@entity859 and @entity5834 modulate locomotor activity and striatal gene expression, partially through the activation and blockade of striatal A(2A) receptors, respectively. The elucidation of the roles of these receptors benefits from the construction of A(2A) receptor-deficient @entity19 (A(2A)-R(-/-)). These @entity19 presented alterations in locomotor behaviour and striatal expression of genes studied so far, which are unexpected regarding the specific expression of A(2A) receptor by striatopallidal neurones. To clarify the functions of A(2A) receptors in the striatum and to identify the mechanisms leading to these unexpected modifications, we studied the basal expression of immediate early and constitutive genes as well as @entity935 and @entity2227 neurotransmission in the striatum. Basal zif268 and arc mRNAs expression was reduced in mutant @entity19 by 60-80%, not only in the striatum but also widespread in the cerebral cortex and hippocampus. Striatal expression of @entity10501 and enkephalin mRNAs was reduced by about 50% and 30%, respectively, whereas the expression of GAD67 and @entity16707 mRNAs was slightly increased and unaltered, respectively. In vivo microdialysis in the striatum revealed a 45% decrease in the extracellular @entity935 concentration and three-fold increase in extracellular @entity2227 concentration. This was associated with an up-regulation of D(1) and D(2) @entity935 receptors expression but not with changes in ionotropic @entity2227 receptors. The levels of @entity669 hydroxylase and of striatal and cortical glial @entity2227 transporters as well as @entity859 A(1) receptors expression were indistinguishable between A(2A)-R(-/-) and wild-type @entity19 . Altogether these results pointed out that the lack of A(2A) receptors leads to a functional hypodopaminergic state and demonstrated that A(2A) receptors are necessary to maintain a basal level in immediate early and constitutive genes expression in the striatum and cerebral cortex, possibly via their control of @entity935 pathways.

Functional striatal hypodopaminergic activity in @entity19 lacking XXXX A(2A) receptors.

@entity2227 :: ('CHEBI:29987', 'Chemical') :: ['glutamate'] @entity859 :: ('MESH:D000241', 'Chemical') :: ['Adenosine', 'adenosine'] @entity19 :: ('10090', 'Species') :: ['mice'] @entity935 :: ('MESH:D004298', 'Chemical') :: ['dopamine'] @entity5834 :: ('MESH:D002110', 'Chemical') :: ['caffeine'] @entity10501 :: ('21333(Tax:10090)', 'Gene') :: ['substance P'] @entity16707 :: ('14417(Tax:10090)', 'Gene') :: ['GAD65'] @entity669 :: ('CHEBI:18186', 'Chemical') :: ['tyrosine']
@entity859 :: (MESH:D000241,Chemical) :: ['adenosine']
