Figure 3.

Sequence Alignment of NvNa_v2 Channels and Current Recordings from NvNa_v2.1^DKEA and NvNa_v2.1^{NvNav2.5(p−loops)} Channels Expressed in Xenopus Oocytes

(A) Alignment of the pore-loop regions of the five N. vectensis (Nv) channels (see also Figure S3 for spatiotemporal expression of Na_v2 cnidarian channels), as well as a channel from the medusae P. penicillatus (Pp) and C. capillata (Cc) and the mammalian brain channel Na_v1.2. Substitutions of NvNa_v2.1^{NvNav2.5(p−loops)} are underlined and substitutions unique to the Na_v2.5 channel subfamily are in yellow boxes. For current recordings the oocytes were clamped at −80 mV holding potential and currents were elicited by 200 or 500 ms depolarizing voltage pulses from −75 mV to either 50 or 70 mV.

(B) NvNa_v2.1^DKEA in ND96 bath solution.

(C) NvNa_v2.1^DKEA with choline substituting for Na⁺ in the bath solution.

(D) NvNa_v2.1^DKEA with Ca²⁺ in the bath solution chelated by EGTA.

(E and F) NvNa_v2.1^{NvNav2.5(p−loops)} in ND96 bath solution (E) and with choline substituting for Na⁺ (F).

(G) Current-voltage relations of NvNa_v2.1^{NvNav2.5(p−loops)} (E_rev = 46.5 ± 1.2 mV; n = 19). Each point represents mean ± SEM of n cells (see Figure S2 for analysis of the SF in NvNa_v2.1^{NvNav2.5(p−loops)}).