title: Early temporal changes in ecto-nucleotidase activity after cortical stab injury in rat.
abstract: During a variety of insults to the brain adenine nucleotides are released in large quantities from damaged cells, triggering multiple cellular responses to injury. Here, we evaluated changes in extracellular ATP, ADP and AMP hydrolysis at different times (0-24 hours) after unilateral cortical stab injury (CSI) in adult rats. Results demonstrated that 24 hours following CSI, ATP and ADP hydrolyzing activities were not significantly altered in injured cortex. Based on calculated V (ATP)/V (ADP) ratio it was concluded that ATP/ADP hydrolysis was primarily catalyzed by NTPDase1 enzyme form. In contrast, AMP hydrolysis, catalyzed by 5'-nucleotidase, was significantly reduced at least 4 hours following CSI. Kinetic analysis and Lineweaver-Burk transformation of the enzyme velocities obtained over the range of AMP concentrations (0.05-1.50 mM) revealed that inhibition of 5'-nucleotidase activity after CSI was of the uncompetitive type. Taken together our data suggest that injured tissue has reduced potential for extracellular metabolism of adenine nucleotides in early stages after CSI.
authors.affiliation: Institute for Physiology and Biochemistry, Faculty of Biology University Belgrade, Studentski trg 3, 11001 Belgrade, Serbia. nnedel@bf.bio.bg.ac.yu
authors.forename: Nadezda
authors.initials: N
authors.lastname: Nedeljkovic
authors.forename: Ivana
authors.initials: I
authors.lastname: Bjelobaba
authors.forename: Irena
authors.initials: I
authors.lastname: Lavrnja
authors.forename: Danijela
authors.initials: D
authors.lastname: Stojkov
authors.forename: Sanja
authors.initials: S
authors.lastname: Pekovic
authors.forename: Ljubisav
authors.initials: L
authors.lastname: Rakic
authors.forename: Mirjana
authors.initials: M
authors.lastname: Stojiljkovic
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002540:Cerebral Cortex / Q000201:enzymology / Q000293:injuries*; D007700:Kinetics; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D014951:Wounds, Stab / Q000201:enzymology*
chemical_list: D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C027201:ectoATPase