Abstract
The involvement of nitric oxide (NO) and carbon monoxide (CO) in laryngeal innervation of the dog and rat was investigated by immunohistochemistry using antisera against nitric oxide synthase and heme oxygenase, in addition to NADPH-diaphorase histochemistry.
NO and CO are involved in the regulation of blood flow and glandular secretions in the larynx. NO participates in nociception in the larynx although the role of NO is minor in this system. CO is considered not to participate in sensory innervation of the larynx. Nitrergic neurons were found between the muscle fibers of the intrinsic laryngeal muscles suggesting a role in proprioception in place of muscle spindles. Induction of NO was detected in the motoneurons of the nucleus ambiguus after injury to the recurrent laryngeal nerve. Further investigation of this phenomenon would facilitate understanding of the pathogenesis of recurrent laryngeal paralysis.
