[Expression of mRNA for corticoliberin and vasopressin in hypothalamus and amygdala on the background of administration of psychoactive drugs in rats].

Wistar male rats were injected intraperitoneally for 4 days in elevated doses with: (1) physiological saline (control; 0.1 - 0.2 - 0.4 - 0.8 ml/rat), (2) amphetamine (0.5 - 1.0 - 2.0 - 4.0 mg/kg); (3) fentanyl (0.00625 - 0.0125 - 0.025 - 0.05 mg/kg), (4) 40% aqueous ethanol solution (0.5 - 1.0 - 2.0 - 4.0 g/kg), (5) ethaminal sodium (2.5 - 5 - 10 - 20 mg/kg), and (6) dexamethasone (0.5 - 1.0 - 2.0 - 4.0 mg/kg). The forced regime of drug administration led to gradual load of the organism and prevented drug tolerance development. This method is widely used for the formation of drug dependence (or its features) due to various narcotic agents. The maximum level of mRNA expression for corticoliberin was registered in amygdala after the administration of dexamethasone (0.46 units compared to beta-actin), and the minimum level was observed after treatment with sodium ethaminal (0.07) and fentanyl (0.037). In hypothalamus, sodium ethaminal produced elevated mRNA expression (0.8 units), followed by ethanol (0.37) and fentanyl (0.039). Amphetamine activated mRNA expression for corticoliberin neither in hypothalamus nor in amygdala for all of the drugs studied. The mRNA expression for vasopressin was also not registered for all drugs in hypothalamus and amygdala. Therefore, the reinforcing system of hypothalamus supports the typical reaction on the administration of narcotic agents, while the extended amygdala system includes both the proper reinforcement and the stress reactivity elements.