Electric shock titration: effects of meperidine, anileridine and alphaprodine.

The effects of meperidine, anileridine and a alphaprodine were studied in the squirrel monkey whose behavior was maintained under a 2.0-sec schedule of shock increment. Low doses of all three drugs had no effect, whereas higher doses decreased responding at the zero shock intensity. Slightly higher doses of meperidine and anileridine increased responding at the zero shock intensity and produced convulsions.