Effect of tri-O-cresyl phosphate (TOCP) poisoning on sensory nerve terminations of slow loris (Nycticebus coucang coucang).

Abstract

Sensory nerve terminations in the oral and digital tissues of slow loris (Nycticebus coucang coucang) were studied after topical or systemic administration of TOCP. Histochemical studies revealed a reduction of AChE and complete absence of ChE in sensory nerve terminations. In electron microscopy the light cells of taste buds showed vacuolization, degenerating mitochondria, distended endoplasmic reticulum, vesicle formation and “cytosegregosomes” while dark cells also has unusual shaped dense core granular vesicles (1,200–2,500 A diameter). The axons were “ballooned” with fragmenting mitochondria, some agranular vesicles and disorientated neurotubules lying in a dispersed, lightly granular axoplasm. Moreover, the Nauta-Gygax method (1954) revealed degenerative changes in the digital sensory end-organs as well as in the distal portion of the sensory nerve fibres. The significance of these findings is discussed.