Hideaki Motosugi

Distribution of NADPH-diaphorase positive nerve fibers in the rat nasal mucosa

Nasal mucosa was investigated by NADPH-diaphorase histochemistry. Positive fibers were distributed around blood vessels, seromucous glands and in the subepithelial layer. The pterygopalatine, trigeminal and superior cervical ganglia were also studied to examine the origin of these fibers. Many neurons in the pterygopalatine ganglion were labeled, and a few neurons were stained in the trigeminal ganglion. No perikarya were labeled in the superior cervical ganglion. Therefore, most of the labeled fibers must be originating from the pterygopalatine ganglion, and the rest of them may originate from the trigeminal ganglion. These results suggest that nitric oxide may have some role in the nervous control of the nasal mucosa.

Pathophysiological features of the nasal mucosa in patients with idiopathic rhinitis compared to allergic rhinitis.

Background: The literature on abnormality of vasomotor responses of the nasal mucosa to cold stimulation of the skin in idiopathic rhinitis is conflicting. The objective of this study was to elucidate pathophysiological features of the nasal mucosa in idiopathic rhinitis compared to allergic rhinitis. Methods: The following were studied in patients with idiopathic rhinitis and allergic rhinitis and in normal controls: (1) threshold of the nasal reaction to histamine; (2) inflammatory cells in nasal lavage and scraped nasal mucosal epithelium, and (3) nasal vasomotor response to cold stimulation of the feet evaluated by acoustic rhinometry. Results: Inflammatory cells were not found to be involved in idiopathic rhinitis. Nasal reactivity to histamine was significantly enhanced in patients with idiopathic rhinitis compared to normal controls, but was significantly lower compared to those with allergic rhinitis. The most prominent finding in idiopathic rhinitis was nasal mucosal swelling induced by cold stimulation of the feet. While in normal controls, cold stimulation of the feet caused mucosal contraction due to sympathetic excitation, sympathetic nasal vasomotor response in idiopathic rhinitis patients was significantly inhibited and caused mucosal swelling and enhanced nasal secretion. Mucosal reactions observed in allergic rhinitis were between those observed in idiopathic rhinitis and in normal controls. Cold stimulation of the feet increased systolic blood pressure by 5–15 mm Hg, but the degree of increase observed in the 3 groups was almost equal. Conclusions: The above findings indicate that patients with idiopathic rhinitis have abnormalities that inhibit sympathetic reactions and enhance parasympathetic vasomotor response at peripheral levels, possibly in the nasal mucosa.

Role of Substance P in the Vascular Response of Nasal Mucosa in Nasal Allergy

The effects of topically administered substance P (SP) on nasal blood flow and nasal airway resistance (NAR) were evaluated in 11 subjects with perennial nasal allergy. The change in NAR induced by SP was compared with those induced by nasal challenge with histamine, leukotriene EM (LTD4), and antigen. In doses ⩾ 16 nmol, SP caused a significant increase of nasal blood flow within 5 minutes that lasted for less than 20 minutes. In doses ⩾16 nmol, SP caused a dose-dependent, short-lasting, significant increase in NAR. The magnitude of the increase in NAR was LTD4 > SP > histamine when compared on a molar basis. Our results may suggest that SP released from C fiber terminals is partially involved in an early nasal vascular response after antigen challenge by acting on adjacent vascular smooth muscle to cause a transient vasodilatation of both resistance and capacitance vessels only while sensory stimulation persists in subjects with nasal allergy.

Role of capsaicin-sensitive trigeminal nerves in development of hyperreactive nasal symptoms in guinea pig model of nasal allergy.

The effect of capsaicin pretreatment on frequency of sneezing, decrease of nasal patency, and increase of vascular dye leakage induced by antigen or histamine challenge on the guinea pig nasal mucosa was investigated. The animals were sensitized intraperitoneally with ovalbumin. Capsaicin pretreatment significantly inhibited sneezing induced by nasal challenge with histamine and antigen, indicating that capsaicin-sensitive sensory nerves constitute an afferent pathway of the sneezing reflex in nasal allergy. Although capsaicin pretreatment tended to inhibit the decrease of nasal patency and the increase of vascular dye leakage of the nasal mucosa induced by antigen challenge, this tendency was not statistically significant. The present study indicated that the participation of a local reflex via capsaicin-sensitive trigeminal nerves in nasal vascular responses observed after antigen challenge in the guinea pig model of nasal allergy is rather small compared to the large direct vascular effects of chemical mediators released from basophilic cells in the nasal mucosa.

Enhancement of Submicroscopic Damage of the Nasal Epithelium by Topic Al Allergen Challenge in Patients with Perennial Nasal Allergy

The purposes of this study were to clarify whether damage of the nasal epithelium exists in patients with nasal allergy, and how the morphology of the epithelium changes after topical allergen challenge. Electron microscopy revealed 2 characteristic features in the nasal epithelium of patients with perennial nasal allergy — an increase in the number of epithelial cells with cytoplasmic vacuoles, and markedly widened intercellular spaces — although these changes were unclear under light microscopy. The density of vacuolated cells significantly increased 24 hours after allergen challenge. Further, the number of eosinophils that were associated with vacuolated cells was significantly higher in patients with nasal allergy than in controls. These morphological changes, thus, were considered to be types of damage to the nasal epithelium associated with nasal allergy. Such changes may be among the causes of nasal hyperreactivity, which is an important feature of nasal allergy.

Time course of changes in absorption of macromolecule through the nasal mucosa after antigen challenge in guinea pig model of allergic rhinitis.

The time course of changes in absorption of horseradish peroxidase (HRP) through the nasal mucosa after antigen challenge was evaluated in a guinea pig model of allergic rhinitis immunized with ovalbumin. Before and at 5 minutes, 4 hours, and 24 hours after nasal antigen challenge, both nasal cavities were filled with 5% HRP solution for 30 minutes, and blood was obtained to measure serum HRP levels by enzyme-linked immunosorbent assay. In immunized animals, the serum HRP levels were 2.3 times higher than those of normal controls (p < .05) before antigen challenge, which was performed 7 days after a series of nasal antigenic sensitizations. At 5 to 35 minutes after antigen challenge, the HRP levels decreased to one sixth of the prechallenge levels (p < .05), and they did not show a difference from the control levels. However, they increased markedly at 4 and 24 hours after antigen challenge (p < .01). The present study suggests that the absorption of macromolecules through the allergic nasal mucosa is enhanced markedly, depending upon the time course after antigen challenge, although it shows no apparent difference from normal controls during the dominant exudative process.

Recent Experiences with Four Patients with Rhinogenic Intracranial Complications.

Case 1: A 21-year-old male had abscess of the brain and interhemispheric subdural area secondary to acute frontal sinusitis. Case 2: A 55-yera-old female had two brain abscesses. Case 3: A 15-year-old female had an epidural abscess secondary to acute frontal sinusitis. Case 4: A 15-year-old male had a subdural abscess. All 4 patients were treated successfully. The developpment of antibiotic therapy has reduced the incidence of rhinogenic intracranial complications, but 38 cases were reported in the past 10 years. Careful observation, prompt diagnosis and early treatment are very important.