The effect of galactose metabolic disorders on rat brain acetylcholinesterase activity.
To evaluate whether in classical galactosemia galactose (Gal), galactose-1-phosphate (Gal-1-P) and galactitol (Galtol) affect brain acetylcholinesterase (AChE) activity, various concentrations (1-16 mM) of these compounds were preincubated with brain homogenates of suckling rats as well as with pure eel Electroforus electricus AChE at 37 degrees C for 1 h. Initially, Galtol (up to 2.0 mM) increased (25%) AChE activity which decreased. thereafter, reaching the control value in high Galtol concentrations. Gal-1-P decreased gradually the enzyme activity reaching a plateau (38%), when incubated with 8-16 mM. However, when the usually found 2 mM of Galtol and 2 mM of Gal-1-P, concentrations in galactosemia were added in the incubation mixture simultaneously, brain AChE was stimulated (16%). Galtol or Gal-1-P modulated brain AChE as well as enzyme activity of E.electricus in the same way. Gal, Glucose (Glu) and glucose-1-phosphate (Glu-1-P) had no effect on AChE activity. It is suggested that Galtol as well as Gal-1-P can affect acetylcholine degradation acting directly on AChE molecule. Consequently the direct action of these substances on the enzyme might explain the brain cholinergic dysfunction in untreated galactosemia patients.
Tsakiris
S
S
Department of Experimental Physiology, University of Athens, Medical School, Greece. stsakir@cc.uoa.gr
Schulpis
K H
KH
D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000201:enzymology*; D005260:Female; D004376:Galactitol / Q000494:pharmacology; D005690:Galactose / Q000494:pharmacology; D005693:Galactosemias / Q000201:enzymology*; D005695:Galactosephosphates / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D051381:Rats; D017208:Rats, Wistar
D005695:Galactosephosphates; D004376:Galactitol; C029973:galactose-1-phosphate; D000110:Acetylcholinesterase; D005690:Galactose