CCG-203920 potentiated NOP response in mouse striatal slices
Relying on the well-established NOP receptor inhibitory activity on D1
signaling (Olianas et al. , 2008),
we next investigated whether RGS4 could affect the AT-403 mediated
inhibition of the SKF-38393-induced ERK-positive cell number in slices
of mouse striatum (Fig. 3). Application of the D1 receptor agonist
SKF-38393 (100 μM) to striatal slices of naïve mice caused an
approximately four-fold increase in the number of pERK immunoreactive
cells over basal (three-way ANOVA, F1,42=213.909; Fig.
3). AT-403 alone (30 nM) had no effect on basal pERK levels but reduced
D1 receptor-mediated response by 56% (three-way ANOVA,
F1,42=102.746). CCG-203920, which was ineffective alone,
significantly potentiated the effects of AT-403 (three-way ANOVA,
F1,42=9.222). In fact, when co-applied with CCG-203920,
AT-403 fully inhibited D1 stimulation.