The aim of this work is a comparison of repeated peroral (p.o.) administration, i.e., three consecutive doses separated by 24-hour intervals of acetyl-L-carnitine (ALC) and L-carnitine (CRT) on the antiacetylcholinesterase potency of 7-methoxytacrine (MEOTA) given intramuscularly (i.m.) in a dose of 100 mg/kg. Changes of acetylcholinesterase activity were determined in the frontal cortex, hippocampus, medial septum, and basal ganglia in rats.
Repeated administration of CRT in doses of 100, 250, 300 and 400 mg/kg augmented the anticholinesterase activity of MEOTA in the frontal cortex and septum, higher doses of 250, 300 and 400 mg/kg also increased inhibitory activity of MEOTA in the basal ganglia, while none of doses tested did not influence the inhibitory activity of MEOTA in the hippocampus.
Repeated administration of ALC in doses of 100, 200, 250, 300 and 400 mg/kg did not influence anticholinesterase activity of MEOTA in the frontal cortex, hippocampus and basal ganglia, moreover, the inhibitory effect of MEOTA in the septum was abolished.
The results obtained suggest different mechanisms of the mutual interaction of CRT with MEOTA on the one hand, and ALC with the same drug on the other hand.

Keywords: Toxicology; acetyl-L-carnitine; L-carnitine; acetylcholinesterase