Role of group II metabotropic glutamate receptors 2/3 and group I metabotropic glutamate receptor 5 in developing rat medial vestibular nuclei.
In brainstem slices from developing rats, metabotropic glutamate receptors mGluR2/3 and mGluR5 play different inhibitory roles in synaptic transmission and plasticity of the medial vestibular nuclei. The mGluR2/3 block (LY341495) reduces the occurrence of long-term depression after vestibular afferent high frequency stimulation at P8-P10, and increases that of long-term potentiation, while the mGluR5 block prevents high frequency stimulation long-term depression. Later on, the receptor block does not influence high frequency stimulation effects. In addition, while mGluR2/3 agonist (APDC) always provokes a transient reduction of synaptic responses, that of mGluR5 (CHPG) induces long-term depression per se at P8-P10. These results show a key role of mGluR5 in inducing high frequency stimulation long-term depression in developing medial vestibular nuclei, while mGluR2/3 modulate synaptic transmission, probably through presynaptic control of glutamate release.
Grassi
Silvarosa
S
Department of Internal Medicine, Section of Human Physiology, University of Perugia, I-06100 Perugia, Italy. sgrassi@unipg.it
Frondaroli
Adele
A
Pettorossi
Vito Enrico
VE
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000367:Age Factors; D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D036881:Long-Term Synaptic Depression / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D010648:Phenylacetates / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000502:physiology*; D018092:Kainic Acid Receptors / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D014726:Vestibular Nuclei / Q000254:growth & development* / Q000378:metabolism; D014966:Xanthenes / Q000494:pharmacology
D015763:2-Amino-5-phosphonovalerate; D000596:Amino Acids; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D005998:Glycine; D010648:Phenylacetates; D018091:Receptors, AMPA; D018092:Kainic Acid Receptors; D014966:Xanthenes; C107349:2-chloro-5-hydroxyphenylglycine; C114624:LY 341495; C104722:glutamate receptor ionotropic, AMPA 2