The effect of certain anions on muscle resting potential in Tenebrio molitor

Experiments were carried out on longitudinal ventral muscles of the mealworm larva (Tenebrio molitor) using conventional microelectrode methods. Both sodium nitrate and sodium sulphate depolarized the fibres markedly, whereas sodium propionate exerted an hyperpolarizing influence. It is concluded that the differences in the mode of action are due to different permeabilities of the membrane to the applied anions. The results obtained confirm also the concept of a multi-ionic electrode with respect to insect muscle fibres.