Figure 3.

Adenosine-dependent modulation by dipyridamole on the locomotor activation induced by dopamine receptor agonists in reserpinized mice. Locomotor activity in male C57BL/6J mice (20–30 g) 20 h after administration of reserpine (5 mg/kg, s.c.; method described in detail in Marcellino et al., 2008) induced by the D1R agonist SKF81297 (5 mg/kg, i.p.; SKF; A) or the D2R agonist quinpirole (5 mg/kg, i.p.; QUIN; B), with or without the previous administration of dipyridamole (10, 30 or 100 mg/kg, i.p., 15 min before SKF or QUIN; 10DIP, 30DIP, or 100DIP) or caffeine (30 mg/kg, i.p., 30 min before SKF or QUIN; CAFF). All animals received three i.p. injections, with either drugs or the corresponding vehicle. One reserpinized group also received caffeine without dipyridamole or dopamine agonists. The dashed line represents the average locomotor activity of reserpinized mice receiving only vehicle administrations. Statistical differences were analyzed by one-way ANOVA followed by Newman-Keuls post-hoc test; ^*, ^**, and ^***: p < 0.05, p < 0.01 and p < 0.001, respectively, as compared with either SKF or QUIN.