The present experiments used CGP 35348, a selective GABAB receptor antagonist with a significantly higher affinity for post- versus presynaptic receptors, to dissociate the role of antagonist concentration versus stimulation mode in determining whether GABAB receptor blockade facilitates or suppresses long-term potentiation (LTP). The antagonist was applied by pressure ejection to one of two re...

We investigated the cellular mechanism underlying presynaptic regulation of olfactory receptor neuron (ORN) input to the mouse olfactory bulb using optical imaging techniques that selectively report activity in the ORN presynaptic terminal. First, we loaded ORNs with calcium-sensitive dye and imaged stimulus-evoked calcium influx in a slice preparation. Single olfactory nerve shocks evoked rapi...

GABAB receptors are a subclass of receptors for gamma-amino-n-butyric acid (GABA) that are also activated by the antispastic drug beta-p-chlorophenyl-GABA (baclofen). One effect of baclofen is to inhibit excitatory transmission from CA3 to CA1 hippocampal pyramidal cells. To identify the ionic mechanism of GABAB-receptor-mediated depression, we have studied the effect of baclofen and GABA on io...

Long-term potentiation of synpatic transmission (LTP) of the perforant path--dentate gyrus synapse is induced by 5 Hz, theta-like stimulation patterns. Such stimuli induce plasticity that is most likely driven by a decrease in synaptic inhibition (disinhibition) mediated by GABAB autoreceptors. In the present study, we demonstrate that LTP induced in this manner is completely antagonized by eth...

BACKGROUND The ventral tegmental area (VTA) is well known for its role in cardiovascular control. It is demonstrated that about 20-30% of the VTA neurons are GABAergic though their role in cardiovascular control is not yet understood. This study is carried out to find the effects of GABA A and GABA B receptors on cardiovascular response of the VTA. METHODS Experiments were performed on uretha...

After its release from interneurons in the CNS, the major inhibitory neurotransmitter GABA is taken up by GABA transporters (GATs). The predominant neuronal GABA transporter GAT1 is localized in GABAergic axons and nerve terminals, where it is thought to influence GABAergic synaptic transmission, but the details of this regulation are unclear. To address this issue, we have generated a strain o...

The object of this study was to examine the relationship between excitatory postsynaptic potential (EPSP) amplitude, posttetanic potentiation, and EPSP amplitude modulation at synapses made by group Ia afferents on motoneurons in the rat. These relationships were evaluated in cells in untreated rats and in cells in rats treated with the gamma-aminobutyric acid-B (GABAB) receptor agonist baclofe...

Neuronal G-protein-gated potassium (GIRK) channels mediate the inhibitory effects of many neurotransmitters. Although the overlapping distribution of GIRK subunits suggests that channel composition varies in the CNS, little direct evidence supports the existence of structural or functional diversity in the neuronal GIRK channel repertoire. Here we show that the GIRK channels linked to GABAB rec...

GABAB ( -aminobutyric acid, type B) is a heterodimeric G-protein-coupled receptor. The GABAB1 subunit, which contains an endoplasmic reticulum retention sequence, is only transported to the cell surface when it is associated with the GABAB2 subunit. Fluorescence recovery after photobleaching studies in transfected COS-7 cells and hippocampal neurons revealed that GABAB2 diffuses slowly within t...

Previously, we reported that the expression of cytochrome oxidase in a number of brain stem nuclei exhibited a plateau or reduction at postnatal day (P) 3-4 and a dramatic decrease at P12, against a general increase with age. The present study examined the expression of glutamate, N-methyl-D-aspartate receptor subunit 1 (NMDAR1), GABA, GABAB receptors, glycine receptors, and glutamate receptor ...