Inhibiting dopamine reuptake blocks the induction of long-term potentiation and depression in the lateral entorhinal cortex of awake rats.
Synaptic plasticity in olfactory inputs to the lateral entorhinal cortex may result in lasting changes in the processing of olfactory stimuli. Changes in dopaminergic tone can have strong effects on basal evoked synaptic responses in the superficial layers of the entorhinal cortex, and the current study investigated whether dopamine may modulate the induction of long-term potentiation (LTP) and depression (LTD) in piriform cortex inputs to layer II of the lateral entorhinal cortex in awake rats. Groups of animals were pretreated with either saline or the selective dopamine reuptake inhibitor GBR12909 prior to low or high frequency stimulation to induce LTD or LTP. In saline-treated groups, synaptic responses were potentiated to 122.4+/-6.4% of baseline levels following LTP induction, and were reduced to 84.5+/-4.9% following induction of LTD. Changes in synaptic responses were maintained for up to 60min and returned to baseline levels within 24h. In contrast, induction of both LTP and LTD was blocked in rats pretreated with GBR12909. Dopaminergic suppression of synaptic plasticity in the entorhinal cortex may serve to restrain activity-dependent plasticity during reward-relevant behavioral states or during processing of novel stimuli.
Caruana
Douglas A
DA
Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, 7141 Sherbrooke Street West, Rm.SP-244, Montréal, Que. H4B 1R6, Canada.
Reed
Sean J
SJ
Sliz
Diane J
DJ
Chapman
C Andrew
CA
D000344:Afferent Pathways / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D004558:Electric Stimulation; D018728:Entorhinal Cortex / Q000187:drug effects / Q000378:metabolism*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D036881:Long-Term Synaptic Depression / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology; D009833:Olfactory Pathways / Q000187:drug effects / Q000502:physiology; D010879:Piperazines / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D012201:Reward; D009435:Synaptic Transmission / Q000502:physiology; D017557:Ventral Tegmental Area / Q000502:physiology
D018765:Dopamine Uptake Inhibitors; D010879:Piperazines; C043425:vanoxerine; D004298:Dopamine