Abstract
Possible toxic effects of hexachlorophene (HCP) on sympathetic adrenergic nerves were studied using Falck-Hillarp fluorescence histochemistry on whole-mounts of albino rat irides. HCP dissolved in 5 μl DMSO, or DMSO alone, was injected into the anterior chamber of the eye. HCP caused a dose-dependent degeneration of adrenergic nerves, first observable after 7 μg and profound after 21 μg. One and 3 days after 35 μg of HCP there was an almost total loss of adrenergic nerves. Regeneration from remaining non-terminal axons led to an almost complete reformation of the adrenergic nerve plexus after 18 days. The results demonstrate a new aspect of hexachlorophene neurotoxicity, degeneration of peripheral adrenergic nerve terminals and suggest that neurotoxic actions on thin unmyelinated fiber systems should be looked for also in the central nervous system (CNS).