title: Altered distribution and function of A2A adenosine receptors in the brain of WAG/Rij rats with genetic absence epilepsy, before and after appearance of the disease.
abstract: The involvement of excitatory adenosine A(2A) receptors (A(2A)Rs), which probably contribute to the pathophysiology of convulsive seizures, has never been investigated in absence epilepsy. Here, we examined the distribution and function of A(2A)Rs in the brain of Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats, a model of human absence epilepsy in which disease onset occurs 2-3 months after birth. In the cerebral areas that are mostly involved in the generation of absence seizures (somatosensory cortex, reticular and ventrobasal thalamic nuclei), A(2A)R density was lower in presymptomatic WAG/Rij rats than in control rats, as evaluated by immunohistochemistry and western blotting. Accordingly, in cortical/thalamic slices prepared from the brain of these rats, A(2A)R stimulation with the agonist 2-[4-(-2-carboxyethyl)-phenylamino]-5'-N-ethylcarboxamido-adenosine failed to modulate either cAMP formation, mitogen-activated protein kinase system, or K(+)-evoked glutamate release. In contrast, A(2A)R expression, signalling and function were significantly enhanced in brain slices from epileptic WAG/Rij rats as compared with matched control animals. Additionally, the in vivo injection of the A(2A)R agonist CGS21680, or the antagonist 5-amino-7-(2-phenylethyl)-2-(2-fuyl)-pyrazolo-(4,3-c)1,2,4-triazolo(1,5-c)-pyrimidine, in the examined brain areas of epileptic rats, increased and decreased, respectively, the number/duration of recorded spontaneous spike-wave discharges in a dose-dependent manner during a 1-5 h post-treatment period. Our results support the hypothesis that alteration of excitatory A(2A)R is involved in the pathogenesis of absence seizures and might represent a new interesting target for the therapeutic management of this disease.
authors.affiliation: Department of Biomedical Sciences, University of Chieti, Medical School, Chieti, Italy.
authors.forename: Iolanda
authors.initials: I
authors.lastname: D'Alimonte
authors.forename: Mariagrazia
authors.initials: M
authors.lastname: D'Auro
authors.forename: Rita
authors.initials: R
authors.lastname: Citraro
authors.forename: Francesca
authors.initials: F
authors.lastname: Biagioni
authors.forename: Shucui
authors.initials: S
authors.lastname: Jiang
authors.forename: Eleonora
authors.initials: E
authors.lastname: Nargi
authors.forename: Silvana
authors.initials: S
authors.lastname: Buccella
authors.forename: Patrizia
authors.initials: P
authors.lastname: Di Iorio
authors.forename: Patricia
authors.initials: P
authors.lastname: Giuliani
authors.forename: Patrizia
authors.initials: P
authors.lastname: Ballerini
authors.forename: Francesco
authors.initials: F
authors.lastname: Caciagli
authors.forename: Emilio
authors.initials: E
authors.lastname: Russo
authors.forename: Giovambattista
authors.initials: G
authors.lastname: De Sarro
authors.forename: Renata
authors.initials: R
authors.lastname: Ciccarelli
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D004195:Disease Models, Animal; D018450:Disease Progression; D004569:Electroencephalography; D004832:Epilepsy, Absence / Q000235:genetics / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism; D007150:Immunohistochemistry; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008845:Microinjections; D010627:Phenethylamines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D043705:Receptor, Adenosine A2A / Q000378:metabolism*; D013003:Somatosensory Cortex / Q000187:drug effects / Q000378:metabolism*; D013788:Thalamus / Q000187:drug effects / Q000378:metabolism*; D014230:Triazoles / Q000494:pharmacology
chemical_list: C098657:5-amino-7-(2-phenylethyl)-2-(2-furyl)pyrazolo(4,3-e)-1,2,4-triazolo(1,5-c)pyrimidine; D010627:Phenethylamines; D011743:Pyrimidines; D043705:Receptor, Adenosine A2A; D014230:Triazoles; C061282:2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine; D018698:Glutamic Acid; D000241:Adenosine