Suckling rat brain regional distribution of acetylcholinesterase activity in galactosaemia in vitro

We aimed to evaluate the effect of in vitro galactosaemia on acetylcholinesterase (AChE) activity in different suckling rat brain regions. Various concentrations of galactose (Gal), galactose-1-phosphate (Gal-1-P) and/or galactitol (Galtol) were preincubated for 1 h with homogenates from frontal cortex, hippocampus and for 1-3 h with hypothalamus homogenates at 37( composite function)C. AChE activity was determined spectrophotometrically. Mixture A (Gal-1-P (2 mM), Galtol (2 mM), and Gal (4 mM) (=brain concentrations in classical galactosaemia)) or mixture B (Galtol (2 mM) and Gal (1 mM) (=brain concentrations in galactokinase deficiency galactosaemia)) inhibited by 18-20% (P < 0.01) AChE activity in frontal cortex or hippocampus homogenates. Gal-1-P (2-8 mM) reduced AChE activity by 20% (P < 0.01) on frontal cortex and hippocampus homogenates. Galtol (2-8 mM) resulted in an AChE inhibition (20-22% (P < 0.01)) in hippocampus, 2 mM of the substance had the same effect (20%, P < 0.01) on frontal cortex, whereas higher concentrations (4-8 mM) failed to decrease the enzyme activity anymore. Gal (1-8 mM) did not change AChE activity in the studied areas. Additionally, the hypothalamus enzyme activity was measured considerably high and remained unaltered in the presence of the above compounds. In conclusion, AChE activity was significantly higher in hypothalamus compared with those in frontal cortex and hippocampus. Frontal cortex and hippocampus AChE was significantly inhibited by Gal derivatives, whereas hypothalamus AChE activity remained unaltered possibly due to the histologically different innervation of this area.