Effects of Dalargin on Changes in Anxiety in Rats with Different Individual-Typological Behavioral Characteristics in a Model of PTSD

Active and passive animals were selected from an overall population of Wistar rats using indexes of behavioral activity (IBA) and passivity (IBP) determined on testing in a T mazel; the elevated plus maze (EPM) was then used to divide animals into low-anxiety (active (ALA) and passive (PLA)) and high-anxiety (active (AHA) and passive (PHA)) groups. An experimental analog of PTSD was created using water immersion in the stress–restress paradigm. At 20 days after the first stress, experimental rats received intramuscular dalargin solution (0.1 mg/kg) for a week, while control rats received the same volume of physiological saline. All animals were tested in the EPM two days after one-week courses of injections. ALA rats with the PTSD model showed only a reduction in total motor-exploratory activity; the action of dalargin in the PTSD model was to promote increases in reactive anxiety in these animals. AHA rats with the PTSD model showed a decrease in total motor-exploratory activity and a simultaneous increase in their initially high anxiety; dalargin had an antistress action in these animals. PLA rats with the PTSD model showed decreased total motor-exploratory activity and increased reactive anxiety; injections of dalargin accelerated and enhanced the development of the PTSD-like state. PHA rats with the model of PTSD showed no notable changes in behavioral characteristics; dalargin injections had no visible effect on the behavior of these animals in the EPM. © 2022, Springer Nature Switzerland AG.