TY - JOUR
T1 - Functional and ultrastructural analysis of group I mGluR in striatal fast-spiking interneurons
AU - Bonsi, Paola
AU - Sciamanna, Giuseppe
AU - Mitrano, Darlene A.
AU - Cuomo, Dario
AU - Bernardi, Giorgio
AU - Platania, Paola
AU - Smith, Yoland
AU - Pisani, Antonio
PY - 2007/3
Y1 - 2007/3
N2 - Striatal parvalbumin-containing fast-spiking (FS) interneurons provide a powerful feedforward GABAergic inhibition on spiny projection neurons, through a widespread arborization and electrical coupling. Modulation of FS interneuron activity might therefore strongly affect striatal output. Metabotropic glutamate receptors (mGluRs) exert a modulatory action at various levels in the striatum. We performed electrophysiological recordings from a rat striatal slice preparation to investigate the effects of group I mGluR activation on both the intrinsic and synaptic properties of FS interneurons. Bath-application of the group I mGluR agonist, (S)-3,5-dihydroxyphenylglycine (3,5-DHPG), caused a dose-dependent depolarizing response. Both (S)-(+)-α-amino-4-carboxy-2- methylbenzeneacetic acid (LY367385) and 7-(hydroxyimino)cyclopropa[b]chromen-1a- carboxylate ethyl ester (CPCCOEt), selective mGluR1 antagonists, significantly reduced the amplitude of the membrane depolarization caused by 3,5-DHPG application. Conversely, mGluR5 antagonists, 2-methyl-6-(phenylethylnyl)pyridine hydrochloride (MPEP) and 6-methyl-2-(phenylazo)-3-pyridinol (SIB1757), were unable to affect the response to 3,5-DHPG, suggesting that only mGluR1 contributes to the 3,5-DHPG-mediated excitatory action on FS interneurons. Furthermore, mGluR1 blockade significantly decreased the amplitude of the glutamatergic postsynaptic potentials, whereas the mGluR5 antagonist application produced a small nonsignificant inhibitory effect. Surprisingly, our electron microscopic data demonstrate that the immunoreactivity for both mGluR1a and mGluR5 is expressed extrasynaptically on the plasma membrane of parvalbumin-immunoreactive dendrites of FS interneurons. Together, these results suggest that despite a common pattern of distribution, mGluR1 and mGluR5 exert distinct functions in the modulation of FS interneuron activity.
AB - Striatal parvalbumin-containing fast-spiking (FS) interneurons provide a powerful feedforward GABAergic inhibition on spiny projection neurons, through a widespread arborization and electrical coupling. Modulation of FS interneuron activity might therefore strongly affect striatal output. Metabotropic glutamate receptors (mGluRs) exert a modulatory action at various levels in the striatum. We performed electrophysiological recordings from a rat striatal slice preparation to investigate the effects of group I mGluR activation on both the intrinsic and synaptic properties of FS interneurons. Bath-application of the group I mGluR agonist, (S)-3,5-dihydroxyphenylglycine (3,5-DHPG), caused a dose-dependent depolarizing response. Both (S)-(+)-α-amino-4-carboxy-2- methylbenzeneacetic acid (LY367385) and 7-(hydroxyimino)cyclopropa[b]chromen-1a- carboxylate ethyl ester (CPCCOEt), selective mGluR1 antagonists, significantly reduced the amplitude of the membrane depolarization caused by 3,5-DHPG application. Conversely, mGluR5 antagonists, 2-methyl-6-(phenylethylnyl)pyridine hydrochloride (MPEP) and 6-methyl-2-(phenylazo)-3-pyridinol (SIB1757), were unable to affect the response to 3,5-DHPG, suggesting that only mGluR1 contributes to the 3,5-DHPG-mediated excitatory action on FS interneurons. Furthermore, mGluR1 blockade significantly decreased the amplitude of the glutamatergic postsynaptic potentials, whereas the mGluR5 antagonist application produced a small nonsignificant inhibitory effect. Surprisingly, our electron microscopic data demonstrate that the immunoreactivity for both mGluR1a and mGluR5 is expressed extrasynaptically on the plasma membrane of parvalbumin-immunoreactive dendrites of FS interneurons. Together, these results suggest that despite a common pattern of distribution, mGluR1 and mGluR5 exert distinct functions in the modulation of FS interneuron activity.
KW - GABAergic interneuron
KW - mGluR1
KW - mGluR5
KW - Rat
KW - Striatum
UR - http://www.scopus.com/inward/record.url?scp=34147102199&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34147102199&partnerID=8YFLogxK
U2 - 10.1111/j.1460-9568.2007.05383.x
DO - 10.1111/j.1460-9568.2007.05383.x
M3 - Article
C2 - 17425558
AN - SCOPUS:34147102199
VL - 25
SP - 1319
EP - 1331
JO - European Journal of Neuroscience
JF - European Journal of Neuroscience
SN - 0953-816X
IS - 5
ER -