[Depolarizing action of dopamine on the motor neurons of an isolated segment of the spinal cord in rat pups].

The dopamine effect on the ventral root potential was studied in the experiment with the isolated superfused spinal cord of 13-18-day old rats. It was established that application of dopamine in concentration of 1.10(-6)-1.10(-2) mol/l caused the reversible dose-dependent depolarization in the motoneurons. Depolarization was retained in the calcium-free solution with magnesium or manganese ions. An increase of the motoneurons frequency discharges was observed simultaneously with the slow ventral root depolarization. The segmental reflex response evoked by dorsal root stimulation was depressed against the background of depolarization.