General anesthesia mediated by effects on ion channels

Figure 3 The structure of Hyperpolarization activated cyclic nucleotide channels. Hyperpolarization activated cyclic nucleotide (HCN) channels are made of four subunits. Each subunit contained six trans-membrane segments and S4 acts as the voltage sensor. The pore and filter for ion selection is between S5 and S6. The C-terminal of the HCN channel domain includes the cyclic nucleotide-binding domain (bottom). The domain of the C-linker consists of six a-helices.