Prenatal availability of choline alters the development of acetylcholinesterase in the rat hippocampus

Choline (Ch) supplementation during embryonic days (ED) 12-17 enhances spat ial and temporal memory in adult and aged rats, whereas prenatal Ch deficie ncy impairs attention performance and accelerates age-related declines in t emporal processing. To characterize the neurochemical and neuroanatomical m echanisms that may mediate these behavioral effects in rats, we studied the development [postnatal days (PD) 1, 3, 7, 17, 27, 35, 90, and 26 months po stnatally] of acetylcholinesterase (AChE) activity in hippocampus, neocorte x and striatum as a function of prenatal Ch availability. We further measur ed the density of AChE-positive laminae (PD27 and PD90) and interneurons (P D20) in the hippocampus as a function of prenatal Ch availability. During E D11-ED17 pregnant Sprague-Dawley rats received a Ch-deficient, control or C h-supplemented diet (average Ch intake 0, 1.3 and 4.6 mmol/kg/day, respecti vely). Prenatal Ch deficiency increased hippocampal AChE activity as compar ed to control animals in both males and females from the 2nd to 5th week po stnatally. Moreover, prenatal Ch supplementation reduced hippocampal AChE a ctivity as compared to control animals over the same developmental period. There was no effect of prenatal Ch status on either cortical or striatal AC hE activity at any age measured, and by PD90 the effect of Ch on hippocampa l AChE was no longer observed. In order to localize the early changes in hi ppocampal AChE activity anatomically, frozen coronal brain sections (PD20, PD27, PD90) were stained histochemically for AChE. Consistent with biochemi cal results, the AChE staining intensity was reduced in PD27 hippocampal la minae in the Ch-supplemented group and increased in the Ch-deficient group compared to control animals. There was no effect of the diet on hippocampal AChE staining intensity on PD90. In addition, the prenatal Ch availability was found to alter the size and density of AChE-positive PD20 interneurons . These results show that prenatal Ch availability has longterm consequence s on the development of the hippocampal cholinergic system.