Shinobu Koike

Nitrergic Innervation of the Rat Larynx Measured by Nitric Oxide Synthase Immunohistochemistry and Nadph-Diaphorase Histochemistry

We evaluated the involvement of nitric oxide (NO) in the laryngeal innervation of rats using NADPH-diaphorase (NADPH-d) histochemistry and neuronal nitric oxide synthase (nNOS) immunohistochemistry. The findings obtained by NADPH-d histochemistry were identical with those obtained by nNOS immunohistochemistry, indicating that NADPH-d is nNOS in the laryngeal innervation system. We found NADPH-d-positive nerve fibers in every region of the larynx. In the epithelia of the mucosa, a small number of NADPH-d-positive nerve fibers were detected. The plexus of NADPH-d-positive nerve fibers was commonly found in the lamina propria, and some of these fibers were clearly associated with blood vessels. We also noted NADPH-d-positive nerve fibers in the region of laryngeal glands. Some of these fibers appeared to terminate in the glandular cells. We found NADPH-d-positive nerve fibers with varicosities in the intrinsic laryngeal muscle and free-ending nerve fibers on the muscle fiber. Motor end plate-like structures were positive for NADPH-d histochemistry. The NADPH-d-positive nerve fibers appeared to terminate at motor end plate-like structures in two of nine rats examined. A cluster of NADPH-d-positive neurons were occasionally present in the lamina propria of the laryngeal mucosa, in the connective tissue between the thyroid cartilage and intrinsic laryngeal muscle, and in the connective tissue near the cricoarytenoid joint. The present findings suggest that NO participates in the autonomic, sensory, and motor innervation of the larynx.

Distribution of vanilloid receptors in the rat laryngeal innervation.

Objective Capsaicin is known to selectively activate nociceptic sensory neurons through vanilloid receptors. In this study we investigated the distribution of vanilloid receptor subtype 1 (VR1) and vanilloid receptor-like protein 1 (VRL-1) in the rat larynx. Material and Methods The distributions of VR1 and VRL-1 were determined immunohistochemically. The colocalization of vanilloid receptors with common choline acetyltransferase (cChAT), vasoactive intestinal polypeptide (VIP), substance P (SP) and neuronal nitric oxide synthase (nNOS) was also studied using an immunohistochemical double-labeling technique. Results VRL-1-positive fibers were detected in the laryngeal epithelium and lamina propria. VR1-positive nerve fibers were seen in the lamina propria but not in the mucosal epithelium. VR1- and VRL-1-positive cells were distributed in the intralaryngeal ganglia and colocalization of capsaicin receptors with VIP, nNOS and cChAT was seen. Conclusion These findings suggest that these capsaicin receptors participate in the parasympathetic innervation as well as in nociception of the rat larynx.

Nitrergic neurons in the canine intrinsic laryngeal muscle

Nitrergic ganglionic cells located in the canine intrinsic laryngeal muscle were studied by NADPH-diaphorase (NADPH-d) histochemistry and neuronal nitric oxide synthase (nNOS) immunohistochemistry. Cells intensely stained by NADPH-d histochemistry were found between the striated muscle fibers of the intrinsic laryngeal muscle. Most of these cells were bipolar or pseudounipolar in form. Some NADPH-d negative cells were observed to be enveloped in a mesh by varicose NADPH-d positive nerve fibers. The findings obtained by nNOS immunohistochemistry corresponded well with those obtained by NADPH-d histochemistry, indicating that NADPH-d activity in the ganglion in the intrinsic laryngeal muscle is nNOS. The present findings clearly indicate that some of the ganglion cells located in the canine intrinsic laryngeal muscle are nitrergic, and that the ganglionic cells synapse together with the participation of nitric oxide in integrating ganglionic cells.

Neurotransmitters and neuromodulators involved in laryngeal innervation

The distribution and role of neurotransmitters and neuromodulators in laryngeal innervation are reviewed, and our recent findings regarding the nitrergic innervation of the larynx are demonstrated for the better understanding of the complexity of the laryngeal innervation system. Noradrenergic innervation of the larynx was studied with fluorescence histochemistry and electron microscopy after application of 5-hydroxydopamine. These studies confirmed the existence of noradrenergic innervation for the submucosal glands and blood vessels, and the origin and course of noradrenergic nerve fibers contained in the laryngeal nerves and their destinations in the larynx. Cholinergic innervation of the larynx has not been clarified in detail. Many kinds of neuropeptides have been demonstrated to be involved in laryngeal innervation. Vasoactive intestinal polypeptide originating from intralaryngeal ganglionic neurons participates in laryngeal vasodilation and reduction of laryngeal seromucous secretion. Neuropeptide Y nerve fibers are few in the larynx, and most originate from the superior cervical ganglion. They are distributed around the large or medium-sized blood vessels, especially arteries. They are also associated with excretory structures. Substance P was the first neuropeptide found to be a sensory neurotransmitter in the laryngeal afferent system. It is also involved in regulation of laryngeal blood flow and secretion. Calcitonin gene—related peptide is associated with the sensory, autonomic, and motor innervation of the larynx. The majority of enkephalin nerve fibers are located close to excretory structures, although no information on the physiological significance of enkephalin is available. In addition to the above neuropeptides, the peptides histidine isoleucine, histidine methionine, and helospectin have been shown to exist in the larynx. The nitrergic innervation of the larynx has been recently studied with NADPH-diaphorase histochemistry and immunohistochemistry using antiserum against nitric oxide synthase. Nitric oxide originates from the neurons in the intralaryngeal ganglia and is believed to modulate blood flow and secretion of the larynx. It controls the laryngeal exocrine secretion in cooperation with intrinsic vasoactive intestinal polypeptide and/or extrinsic calcitonin gene—related peptide. Nitric oxide from the nodose ganglion may modulate nociception of the larynx. The existence of nitrergic neurons located in the intrinsic laryngeal muscles has been demonstrated. Many of them are bipolar or pseudounipolar, so they might be sensory in nature. The effect of injury of the recurrent laryngeal nerve on the induction of nitric oxide synthase in the laryngeal motoneurons is also discussed.

Capsaicin receptor expression in rat laryngeal innervation.

Capsaicin elicits a sensation of burning pain by selectively activating sensory neurons that convey information about noxious stimuli to the central nervous system. Vanilloid receptor subtype 1 (VR1) and the vanilloid receptor-like protein 1 (VRL-1) are activated, not only by capsaicin, but also by noxious heat and protons, and it has been suggested that they are polymodal nociceptors. We investigated the expression of VR1 and VRL-1 in the rat larynx and nodose ganglion using VR1 and VRL-1 immunohistochemical analysis with visualization by diaminobenzidine reaction. Fibers positive for VRL-1 were detected in the laryngeal epithelium and lamina propria. Cells positive for VRL-1 were distributed in the intralaryngeal ganglia. Half of the neurons in the nodose ganglion had VR-1 immunoreactivity, and almost 10% of the nodose ganglion neurons were positive for VRL-1. These findings suggest that these capsaicin receptors play an important role in the nociception of the laryngeal innervation.

Neurotransmitters for the canine inferior pharyngeal constrictor muscle

The inferior pharyngeal constrictor muscle plays an important role at the pharyngeal phase of deglutition and is anatomically composed of the thyropharyngeal muscle and cricopharyngeal muscle. In this study we investigated the distribution pattern of neuropeptidergic and catecholaminergic nerve fibers in the thyropharyngeal muscle and cricopharyngeal muscle of seven puppies by immunohistochemistry. Some of the calcitonin gene-related peptide-, substance P-, vasoactive intestinal polypeptide-, and tyrosine hydroxylase-immunoreactive nerve fibers were found to lie parallel to the muscle fibers in both the thyropharyngeal muscle and cricopharyngeal muscle. Nerve fibers with immunoreactivity to all substances examined were found to be associated with blood vessels in both the thyropharyngeal muscle and cricopharyngeal muscle, and the number of calcitonin gene-related peptide, neuropeptide Y, and tyrosine hydroxylase nerve fibers was higher than the number of substance P, vasoactive intestinal polypeptide, and galanin nerve fibers. Motor end plate-like structures with calcitonin gene-related peptide immunoreactivity were found in both the thyropharyngeal muscle and cricopharyngeal muscle. These structures in the cricopharyngeal muscle were clearly less than those in the thyropharyngeal muscle. Some clusters of neurons were detected only in the cricopharyngeal muscle of all dogs examined. Substance P-, vasoactive intestinal polypeptide-, galanin-, and neuropeptide Y-immunoreactive neurons were found in this ganglion, and the vasoactive intestinal polypeptide-immunoreactive neurons were the most abundant. Abundant calcitonin gene-related peptide- and vasoactive intestinal polypeptide-immunoreactive nerve fibers, and some substance P- and galanin-immunoreactive nerve fibers were distributed in the ganglion.(ABSTRACT TRUNCATED AT 250 WORDS)

Participation of TRPV1 and TRPV2 in the rat laryngeal sensory innervation.

Laryngeal sensory innervation is essential to the laryngeal defense system. We investigated the participation of TRPV1 and its homologue TRPV2 in the rat laryngeal sensory innervation using immunohistochemistry and the neuronal tracer, fluoro-gold (FG). After injection of FG into the internal branch of the superior laryngeal nerve, FG-labeled neurons were seen in the rostral part of the nodose ganglion (NG). Neurons immunoreactive for TRPV1 or TRPV2 were distributed throughout the NG. TRPV1 immunoreactivity was seen in 49.0+/-4.5% of the FG-labeled neurons, while TRPV2 immunoreactivity was seen in 12.5+/-4.1% of the FG-labeled neurons. These findings suggest that both TRPV1 and TRPV2 participate in laryngeal nociception, but that TRPV1 may have a particularly important role.

A case of angiosarcoma of the nasal cavity successfully treated with recombinant interleukin-2.

Angiosarcomas very rarely arise in the nose and paranasal sinuses, with an incidence of about 4%. To our knowledge, there have been only 4 reported cases in the literature. This paper reports a case of angiosarcoma arising in the nasal cavity that decreased in size after the administration of recombinant interleukin-2 (rIL-2), with a brief review of the literature. A 55-year-old male with a chief complaint of frequent epistaxis on the left side was referred to our department for close examination on January 21, 2000. His past and family histories were unremarkable. No abnormal findings were noted in the ear, pharynx, larynx, or neck. Examination of blood coagulation was normal. Enhanced CT showed a mass lesion with an enhancement effect in the left nasal cavity. T1-weighted images of MRI also demonstrated an enhanced tumor in the left nasal cavity (Fig 1a). After septal correction surgery on April 20, 2000, a dark red tumor was found in the left nasal cavity. A biopsy specimen was taken during surgery. Pathological examination of HE-stained sections showed proliferation and irregular arrangement of vascular endothelial cells (Fig 1b and c). Immunohistochemical analyses using CD34 showed a specifically positive staining corresponding to vascular endothelial cells. We concluded that the nasal tumor was angiosarcoma. Angiography of the left carotid artery was performed on May 8, 2000. The tumor was supplied by both the anterior ethmoid artery, a branch of the internal carotid artery, and the greater palatine artery, a branch of the external carotid

Nitric Oxide Synthase and NADPH-diaphorase in Neurons of the Rat, Dog and Guinea Pig Nodose Ganglia

Localization of nitric oxide synthase (NOS) in the nodose ganglia of the dog, rat and guinea pig was investigated. A double-staining technique of NOS immunohistochemistry and NADPH-diaphorase (NADPHd) histochemistry was used; then the ratio of NADPHd-positive and NOS-positive cells to the total cells was calculated. The distribution of positive cells within the canine nodose ganglion was also investigated. NADPHd-positive neurons were detected in all the ganglia. Three intensities of reactivity to NADPHd histochemistry (strong, weak or negative) were detected in the neurons of all three species. There were more cells that stained strongly for NADPHd in the rat, but fewer in the dog and guinea pig, indicating that a species difference may exist. NADPHd-positive neurons were less abundant in the rostral third of the canine nodose ganglion than in the middle or caudal thirds. NADPHd reactivity was completely co-localized to the cells that demonstrated neuronal NOS immunoreactivity in the canine nodose ganglion. Thus, NADPHd histochemical reactivity may be a reliable marker of NOS in the nodose ganglion.

Induction of Nitric Oxide Synthase Activity in Nucleus Ambiguus Motoneurons after Injury to the Rat Recurrent Laryngeal Nerve

Recent studies have implicated nitric oxide (NO) in neuronal degeneration and plasticity in the motor nervous system. In the present study, we investigated the induction of nitric oxide synthase (NOS) in the motoneurons in the nucleus ambiguus (NA) after injury to the rat recurrent laryngeal nerve (RLN) using nicotinamide-adenine-dinucleotide-phosphate-diaphorase (NADPH-d) histochemistry. NADPH-d reactivity was clearly induced in motoneurons in the ipsilateral NA after transection or avulsion of the RLN, compared with control animals. This finding suggests that NO may play an important role in the pathogenesis of RLN paralysis. Another interesting finding in the present study was the induction of NADPH-d reactivity in nerve terminals of the NA after RLN injury. This finding suggests that RLN injury has some effect on nitrergic input to the NA and a direct effect on the motoneurons.Recent studies have implicated nitric oxide (NO) in neuronal degeneration and plasticity in the motor nervous system. In the present study, we investigated the induction of nitric oxide synthase (NOS) in the motoneurons in the nucleus ambiguus (NA) after injury to the rat recurrent laryngeal nerve (RLN) using nicotinamide-adenine-dinucleotide-phosphate-diaphorase (NADPH-d) histochemistry. NADPH-d reactivity was clearly induced in motoneurons in the ipsilateral NA after transection or avulsion of the RLN, compared with control animals. This finding suggests that NO may play an important role in the pathogenesis of RLN paralysis. Another interesting finding in the present study was the induction of NADPH-d reactivity in nerve terminals of the NA after RLN injury. This finding suggests that RLN injury has some effect on nitrergic input to the NA and a direct effect on the motoneurons.