Figure 2. A cationic non-selective channel blocked by external Mg²⁺ is expressed in oocytes and eggs.

(a,b) Whole-cell voltage clamp recordings from oocytes and eggs. (a) Left panel: Current evoked from a voltage ramp from −100 to +100 mV in the absence (red trace) and presence of 10 mM external Mg²⁺ (black trace) in GV oocytes. Right panel: Averaged current recorded at +80 mV (7, 1 ± 1, 25 pA/pF for recordings in absence of Mg²⁺; n = 4. 3, 2 ± 1, 62 pA/pF for recordings in presence of external Mg²⁺; n = 4). (b) Current evoked from a voltage ramp from −100 to +100 mV in the absence (red trace) and presence of 10 mM external Mg²⁺ (black trace) in MII eggs. Right panel: Averaged current recorded at +80 mV. (5 ± 1, 7 pA/pF for recordings in absence of Mg²⁺; n = 3. 1, 7 ± 0, 85 pA/pF for recordings in presence of external Mg²⁺; n = 3). ± SD. ***P < 0.001, *P < 0.05.