Anterior Ethmoidal Nerve Research Articles

The neuronal circuit of augmenting effects on intrinsic laryngeal muscle activities induced by nasal air-jet stimulation in decerebrate cats

We previously demonstrated that during nasal air-jet stimulation, both the activities of intrinsic laryngeal adductor and abductor muscles persistently increase, whereas the respiratory cycle prolongs and the activity of diaphragm decreases [Am. J. Rhinol. 9 (1995) 203–208; Neurosci. Res. 31 (1998) 137–146]. The purpose of this study was to clarify the neuronal circuit underlying the augmentation of intrinsic laryngeal muscles evoked by nasal air-jet stimulation. The immunohistologic analysis of Fos-expression was reported to determine the distribution of activated neurons in cat brainstem evoked by sneeze-inducing air puff stimulation of the nasal mucosa [Brain Res. 687 (1995) 143–154]. In sneezing cats, immunoreactivity was evoked in projection areas of the ethmoidal afferents, e.g. the subnuclei caudalis, interpolaris and in interstitial islands of the trigeminal sensory complex. Immunoreactivity was also enhanced in the solitary complex, the nucleus retroambiguus, the pontine parabrachial area and the lateral aspect of the parvocellular reticular formation [Brain Res. 687 (1995) 143–154]. In the present study, we focussed on the parvocellular reticular nucleus (PRN) as a relay of the neural circuit contributed to the augmentation of intrinsic laryngeal muscles evoked by nasal air-jet stimulation. We recorded the neuronal behavior of PRN during the nasal air-jet stimulation in precollicular-postmammillary decerebrate cats. As the results, 24% (17/71) of recorded neurons which were activated orthodromically by the electrical stimulation to anterior ethmoidal nerve, increased their firing rates in response to the nasal air-jet stimulation. Furthermore, spike-triggered averaging method revealed that four of these 17 PRN neurons activated intrinsic laryngeal muscles, suggesting that such neurons have excitatory projections to the intrinsic laryngeal muscle motoneurons in the nucleus ambiguus. These results suggest that the some of PRN neuron play a role in augmentation of the intrinsic laryngeal muscles activities during nasal air-jet stimulation.

Orbital Passage of Pterygopalatine Ganglion Efferents to Paranasal Sinuses and Nasal Mucosa in Man

Parasympathetic nerves of pterygopalatine ganglion origin are considered to enter the orbit and distribute to the nasal mucosa with the anterior ethmoidal nerve. As their distribution has never been demonstrated the present study was undertaken to seek evidence of their passage and to identify their relationship with the ethmoidal nerves. The soft tissues of the pterygopalatine fossa and orbit from sixteen sides of twelve cadavers were removed in one piece and either dissected or cut coronally into slabs and prepared histologically using montages of thin resin-embedded sections at intervals suitable for nerve path tracing. Several of the rami orbitales passing mediodorsally from the ganglion enter the orbit apically, branch and enter the posterior ethmoidal foramen terminating in the lining of the paranasal sinuses and others advance to enter the anterior ethmoidal canal to reach the nasal mucosa. No junctions were made with ethmoidal nerves within the orbit or the canal. Failure of surgical lesions of the anterior ethmoidal nerve as a treatment for vasomotor rhinitis may be attributed to the sparing of the separate parasympathetic nerves. Appropriate chemical lesions, on the other hand, could ensure destruction of isolated parasympathetic nerves while limiting damage to the larger anterior ethmoidal nerve.

Trigemino-autonomic connections in the muskrat: the neural substrate for the diving response

Stimulation of the anterior ethmoidal nerve of the muskrat produces a cardiorespiratory depression similar to the diving response. This includes an apnea, a parasympathetic bradycardia, and a selective increase in sympathetic vascular tone. However, the brainstem circuitry that links the afferent stimulus to the efferent autonomic responses is unknown. We used the anterograde transneuronal transport of the herpes simplex virus (HSV-1), strain 129, after its injection into the anterior ethmoidal nerve to determine the primary, secondary, and tertiary brainstem relays responsible for this cardiorespiratory response. In an effort to check the validity of this relatively untested tracer, we also injected the medullary dorsal horn with biotinylated dextran amine to determine the secondary trigemino-autonomic projections. Approximately 1 μl (6×10 6 PFU) of the HSV-1 virus was injected directly into the anterior ethmoidal nerve of muskrats. After 2–6 days, their trigeminal ganglions, spinal cords and brainstems were cut and immunohistologically processed for HSV-1. Initially (2 days), HSV-1 was observed only in the trigeminal ganglion. After approximately 3 days, HSV-1 was observed first in many brainstem areas optimally labeled between 4 and 4.5 days. In these cases, the ventrolateral superficial medullary dorsal horn, the ventral paratrigeminal nucleus and the interface between the interpolar and caudal subnuclei were labeled ipsilaterally. The nucleus tractus solitarius (NTS), especially its ventrolateral, dorsolateral, and commissural subnuclei were labeled as well as the caudal, intermediate and rostral ventrolateral medulla. Within the pons, the superior salivatory nucleus, the A5 area, the ventrolateral part of the parabrachial nucleus and the Kölliker–Fuse nucleus were labeled. Only after a survival of 4 days or more, the locus coeruleus, the nucleus raphe magnus, the nucleus paragigantocellularis, pars alpha, and the pontine raphe nucleus were labeled. Injections of biotinylated dextran amine were made into the medullary dorsal horn (MDH) in a location similar to that labeled after the viral injections. Fine fibers and terminals were labeled in the same brainstem areas labeled after injections of HSV-1 into the anterior ethmoidal nerve. This study outlines the potential brainstem circuit for the diving response, the most powerful autonomic reflex known. It also confirms the efficacy for using HSV-1, strain 129, as an anterograde transneuronal transport method.

Electrical stimulation of the anterior ethmoidal nerve produces the diving response

Stimulation of the upper respiratory tract usually produces apnea, but it can also produce a vagally mediated bradycardia and a sympathetically mediated increase in peripheral vascular resistance. This cardiorespiratory response, often called the diving response, is usually initiated by nasal stimulation. The purpose of this research was to investigate the anterior ethmoidal nerve (AEN) that innervates the nasal mucosa of muskrats ( Ondatra zibethicus). Electrical stimulation of the AEN (typically 50 Hz, 100 μs and 500 μA) produced immediate and sustained bradycardia and cessation of respiration similar to that of the diving response. Heart rate (HR) significantly decreased from 264±18 to 121±8 bpm, with a concurrent 4.2±0.9 s apnea, during the 5 s stimulation period. BP decreased from 97.9±4.8 to 91.2±6.4 mmHg. Using estimations from (1) cross-sectional areas of AEN trigeminal ganglion cells labeled with WGA-HRP, and (2) electron microscopic analysis of the AEN, we found that approximately 65% of the AEN is composed of unmyelinated C-fibers. In addition, 72.4% of myelinated fibers from the nerves that innervate the nasal passages were of small diameter (<6 μm, presumably Aδ fibers). Thus, the AEN of the muskrat contains a high concentration of small diameter fibers (89.8%). We conclude that electrical stimulation of small diameter fibers within the AEN of muskrats can produce the cardiovascular and respiratory responses similar to that of the diving response.

Upper airway motor outputs during sneezing and coughing in decerebrate cats

The purposes of the present study were to determine which upper airway movements cause a difference in the expiratory airflow pathway between sneezing and coughing, and to develop a new animal model for studying the neural mechanism of sneezing in paralyzed animals, i.e. fictive sneezing. We compared the upper airway motor patterns of sneezing and coughing, induced by electrical stimulation of the anterior ethmoidal nerve (AEN) and superior laryngeal nerve, respectively, in non-paralyzed decerebrate cats. Respiratory and laryngeal motor patterns that consisted of an inspiration phase, compression phase, and expulsion phase were observed for both sneezing and coughing. The main difference was observed in the activity of the elevator of the back of the tongue, styloglossus (SG) muscle, which was explosively activated during the expulsion phase of sneezing, whereas it was virtually silent during coughing. The nasopharyngeal closers were weakly to moderately activated during sneezing. Their activities during coughing were weaker than during sneezing. Furthermore, the AEN-induced activities of the phrenic and abdominal nerves and the lateral branch of the hypoglossal nerve (lat-XII), which innervates the SG muscle, in paralyzed cats were consistent with the activities of the diaphragm, abdominal, and SG muscles during actual sneezing in non-paralyzed cats. Thus, we conclude that tongue movement is the main difference in the motor outputs between sneezing and coughing, which probably causes greater nasal airflow in sneezing, and that it is necessary to record the activity of the lat-XII to identify fictive sneezing in paralyzed cats.

気道反射における喉頭の機能, 調節機構

The glottis closes during not only cough reflex but also sneezing. It indicates that the activity of laryngeal motor neurons within the nucleus ambiguus is influenced by both the superior laryngeal and the trigeminal afferents. In this study, the convergence of inputs originated from the superior laryngeal and the anterior ethmoidal nerves is examined in decerebrate cats. Thirty two neurons are activated orthodromically by ipsilateral stimulation to the superior laryngeal nerve. Fifty eight neurons are activated orthodromically by ipsilateral stimulation to the anterior ethmoidal nerve. These two neuronal groups are overlapped each other in the nucleus reticularis parvicellularis of medulla. However, the neurons receiving afferents from the superior laryngeal nerve tend to exist in the dorso-lateral portion of the nucleus, while the neurons receiving afferents from the ethmoidal nerve tend to exist in the medio-ventral portion. Seven neurons receive afferents from both nerves. Most of these neurons are located in the overlapped area of two neuronal groups, which is apart from the nucleus ambiguus. The projectional pattern that different inputs converge into the reticular neurons outside of the nucleus ambiguus can be useful for evoking the adequate airway reflex related to the larynx.

Role of respiratory and non-respiratory neurones in the region of the NTS in the elaboration of the sneeze reflex in cat

Extracellular recordings were made in the dorsal respiratory group (DRG) and adjacent reticular formation following single-shock stimulation of the anterior ethmoidal nerve (AEN) and during sneeze evoked by repetitive stimulation of the AEN in nembutal-anaesthetized, curarized and ventilated cats. These neurones were characterised according to (i) their activity during the respiratory cycle (as inspiratory augmenting or decrementing (I Aug or I Dec), expiratory augmenting or decrementing (E Aug or E Dec), silent or tonic), and (ii) their axonal projection (bulbospinal or non-bulbospinal–non-vagal (BS or NBS–NV)). Following single-shock stimulation of the AEN, most of the inspiratory neurones were transiently inhibited, whereas E Aug neurones were activated and E Dec neurones were activated and then inhibited. Silent neurones responded with a multispike or a paucispike pattern. Following repetitive stimulation of the AEN and during the resulting sneeze reflex, I Aug neurones increased their activity in parallel with the phrenic activity, I Dec neurones fired at the onset and at the end of the inspiration, E Dec and some silent neurones fired either during the compressive phase or after the expulsive phase, whereas E Aug and some silent neurones fired during the expulsive phase. We conclude that sneeze involves a reconfiguration of the central respiratory drive which uses, at least partly, the respiratory network to trigger a non-ventilatory defensive motor act.

Middle turbinate headache syndrome.

The middle turbinate and nasal septum are innervated by the anterior ethmoidal nerve, a branch of the ophthalmic division of the trigeminal nerve. As reported in the classical work of Wolff (1948), stimulation of these regions causes pain in the medial canthus of the supraorbital region. Periorbital pain due to middle turbinate compression against the septum or the lateral wall of the nose may be due to congestion of the nasal mucosa or to pneumatization of the middle turbinate (concha bullosa). The diagnosis is made by exclusion and requires a high index of suspicion, anterior rhinoscopy, computerized tomography (CT), and confirmation by the lidocaine test. We present five cases of middle turbinate headache syndrome, all with concha bullosa. Four were treated surgically by partial middle turbinectomy and septoplasty more than 1 year ago, with excellent results. One patient refused surgical treatment which was suggested after failure of medical treatment with antihistamines, decongestants, and a topical corticosteroid, and continues to be symptomatic. Despite the small number of cases studied, the authors concluded that the procedure used was effective for the resolution of headache.

Unilateral Trigeminal Nerve Branch Lesion (V1 and V2) at the Skull Base and Nasal Capsule Growth in Rabbits

The effects of long-term afferent denervation on midfacial and nasal capsule growth after craniofacial or skull base surgery are unknown. Experimental studies suggest that afferent nerves may play a role in regulating craniofacial growth through neurotrophic influences. The present study was designed to assess the effects of nasal capsule afferent (V1 and V2) denervation on nasal capsule growth in the rabbit. Eighteen 1 1/2-week-old rabbits were evenly divided into three groups: unoperated controls, sham controls, and animals with unilateral anterior ethmoid and sphenopalatine nerve lesions. The nerves were lesioned at the skull base with electrocautery through an intraorbital approach at 1 1/2 weeks of age. Lateral head radiographs and dental study models were taken at 1 1/2, 3 1/2, 6, and 12 weeks of age. By 3 1/2 weeks of age, sham controls and animals with nerve lesions exhibited significant (p < 0.05) reductions in nasal capsule area and height compared with unoperated control animals; the lesioned animals were more severely affected. However, by 6 weeks no differences were noted between the sham and lesioned groups, which were both smaller than unoperated controls through 12 weeks of age. Results suggest that acute nasal capsule growth deficits are a consequence of surgery as well as afferent denervation, with a greater deficit in the latter group, possibly through neurotrophic interruption. Such deficits may not be a permanent effect in the rabbit model.

Nasal receptors responding to noxious chemical irritants

This study was performed to investigate the chemoreception of trigeminal afferents in the nose. Single unit activity was recorded from the anterior ethmoidal nerve in the anesthetized guinea pig breathing through a tracheostomy during nasal instillation of capsaicin (0.3 mM), nicotine (6 mM) and ammonia (1.5 M) solutions or with distilled water. Out of 36 fibers recorded, nineteen were stimulated by capsaicin, six by nicotine and seventeen by ammonia. Among those of fibers, two were stimulated by both capsaicin and nicotine, six by both capsaicin and ammonia and one nicotine-responsive fiber was also stimulated by ammonia. A large proportion of capsaicin- and nicotine-responsive fibers exhibited long lasting discharges (170.4 ± 17.7 sec and 120.7 ± 29.3 sec, respectively), and were not stimulated by the second application of the same substance. However, fibers responding to ammonia discharged for a shorter time (31.5 ± 6.5 sec), indicating a rapid adaptation. These results indicate that the ethmoidal nerve possesses a well-developed responsiveness to noxious stimuli. The nociceptive component of this nerve may be related to the various cardiorespiratory responses that can be elicited from the nasal cavity and also to local axonal reflexes (neurogenic inflammation) due to the release of chemical mediators from C-fiber endings.

Postnatal development of the anterior ethmoidal nerve in cats: Unmyelinated and myelinated nerve fiber analysis

This is the first quantitative electron microscopic study of anterior ethmoidal nerve in adult and newborn cats. The adult nerve comprises about 1,000 myelinated fibers including Aδ (65%) and Aβ (35%) fibers and 6,000 unmyelinated fibers. At birth, only 27% of the adult myelinated fibers complement is already present. The immaturity of the nerve is discussed in relation to that of the sneeze reflex.

Influence of trigeminal nasal afferents on bulbar respiratory neuronal activity

This study examined the influence of nasal trigeminal afferents, the anterior ethmoidal nerve (AEN) and posterior nasal nerves (PNN) on the spike discharges of respiratory-related neurons recorded in the ventral respiratory group (VRG) (2.6–3.5 mm lateral to the midline, from 1 mm rostral to 3 mm caudal to the obex and at depth of 2–4 mm below the dorsal surface). Electrical stimulations to the AEN and PNN were administered to 10 pentobarbital anaesthetized cats and to 8 ketamine anaesthetized, vagotomized, curarized and ventilated cats. Single shock stimulations of either nerve evoked transient and total inhibition of inspiratory activities. Expiratory-related neurons of the VRG presented three patterns of activity in response to stimulation:excitation, inhibition or inhibition followed by excitation. More generally, expiratory units are activated with a short latency. In the course of repetitive stimulation of the AEN and PNN we observed a prolongation of the spontaneous inspiratory discharge which presented transient, short inhibition in response to each shock. Most expiratory units presented a short activation which was synchronous with the transient inhibition of inspiratory activities. When repetitive stimulation provoked a sneeze-like response, we observed a progressive increase in the duration of transient inspiratory inhibition first, associated with a progressive reinforcement of transient expiratory activation. Secondarily, just before the expiratory thrust, we noted a stronger inhibition of the inspiratory activity which preceded a high-frequency (400 Hz) expiratory discharge. Nasal afferents exert a forceful excitatory effect on bulbospinal (BS) and non-bulbospinal—non-vagal (NBS-NV) expiratory cells of the VRG. The effects due to vagotomy and curarization are discussed.

頭痛の原因となった小さなし骨洞骨腫

Small osteomas of the frontal and ethmoid sinuses usually cause no symptoms. When they enlarge, they may produce symptoms such as facial pain, headache, or infection due to obstruction of the nasofrontal ducts.A possible unique association of a small osteoma of the ethmoid sinus with headache is described. The headache of a 44-year-old female was completely relieved by removal of the osteoma compressing the anterior ethmoid nerve. The operative findings revealed that the nasofrontal duct was patent and there was no infection in the frontal and ethmoid sinuses.

Trigeminal nasal receptors related to respiration and to various stimuli in cats

In twenty adult cats of either sex under nembutal anaesthesia, we aimed at delineating the sensitive territory of trigeminal nerves innervating the nasal mucosa. The different trigeminal nerves (anterior ethmoidal, posterior nasal and infraorbital nerves) were dissected in the orbit. Activity of these nerves was recorded during spontaneous nasal and tracheal breathing and in response to various stimuli: mechanical (manual probing and air jets) and irritants (ammonia vapours). Multiple and unitary activity recorded in nerve filaments enabled a classification of the receptors on the basis of their discharge pattern as rapidly-, intermediately- or slowly adapting receptors, and as drive or non-drive nasal receptors depending on whether or not the respiratory modulation was preserved during tracheal breathing.

Trigeminal afferences implied in the triggering or inhibition of sneezing in cats

The aim of this study was to precise the role of the different trigeminal nerve branches involved in innervation of the nostril in triggering the sneeze reflex. Electrical stimulation of the anterior ethmoidal, posterior nasal and infraorbital nerves was performed in anaesthetized cats. Stimulation of these 3 nerves produced sneezing identical to that induced by mechanical stimulation. Our results emphasize inhibition of the sneeze reflex related to stimulation of the anterior ethmoidal or the posterior nasal nerves by stimulation of the infraorbital nerve.

Post-traumatic external nasal neuralgia—an often missed cause of facial pain?

Pain about the bridge of the nose is often a diagnostic dilemma. There is an important recognizable subgroup who may, as a consequence of involvement of the external nasal nerve in nasal injury, exhibit neuralgic pain after a latent interval. Temporary relief by anaesthesia can be achieved and cure is possible by division of the anterior ethmoidal nerve. This rare cause of facial pain is presented using two illustrative cases.

ヒト前し骨神経の走行と分布

The anterior ethmoidal nerve (a.e.n.) was examined in 10 human adults (40-89 years old) and 5 fetuses (7 months). A.e.n. arises from the naso-ciliary++ nerve, which is the first division of the trigeminal nerve. From this point to the crista galli, a.e.ns. were observed under a dissection microscope in relation to their direction and distribution. The following results were obtained: 1) The number of a.e.n. i. The number of a.e.n. was 1 to 3 (1.45 on average) when they arose from the naso-ciliary nerve in the adults. ii. In the fetuses, the number of a.e.n. was 1 to 2 (1.1 on average). 2) The length of a.e.n. i. The length was 12.0 mm to 24.0 mm (17.3 mm on average) in the adults. ii. In the fetuses, the length was 2.0 mm to 7.0 mm (5.0 mm on average). 3) The anterior ethmoidal branch (e.b.). The anterior ethmoidal branch (e.b.) supplies the mucous membrane of the ethmoidal sinus. i. The number of e.bs. was 20 on the right side and 22 on the left in 8 adult cases. In the upper wall of the ethmoidal sinus, the number of e.bs. was 1.0 on average. In the medial wall of the ethmoidal sinus, the number of e.bs. was also 1.0 on average. In the lateral wall of the ethmoidal sinus, the number of e.bs. was 0.2 on average. ii. The number of e.bs. was 3 on the right side and 2 on the left in 3 fetus cases. In the upper wall of the ethmoidal sinus, the number of e.bs. was 0.2 on average. In the medial wall of the ethmoidal sinus, the number of e.bs. was 0.3 on average. No e.bs. were found in the lateral wall. 4) The anterior ethmoidal foramen. The anterior ethmoidal foramen was examined to determine its positional relation to the angle of the crista galli. i. The angle was 40.0 degrees to 10.0 degrees and 30.0 degrees on average in the adults. ii. In the fetuses, the angle was 50.0 degrees to 20.0 degrees and 43.2 degrees on average.

Nasal ‘flow’ receptors of the rat

This study was performed to identify trigeminal nasal ‘flow’ receptors and to investigate their firing characteristics. For this purpose, single unit afferent activity was recorded from the anterior ethmoidal nerve in anesthetized rats breathing through the nose or a tracheostomy. In fourteen rats breathing through the nose, 40 of 73 endings tested were identified as ‘flow’ receptors for the following characteristics: their spontaneous activity had an inspiratory modulation that disappeared during nasal occlusions, they were markedly stimulated by exposure to cold air and inhibited by warm air. In eleven rats breathing through a tracheostomy, 85 endings were identified as ‘flow’ receptors being stimulated by a constant nasal airflow (100–300 ml/min) with room air (22–26°C) or cold air (0–15°C), but inhibited with warm air (30–45°C). Fifty-five ‘flow’ receptors (Type R1 and R2) exhibited a dynamic response to the constant airflow, while the other 30 receptors (Type S) showed a static response. A large proportion of ‘flow’ receptors (more than 52%) were responsive to tactile stimuli. For all the flow receptors, a decrease in intranasal temperature was the primary factor to excite them. These results suggest that the trigeminal nerve has a number of ‘flow’ receptors which operate as thermoreceptors.

前し骨神経由来の頭痛を来した前頭洞骨腫

Headache is a common symptom with various causes. Headache which originate in a frontal osteoma are generally caused by a mucocele or pyocele, which blocks the nasofrontal duct. We report an additional cause of headache due to compression of the anterior ethmoidal nerve.The headache of a 22-year-old female was completely relieved by removal of a small osteoma compressing the anterior ethmoidal nerve. The nasofrontal duct was patent and there was neither pyocele nor mucocele in the frontal sinus.On the basis of the operative findings and the relief of the headache, the authors conclude that osteomas accompanied by headache should be removed even when small without a suspected mucocele or pyocele.

The cribriform plate and cerebrospinal fluid rhinorrhoea.

IN a study of 65 cribriform plates from dried adult skulls the classical arrangement of the openings into medial, middle and lateral rows was observed in all but 2 cases. A nasal slit was present in 34 plates while in a further 16 the slit was replaced by a group of large openings. In 15 (23%) of the plates there was no nasal slit or analogous feature for the transmission of the anterior ethmoidal nerve. Bony defects establishing communication with the ethmoidal air cells were present in 9 plates. The microscopic appearance of these defects is consistent with their production by a process of “focal atrophy”. The dimensions of these abnormal openings, of the nasal slits and of the openings in the medial row of the plate are sufficiently large for them to be the site of leakage in non-traumatic cerebrospinal fluid rhinorrhoea.