[Effect of cholin- and serotoninergic substances on self stimulation in rats]

The influence of choline- and serotoninergic agents on the pedal self-stimulation (SS) was studied in male rats of Wistar line. Physostigmine decreased the frequency of pressing on the pedal whereas fluoxetine didn't influence SS. Scopolamine activated SS and lowered the threshold of the SS-reaction. P-chloroamphetamine effect depended on the action phase of the drug and was manifested both in depression and activation of SS. Preliminary administration of fluoxetine decreased the activating effect of scopolamine and enhanced the depressing effect of physostigmine. A combination of p-chloroamphetamine and cholinergic agents was accompanied by a tendency toward weakening of depressing effect of physostigmine and toward enhancing of activating effect of scopolamine. It is suggested that serotoninergic mechanisms in case of changes in activity of cholinergic processes, depress the system of positive reinforcement. A functional interaction of choline- and serotoninergic neurotransmitter systems seems probable.