AN ION-SENSITIVE MICROELECTRODE STUDY ON THE EFFECT OF A HIGH-CONCENTRATION OF IVERMECTIN ON CHLORIDE BALANCE IN THE SOMATIC MUSCLE BAG CELLS OF ASCARIS-SUUM

Ivermectin has been shown to increase chloride conductances of inverte brate cells. On the muscle cells of the parasitic nematode Ascaris, iv ermectin acts as both a GABA receptor antagonist and a chloride channe l opener. In this study, ion-sensitive microelectrodes were used to in vestigate the effect of ivermectin on intracellular Cl- concentration of the somatic muscle bag cells of Ascaris suum. Incubation of muscle cells with ivermectin (10 mum in 1 % dimethyl sulphoxide vehicle for 6 0 min) increased intracellular Cl- by 2.9 mm or 15 % compared to contr ols (P < 0.01, n = 6).