Fig. 5.

Cardiac ganglia neurons express select voltage-dependent sodium channels, and preferential Na_v1.7 blockade can attenuate PACAP-enhanced excitability. Semiquantitative PCRs demonstrate Na_V1.3 and Na_V1.7 transcript expression in cardiac ganglia; Na_V1.2 and Na_V1.6 expression was not evident in these tissues. Stellate ganglia contained transcripts for all 4 sodium channel α-subunits. NTC, no template control. B: cardiac neuron pretreatment with the Na_V1.7 blocker PF-04856264 suppressed the PACAP-induced increase in cardiac neuron excitability. Averaged excitability curve was generated for 5 cells during exposure to 20 nM PACAP (■) and 8 cells pretreated with PF-04856264 (PF) and then exposed to PF-04856264 + 20 nM PACAP (4 cells at 100 nM PF-04856264 and 4 cells at 500 nM PF-04856264) (●). *Number of action potentials for PF-04856264 + PACAP is statistically different from PACAP alone at the indicated current steps.