Figure 10.

A_2A-AR expression per se can increase heart rate in vivo. Heart rate (HR) of freely moving WT (n = 8) and A_2A-TG mice (n = 5) was telemetrically recorded within 24 h (A). Mean HR is plotted in hourly intervals. ^★p < 0.05 vs. WT. ^#p < 0.05 analysis of variances of the whole curves between A_2A-TG and WT. Under resting conditions, ECGs (Ctr) were telemetrically recorded, and 1 h after CGS 21680 injection (40 µg kg⁻¹), all arrhythmic events were assessed in the following hour. CGS 21680 increased under these conditions the heart rate in A_2A-TG but not WT mice (B). Moreover, CGS 21680 injection was accompanied by a higher incidence of ventricular extrasystoles in A_2A-TG than in WT (C). ^#p < 0.05 vs. Ctr, ^★p < 0.05 vs. WT.