Long-term potentiation at excitatory amino acid synapses on midbrain dopamine neurons

EVIDENCE suggests that a process analogous to longterm potentiation (LTP) m ay underlie the enhanced behavioural responses attending chronic administra tion of amphetamine and cocaine in animals (behavioural sensitization). Aug mented excitatory amino acid (EAA)mediated transmission at the level of mid brain dopamine neurons has been implicated as a change critical to the deve lopment of sensitization. Here we provide an initial demonstration that EAA synapses on dopamine neurons can undergo plasticity. Tetanic stimulation o f the subthalamic nucleus induced a long-lasting increase (39.2+/-10.4%) in the amplitude of excitatory postsynaptic potentials recorded in dopamine n eurons of the substantia nigra. This LTP, which did not occur in the presen ce of NMDA antagonists, may constitute the mechanism that lies at the heart of sensitization. (C) 1999 Lippincott Williams & Wilkins.