Piracetam prevents scopolamine-induced memory impairment and decrease of NTPDase, 5'-nucleotidase and adenosine deaminase activities.

Autor: Marisco PC; Graduation Program in Pharmacology, Center of Health Sciences (CCS), Federal University of Santa Maria, Santa Maria, RS, CEP 97105-900, Brazil., Carvalho FB, Rosa MM, Girardi BA, Gutierres JM, Jaques JA, Salla AP, Pimentel VC, Schetinger MR, Leal DB, Mello CF, Rubin MA
Jazyk: angličtina
Zdroj: Neurochemical research [Neurochem Res] 2013 Aug; Vol. 38 (8), pp. 1704-14. Date of Electronic Publication: 2013 May 16.
DOI: 10.1007/s11064-013-1072-6
Abstrakt: Piracetam improves cognitive function in animals and in human beings, but its mechanism of action is still not completely known. In the present study, we investigated whether enzymes involved in extracellular adenine nucleotide metabolism, adenosine triphosphate diphosphohydrolase (NTPDase), 5'-nucleotidase and adenosine deaminase (ADA) are affected by piracetam in the hippocampus and cerebral cortex of animals subjected to scopolamine-induced memory impairment. Piracetam (0.02 μmol/5 μL, intracerebroventricular, 60 min pre-training) prevented memory impairment induced by scopolamine (1 mg/kg, intraperitoneal, immediately post-training) in the inhibitory avoidance learning and in the object recognition task. Scopolamine reduced the activity of NTPDase in hippocampus (53 % for ATP and 53 % for ADP hydrolysis) and cerebral cortex (28 % for ATP hydrolysis). Scopolamine also decreased the activity of 5'-nucleotidase (43 %) and ADA (91 %) in hippocampus. The same effect was observed in the cerebral cortex for 5'-nucleotidase (38 %) and ADA (68 %) activities. Piracetam fully prevented scopolamine-induced memory impairment and decrease of NTPDase, 5'-nucleotidase and adenosine deaminase activities in synaptosomes from cerebral cortex and hippocampus. In vitro experiments show that piracetam and scopolamine did not alter enzymatic activity in cerebral cortex synaptosomes. Moreover, piracetam prevented scopolamine-induced increase of TBARS levels in hippocampus and cerebral cortex. These results suggest that piracetam-induced improvement of memory is associated with protection against oxidative stress and maintenance of NTPDase, 5'-nucleotidase and ADA activities, and suggest the purinergic system as a putative target of piracetam.
Databáze: MEDLINE
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