Antagonismes des effets centraux et périphériques de la trémorine par deux parasympathicolytiques: L'atropine et la scopolamine

Summary

Administered to rats trained in an operant conditioning situation on a fixed interval schedule of reinforcement (FI) or on a schedule of differential reinforcement of low rates of responding (DRL), tremorine in doses of 0.5–5 mg/kg intraperitoneally depressed the rate of responding. The rats trained on the DRL-schedule were slightly more resistent to tremorine than the rats trained on the FI-schedule. In both types the effect increased with increasing doses. Administration of atropine (1 mg/kg i. p.) or scopolamine (0.8 mg/kg i. p.) increased the rate of responding. In contrast to scopolamine, atropine did not alter the distribution of responses in time. In a third experiment, the subjects received 5 mg/kg tremorine, plus 1 mg/kg atropine or 0.8 mg/kg scopolamine. The behavioural effects of tremorine, observed in the first experiment, were antagonized by both drugs, the temporal regulation showing a pattern similar to the pattern obtained under the antagonizing drug alone.