Autometallographic detection of silver in hypothalamic neurons of rats exposed to silver nitrate.

The silver amplification technique, autometallography, has been used to reveal silver accumulation in neurons in the hypothalamus of male Wistar-Kyoto rats. Silver penetrated the blood-brain barrier after exposure to silver nitrate, and differences in staining intensity were found between the hypothalamic nuclei. When using light microscopy, the silver staining of the hypothalamic neurons was highly heterogeneous. Silver was detected exclusively in lysosomes of the loaded neurons. Aspects of this heterogeneous localization are discussed in relation to the distribution of autometallographically developed gold and mercury.