neuropil and nerve cells. Use of compound RGPU-189 (salifen) had a greater correcting action, as rats showed a decreased level of expression of iNOS-IRM in the cytoplasm of the perikarya of neurons in the granular layer of the dentate gyrus, along with decreases in the relative iNOS-IRM area in the neuropil and nerve cells to the levels of these parameters in the control group. Conclusions. Rats of mature age with an experimental model of depression displayed an increased level of expression of iNOS-IRM, decreases in which were seen as a result of pharmacological correction with compound RGPU-189 (salifen), which may be evidence that this compound has a predominant neuroprotective effect on GABAergic neurotransmission mechanisms.