Heterosynaptic crosstalk

GABA-glutamate metabotropic receptors interactively control glutamate release in solitary tract nucleus

L. G. Fernandes, Y. H. Jin, Michael Andresen

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Synaptic terminals often contain metabotropic receptors that act as autoreceptors to control neurotransmitter release. Less appreciated is the heterosynaptic crossover of glutamate receptors to control GABA release and vice versa GABA receptors which control glutamate release. In the brainstem, activation of solitary tract (ST) afferents releases glutamate onto second-order neurons within the solitary tract nucleus (NTS). Multiple metabotropic receptors are expressed in NTS for glutamate (mGluRs) and for GABA (GABA B). The present report identifies mGluR regulation of glutamate release at second and higher order sensory neurons in NTS slices. We found strong inhibition of glutamate release to group II and III mGluR activation on mechanically isolated NTS neurons. However, the same mGluR-selective antagonists paradoxically decreased glutamate release (miniature, mEPSCs) at identified second-order NTS neurons. Unaltered amplitudes were consistent with selective presynaptic mGluR actions. GABA B blockade in slices resolved the paradoxical differences and revealed a group II/III mGluR negative feedback of mEPSC frequency similar to isolated neurons. Thus, the balance of glutamate control is tipped by mGluR receptors on GABA terminals resulting in predominating heterosynaptic GABA B inhibition of glutamate release. Regulation by mGluR or GABA B was not consistently evident in excitatory postsynaptic currents (EPSCs) in higher-order NTS neurons demonstrating metabotropic receptor distinctions in processing at different NTS pathway stages. These cellular localizations may figure importantly in understanding interventions such as brain-penetrant compounds or microinjections. We conclude that afferent glutamate release in NTS produces a coordinate presynaptic activation of co-localized mGluR and GABA B feedback on cranial afferent terminals to regulate glutamate release.

Original languageEnglish (US)
Pages (from-to)1-9
Number of pages9
JournalNeuroscience
Volume174
DOIs
StatePublished - Feb 3 2011

Fingerprint

Metabotropic Glutamate Receptors
Solitary Nucleus
gamma-Aminobutyric Acid
Glutamic Acid
Neurons
GABA Receptors
Autoreceptors
Excitatory Postsynaptic Potentials
Presynaptic Terminals
Glutamate Receptors
Microinjections
Sensory Receptor Cells
Brain Stem
Neurotransmitter Agents

Keywords

  • Autonomic
  • Brain stem
  • Nucleus tractus solitarius
  • Presynaptic modulation

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Heterosynaptic crosstalk : GABA-glutamate metabotropic receptors interactively control glutamate release in solitary tract nucleus. / Fernandes, L. G.; Jin, Y. H.; Andresen, Michael.

In: Neuroscience, Vol. 174, 03.02.2011, p. 1-9.

Research output: Contribution to journalArticle

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