Figure 7.
Crosstalk of D1R (a) and D2R (b) antagonists on the [Ca2+]i changes of striatal D1R- and D2R-expressing neurons in response to cocaine (8 mg/kg, i.p.). 1, 2, [Ca2+]i images at baseline and t = 25 min after cocaine injection. 3, EGFP images of D2R (a) and D1R (b) neurons. 4, Ca2+ and EGFP images overlapped to identify [Ca2+]i from D2R (a) and D1R (b) neurons. 5, Δ[Ca2+]i from individual D2R (a) and D1R (b) neurons (dark solid curves), and their averaged changes (blue bold curve for D2R neurons, red bold curve for D1R neurons). 6, Δ[Ca2+]i images at t = 25 min. Cocaine-evoked [Ca2+]i decrease in D2R neurons were effectively inhibited by the D1 antagonist down to −0.9 ± 0.6% (n = 16, p < 0.0001), whereas cocaine-evoked [Ca2+]i increase in striatal D1R neurons were partially inhibited by the D2 antagonist from 8.3 ± 2.4% (Fig. 4a5) to 2.5 ± 0.7% (n = 15, p < 0.0001).