Receptor-binding changes in copper-deficient rats

Male weanling Sprague-Dawley rats were fed a copper-deficient diet for 40 days. Copper-deficient rats weighed significantly (p < 0.001) less (175 ± 7 g) than copper-supple-mented rats (230 ± 6 g). Hematocrits were also significantly (p < 0.001) decreased in deficient as compared to control animals from 43 ± 0.6 to 30 ± 2.7%. The binding of³H-QNB to striatal and cerebellar membrane muscarinic receptors from control and deficient rats increased from 594 ± 25 to 704 ± 31 (p < 0.02) and from 19 ± 2 to 28 ± 3 (p < 0.01) pmol/g protein, respectively. Similarly, ³H-muscimol binding to GABA receptors (cerebellum) also increased from 39 ± 5 to 58 ± 3 (p < 0.02) pmol/g protein.³H-diazepam binding to benzodiazepine receptors in deficient versus control animal frontal cortex membranes decreased from 92 ± 8 to 75 ± 5 (p < 0.02) pmol/g protein, respectively. These results may help explain CNS manifestations of copper deficiency.