Table 1.

Dopamine D1- and D2-like receptor binding in the developing neostriatum

Age	E13	E14	E15	E17	P0
nCi/mg tissue equivalent (mean ± SEM)
D1-like binding	0.065 ± 0.023	1.552 ± 0.103	2.09 ± 0.217	4.068 ± 0.575	5.466 ± 0.569
D2-like binding	0.017 ± 0.014	0.262 ± 0.01	0.224 ± 0.037	0.893 ± 0.181	1.06 ± 0.213
Femtomoles of bound ligand per milligram of tissue
D1-like binding	0.927	22.038	29.680	57.769	77.6223
D2-like binding	0.219	3.295	2.823	11.253	13.360

The binding intensities were standardized to nanocuries per milligram (nCi/mg) of tissue equivalent across the different replications by calibration against tritiated polymer standards. Then, the nCi/mg of tissue equivalent values were converted to femtomoles of bound ligand per milligram of tissue on the basis of the specific activity of the antagonists used. Both D1- and D2-like binding increases during development.