Table 3.

Drd1a-agonist activation of ERK1/2 in striatal neurons in wild-type and DARPP-32 KO mice

Striatal region	Wild type		DARPP-32 KO		Comparison of wild-type and KO DA-depleted striatum
	DA-intact	DA-depleted	DA-intact	DA-depleted	p value
Dorsal lateral	3.5	46.5	4.2	50.5	0.220NS
Dorsal medial	13.5	49.2	10.0	56.2	0.078NS
Accumbens	24.7	50.8	20.3	49.2	0.409NS

Treatment groups receiving Drd1a agonist (SKF-81297; 5 mg/kg) had unilateral 6-OHDA lesions of the nigrostriatal dopamine pathway. Phospho-ERK1/2-immunoreactive neurons were counted in the DA-intact and DA-depleted striatum in wild-type and DARPP-32 knock-out animals. Cell counts are the average from six animals per treatment group (n = 5) measured in a 100 μm² area in each region. Wilcoxon's rank sum test was performed to compare the DA-depleted striatum from the wild-type and DARPP-32 KO animals. There was no significant difference (NS, p > 0.01) between wild-type and DARPP-32 KO animals in the numbers of neurons displaying Drd1a agonist-activated ERK1/2 in the DA-depleted striatum.

**p < 0.01 < NS.