Intralaryngeal Ganglion

Abstract

The intralaryngeal ganglia are large ganglia situated in the periventricular area along the internal branch of the superior laryngeal nerve and are regarded to be parasympathetic ganglia because of their localization and the immunoreactivity they display. The proximity of the ganglia to the glands and vessels in the larynx resemble that of the parasympathetic postganglionic neurons existing close to their target organs in the intestine. Almost all the ganglionic neurons in the intralaryngeal ganglia are positive to acetylcholine esterase histochemistry and therefore presumably cholinergic. Most of the neurons in the intralaryngeal ganglia are vasoactive intestinal polypeptide positive, few of them tyrosine hydroxylase, or substance P positive but none calcitonin gene-related peptide positive. Neuronal nitric oxide synthase and heme oxyganase-2 are also seen in many of the ganglionic neurons and are sometimes colocalized. Nociceptic receptors with the potential ability to integrate various stimuli into their output, such as transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential vanilloid 2 (TRPV2), are also localized in neurons of the intralaryngeal ganglia. These may help provide prompt response to stimuli by processing various inputs in the vicinity of the target tissue and integrating them into outputs controlling vascular tension or glandular secretion.