Distribution and clinical significance of the autonomic nervous system in the human nasal mucosa

Cadaveric analysis of autonomic nerve fiber density in posterior nasal, posterolateral nasal, and anterior ethmoid nerves

KEY POINTS

Autonomic nerve densities were equivalent in posterior nasal (PNN), posterolateral nasal (PLNN), and anterior ethmoid nerves (AEN). Rhinitis studies should explore the utility of PLNN and/or AEN transection over PNN alone.

Improvement in Nasal Symptoms of Chronic Rhinitis after Cryoablation of the Posterior Nasal Nerve

Objective

To determine the efficacy of posterior nasal nerve (PNN) cryoablation for improving the symptoms of chronic rhinitis.

Study Design

Retrospective cohort study.

Setting

A private practice.

Methods

This study evaluated medication usage and adverse effects of in-office PNN cryoablation with a handheld device in patients > 18 years with chronic (>6 months) allergic or nonallergic rhinitis for whom medical management failed. The total nasal symptom score (TNSS) and mini rhinoconjunctivitis quality of life questionnaire (mRQLQ) scores were compared before and after treatment.

Results

This study included 127 patients with a mean age of 52.4 ± 16.9 years; 60.6% of patients were female and 49.6% had allergic rhinitis. Mean symptom scores decreased from 5.94 (95% confidence interval [CI], 5.51-6.43) to 3.44 (95% CI, 2.97-3.81, P < .001) after the procedure, with clinically important decreases in 75 (59.1%) patients. For patients with baseline TNSS values of ≥4, 63.5% (66/104) had a clinically important decrease, whereas only 39.1% (9/23) of those with the lower baseline did (P = .04). Mean mRQLQ scores also decreased from 2.51 (95% CI, 2.29-2.72) to 1.28 (95% CI, 1.20-1.47, P < .001) after the procedure. Seventy-eight of 273 (28.6%) medications were discontinued after the procedure. Adverse effects occurred in 18.1% (23/127) of patients with headache as the most common.

Conclusion

PNN cryoablation improves nasal symptoms and quality of life in patients with chronic rhinitis. Patients with a higher baseline TNSS are more likely to experience significant symptomatic improvement.

Post-dural puncture headache accompanied by obvious nasal congestion: A case report

INTRODUCTION

Post-dural puncture headache (PDPH) is the most common complication of intraspinal nerve block in gravida. PDPH may be accompanied by neck stiffness, tinnitus, hearing loss, photophobia or nausea.

PATIENT CONCERNS

A 33-year-old woman whose dura was accidentally punctured during labor analgesia complained of severe headache, dizziness, and nasal congestion; these symptoms aggravated when she looked up, and her sense of smell was normal 8 hours after catheter removal.

DIAGNOSES

Based on the patient's complaints and clinical appearance, diagnosis of PDPH was considered.

INTERVENTIONS

Nasal congestion disappeared with headache and dizziness after epidural injections of saline. The puerpera received saline injections 4 times; after treatment, she was discharged from the hospital when the symptoms did not limit her daily movement.

OUTCOMES

The symptoms disappeared completely on the seventh day of telephone follow-up visit. The mechanism of her nasal obstruction is not very clear.

CONCLUSION

We believe it is caused by the pulling of the intracranial nerve as the brain tissue sinks and shifts due to the decrease in intracranial pressure.

Cryosurgical posterior nasal tissue ablation for the treatment of rhinitis

Background

Endoscopic posterior nasal nerve (PNN) resection has been described as an efficacious surgical treatment of allergic and nonallergic rhinitis, but the requirement for surgery under general anesthesia has limited its acceptance. We report the first series of patients treated for chronic rhinitis using a novel device designed for office‐based cryosurgical ablation of the PNN.

Methods

Twenty‐seven patients with chronic rhinorrhea and/or nasal congestion for >3 months were recruited (allergic or nonallergic rhinitis), with minimum rhinorrhea and/or congestion subscores of 2 as part of the Total Nasal Symptom Score [TNSS]). Under local anesthesia, the cryotherapy device was applied endoscopically to the posterior middle meatus and was used to freeze the PNN region bilaterally. Patients were followed up after 7, 30, 90, 180, and 365 days to assess TNSS.

Results

The procedure was successfully completed in 100% of patients, with no complications; 74% reported no or mild discomfort by the first postprocedure day. TNSS was reduced significantly at 30 days (mean ± standard deviation: 6.2 ± 0.5 at baseline, 2.6 ± 0.3 at 30 days, n = 27, p < 0.001), with continued reduction at 90 (2.7 ± 0.4, n = 24, p < 0.001), 180 (2.3 ± 0.5, n = 21, p < 0.001), and 365 days (1.9 ± 0.3, n = 15, p < 0.001). Both rhinorrhea and congestion subscores decreased significantly at 30, 90, 180, and 365 days compared to baseline (p < 0.001). Allergic and nonallergic subcohorts both appeared to benefit from treatment.

Conclusion

Office‐based cryotherapy of the PNN region is safe and well tolerated. Symptom scores were significantly decreased by 7 days postprocedure and remained lower at 30, 90, 180, and 365 days.

Immunohistochemical localization of subtypes of muscarinic receptors in human inferior turbinate mucosa

The regulation of glandular secretions and vasomotor tone in human nasal mucosa implicates muscarinic receptors. There are 5 recognized classes (m1 through m5) of muscarinic receptor subtypes, and the aim of our study was to localize muscarinic receptor subtypes (m1 through m5) in human inferior turbinate mucosa by an immunohistochemical method. We found m1 and m2 receptors distributed on glands, arteries, veins, and epithelia; m4 receptors were found around arteries; and m5 receptors were identified on glands and arteries. We found m3 receptors to be the most extensively distributed on glands, arteries, and veins of all of the muscarinic receptor subtypes. The m3 receptor is probably important in the physiology of the human inferior turbinate. This study may help identify the best target for more selective muscarinic drugs and guide the treatment of allergic and nonallergic rhinitis.

Clinical manifestations of the release of histamine and other inflammatory mediators

This article reviews the symptoms that are characteristic of the early- and late-phase allergic reaction. Each of the cardinal symptoms of seasonal allergic rhinitis (sneezing, pruritus, rhinorrhea, congestion) is discussed, as is the role of various chemical mediators in the expression of these clinical manifestations.

Distribution and quantity of neuroendocrine markers in allergic rhinitis

Neuroendocrine components exist in the human nasal mucosa. However, the pathophysiological and neuroimmunological roles of the regulatory peptides in allergic rhinitis (AR) require further investigation. To analyse the functional morphology and quantify the tissue concentration of regulatory peptides in the nasal mucosa of AR subjects, human inferior turbinate mucosa specimens from 25 patients with AR, 20 patients with non-allergic rhinitis and 10 patients without any nasal diseases were investigated. Using immunohistochemistry and radioimmunoassays, we detected the presence, distribution and concentrations of various neuropeptides [vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), substance P (SP) and calcitonin gene-related peptide (CGRP)] and general neuroendocrine markers (neuron-specific enolase and chromogranin A). Quantitative analysis of the stained fibres and cells was performed using a graphic AutoCAD program. The presence and distribution of NPY, CGRP and SP nerve fibres and neuroendocrine cells were similar among the three subject groups. AR subjects had significantly higher tissue concentrations of VIP and SP. AR subjects had increased numbers of VIP fibres which predominantly innervated vessels. Thus, VIP and SP play important neuroimmunological roles in the pathogenesis of AR.

Neuropeptide innervation and neuroendocrine cells in allergic rhinitis and chronic hypertrophic rhinitis

BACKGROUND

The neuropeptides and neuroendocrine cells are proven to exist in the human nasal mucosa. However, the pathophysiological and neuroimmunological roles of regulatory peptides in human nasal diseases require further investigation.

OBJECTIVES

To investigate and compare the functional morphology and quantify the tissue concentration of regulatory peptides in the nasal mucosas of normal, allergic rhinitis (AR) and chronic hypertrophic rhinitis (CHR) subjects.

METHODS

Human inferior turbinate mucosa specimens from 28 patients with AR, 25 patients with CHR and 15 patients without any nasal diseases were investigated. Using immunohistochemistry and radioimmunoassays, we detected the presence, distribution and concentrations of various neuropeptides (vasoactive intestinal peptides [VIP], neuropeptide Y [NPY], substance P [SP], calcitonin gene-related peptides [CGRP]) and general neuroendocrine markers (neurone-specific enolase, chromogranin A and somatostatin). Quantitative analysis of the stained fibres and cells were performed using a graphic AutoCAD program.

RESULTS

The presence and distribution of NPY, CGRP, and SP nerve fibres and neuroendocrine cells were similar among the three subject groups. AR subjects had significantly higher VIP and SP tissue concentrations. VIP fibres had highest density in AR subjects and these fibers predominantly innervated vessels. In CHR, VIP fibres primarily innervated glands.

CONCLUSIONS

VIP and SP may play an important neuroimmunological role in the pathogenesis of AR. VIP may lead to the hypertrophic changes of submucosal glands in the pathogenesis of CHR.

Anterior Ethmoidal Glycerol Rhizotomy for Vasomotor Rhinitis

The treatment of vasomotor rhinitis by anterior ethmoidal glycerol rhizotomy (AEGR) was assessed in 78 patients with a follow-up period ranging from 12 to 15 months. The reduction of nasal hypersecretion obtained with AEGR was maintained over six months. At the final assessment, sixty patients (76.9%) reported complete relief of symptoms and are taking no medications; seven (8.9%) were improved with minimal drug therapy required for symptom relief; and 11.9% had poor results with unsatisfactory control even with medication. Nineteen patients required a second treatment because of an initial suboptimal injection or recurrence. Apparently, this method offers those patients with vasomotor rhinitis a valid option for treatment of clinical symptoms, with the additional benefit of experiencing no serious complications when compared with vidian neurectomy.

Presence of neuropeptides in human nasal polyps

The pathophysiological effects of non-cholinergic, non-adrenergic neuropeptides are well known in the nasal mucosa, but unclear in the polyps. Since the pathophysiological roles of neuropeptides depend on their presence in the target tissue, specimens of nasal polyps were removed from 20 patients and examined for the presence of vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), dopamine-beta-hydroxylase (DBH), substance P (SP) and calcitonin gene-related peptide (CGRP). To visualize these neuropeptide fibers, immunohistochemical staining by the peroxidase-anti-peroxidase method and color reaction by Nickel enhancement of diaminobenzidine (DAB) were used. Fine varicose neuropeptides immunostained fibers were predominantly distributed in the pedicle of the polyps. No neuropeptides were found in the mucosal epithelium and subepithelium. NPY fibers were predominantly seen around the thick wall vessels, whereas the VIP fibers were mainly to be found in close proximity to the submucosal glands and fairly close to the vessels. SP or CGRP fibers were not found in the polyps. VIP and NPY in the pedicle of the polyps may be present in connection with mucosal inflammation, tissue edema and cystic degeneration of the glands in the early stage of polyp formation. Thus these neuropeptides may contribute to the development and growth of nasal polyps.

Muscarinic receptor subtypes in human nasal mucosa: characterization, autoradiographic localization, and function in vitro

Muscarinic receptors play important roles in the regulation of glandular secretion and vasomotor tone in human nasal mucosa. M1, M2, and M3 muscarinic receptor subtypes were pharmacologically characterized in human inferior turbinates by receptor-binding assays using [3H](-)quinuclidinyl benzilate (QNB, identifies total muscarinic receptors) and [3H]-pirenzepine (PZ). Receptors were localized by autoradiography, and their function examined in vitro by assaying mucus secretion from cultured nasal mucosal explants. In competition assays, PZ was employed as a selective muscarinic antagonist for M1 receptors, gallamine and AF-DX 116 for M2 receptors, and 4-DAMP for M3 receptors. These ligands are selective at low nanomolar concentrations, but can interact with other muscarinic receptors at higher concentrations. It is not known if they can interact with putative M4 and M5 muscarinic receptor subtypes. Using [3H](-)QNB, total muscarinic receptor binding was 688.4 +/- 49.6 fmol/mg protein (Bmax), with a Kd of 1.47 +/- 0.13 nM. [3H]-PZ bound to 45% of the total QNB binding sites. In competition experiments, 4-DAMP displaced [3H](-)QNB with the lowest IC50, followed by PZ and AF-DX 116. Autoradiograms demonstrated that [3H](-)QNB binding was completely displaced by 4-DAMP, partially displaced by PZ, but not displaced by gallamine or AF-DX 116, and suggested that M1 and M3 subtypes coexist in submucosal glands. The localization of M1 receptors on submucosal glands was confirmed by direct labeling with [3H]-PZ. [3H]-PZ also labeled vessels, but with a low silver grain density. Autoradiographic [3H]-QNB binding was displaced by 4-DAMP and atropine, but not by PZ, gallamine, or AF-DX 116. In studies of mucus secretion in vitro, 4-DAMP significantly inhibited methacholine-induced secretion. Although less effective, PZ also had significant inhibitory effects. Neither gallamine nor AF-DX 116 had any inhibitory effect. M1 receptors (PZ binding sites) may regulate glandular secretion while M3 receptors (4-DAMP binding sites) may regulate glandular secretion and vasomotor tone in human nasal mucosa.

Measurement of multiple microcirculatory parameters in human nasal mucosa using laser-Doppler velocimetry

LDV has been modified to measure four microcirculatory responses in human nasal mucosa. Resting nasal blood flow was measured in 115 observations in 23 nonatopic subjects and 111 observations in 21 atopic subjects with allergic nasal disease. Other parameters measured concurrently were the number density of moving red blood cells (RBC), mean RBC speed, and flow pulsatility. Challenges with aerosolized buffered saline or water had no significant effect on any parameter. By contrast, nasal application of alpha-adrenergic agonists, oxymetazoline and phenylephrine, produced significant dose-dependent reductions in flow without any significant change in RBC number density. These results suggest a selective alpha-agonist effect on resistance vessels but not on capacitance vessels. Topical cholinergic stimulation with methacholine selectively reduced the RBC number density without affecting other parameters. These modifications of LDV may prove useful in analyzing nasal responses to provocation and determining the sites of action of vasoactive agents on the microcirculation.

The effect of ipratropium bromide on nasal hypersecretion induced by methacholine in patients with vasomotor rhinitis. A double-blind, cross-over, placebo-controlled and randomized dose-response study

The effect of various doses of ipratropium bromide aerosol on nasal hypersecretion induced by five concentrations methacholine was studied in 24 patients with vasomotor rhinitis and excessive watery nasal secretion. The volume of nasal secretion was greater with each of the five increasing doses of methacholine from 7.5 to 120 mg/ml. The median volume of nasal secretion was alike in all patients after administration of methacholine only and after treatment by placebo followed by methacholine. When the patients were treated with ipratropium bromide prior to administering methacholine the volume of secretion was reduced significantly. With doses of 40 micrograms and 100 micrograms of ipratropium to each nostril a similar reduction in the volume of secretion occurred but a still greater reduction by the application of 200 micrograms of ipratropium when compared with treatment by the placebo. While the volume of secretion increased with each increasing concentration of methacholine, a similar pattern of reduced secretion for each concentration of methacholine was seen with each greater concentration of ipratropium. In patients with vasomotor rhinitis, treatment with ipratropium bromide was found to reduce significantly the hypersecretion induced by methacholine when compared with treatment by the placebo. This reduction was greater with greater doses of ipratropium.

Pathophysiology of rhinitis. 1. Assessment of the sources of protein in methacholine-induced nasal secretions

Nasal provocation tests with normal saline and methacholine (MC) were performed in 25 atopic and 27 nonatopic subjects in an effort to assess the sources of protein in induced airway secretions. Nasal lavages obtained at baseline and after provocation were analyzed for albumin, total protein, secretory IgA (sIgA), and total IgA. Compared with baseline levels or saline provocation, MC provocation increased the secretion of albumin (p less than 0.025), total protein (p less than 0.001), sIgA (p less than 0.025), and total IgA (p less than 0.025), but did not significantly affect the relative proportions of albumin-to-total protein (albumin percent) or sIgA-to-total IgA (sIgA/total IgA ratio). Nasal pretreatment with atropine significantly inhibited MC-induced secretion of all 4 proteins, again without affecting the albumin percent or the sIgA/total IgA ratio. Because MC is known to stimulate atropine-inhibitable secretion of glandular products, these data suggest that sIgA and albumin may accompany glandular secretions. Immunohistochemical analyses of nasal turbinates confirmed that secretory component was found only on serous cells within submucous glands. Thus, it appears that cholinergic stimulation may regulate sIgA secretion and thereby participate in local nasal (and possibly respiratory tract) immunity.

Secretion, pain and sneezing induced by the application of capsaicin to the nasal mucosa in man

1. Topical application of capsaicin to the human nasal mucosa induced a burning sensation and sneezing. A dose-dependent seromucous nasal secretion was also observed. Capsaicin (75 micrograms) was more potent than methacholine (50 mg) in producing nasal secretion, while topical histamine (200 micrograms), substance P (135 micrograms) and calcitonin gene-related peptide (36 micrograms) did not induce rhinorrhea. 2. Pretreatment with either topical ipratropium bromide, systemic dexchlorpheniramine or indomethacin did not influence the effects induced by capsaicin. Topical pretreatment with lidocaine inhibited the painful sensation but failed to block the rhinorrhea. Desensitization to the effects of capsaicin occurred following 4-5 subsequent applications, and full recovery was observed within 30-40 days. 3. It is proposed that the effects of capsaicin in human nasal mucosa are due to excitation of primary afferent neurones that (a) convey burning and painful sensation, (b) evoke a sneezing reflex and (c) induce nasal secretion by releasing transmitter(s) from their peripheral terminals.

Distribution of noradrenergic nerve fibers in canine nasal mucosa following selective neurectomies

In this study, we have used noradrenergic histofluorescence and selective neurectomies of the vidian, ethmoid and caudal nasal nerves to evaluate the distribution of postganglionic sympathetic fibers in the canine nasal mucosa. In conjunction with the histochemical localization of the noradrenergic fibers in the nasal mucosa after vidian neurectomy, the norepinephrine content of the mucosa was also evaluated using high-performance liquid chromatography. Unilateral neurectomy of the superior cervical ganglion (SCG) resulted in the unilateral disappearance of all noradrenergic histofluorescence in the nasal mucosa, while no morphological changes in noradrenergic fibers could be identified after neurectomy of the cervical sympathetic trunk 1 cm below the SCG. Ethmoid neurectomy caused the disappearance of noradrenergic fibers of the upper third of the nasal mucosa, while vidian neurectomy resulted in a partial loss of noradrenergic fibers in the lower two-thirds of the nasal mucosa. The loss was chiefly in the area adjacent to venous sinusoids and was responsible for 50% of the norepinephrine content of this tissue. We concluded that all the postganglionic sympathetic fibers are from the ipsilateral SCG. Some of them travel via the ethmoid nerve and innervate the upper third of the nasal mucosa. The remaining fibers travel via the vidian nerve and perhaps the vessel walls of the supplying arteries and innervate the lower two-thirds of the nasal mucosa. The vidian nerve chiefly innervates the venous sinusoids of the lower two-thirds of the nasal mucosa.

Retrograde axonal transport of true blue dye by the peripheral autonomic nerves in canine nasal mucosa

In this study we employed retrograde axonal transport of (E)-2,2'-vinylendi-benzofuran-5-carboxamidin-diaceturate+ ++ or true blue (TB) to study the peripheral autonomic innervation of the canine nasal mucosa. After injection of TB into the nasal mucosa, labeled neurons were found in the ipsilateral sphenopalatine ganglion (SPG) and the superior cervical ganglion (SCG). There were no labeled neurons in the middle cervical or stellate ganglia. This indicated that the origin of the postganglionic sympathetic fibers of the nasal mucosa was only from the ipsilateral SCG. When TB was injected into the nasal mucosa of dogs following a caudal or ethmoidal neurectomy, labeled neurons could still be found in the SPG and SCG. When TB was injected into the nasal mucosa of dogs following ethmoidal and vidian neurectomies or with maxillary neurectomy added, some labeled neurons could still be found in both the ipsilateral SPG and SCG. These results support the concept that another pathway--perhaps perivascular--exists for postganglionic sympathetic fibers other than the vidian and ethmoidal nerves. Labeled neurons were still observed in SPG when TB was applied to the canine nasal mucosa following neurectomy of either the ethmoidal or the caudal nasal nerve. However, retrograde labeled neurons could not be found in SPG following simultaneous neurectomies of the ethmoidal and caudal nasal nerves. These results show that the postganglionic parasympathetic fibers originating in the SPG travel along the ethmoidal and caudal nasal nerves.

Autonomic microganglia of the nasal mucosa and their relation to vasomotor rhinitis

The classical concept of the autonomic innervation of the nasal mucosa states that the postganglionic sympathetic neurones lie in the superior cervical ganglion and those of the postganglionic parasympathetic neurones are in the pterygopalatine ganglion. We have carried out a study of the fine structure of the respiratory nasal mucosa in man and in the cat using the techniques described by Jabonero, Champy Maillet and Koelle-Friedenwald. The most striking finding was the presence of microganglia deep within the mucosa of the inferior turbinate close to the glands. These microganglia were cholinergic in nature since they demonstrated a positive reaction to anticholinesterase. From this we deduce that the nasal parasympathetic pathway has its postganglionic neurones not only in the pterygopalatine ganglion but also in these microganglia of the inferior turbinate. Each of four groups of cats were submitted to different techniques, including administration of neostigmine, inferior turbinectomy and Vidian neurectomy. Resection of the microganglia by means of turbinectomy reduced the hypersecretion caused by neostigmine and this was most noticeable when a Vidian neurectomy was carried out in addition.

Characterization of alpha-adrenoceptors in the vasculature of the canine nasal mucosa

alpha-Adrenoceptors present in the vasculature of the nasal mucosa in beta-adrenoceptor blocked dogs have been characterized pharmacologically using selective alpha 1- and alpha 2-adrenoceptor agonists and antagonists. In pentobarbitone-anaesthetized dogs, intra-arterial (i.a.) administration of the selective alpha 1-agonists cirazoline and phenylephrine, the selective alpha 2-agonist UK-14,304 and the mixed alpha 1/alpha 2-agonists adrenaline, noradrenaline and oxymetazoline produced dose-related nasal vasoconstrictor responses (as measured by decreases in nasal cavity pressure). The rank order of agonist potency was adrenaline greater than oxymetazoline = UK-14,304 greater than noradrenaline greater than cirazoline greater than phenylephrine. The nasal response to cirazoline was inhibited by the selective alpha 1-adrenoceptor antagonist prazosin but not by the new, potent selective alpha 2-adrenoceptor antagonist RX811059. In contrast, UK-14,304 was inhibited only by RX811059. Either prazosin or RX811059 reduced the effect of the mixed agonist adrenaline. In spinal dogs, the noradrenaline-evoked fall in nasal cavity pressure was reduced by either prazosin or RX811059. Prazosin attenuated markedly the nasal vasoconstrictor response to electrical stimulation of postganglionic fibres emerging from the superior cervical ganglion (SNS) whereas RX811059 was ineffective. Administration of the neuronal re-uptake inhibitor cocaine potentiated the effect of i.a. noradrenaline but reduced marginally the maximal response to SNS. After cocaine, RX811059 enhanced the effect of SNS and attenuated the response to noradrenaline. Prazosin reduced effectively the responses to both SNS and noradrenaline after cocaine. Pretreatment with the alpha 2-agonist UK-14,304 did not affect the response to noradrenaline in the nasal cavity but evoked a persistent (up to 2 h) reduction in the response to SNS. RX811059 antagonized the inhibitory effect of UK-14,304. These results demonstrate that both postjunctional alpha 1- and alpha 2-adrenoceptors mediating vasoconstriction are present in the canine nasal mucosa. In addition, sympathetic neurones innervating the nasal mucosa are characterized by a very efficient re-uptake process and contain prejunctional alpha 2-adrenoceptors.

Adrenoceptors in the control of human nasal mucosal blood flow

The blood flow in the human nasal mucosa is controlled by the functional state of the resistance vessels. This blood flow was studied by means of the 133Xe washout method. Using topical application of drugs that stimulate or block adrenoceptors, including clinical doses of nasal decongestants, we classified the adrenoceptors of the resistance vessels in the mucosa. The results suggest that stimulation of alpha2-adrenoceptors causes a reduction of nasal mucosal blood flow; stimulation of alpha1- and beta2-adrenoceptors seems to have no significant effects. Drugs that selectively stimulate alpha2-adrenoceptors, as well as those with preference for alpha1-adrenoceptors, cause nasal decongestion. To avoid the negative effects of a nasal mucosal blood flow reduction, it is suggested that a nasal decongestant with an alpha1-adrenoceptor stimulating effect should be preferable to a drug acting mainly on alpha2-adrenoceptors, provided that the decongestive effects are equal.

Effects of antidromic trigeminal nerve stimulation in relation to parasympathetic vasodilation in cat nasal mucosa

High threshold stimulation of the trigeminal nerve in sympathectomized cats caused an atropine and hexamethonium resistant vasodilation in the nasal mucosa. Stimulation of efferent parasympathetic neurons to the nose caused a partially atropine sensitive vasodilation which was abolished by hexamethonium. Combined trigeminal and parasympathetic nerve stimulation did not reveal any obvious functional interactions between these two systems. Local intra-arterial infusions of substance P, VIP and acetylcholine caused a dose dependent vasodilation in the nasal mucosa. The relative vasodilatory potencies were substance P greater than to VIP greater than acetylcholine. Local infusions of capsaicin, known to release substance P from nerve endings, caused a marked longlasting biphasic vasodilation which was atropine and hexamethonium resistant. In conclusion, the present findings illustrate the presence of two vasodilator mechanisms of different nervous origin in the nasal mucosa. The trigeminal response is probably mediated via release of substance P, while the parasympathetic effect seems to be caused by acetylcholine and VIP.

Innervation of the mucosa of rabbit maxillary sinus. II. Demonstration of catecholamine fluorescence and acetylcholinesterase activity

The innervation of the rabbit maxillary sinus mucosa has been studied with histochemical techniques, using the glyoxylic acid-induced fluorescence for the demonstration of catecholamines and the acetylcholinesterase method. A dense acetylcholinesterase-positive nerve plexus can be demonstrated around the secretory end-pieces, the efferent ducts, the blood vessels in the lamina propria, and rarely but regularly in the ciliated epithelium. A doubtless identification of these nerve fibres to be cholinergic does not seem possible. The adrenergic innervation is lacking within the epithelium, but can be seen near the muscle layers around blood vessels and in the lamina propria. An additional sympathetic control of the glandular activity is not excluded.

Histochemical demonstration of peripheral autonomic innervation in canine nasal mucosa by retrograde axonal transport of horseradish perioxidase

The peripheral autonomic nervous pathways of the nasal mucosa in dogs were investigated by the horseradish peroxidase (HRP) method. HRP was applied to the nasal mucosa, caudal nasal nerve, ethmoidal nerve, vidian nerve and pterygopalatine ganglion in 20 dogs, and retrogradely labelled neurons were observed in the superior cervical ganglion (SCG) and the pterygopalatine ganglion (PPG) by the blue reaction method. It was suggested that the vidian nerve, the maxillary branch of the trigeminal nerve, the caudal nasal nerve, the pterygopalatine nerve and the ethmoidal nerve contained the postganglionic sympathetic fibres which originated in SCG and terminated in the nasal mucosa. Moreover, other sympathetic pathways, such as those around the blood vessels, were also suggested to be a main route. It was suggested that the postganglionic parasympathetic fibers originating in PPG travelled along the caudal nasal nerve and the ethmoidal nerve.

Neurophysiological mechanism of shrinkage of nasal mucosa induced by exercise

Change of serum norepinephrine level and nasal patency were measured in 10 normal volunteers during exercise and effect of unilateral cervical sympathetic ganglion block on exercise-induced shrinkage of nasal mucosa was evaluated. Serum norepinephrine elevated markedly after 10-min exercise. Unilateral blocking of cervical ganglion completely inhibited mucosal shrinkage induced by exercise in 8 of 10 subjects. Mucosal shrinkage during exercise in these subjects was assumed to be mediated through cervical sympathetic ganglion, and not by increase in circulating cathecolamine. However, in 2 subjects, moderate shrinkage of the nasal mucosa was observed in 10-min after initiation of exercise. It was impossible to rule out some effect of circulating cathecolamine on the capacitance vessels of the nasal mucosa completely.

Role of the vidian nerve in nasal allergy

Clinical studies were performed to evaluate the role of the vidian nerve at onset of symptoms in nasal allergy. A localized area of one side of the nasal cavity was stimulated with known allergen and 0.1% histamine chloride in patients with perennial nasal allergy. The effect of unilateral vidian neurectomy and sensory anesthesia on glandular and vascular response was evaluated. With localized nasal stimulation, hyperrhinorrhea was seen in both sides of the nasal cavity before vidian neurectomy. Unilateral vidian neurectomy blocked hyperrhinorrhea only in that nasal cavity in which the nerve was sectioned. However, hyperrhinorrhea from the contralateral side, with an intact vidian nerve, was blocked with sensory anesthesia of the opposite side of the nasal cavity where the stimulation was applied. Nasal hypersecretion in allergic rhinitis was assumed to be mostly due to stimulation of sensory receptors by a chemical mediator and reflexive stimulation of the nasal glands. Vidian neurectomy, however, did not have any apparent influence on the swelling of the nasal mucosa caused by localized stimulation of allergen and histamine.

Vidian neurectomy: neuroanatomical considerations and a report on a new surgical approach

If conventional treatment fails, vidian neurectomy is a viable alternative for therapy of chronic rhinitis with recurrent polyposis of the nose and sinuses. From a neuroanatomical point of view beneficial and adverse effects of this surgical procedure are discussed. According to our own investigations and experiences, vidian neurectomy should be performed together with clearing out of the sinuses in every case. Beginning with this precondition a new surgical approach was developed: the vidian nerve is detected through a transethmoidal route in the pterygoid canal at the bottom of the sphenoid sinus and dissected using the operation microscope.

Sympathetic nerve pathways to the nasal vasculature of the cat

The sympathetic nerve pathways to the nasal vasculature were examined in 8 cats by recoding the effects of section of the orbital nerves on vasoconstriction produced by cervical sympathetic nerve stimulation. No sympathetic fibres were found in the sphenopalatine and infraorbital nerves. The majority were conveyed by either the Vidian or ethmoidal nerves, the remaining fibres are believed to reach the nasal cavity by the periarterial plexus.

Relationship between the vegetative innervation and the sensibility of the nasal mucosa

Experimentally and clinically, we observed that the parasympathicomimetic reaction of the nasal mucosa was congruent with higher sensitivity of the nasal mucosa. The opposite is true of the sympathicomimetic reaction. The reason for this difference in reaction is connected with the transmitting agent of the vegetative system. This is shown in the provocation of intradermal reaction of different allergens by these transmitting agents.

Selective denervation of the autonomic nerve supply of the nasal mucosa

The autonomic innervation of the nasal mucosa has been studied in normal rats and in rats in which the supplying nerves had seen selectively transected; postoperative survival times varied from 2 weeks up to 18 months. The vascular structures appeared to be innervated both by acetylcholinesterase- and noradrenalin-containing fibres. Furthermore a nerve plexus consisting of both types of fibres was observed in the subepithelial region. The nasal glands however showed only a cholinergic innervation. The pattern of the autonomic nerve supply deduced from these selective denervation experiments does not differ fundamentally from the generally accepted scheme of this system in the nose of other mammals. Denervation occurred within 2 weeks after transection of the supplying nerves, but after longer survival times reinnervation was observed.