Group I mGluRs increase locomotor network excitability in Xenopus tadpoles via presynaptic inhibition of glycinergic neurotransmission.
Eur J Neurosci
; 28(5): 903-13, 2008 Sep.
Article
em En
| MEDLINE
| ID: mdl-18691329
ABSTRACT
The group I metabotropic glutamate receptor agonist (S)-3,5-dihyroxyphenylglycine (DHPG) increases the frequency of rhythmic swimming activity in Xenopus tadpoles. This study explores the possibility that group I receptor modulation occurs in part via depression of inhibitory synaptic transmission. Applications of the glycine receptor antagonist strychnine occluded the effects of DHPG, providing preliminary evidence that group I receptors affect motor network output by reducing glycinergic transmission. This evidence was supported further by intracellular and whole-cell patch-clamp recordings from presumed motorneurons. DHPG applications produced two prominent effects (i) during swimming activity, glycinergic mid-cycle IPSPs were reduced in amplitude; and (ii) during quiescent periods, the frequency of spontaneous miniature IPSPs was also reduced. No change in membrane potential or input resistance following group I receptor activation was detected. The reduction in fast synaptic inhibition provides a plausible explanation for the increased excitability of the locomotor network, although other contributory mechanisms activated in parallel by group I receptors cannot be discounted. Aspects of this work have been published previously in abstract form [R. J. Chapman & K. T. Sillar (2003) SFN Abstracts 277.8].
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Medula Espinal
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Receptores de Glutamato Metabotrópico
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Glicina
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Larva
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Rede Nervosa
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Inibição Neural
Limite:
Animals
Idioma:
En
Ano de publicação:
2008
Tipo de documento:
Article