D(2)-like dopamine receptors differentially regulate unitary IPSCs depending on presynaptic GABAergic neuron subtypes in rat nucleus accumbens shell.
J Neurophysiol
; 107(2): 692-703, 2012 Jan.
Article
en En
| MEDLINE
| ID: mdl-22049335
In the nucleus accumbens (NAc), a medium spiny (MS) neuron receives GABAergic inputs from two major sources: fast-spiking (FS) neurons and other, adjacent MS neurons. These two types of inhibitory synapses are considered to play different roles in output activities, i.e., FSâMS connections suppress output from the NAc whereas MSâMS connections contribute to lateral inhibition. In the present study, we focused on the electrophysiological properties of unitary inhibitory postsynaptic currents (uIPSCs) obtained from MSâMS connections and FSâMS connections and examined the effects of quinpirole, a dopamine D(2)-like receptor agonist, on uIPSCs with multiple whole cell patch-clamp recording. Application of quinpirole (1 µM) reliably suppressed the amplitude of uIPSCs by 29.6% in MSâMS connections, with increases in paired-pulse ratio and failure rate. The suppressive effects of quinpirole on uIPSCs were mimicked by 1 µM PD128907, a D(2/3) receptor agonist, whereas quinpirole-induced suppression of uISPCs was blocked by preapplication of 1 µM sulpiride or 10 µM nafadotride, both D(2/3) receptor antagonists. On the other hand, quinpirole (1 µM) had divergent effects on FSâMS connections, i.e., quinpirole increased uIPSC amplitude in 38.1% of FSâMS connections and 23.8% of FSâMS connections were suppressed by quinpirole. Analysis of coefficient of variation in uIPSC amplitude implied the involvement of presynaptic mechanisms in quinpirole-induced effects on uIPSCs. These results suggest that activation of D(2)-like receptors facilitates outputs from MS neurons in the NAc by reducing lateral inhibition during a dormant period of FS neuron activities.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Receptores de Dopamina D2
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Terminales Presinápticos
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Potenciales Postsinápticos Inhibidores
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Neuronas GABAérgicas
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Núcleo Accumbens
Límite:
Animals
Idioma:
En
Revista:
J Neurophysiol
Año:
2012
Tipo del documento:
Article
País de afiliación:
Japón
Pais de publicación:
Estados Unidos