title: P2X2 and P2X4 receptor expression is regulated by a GABA(A) receptor-mediated mechanism in the gerbil hippocampus.
abstract: Fast responses to extracellular ATP are mediated by the activation of P2X receptors. Native and cloned P2X receptors are permeable to monovalent cations such as Na+ and K+ as well as divalent cations such as Ca2+. However, altered P2X receptor expression has not been definitively determined under pathological conditions, particularly in epilepsy. Here we show that, in the seizure-sensitive (SS) gerbil hippocampus, a recognized genetic epilepsy model, the expressions of both P2X2 and P2X4 receptors are markedly decreased as compared with that in the seizure-resistant (SR) gerbil. These alterations are closely related to changes in gamma-aminobutyric acid (GABA) concentrations induced by vigabatrin (VGB) or 3-mercaptopropionic acid (3-MPA) treatment. Furthermore, the regulation of both P2X receptor expression in the gerbil hippocampus was mediated by the GABA(A) receptor, not GABA(B). These results suggest that the GABA(A) receptor-mediated modulation of P2X receptor expression may play an important role in the regulation of neuronal excitability.
authors.affiliation: Department of Anatomy, College of Medicine, Hallym University, Chunchon 200-702, South Korea. tckang@hallym.ac.kr
authors.forename: Tae-Cheon
authors.initials: TC
authors.lastname: Kang
authors.forename: Sung-Jin
authors.initials: SJ
authors.lastname: An
authors.forename: Seung-Kook
authors.initials: SK
authors.lastname: Park
authors.forename: In-Koo
authors.initials: IK
authors.lastname: Hwang
authors.forename: Moo Ho
authors.initials: MH
authors.lastname: Won
mesh_terms: D015097:3-Mercaptopropionic Acid / Q000494:pharmacology; D000818:Animals; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004827:Epilepsy / Q000235:genetics / Q000378:metabolism; D018682:GABA Agents / Q000494:pharmacology; D005849:Gerbillinae; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011963:Receptors, GABA-A / Q000502:physiology*; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000378:metabolism*; D058476:Receptors, Purinergic P2X2; D058848:Receptors, Purinergic P2X4; D013045:Species Specificity; D020888:Vigabatrin / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D018682:GABA Agents; C546401:P2RX2 protein, human; C548226:P2RX4 protein, human; D012333:RNA, Messenger; D011963:Receptors, GABA-A; D018048:Receptors, Purinergic P2; D058476:Receptors, Purinergic P2X2; D058848:Receptors, Purinergic P2X4; D015097:3-Mercaptopropionic Acid; D020888:Vigabatrin