title: Hormetic acute response and chronic effect of ethanol on adenine nucleotide hydrolysis in rat platelets.
abstract: The objective of this study was to verify the acute and chronic effects of ethanol on platelet NTPDase and 5'-nucleotidase activities. These enzymes modulate platelet function by regulating adenine nucleotide bioavailability and adenosine production. In the acute treatment, doses of 0.8, 2.0, 4.0, 6.0 and 8.0 g/kg ethanol were administered via orogastric tube, and induced a biphasic or hormetic effect on ATP, ADP and AMP platelet hydrolysis. Ethanol at a dose of 0.8 and 2.0 g/kg increased NTPDase activity (44 and 35%, P < 0.0001) with ATP as substrate, whereas when ADP was used there was only a tendency for NTPDase activity to increase. ATP and ADP hydrolysis decreased by 31-77% (P < 0.0001) in 4.0, 6.0 and 8.0 g/kg of ethanol compared to the control. AMP hydrolysis showed a tendency to increase at ethanol doses of 0.8 and 2.0 g/kg, but was inhibited by 45-100% (P < 0.0001) at the higher doses. Chronic treatment consisted of the oral administration of 20% ethanol solution during 31 weeks as the only source of liquid and inhibited NTPDase activity (15 and 20%, P < 0.05) with ATP and ADP as substrate, respectively. However, AMP hydrolysis by 5'-nucleotidase increased by 40% (P < 0.05). Thus, we speculate that the effects of ethanol on NTPDase and 5'-nucleotidase activities could be related with the platelets alterations commonly observed in alcohol users.
authors.affiliation: Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS 97105-900, Brazil.
authors.forename: Glaecir R Mundstock
authors.initials: GR
authors.lastname: Dias
authors.forename: Maria Rosa Chitolina
authors.initials: MR
authors.lastname: Schetinger
authors.forename: Roselia
authors.initials: R
authors.lastname: Spanevello
authors.forename: Cinthia Melazzo
authors.initials: CM
authors.lastname: Mazzanti
authors.forename: Roberta
authors.initials: R
authors.lastname: Schmatz
authors.forename: Vânia Lúcia
authors.initials: VL
authors.lastname: Loro
authors.forename: Vera Maria
authors.initials: VM
authors.lastname: Morsch
mesh_terms: D015720:5'-Nucleotidase / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism; D000227:Adenine Nucleotides / Q000378:metabolism*; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000633:toxicity*; D006868:Hydrolysis / Q000187:drug effects; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D023382:Toxicity Tests, Acute; D036401:Toxicity Tests, Chronic
chemical_list: D000227:Adenine Nucleotides; D000431:Ethanol; D015720:5'-Nucleotidase