PMC

(A) Circulating mercury (red dots) enters brain capillaries and passes into endothelial cells. Mercury passes through the perivascular space and is taken up by the endfeet of perivascular astrocytes. (B) Mercury collects in the cell bodies of perivascular astrocytes and is passed through gap junctions into neurons and oligodendrocytes. (C) Within neurons and oligodendrocytes, mercury is located within lysosomes, attached to mitochondria, endoplasmic reticulum, Golgi apparatus, and nuclear membranes, and free in the cytoplasm. (D) Mercury is removed from neurons through gap junctions into adjacent astrocytes, which transfer the mercury to venules. (E) Mercury enters the lumen of venules and is removed from the brain. Some mercury enters the perivenular space. (F) Some capillary mercury enters the interstitial fluid directly. (G) Some forms or mercury pass through the cell membrane directly into the interstitial space. (H) Interstitial mercury enters the perivenular space via the glymphatic pathway and exits the brain through the cerebrospinal fluid.

(A) Dense particulate mercury is seen in LGN parvocellular neurons (upper right, high power view in box 1). Magnocellular neurons (lower left, high power view in box 2) have less dense mercury on average than parvocellular neurons. A few small cells (eg, arrowhead) in the koniocellular layer contain mercury. AMG/hematoxylin. (B) Dense mercury deposits are seen in the shrunken cytoplasm of some oligodendrocyte cell bodies (eg, in boxes 1 and 2). Most neurons (eg, circled) contain mercury. One capillary (arrow) is mercury-free. AMG/Luxol fast blue. (C) Fine particulate mercury is seen in all LGN neurons (eg, box) and diffuse faint mercury staining is seen in the neuropil. Longitudinal (arrow) and transverse (arrowhead) capillary profiles show mercury in endothelial cells. AMG/hematoxylin. (D) Moderate scattered particulate mercury is seen, on a background of light yellow-brown lipofuscin, in many LGN neurons (eg, circled, and box). A capillary (arrow) has dense endothelial mercury. AMG/hematoxylin. G: identify number.

Correlations among mercury concentrations (a) Total blood mercury and blood methyl mercury; (b) Total blood mercury and hair mercury; (c) Total blood mercury and urine mercury; (d) Blood methyl mercury and hair mercury.

(A) Hypothetical model of changes in blood mercury with respect to physiologically dynamic events in the annual cycle of a biannually molting, migratory songbird. This simplified model assumes a constant mercury exposure year-round and is intended only to represent potential relative changes in blood mercury due to physiologically dynamic events in an individual's annual cycle. Between prebasic and prealternate molts, mercury increases during the non-breeding season (a, h); at spring prealternate molt, mercury decreases (b); females deposit mercury into eggs (c); mercury increases between prealternate and prebasic molts during the summer [d (males), e (females)], reaching a maximum before fall prebasic molt (f); following prebasic fall molt, mercury is depleted (g). (B) Blood mercury data with a smoothed best-fit line for breeding and non-breeding Nelson's Sparrow populations at JBON and WBNC, respectively (refer to for capture location information).