Figure 1.

The experimental paradigm. A stimulation block with randomly distributed stimulations at 0.4 to 2.0 mA was followed by a 60-min waiting period (wash in of vehicle/inhibitors), followed by a second stimulation block analogous to the first one. Each experimental group consisted of six animals. The first group served as the time control series. After the first block, superfusion was switched to aCSF+vehicle (v, ethanol 0.5%). In a second, Kir channel inhibition group, superfusion was switched to aCSF plus vehicle containing 500 μmol/L BaCl₂. In the third group, combined inhibition of nNOS, COX, CYP450 epoxygenase, and adenosine receptors was achieved with superfusion of aCSF containing vehicle, L-NNA (1 mmol/L), indomethacin (500 μmol/L), MS-PPOH (20 μmol/L), and theophylline (50 μmol/L). In the fourth group, BaCl₂ (500 μmol/L) was added on top of the inhibitory cocktail of group 3.