lonotropic and metabotropic (mGluR1 a) glutamate receptors were reported to be segregated from each other within the postsynaptic membrane at individual synapses. In order to establish whether this pattern of distribution applies to the hippocampal principal cells and to other postsynaptic metabotropic glutamate receptors, the mGluR1alb/c and mGluR5 subtypes were localized by immunocytochemistr...

Astrocytes synthesize and release endozepines, a family of regulatory peptides, including the octadecaneuropeptide (ODN) an endogenous ligand of both central-type benzodiazepine (CBR) and metabotropic receptors. We have recently shown that ODN exerts a protective effect against hydrogen peroxide (H(2)O(2))-induced oxidative stress in astrocytes. The purpose of the present study was to determine...

BACKGROUND Sustained vascular smooth muscle contraction is mediated by extracellular Ca(2+) influx through L-type voltage-gated Ca(2+) channels (VGCC) and RhoA/Rho-associated kinase (ROCK)-dependent Ca(2+) sensitization of the contractile machinery. VGCC activation can also trigger an ion-independent metabotropic pathway that involves G-protein/phospholipase C activation, inositol 1,4,5-trispho...

Metabotropic receptors modulate numerous cellular processes by intracellular Ca2+ signaling, but less is known about their role in regulating mitochondrial metabolic function within the CNS. In this study, we demonstrate in area CA3 of rat organotypic hippocampal slice cultures that glutamatergic, serotonergic, and muscarinic metabotropic receptor ligands, namely trans-azetidine-2,4-dicarboxyli...

The role of metabotropic excitatory amino acid receptors in seizures and brain injury was examined using the selective metabotropic agonist 1S,3R-ACPD [(1S,3R)-1-aminocyclopentane-1-3-dicarboxylic acid] in 7-d-old neonatal rats. Systemic administration of 1S,3R-ACPD produced dose-dependent convulsions (ED50 = 16 mg/kg, i.p.) that were stereoselective for the active metabotropic ACPD isomer, sin...

The mechanisms of Ca2+ responses evoked in hippocampal glial cells in situ, by local application of glutamate and by synaptic activation, were studied in slices from juvenile rats using the membrane permeant fluorescent Ca2+ indicator fluo-3AM and confocal microscopy. Ca2+ responses induced by local application of glutamate were unaffected by the sodium channel blocker tetrodotoxin and were the...