NADPH-diaphorase Activity in the Vestibular End Organs of the Guinea Pig

抄録

The localization of nicotinamide-adenine dinucleotide hydrogen phosphate (NADPH)-diaphorase was investigated in the vestibular organ of the pigmented guinea pig by a histochemical method. Intense reactivity to NADPH-diaphorase was found in the cytoplasm of both type I and type II vestibular sensory cells, whereas there was no reactivity in their nuclei and sensory hairs. The afferent nerve chalices were usually not stained. Supporting cells displayed no staining. The cytoplasm of other fluid transporting cells, as well as of vestibular ganglion cells, revealed weak to moderate NADPH-diaphorase activity. These findings support the hypothesis that nitric oxide is a mediator of neurotransmission in the vestibular system in sensory cells and ganglia. Nitric oxide in the fluid transporting cells may play an important role in maintaining endolymph and ion homeostasis.