Functional development of dopamine receptors in the rat forebrain.

Dopamine (DA) was injected unilaterally into the dorsal caudate-putamen (D-CPU), ventral caudate-putamen (V-CPU), piriform cortex (PIR), olfactory tubercle (OTU) and frontal cortex (FC) of two day old rats and rotational behavior observed. Injection of DA into D-CPU, PIR, and OTU produced a contralateral postural deviation which differed significantly from the ipsilateral deviation produced by control injections. Only DA injections into PIR and OTU produced contralateral turning differing significantly from the effects of control injections. These results suggest that the DA receptors in C-CPU, PIR, and OTU involved in rotational behavior are functionally mature at two days of age and that the two components of rotation, postural deviation (direction) and turning (locomotion), involve different neural systems at this age. The developing rat is suggested as a valuable tool for understanding the neural circuitry and pharmacology of rotational behavior.