Autoradiographic Distribution of 131I-Clioquinol in Canine and Feline

To elucidate the absorption, intracellular location and pathogenicity of clioquinol, micro-autoradiographic studies were done. ¹³¹I-clioquinol was administered under different methods to 6 mongrels, 2 inbred beagles and a cat. Shortly after i.v.- or i.p.-injections of the substance to the mongrels and cat, a high concentration of radioactive grains was seen in the following nervous system: Nerve cells of the spinal root ganglia, spinal grey matter and nuclei in the brain stem; peripheral nerves; capsular cells of the spinal root ganglia; glial cells in the spinal cord, brain stem and periventricular region of the cerebrum. Though in lesser degree, orally administered radioactive clioquinol was also detected in the nervous system of the mongrels. I.p.-injected beagles showed, however, a low concentration of the grains in the nervous system. This may indicate strain-difference of dogs for the neurotoxicity of clioquinol.