[Depolarizing action of dopamine on the endings of the primary afferent fibers of an isolated segment of the spinal cord in rat pups].

The effect of dopamine on the dorsal root potential was studied in the isolated superfused spinal cord of 12-18-day old rats. It was established that application of dopamine in concentration of 1.10(-9)-1.10(-3) mol/l caused the reversible dose-dependent depolarization in the dorsal root. The depolarization was retained in the calcium-free solution with magnesium or manganese ions. Its maximal amplitude reached 1.5 mV. Haloperidol, a dopamine antagonist, decreased depolarization evoked by dopamine. The possibility of dopaminergic brainstem-spinal pathways participation in the control of the sensory information transmission at the spinal cord entrance is discussed.