Activation of group III metabotropic glutamate receptors presynaptically reduces both GABAergic and glutamatergic transmission in the rat globus pallidus.
To investigate the role of group III metabotropic glutamate receptors (mGluRs) in the globus pallidus (GP), whole-cell recordings were performed using rat brain slice preparations. Application of the group III mGluRs specific agonist L(+)-2-amino-4-phosphonobutyric acid (L-AP4) suppressed the amplitude of striatal stimulation-induced IPSCs and internal capsule stimulation-induced EPSCs in most of the GP neurons that were capable of generating repetitive firing without spike accommodation. The suppression of IPSCs and EPSCs was accompanied by an increase in the paired-pulse ratio. The L-AP4 effects were antagonized by (R,S)-alpha-cyclopropyl-4-phosphophenylglycine, a blocker for group II/III mGluRs. L-AP4 reduced the frequency of mIPSCs and mEPSCs without changing their amplitude distribution. L-AP4 failed to change iontophoretic glutamate induced responses. These results suggest that the subthalamo-pallidal glutamatergic input might homo- and hetero-synaptically control GABAergic and glutamatergic transmission in the GP.
Matsui
T
T
Department of Anatomy and Neurobiology, College of Medicine, The University of Tennessee Memphis, 855 Monroe Avenue, Memphis, TN 38163, USA.
Kita
H
H
D000818:Animals; D000831:Animals, Newborn; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004558:Electric Stimulation; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000528:radiation effects; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D005917:Globus Pallidus / Q000166:cytology*; D018698:Glutamic Acid / Q000378:metabolism* / Q000494:pharmacology; D066298:In Vitro Techniques; D020772:Internal Capsule / Q000502:physiology; D007478:Iontophoresis; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009433:Neural Inhibition / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques / Q000379:methods; D010879:Piperazines / Q000494:pharmacology; D011422:Propionates / Q000494:pharmacology; D011724:Pyridazines / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018094:Receptors, Metabotropic Glutamate / Q000187:drug effects / Q000378:metabolism*; D017661:Receptors, Presynaptic / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism* / Q000494:pharmacology
C114785:2-amino-4-phosphono-propinate; D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D010879:Piperazines; D011422:Propionates; D011724:Pyridazines; D011810:Quinoxalines; D018094:Receptors, Metabotropic Glutamate; D017661:Receptors, Presynaptic; C102718:metabotropic glutamate receptor 3; C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; C050592:3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid; C049853:gabazine