Perinatal dietary exposure to soy lecithin: altered sensitivity to central cholinergic stimulation.

The effects of perinatal exposure to soy lecithin preparation (SLP) on the development of cholinergic responses in the rat brain were examined by assessing the ability of intracisternally administered carbachol to stimulate 33Pi incorporation into phospholipids in vivo, an effect of carbachol mediated by muscarinic cholinergic receptors. Maternal intake of SLP produced a suppression of the cholinergic response in the offspring, an effect which was specific in that basal (unstimulated) incorporation rates were not reduced (in fact, they eventually became elevated), nor was the response to another neurotransmitter (dopamine) compromised. The effect occurred early in the preweanling stage, a period in which SLP exposure also enhances development of cholinergic nerve terminals. These results suggest that SLP exposure has a major effect on cholinergic synaptic development and reactivity, followed by secondary changes in other neurotransmitter pathways and by more generalized effects on basal membrane phospholipid turnover.