Calcium current in mouse eggs recorded with the tight-seal,whole-cell voltage-clamp technique

The tight-seal, whole-cell recording technique has been used to voltage-clamp unfertilized eggs of the mouse. Good seal formation was obtained in a solution containing 20 mM Ca²⁺ and the transient inward Ca²⁺ current recorded. This technique offers several advantages over the conventional, two-microelectrodes voltage-clamp: (i) improved signal to noise ratio; (ii) larger membrane-pipette seal resistance; (iii) possibility of very stable, long duration, recordings and (iv) possibility of controlling the intracellular medium. The main disadvantage of the technique, namely the rundown of channels due to loss of intracellular components, was not encountered in this preparation.