Fear behaviors are regulated by adaptive mechanisms that dampen their expression in the absence of danger. By studying circuits and the molecular mechanisms underlying this adaptive response, we show that cholinergic neurons of the medial habenula reduce fear memory expression through GABAB presynaptic excitation. Ablating these neurons or inactivating their GABAB receptors impairs fear extinct...

We have developed a model of gamma-aminobutyric acid (GABA)ergic synaptic transmission mediated by GABAA and GABAB receptors, including cooperativity in the guanine nucleotide binding protein (G protein) cascade mediating the activation of K+ channels by GABAB receptors. If the binding of several G proteins is needed to activate the K+ channels, then only a prolonged activation of GABAB recepto...

The inhibitory neurotransmitter, γ-aminobutyric acid (GABA), activates a variety of receptors in all areas of the central nervous system (CNS). GABA acts at inhibitory synapses in the brain by binding to specific transmembrane receptors in the plasma membrane of both pre and postsynaptic neuronal processes. There are three classes of GABA receptors. GABAA and GABAC receptors are ionotropic in n...

In previous work we have shown that GABAB receptors are required for expression of absence seizures in the lethargic (lh/lh) mouse model; that lh/lh mice have increased numbers of GABAB binding sites compared to nonepileptic littermates (designated +/+); and that the magnitude of the increased number of GABAB receptors in lh/lh mice correlated positively with the frequency of absence seizures. ...

Dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc) are richly innervated by GABAergic neurons. The postsynaptic effects of GABA on SNc DA neurons are mediated by a mixture of GABAA and GABAB receptors. Although activation of GABAA receptors inhibits spike generation, the consequences of GABAB receptor activation are less well characterized. To help fill this gap, perforated p...

Cortical inhibition plays an important role in the processing of sensory information, and the enlargement of receptive fields by the in vivo application of GABAB receptor antagonists indicates that GABAB receptors mediate some of this cortical inhibition. Although there is evidence of postsynaptic GABAB receptors on cortical neurons, there is no evidence of GABAB receptors on thalamocortical te...

Adult neurogenesis is tightly regulated through the interaction of neural stem/progenitor cells (NSCs) with their niche. Neurotransmitters, including GABA activation of GABAA receptor ion channels, are important niche signals. We show that adult mouse hippocampal NSCs and their progeny express metabotropic GABAB receptors. Pharmacological inhibition of GABAB receptors stimulated NSC proliferati...

The mechanosensilla in spider exoskeleton are innervated by bipolar neurons with their cell bodies close to the cuticle and dendrites attached to it. Numerous efferent fibers synapse with peripheral parts of the mechanosensory neurons, with glial cells surrounding the neurons, and with each other. Most of these efferent fibers are immunoreactive to gamma-aminobutyric acid (GABA), and the sensor...

GABAB receptors regulate the intracellular Ca2+ concentration ([Ca2+]i) in a number of cells (e.g., retina, airway epithelium and smooth muscle), but whether they are expressed in vascular endothelial cells and similarly regulate the [Ca2+]i is not known. The purpose of this study was to investigate the expression of GABAB receptors, a subclass of receptors to the inhibitory neurotransmitter γ-...

GABAergic signalling is important for normal sleep in humans and flies. Here we advance the current understanding of GABAergic modulation of daily sleep patterns by focusing on the role of slow metabotropic GABAB receptors in the fruit fly Drosophila melanogaster. We asked whether GABAB-R2 receptors are regulatory elements in sleep regulation in addition to the already identified fast ionotropi...