Table 4.

l-DOPA 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	6.6	51.4	3	58.2	0.183NS
Dorsal medial	16.8	43.8	7.4	50.8	0.111NS
Accumbens	27.8	39.6	20.0	46.0	0.21NS

Treatment groups receiving l -DOPA (20 mg/kg plus 12 mg/kg benserazide for 10 d) 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 five 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 l-DOPA-activated ERK1/2 in the DA-depleted striatum.

**p < 0.01 < NS.