After a five-day adaptation period in activity wheels, four prairie dogs were assigned to a methylphenidate group (2.5 mg/kg, s.c.) and four prairie dogs were assigned to a saline group for ten consecutive daily injections. Half-revolutions of locomotor activity were recorded during seven measurement periods taken daily. During the third measurement period, from 1–3 hrs following injection, the methylphenidate group declined in locomotor activity over the first three days of drug administration.
Key words Methylphenidate - Tolerance - Prairie dogs - Motor activity