We investigated the time course of modulation of synaptic transmission by group II and group III metabotropic glutamate receptors in region CA1 of the hippocampus. In the presence of 50 microM picrotoxin, pressure pulse application of 1 mM glutamate resulted in a fast onset of suppression of synaptic transmission in stratum lacunosum moleculare and a slower onset of suppression in stratum radia...

Pro-inflammatory stimuli evoke an export of glutamate from microglia that is sufficient to contribute to excitotoxicity in neighbouring neurons. Since microglia also express various glutamate receptors themselves, we were interested in the potential feedback of glutamate on this system. Several agonists of mGluRs (metabotropic glutamate receptors) were applied to primary rat microglia, and the ...

Activation of metabotropic glutamate receptors (mGluRs) has multiple effects on the excitability of pyramidal neurons in rat frontal neocortex. Synaptic transmission and intrinsic excitability are both affected. During studies of the effects of quisqualate on synaptic activity, it was observed that quisqualate also induced a slow inward current. Whole-cell patch clamp recordings were obtained f...

The DNA binding activities of some basic region and putative helix-loop-helix (bHLH)-containing transcriptional factors can be inhibited by the Id protein. Because Id contains the HLH motif for dimerization but not the basic amino acid region for DNA binding, heterodimers of Id with bHLH transcriptional factors may not bind to DNA. We have isolated and characterized the gene and cDNA clones for...

Whole-cell recordings of amacrine and ganglion cells in the superfused retina-eyecup preparation of the mudpuppy were obtained in order to determine which excitatory amino acid receptor (EAAR) subtype mediates the synaptic responses of these neurons. All third-order retinal neurons tested were depolarized by kainic acid (KA), KfIIethyl-D-SSpSrtSte (NMDA), and quisqualate (QQ). The responses evo...

Monosodium glutamate (MSG) elicits a taste called umami and interacts synergistically with nucleotide monophosphates such as 5'-inosine monophosphate (IMP) to potentiate this taste intensity. Indeed, the synergistic interaction of nucleotide monophosphates and MSG is a hallmark of umami. We examined interactions between MSG and other taste stimuli, including IMP, by measuring the lick rates of ...

Monosodium glutamate (MSG) elicits a unique taste called umami. A characteristic feature of umami taste is its potentiation by 5′ribonucleotides (primarily GMP and IMP), which also have an umami taste of their own. Based on recent molecular studies, two putative umami receptors have been identified: a truncated variant of the metabotropic glutamate receptor mGluR4 (taste-mGluR4) (Chaudhari et a...

Presynaptic group III metabotropic glutamate receptor (mGluR) activation by exogenous agonists (such as L-2-amino-4-phosphonobutyrate (L-AP4)) potently inhibit transmitter release, but their autoreceptor function has been questioned because endogenous activation during high-frequency stimulation appears to have little impact on synaptic amplitude. We resolve this ambiguity by studying endogenou...

Excessive activation of ionotropic glutamate receptors in the striatum contributes to the pathophysiology of motor symptoms in Parkinson's disease. Metabotropic glutamate (mGlu) receptors regulate striatal excitatory synaptic transmission, and adaptive changes in their function might occur following dopaminergic denervation and chronic levodopa-treatment (L-DOPA). Corticostriatal glutamatergic ...