Metabotropic glutamate receptors have a variety of effects in visual cortex that depend on the age of the animal, the layer of the cortex, and the group of the receptor. Here we describe these effects for group I receptors, using both in vivo and in vitro preparations. The metabotropic group I glutamate receptor agonist 3,5 dihydroxyphenylglycine (DHPG) potentiates the responses to N-methyl-D-a...

We sought to determine whether metabotropic glutamate receptors contribute to frequency-dependent depression of vagal and aortic baroreceptor signal transmission in the nucleus of the solitary tract (NTS) in vivo. In α-chloralose-anesthetized rabbits, we determined the number of extracellular action potentials synaptically evoked by low (1 Hz)- or high-frequency vagal (3-20 Hz) or aortic depres...

The metabotropic GABA receptor (GABA(B)R) regulates calcium influx in neurons. Whole cell voltage-clamp techniques were employed to determine the effects of internal calcium on the activity of GABA(B)Rs. GABA(B)R receptor apparent affinity was maximal when bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid (BAPTA) maintained internal calcium below 70 nM. Apparent affinity was reduced as internal c...

The perirhinal cortex is crucially involved in various forms of learning and memory. Decrements in neuronal responsiveness occur in the perirhinal cortex with stimulus repetition during visual recognition performance. However, very little is known concerning the underlying mechanisms of synaptic transmission and plasticity in this cortical region. In this study, we provide evidence demonstratin...

Fragile X (FX) is the most common genetic cause of intellectual disability and autism. Previous studies have shown that partial inhibition of metabotropic glutamate receptor signaling is sufficient to correct behavioral phenotypes in a mouse model of FX, including audiogenic seizures, open-field hyperactivity and social behavior. These phenotypes model well the epilepsy (15%), hyperactivity (20...

Increased glutamatergic input in the hypothalamic paraventricular nucleus (PVN) plays an important role in the development of hypertension. Group II metabotropic glutamate receptors are expressed in the PVN, but their involvement in regulating synaptic transmission and sympathetic outflow in hypertension is unclear. Here, we show that the group II metabotropic glutamate receptors agonist (2S,2'...

Kann, Oliver, Richard Kovács, and Uwe Heinemann. Metabotropic receptor-mediated Ca signaling elevates mitochondrial Ca and stimulates oxidative metabolism in hippocampal slice cultures. J Neurophysiol 90: 613–621, 2003. First published April 30, 2003; 10.1152/jn.00042.2003. Metabotropic receptors modulate numerous cellular processes by intracellular Ca signaling, but less is known about their r...

Weakly electric fish generate meaningful electromotor behaviors by specific modulations of the discharge of their medullary pacemaker nucleus from which the rhythmic command for each electric organ discharge (EOD) arises. Certain electromotor behaviors seem to involve the activation of specific neurotransmitter receptors on particular target cells within the nucleus, i.e., on pacemaker or on re...

Evidence is accumulating for the role of metabotropic, as well as ionotropic, glutamate receptors in cardiovascular regulation. We sought to determine whether stimulation of metabotropic glutamate receptors in the rostral ventrolateral medulla would evoke enhanced cardiovascular responses in spontaneously hypertensive rats (SHR). Thus, we microinjected (1S,3R)-1-aminocyclopentane-1,3-dicarboxyl...

We studied the effects of activation of the metabotropic glutamate receptors on intrinsic currents of magnocellular n urons of the supraoptic nucleus (SON) with whole cell patch-clamp and conventional intracellular recordings in coronal slices (400 micron) of the rat hypothalamus. Trans-(+/-)-1-amino-1,3-cyclopentane dicarboxylic acid (trans-ACPD, 10-100 microM), a broad-spectrum metabotropic g...