ABSTRACT
The effects of neurotransmitter dopamine and their antagonist haloperidol on the functioning of Ca2+, K+, and Cl– ion channels in the membrane of Chara corallina cells and on the functional properties of their cytoskeleton were studied. The influence of dopamine on the ionic currents of the cells depended on the dose and time of exposure. The influence of neurotransmitter on the membrane structure was reversible, after the removal of dopamine, a complete restoration of the amplitude and the development kinetics of the current was observed. A 24-long incubation of cells in the presence of dopamine produced a drop in the resting potential of the cells, decreased the membrane resistance, and stopped the movement of the cytoplasm. Haloperidol blocked Ca2+ channels and decelerated its activation and deactivation processes. The effect of haloperidol was reversible, after it was removed, and the characteristic of Ca2+ current was restored. Haloperidol inhibited microfilament-depended motion of the cytoplasm. Cytoplasmic streaming was restored after haloperidol was removed from the extracellular solution. Concentration of free Ca2+ ions in the cytoplasm increases in the presence of haloperidol. It is possible that Ca2+ channels target cells’ plasmalemma and possess specific binding sites for dopamine and its antagonists.
