Nervous System Absorption of Lead

Massive entry of Pb from the blood supply into the brain is initicdly inhibited by the blood-brain barrier (BBB) or blood-nerve barrier (BNB). Stumpf et al. have shown that injected Pb is initicdly 

The increased BBB permeability in newborns compared to adults, in addition to differences in absorption rate from the gut 

Using a single tracer dose, Pb accumulates largely in blood vessels and their lining cells. As would be expected fix)m a single dose, little Pb penetrated the BBB into neurons, but that which did 

A great deal of research has been generated on the effects of Pb on neurochemical systems, with most work focused on the neurotransmitter systems for acetylcholine (ACh), norepinephrine (NE), dopamine (DA), serotonin (5HT), and gamma-aminobutyric acid (GABA). Several reviews of the neurochemiced effects of Pb have recently been published. l9  

Studies on the neurochemical effects of Pb on the cholinergic system have assessed the effects in terms of (1) steady-state levels of ACh and its precursor choline (Ch), (2) cholinergic eniymes, (3) rate of ACh release and turnover, (4) synaptosomal transport mechanisms, and (5) pharmacological responses of Pb-exposed animals. 

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