[Dopamine modification of the Ca-component of the action potential in the neuron soma of the mollusk L. stagnalis].

Dopamine has been found to decrease reversibly the action potential rising phase in identified L. stagnalis neurones. Using voltage-clamp and intracellular dialysis techniques it is shown that dopamine inhibits electroexcitable Ca-current, and changes in Ca-current determine those in the action potential shape. Serotonin and adrenaline influence the Ca-current in a similar way as dopamine does. Inhibition of Ca-conductance is found not to be related to possible effect of these neuromediators on intracellular level of free Ca ions or cyclic AMP.