Fig. 3.

Lack of effect of A_2AR and H₃R activation on the depolarization-induced increase in the intracellular Ca²⁺ concentration ([Ca²⁺]_i) in globus pallidus synaptosomes. a Representative traces. Synaptosomes loaded with Fura 2-AM were perfused with Krebs-Ringer-Hepes solution (1 ml/min), and changes in fluorescence were determined by microfluorometry. Drugs under test were present in the solution (open bar) before and during the second depolarization stimulus (25 mM KCl, 20 s, black bars). b Lack of effect of the A_2AR agonist CGS-21680 (10 nM). The ratios of the second over the first K⁺ stimuli (S2/S1) were calculated as described in “Methods” and expressed as means ± SEM from four experiments. AUC, area under the curve. c Lack of effect of CGS-21680 (10 nM) and the H₃R agonist immepip (100 nM). Values are means ± SEM from four experiments. The statistical analysis was performed with Student’s t test