Recurrent dendrodendritic inhibition of accessory olfactory bulb mitral cells requires activation of group I metabotropic glutamate receptors.
Metabotropic glutamate receptors (mGluRs) modulate neural excitability and network tone in many brain regions. Expression of mGluRs is particularly high in the accessory olfactory bulb (AOB), a CNS structure critical for detecting chemicals that identify kin and conspecifics. Because of its relative simplicity and its direct projection to the hypothalamus, the AOB provides a model system for studying how mGluRs affect the flow of encoded sensory information to downstream areas. We investigated the role of group I mGluRs in synaptic processing in AOB slices and found that under control conditions, recurrent inhibition of principal neurons (mitral cells) was completely eliminated by the mGluR1 antagonist LY367385 [(S)-(+)-alpha-amino-4-carboxy-2 methylbenzeneacetic acid]. In addition, the group I mGluR agonist DHPG [(S)-3,5-dihydroxyphenylglycine; 20 microM] induced a dramatic increase in the rate of spontaneous IPSCs. This increase was dependent on voltage-gated calcium channels but persisted even after blockade of ionotropic glutamatergic transmission and sodium channels. Together, these results indicate that mGluR1 plays a critical role in controlling information flow through the AOB and suggest that mGluR1 may be an important locus for experience-dependent changes in synaptic function.
Castro
Jason B
JB
Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
Hovis
Kenneth R
KR
Urban
Nathaniel N
NN
D000818:Animals; D001565:Benzoates / Q000494:pharmacology; D003712:Dendrites / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives / Q000494:pharmacology; D051379:Mice; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D009830:Olfactory Bulb / Q000187:drug effects / Q000502:physiology*; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013997:Time Factors
D001565:Benzoates; D018094:Receptors, Metabotropic Glutamate; C104077:metabotropic glutamate receptor type 1; C079694:alpha-methyl-4-carboxyphenylglycine; D008734:Methoxyhydroxyphenylglycol; D005998:Glycine; C010117:3,4-dihydroxyphenylglycol