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Ultrastructural changes in choroid plexus and learning deficits with low dose Cd exposure
Author(s) -
Villalobos A R,
Tay J. J.,
Bentley K.,
Huang L. S.,
Zarcone T. J.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a378-a
Subject(s) - choroid plexus , endocrinology , medicine , basement membrane , ultrastructure , chemistry , biology , central nervous system , anatomy
Juvenile Sprague‐Dawley rats were administered 0, 0.25 or 0.50 mg cadmium (Cd) per kg by gavage for 21 days (PND 8‐28). Total Cd dose was ~3‐6% of the LD 50 . There were no indications of renal or hepatic toxicity and no differences in growth and somatic development. As per atomic absorption, Cd concentration in choroid plexus was 30‐40X that in blood and brain. Electron microscopy showed concomitant changes in ultrastructure of Cd‐exposed choroid plexus. Tight junctions remained intact, and there was no apparent attenuation of the microvillus or detachment of the epithelium from the basement membrane. However, Cd exposure markedly increased incidence of enlarged cytosolic vacuoles and dilation of intercellular spaces. In isolated plexus from neonatal rats, comparable exposure to Cd induced stress proteins HSP70, HO‐1 and MT‐1. Rats exposed to Cd also displayed central neural deficits. At 0.5 mg/kg, Cd reduced brain weight (normalized to body weight). At this same dose, operant learning was retarded; the first reinforced operant response was observed at 60 min (vs. 15 min, no Cd); however, locomotor and exploratory behavior were similar among groups. Reduced brain weight and impaired operant learning have been previously associated with choline‐deficiency in rats. Given the association of transport capacity to ultrastructure and cell stress in transporting epithelia, these data suggest that Cd may also alter transport of solutes, such as choline, and fluid secretion by choroid plexus. NIEHS‐P30‐ES01247