TY - JOUR
T1 - Selective Ablation of GIRK Channels in Dopamine Neurons Alters Behavioral Effects of Cocaine in Mice
AU - McCall, Nora M.
AU - Kotecki, Lydia
AU - Dominguez-Lopez, Sergio
AU - Marron Fernandez De Velasco, Ezequiel
AU - Carlblom, Nicholas
AU - Sharpe, Amanda L.
AU - Beckstead, Michael J.
AU - Wickman, Kevin
N1 - Publisher Copyright:
© 2017 American College of Neuropsychopharmacology. All rights reserved.
PY - 2017/2/1
Y1 - 2017/2/1
N2 - The increase in dopamine (DA) neurotransmission stimulated by in vivo cocaine exposure is tempered by G protein-dependent inhibitory feedback mechanisms in DA neurons of the ventral tegmental area (VTA). G protein-gated inwardly rectifying K + (GIRK/Kir3) channels mediate the direct inhibitory effect of GABA B receptor (GABA B R) and D 2 DA receptor (D 2 R) activation in VTA DA neurons. Here we examined the effect of the DA neuron-specific loss of GIRK channels on D 2 R-dependent regulation of VTA DA neuron excitability and on cocaine-induced, reward-related behaviors. Selective ablation of Girk2 in DA neurons did not alter the baseline excitability of VTA DA neurons but significantly reduced the magnitude of D 2 R-dependent inhibitory somatodendritic currents and blunted the impact of D 2 R activation on spontaneous activity and neuronal excitability. Mice lacking GIRK channels in DA neurons exhibited increased locomotor activation in response to acute cocaine administration and an altered locomotor sensitization profile, as well as increased responding for and intake of cocaine in an intravenous self-Administration test. These mice, however, showed unaltered cocaine-induced conditioned place preference. Collectively, our data suggest that feedback inhibition to VTA DA neurons, mediated by GIRK channel activation, tempers the locomotor stimulatory effect of cocaine while also modulating the reinforcing effect of cocaine in an operant-based self-Administration task.
AB - The increase in dopamine (DA) neurotransmission stimulated by in vivo cocaine exposure is tempered by G protein-dependent inhibitory feedback mechanisms in DA neurons of the ventral tegmental area (VTA). G protein-gated inwardly rectifying K + (GIRK/Kir3) channels mediate the direct inhibitory effect of GABA B receptor (GABA B R) and D 2 DA receptor (D 2 R) activation in VTA DA neurons. Here we examined the effect of the DA neuron-specific loss of GIRK channels on D 2 R-dependent regulation of VTA DA neuron excitability and on cocaine-induced, reward-related behaviors. Selective ablation of Girk2 in DA neurons did not alter the baseline excitability of VTA DA neurons but significantly reduced the magnitude of D 2 R-dependent inhibitory somatodendritic currents and blunted the impact of D 2 R activation on spontaneous activity and neuronal excitability. Mice lacking GIRK channels in DA neurons exhibited increased locomotor activation in response to acute cocaine administration and an altered locomotor sensitization profile, as well as increased responding for and intake of cocaine in an intravenous self-Administration test. These mice, however, showed unaltered cocaine-induced conditioned place preference. Collectively, our data suggest that feedback inhibition to VTA DA neurons, mediated by GIRK channel activation, tempers the locomotor stimulatory effect of cocaine while also modulating the reinforcing effect of cocaine in an operant-based self-Administration task.
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U2 - 10.1038/npp.2016.138
DO - 10.1038/npp.2016.138
M3 - Article
C2 - 27468917
AN - SCOPUS:84983438390
SN - 0893-133X
VL - 42
SP - 707
EP - 715
JO - Neuropsychopharmacology
JF - Neuropsychopharmacology
IS - 3
ER -