Fig. 6.

GIRK blockade prevents adenosine-induced rate slowing

(a) Representative action SAN potential in CTL (top) and HF (bottom) exposed to ADO in the presence of GIRK antagonist TPQ (b) Firing rate reduction, (c) SDD reduction, and (d) MDP reduction from BL compared in presence of ADO+TPQ compared to ADO alone. Action potential parameters from Fig. 2 were compared with their respective group (HF or control) + TPQ via one-way ANOVA. SAN cells were isolated from 4 CTL dogs and 2 HF dogs.