Figure 4

HyNaCs are insensitive to Hydra-RFamides III to V. Representative current trace showing activation of HyNaCs by the removal of extracellular divalent cations or by 5 μM Hydra-RFamide I. In contrast, 5 μM Hydra-RFamide III, IV or V did not elicit a current for any functional HyNaC heterotrimer; a current trace from HyNaC2/11/5 is shown as an example. Dashed line represents the zero current level. Amino acid sequences of Hydra-RFamides I to V are shown at the bottom. HyNaC, Hydra Na⁺ channel.