In vivo and in vitro effects of hyperglycemia on Naplus-Kplus, Caplus2, Mgplus2-dependent ATPases activity in brain synaptosomes of aging rats

• Autorzy: Torlinska T. , Grochowalska A. , Kupisz J. , Skoracka J. , Kojo S.
• Języki publikacji: EN

Abstrakty

EN

Cerebral metabolism of glucose, one of the determinants of tissue ATP level, is crucial for the CNS function. The activity of P-type pumps: Na+, K+-ATPase, Ca+2-ATPase and Mg+2-ATPase were examined in rat brain synaptosomes to determine if changes in the enzyme activity related to aging are potentially associated with alterations in glucose homeostasis. Male Wistar rats (newborn, 3- and 18-month-old) were sacrificed by decapitation and synaptic plasma membranes were isolated from brains. In vivo study demonstrated that 18-month-old rats were characterized by hyperglycemia, hyperinsulinemia and increased total antyoxidative status (TAS) level. These conditions had a different impact on activities of the ATPases tested in vivo: only the activity of Ca+2-ATPase decreased whereas that of Mg+2-ATPase increased significantly. In vitro experiments, prior incubation of isolated synaptosomes with glucose of concentrations corresponding to normoglycemia in vivo (4.5 - 6.5 mM), stimulated Ca+2-ATPase activity, whereas higher glucose concentrations (10.0 - 12.5 mM) inhibited significantly the enzyme activity. The most sensitive to hyperglycemia appeared Na+, K+-ATPase in old rats synaptosomes with the progressive decline starting at 6.5 mM glucose. The activity of Mg+2-ATPase was not inhibited in vitro even at high glucose concentrations that may explain the increased in vivo, activity of this enzyme in old, hyperglycemic rats.

Słowa kluczowe

EN

in vivo; in vitro; hyperglycemia; hyperinsulinemia; ATPase activity; brain synaptosome; synaptosome; aging; rat; cerebral metabolism; glucose; enzyme activity; synaptic plasma membrane; total antioxidant status

• Wydawca: -
• Czasopismo: Journal of Physiology and Pharmacology. Supplement
• Rocznik: 2006
• Tom: 57
• Numer: 7
• Opis fizyczny: p.145-158,fig.,ref.

Twórcy

autor

Torlinska T.

• University of Medical Sciences, Swiecicki Str. 6, 60-781 Poznan, Poland

autor

Grochowalska A.

autor

Kupisz J.

autor

Skoracka J.

autor

Kojo S.