Background dopamine concentration dependently facilitates long-term potentiation in rat prefrontal cortex through postsynaptic activation of extracellular signal-regulated kinases.
Altered levels of tonic/background dopamine in prefrontal cortex (PFC) may underlie modifications of executive cognitive function. We showed previously in rat PFC slices that exogenously supplied background dopamine facilitates induction of long-term potentiation (LTP), a possible cellular substrate for the long-term component of executive cognitive function. In the present study, we characterized cellular and molecular mechanisms underlying this modulatory dopamine effect. We show first that the LTP-facilitating effect of tonic/background dopamine follows an inverted-U shape concentration curve and that the effective level of background dopamine slowly activates postsynaptic extracellular signal-regulated kinases (ERKs) to facilitate LTP. Furthermore, we show the evidence that LTP-inducing high-frequency stimulation evokes endogenous release of dopamine in PFC slices. This fast dopamine serves as a trigger for LTP in the presence of the background dopamine. In its absence, the endogenous dopamine triggered, instead, long-term depression. These results indicate that appropriate levels of tonic/background dopamine serve to activate critical molecular factors in PFC neurons and thereby facilitate induction of synaptic potentiation.
Kolomiets
B
B
Laboratory of Neuromodulation, Neuronal Plasticity and Cognition, CNRS-UMR7102, Université Paris VI Pierre et Marie Curie, Paris, France.
Marzo
A
A
Caboche
J
J
Vanhoutte
P
P
Otani
S
S
D000818:Animals; D002478:Cells, Cultured; D004298:Dopamine / Q000378:metabolism*; D004789:Enzyme Activation; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D048049:Extracellular Signal-Regulated MAP Kinases; D004298:Dopamine