Kallman W M, Isaac W
Psychopharmacologia. 1975;40(4):313-8. doi: 10.1007/BF00421469.
The dose-response relationships for three stimulants have been explored. These drugs have been shown to differ in potency and, with successive doubling of doses, have been found to have dose-response curves of differing slopes. In addition, the relationship between dose and activity level was not the same for younger and older rats. The relationship between dosage of both d-amphetamine and methylphenidate and locomotor activity was not the same in the light and the dark. The latter finding suggests a difference between these two stimulants and the third stimulant studied, caffeine, whose effects where unaltered by ambient illumination level.