The distribution of dopamine in the brain of a tortoise, Geochelone chilensis (Gray).

1. Dopamine was found in the tortoise brain; the highest concentration (3.7 mug/g) occurred in a region of the telencephalon containing the nucleus basalis and cortex olfactoria. This region may be considered similar to the mammalian and avian corpus striatum with respect to dopamine.2. The administration of reserpine or prenylamine substantially decreased the concentration of dopamine in the tortoise brain. This effect appeared later and lasted longer than in birds or mammals. When these drugs were given in doses which nearly depleted brain dopamine the characteristic signs observed in birds or mammals were not present.