title: Functional role of the polymorphic 647 T/C variant of ENT1 (SLC29A1) and its association with alcohol withdrawal seizures.
abstract: BACKGROUND
  Adenosine is involved in several neurological and behavioral disorders including alcoholism. In cultured cell and animal studies, type 1 equilibrative nucleoside transporter (ENT1, slc29a1), which regulates adenosine levels, is known to regulate ethanol sensitivity and preference. Interestingly, in humans, the ENT1 (SLC29A1) gene contains a non-synonymous single nucleotide polymorphism (647 T/C; rs45573936) that might be involved in the functional change of ENT1.
  
  
  RESULTS
  Our functional analysis showed that prolonged ethanol exposure increased adenosine uptake activity of mutant cells (ENT1-216Thr) compared to wild-type (ENT1-216Ile) transfected cells, which might result in reduced extracellular adenosine levels. We found that mice lacking ENT1 displayed increased propensity to ethanol withdrawal seizures compared to wild-type littermates. We further investigated a possible association of the 647C variant with alcoholism and the history of alcohol withdrawal seizures in subjects of European ancestry recruited from two independent sites. Analyses of the combined data set showed an association of the 647C variant and alcohol dependence with withdrawal seizures at the nominally significant level.
  
  
  CONCLUSIONS
  Together with the functional data, our findings suggest a potential contribution of a genetic variant of ENT1 to the development of alcoholism with increased risk of alcohol withdrawal-induced seizures in humans.
authors.affiliation: Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America.
authors.forename: Jeong-Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Victor M
authors.initials: VM
authors.lastname: Karpyak
authors.forename: Joanna M
authors.initials: JM
authors.lastname: Biernacka
authors.forename: Hyung Wook
authors.initials: HW
authors.lastname: Nam
authors.forename: Moonnoh R
authors.initials: MR
authors.lastname: Lee
authors.forename: Ulrich W
authors.initials: UW
authors.lastname: Preuss
authors.forename: Peter
authors.initials: P
authors.lastname: Zill
authors.forename: Gihyun
authors.initials: G
authors.lastname: Yoon
authors.forename: Colin
authors.initials: C
authors.lastname: Colby
authors.forename: David A
authors.initials: DA
authors.lastname: Mrazek
authors.forename: Doo-Sup
authors.initials: DS
authors.lastname: Choi
mesh_terms: D020270:Alcohol Withdrawal Seizures / Q000235:genetics*; D000437:Alcoholism / Q000235:genetics; D000818:Animals; D002460:Cell Line; D018076:DNA, Complementary; D033721:Equilibrative Nucleoside Transporter 1 / Q000235:genetics*; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D008817:Mice, Mutant Strains; D020641:Polymorphism, Single Nucleotide; D044465:White People
chemical_list: D018076:DNA, Complementary; D033721:Equilibrative Nucleoside Transporter 1; C438649:SLC29A1 protein, human