Spike frequency adaptation has contributions from the IHERG current (encoded by the human eag-related gene
(HERG); Warmke & Ganetzky, 1994), which develops with
slow kinetics during depolarization and contributes to the
repolarization of the long action potentials typically present
in the heart. IHERG is one of the delayed rectifier currents
(IK(r)) of the heart, and HERG mutations are associated
with one of the cardiac arrhythmia LQT syndromes (LQT2).
See paper for more and details.
Chiesa N, Rosati B, Arcangeli A, Olivotto M, Wanke E (1997) A novel role for HERG K+ channels: spike-frequency adaptation. J Physiol 501 (Pt 2):313-8 [PubMed]