Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2006-5-11
pubmed:abstractText
GABAB1-/- mice, which are devoid of functional GABAB receptors, consistently exhibit marked hyperlocomotion when exposed to a novel environment. Telemetry recordings now revealed that, in a familiar environment, GABAB1-/- mice display an altered pattern of circadian activity but no hyperlocomotion. This indicates that hyperlocomotion is only triggered when GABAB1-/- mice are aroused by novelty. In microdialysis experiments, GABAB1-/- mice exhibited a 2-fold increased extracellular level of dopamine in the striatum. Following D-amphetamine administration, GABAB1-/- mice released less dopamine than wild-type mice, indicative of a reduced cytoplasmic dopamine pool. The hyperdopaminergic state of GABAB1-/- mice is accompanied by molecular changes, including reduced levels of tyrosine hydroxylase mRNA, D1 receptor binding-sites and Ser40 phosphorylation of tyrosine hydroxylase. Tyrosine hydroxylase activity, tissue dopamine content and dopamine metabolism do not appear to be measurably altered. Pharmacological and electrophysiological experiments support that the hyperdopaminergic state of GABAB1-/- mice is not severe enough to inactivate dopamine D2 receptors and to disrupt D2-mediated feedback inhibition of tyrosine hydroxylase activity. The data support that loss of GABAB activity results in a sustained moderate hyperdopaminergic state, which is phenotypically revealed by contextual hyperlocomotor activity. Importantly, the presence of an inhibitory GABA tone on the dopaminergic system mediated by GABAB receptors provides an opportunity for therapeutic intervention.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0022-3042
pubmed:author
pubmed:issnType
Print
pubmed:volume
97
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
979-91
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:16606363-Animals, pubmed-meshheading:16606363-Binding Sites, pubmed-meshheading:16606363-Brain Diseases, Metabolic, pubmed-meshheading:16606363-Corpus Striatum, pubmed-meshheading:16606363-Disease Models, Animal, pubmed-meshheading:16606363-Dopamine, pubmed-meshheading:16606363-Dopamine Agonists, pubmed-meshheading:16606363-Extracellular Fluid, pubmed-meshheading:16606363-Hyperkinesis, pubmed-meshheading:16606363-Mice, pubmed-meshheading:16606363-Mice, Inbred BALB C, pubmed-meshheading:16606363-Mice, Knockout, pubmed-meshheading:16606363-Motor Activity, pubmed-meshheading:16606363-Neural Inhibition, pubmed-meshheading:16606363-Neural Pathways, pubmed-meshheading:16606363-Receptors, Dopamine D1, pubmed-meshheading:16606363-Receptors, GABA-B, pubmed-meshheading:16606363-Tyrosine 3-Monooxygenase, pubmed-meshheading:16606363-Up-Regulation, pubmed-meshheading:16606363-gamma-Aminobutyric Acid
pubmed:year
2006
pubmed:articleTitle
Hyperdopaminergia and altered locomotor activity in GABAB1-deficient mice.
pubmed:affiliation
Institute of Physiology, Department of Clinical Biological Sciences, University of Basel, Basel, Switzerland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't