theophylline ( 1 mm ) and 3-isobutyl-1-methylxanthine ( 0.1 mm ) reversibly increased the slow outward current amplitude , whereas imidazole ( 5 mm ) and tolbutamide ( 5 mm ) caused its reversible decrease .
C0039771
theophylline
C0000096
3-isobutyl-1-methylxanthine