Parasympathetic Fibers Research Articles

How can Frey's syndrome be prevented or treated following parotid surgery?

How can Frey's syndrome be prevented or treated following parotid surgery?

Examining the pupils

Normally, the size of the pupil is determined by the interplay between the iris dilator muscle (innervated by sympathetic fibres) and the iris sphincter muscle (innervated by parasympathetic fibres). The sympathetic fibres originate from the hypothalamus, coursing through the brainstem, spinal cord

Modern management of facial palsy: a review of current literature

Facial nerve dysfunction can severely affect a patient's quality of life. The human face is a focal point for communication and expression. The facial nerve carries motor, sensory, and parasympathetic fibres, so facial palsy results in both a functional and cosmetic impairment. Facial weakness secondary to upper motor neurone lesions will not be discussed in this article. Facial nerve palsy is diagnosed upon clinical presentation with weakness of the facial muscles. There may be immobility of the brow, incomplete lid closure, drooping of the corner of the mouth, impaired closure of the lips, dry eye, hyperacusis, impaired taste, or pain around the ear. There are many causes of unilateral facial palsy that should be considered, including idiopathic, traumatic, infective, neoplastic, congenital, and autoimmune (Box 1). Seventy per cent of facial nerve palsies are diagnosed as Bell's palsy1 with 11–40 new cases per 100 000 each year.2 Bell's palsy disproportionately attacks pregnant women and patients with respiratory tract illness. Bilateral facial palsy is far less common (2% of facial palsies) and typically represents a systemic disorder with multiple manifestations. Bell's palsy is also the most common diagnosis in childhood and accounts for 90% of facial paralysis. Up to 10% of patients with Bell's palsy will experience …

Surgical Management of Nonvascular Lesions Around the Oculomotor Nerve and Reconstruction of the Oculomotor Nerve

he oculomotor nerve is frequently involved with neoplasms involving the petroclival area and the tentorial T notch, as well as by aneurysms involving the internal carotid artery (at the origin of the posterior communicating artery) or the upper basilar artery (especially large or giant aneurysms, and basilar arteryesuperior cerebellar aneurysms). Because of its location in the tentorial notch, oculomotor paralysis is seen in brain herniation syndromes, or after direct trauma. Anatomically, the nerve has 3 distinct areas that it occupies, namely the cisternal segment, the cavernous segment (in the lateral wall of the cavernous sinus), and the orbital segment (in the apex of the orbit). The nerve mainly contains fibers to many of the orbital muscles, but also carries parasympathetic fibers to the pupillary muscle. It is important to note that similar to the facial nerve, many of the muscles controlled by the oculomotor nerve have antagonistic effects (the superior and inferior rectus, for example). This becomes important when one considers the outcome of oculomotor nerve reconstruction.

Sensory denervation with capsaicin reduces ovarian follicular development and delays the onset of puberty in guinea pigs

Introduction: It has been documented that mammalian ovaries receive sympathetic, parasympathetic and sensory nerve fibers. The aim of this work was to investigate the effects of sensory denervation with capsaicin at the first vaginal opening (FVO) on follicular development and the expression of TRPV1 receptors in ovary cells as well as in the dorsal root ganglia (DRGs) and lumbar dorsal spinal cord neurons of guinea pigs. The DRGs and lumbar dorsal spinal cord neurons serve as a nerve connection from the ovaries to the CNS. Materials and Methods: Female guinea pigs received a subcutaneous injection of capsaicin (30 mM) at 10 days of age (P10), while control animals were injected with vehicle. Using light microscopy, we counted healthy preantral follicles (HPF), healthy antral follicles (HAF), atretic preantral follicles (APF), and atretic antral follicles (AAF) in the ovaries at the FVO, and the numbers of TRPV1-positive cells were counted in the ovarian follicles, DRGs, and lumbar dorsal spinal cord (L2-L4) neurons by immunohistochemistry. Results: Guinea pigs treated with capsaicin showed a significant delay of FVO in comparison with the control animals (36 vs. 44 days). In the ovaries, the number of preantral and antral follicles decreased significantly. Additionally, the number of TRPV1-positive thecainterstitial cells of the antral follicles was reduced significantly, and the number of TRPV1-positive neurons in the DRGs and lumbar dorsal spinal cord (L2-L4) decreased. Thus, we showed that TRPV1 receptors throughout the sensory fibers modulate ovarian follicular development and the onset of puberty in guinea pigs. Conclusion: Sensory denervation decreases ovarian follicular development and delays the onset of puberty of guinea pigs. Our data support the idea that through TRPV1 receptors, ovarian afferent fibers sense local stimuli that are sent to the CNS.

Ablation of the sphenopalatine ganglion does not attenuate the infarct reducing effect of vagus nerve stimulation

Electrical stimulation of the cervical vagus nerve reduces infarct size by approximately 50% after cerebral ischemia in rats. The mechanism of ischemic protection by vagus nerve stimulation (VNS) is not known. In this study, we investigated whether the infarct reducing effect of VNS was mediated by activation of the parasympathetic vasodilator fibers that originate from the sphenopalatine ganglion (SPG) and innervate the anterior cerebral circulation. We examined the effects of electrical stimulation of the cervical vagus nerve in two groups of rats: one with and one without SPG ablation. Electrical stimulation was initiated 30 min after induction of ischemia, and lasted for 1h. Measurement of infarct size 24h later revealed that the volume of ischemic damage was smaller in those animals that received VNS treatment (41.32±2.07% vs. 24.19±2.62% of the contralateral hemispheric volume, n=6 in both; p<0.05). SPG ablation did not abolish this effect; the reduction in infarct volume following VNS was 58% in SPG-damaged animals, 41% in SPG-intact animals (p>0.05). In both SPG-intact and SPG-damaged animals VNS treatment resulted in better motor outcome (p<0.05 vs. corresponding controls for both). Our findings show that VNS can protect the brain against acute ischemic injury, and that this effect is not mediated by SPG projections.

Gustatory Sweating in the Submandibular Region Following Neck Dissection: A Case With Thermographic Evaluation and Review of the Literature

Gustatory sweating is a fairly common complication after surgery or injury of the parotid gland.1 The pathogenesis is based on aberrant nerve regeneration between the parasympathetic fibers of the salivary glands and the sympathetic fibers of the cutaneous sweat glands or blood vessels.1 Inappropriate innervation leads to local cutaneous sweating and vasodilation during mastication.1 A similar condition has been reported in the cervical region after neck surgery, such as neck dissection,2-6 submandibular gland excision,7-19 and cervical lymphadenectomy,20 but the frequency of this condition is extremely rare.

Dysautonomies des neuropathies périphériques

The mechanisms of dysautonomic disturbances are varied and mostly acquired. They can result from lesions of sympathetic or parasympathetic vegetative fibers located in the peripheral contingent, or in the somatic contingent by demyelination or axonal loss; or more rarely by cellular bodies in the sympathetic or parasympathetic ganglia. Several chronic peripheral neuropathies can be associated with dysautonomia. Only some causes need to be known because they can be clinically significant. Dysautonomia may be seen during chronic acquired neuropathies but also acute or subacute ones. The most frequent cause in the world is the dysautonomia of the diabetes; it affects all the systems; the cardiovascular dysfunction has an impact on the prognosis for survival when it is severe. Hereditary autonomic neuropathies are rare; they can declare themselves very early during the Riley-Day syndrome or very late during amyloid polyneuropathies due to transthyretin gene mutation. The diagnosis can be confirmed by molecular biology. The dysautonomia is frequent and often severe. These neuropathies justify symptomatic treatment to improve quality of life. For some of them, a specific treatment can be proposed to treat the causal affection to try to stop the progression of the disease.

Asystole induced by radiofrequency catheter ablation of slow pathway

Radiofrequency (RF) catheter ablation is a treatment of choice widely used for a variety of supraventricular tachycardia. Transient sinus and atrioventricular (AV) node dysfunctions may occur during RF application to sites remote from the sinus and AV nodes, but they generally resolve quickly after cessation of RF current. We present a case of two episodes of asystole in a 43-year-old man induced by RF catheter ablation of an AV nodal slow pathway. A Bezold–Jarisch-like reflex, direct stimulation of parasympathetic fibers traveling to the sinus and AV nodes, RF-induced myocardial injury or pain could be responsible for this situation.

Pediatric Head Injury

1. Jeff E. Schunk, MD* 2. Sara A. Schutzman, MD† 1. *Professor, Division of Pediatric Emergency Medicine, Department of Pediatrics, University of Utah School of Medicine, Primary Children’s Medical Center, Salt Lake City, UT. 2. †Assistant Professor, Department of Pediatrics, Harvard Medical School, Senior Associate Physician in Medicine, Division of Emergency Medicine, Department of Medicine, Children’s Hospital Boston, Boston, MA. * Abbreviations: BSF: : basilar skull fracture CSF: : cerebrospinal fluid CT: : computed tomography EDH: : epidural hemorrhage GCS: : Glasgow Coma Scale ICI: : intracranial injury ICP: : intracranial pressure PECARN: : Pediatric Emergency Care Applied Research Network SAH: : subarachnoid hemorrhage SDH: : subdural hemorrhage TBI: : traumatic brain injury Recent studies have provided updated guidelines for the diagnosis of head injury and the management of patients who experience concussions. A multidisciplinary panel has recently issued new guidelines for return to play after head injury. After reading this article, readers should be able to: 1. Understand the anatomy and pathophysiology relevant to pediatric head injuries. 2. Take an appropriate history, perform an appropriate physical examination, and decide what imaging, if any, is warranted in the case of a child with a head injury. 3. Know the characteristics of the various types of intracranial injuries. 4. Understand the proper management of both minor and severe head injuries in children. Pediatric head injury is extremely common. Although the vast majority of children with head trauma have minor injuries, a small number, even among well-appearing children, will have more serious injuries with the potential for deterioration and significant sequelae. The clinician is challenged to discern which few among the many injured are at high risk for intracranial complications. Clinical symptoms are neither completely sensitive nor specific for significant injury: vomiting may be associated with intracranial injury (ICI), but most children who experience vomiting do not have a complication. Computed tomography (CT) accurately identifies ICIs requiring intervention, but also identifies minor lesions with unclear clinical importance (ie, not requiring intervention) and exposes developing brains to ionizing radiation with the associated risks. Although clinical decision rules determine which children are at highest risk and provide a useful clinical framework, they may not necessarily direct care. Additionally, in this era of reliance on imaging, it is important to remember what the clinical examination tells us regarding brain function, information that …

Dysautonomies centrales

Autonomic nervous system (ANS) modulates the function of all body organs through both parasympathetic and sympathetic fibers. Orthostatic hypotension is frequently observed in the course of central nervous system diseases including cortical (stroke, epilepsy, dementias), neurodegenerative (Parkinson's disease, multisystem atrophies) and spinal cord diseases. In some cases, the mechanism of orthostatic hypotension associated with central nervous system diseases involves a dysfunction of peripheral ANS fibers.

Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Potently Dilates Middle Meningeal Arteries: Implications for Migraine

Migraine is a debilitating neurological disorder characterized by mild to severe headache that is often accompanied by aura and other neurological symptoms. Among proposed mechanisms, dilation of the dural vasculature especially the middle meningeal artery (MMA) has been implicated as one component underlying this disorder. Several regulatory peptides from trigeminal sensory and sphenopalatine postganglionic parasympathetic fibers innervating these vessels have been implicated in the process including pituitary adenylate cyclase-activating polypeptide (PACAP). Although PACAP has been well described as a potent dilator in many vascular beds, the effects of PACAP on the dural vasculature are unclear. In the current study, we examined the ability of PACAP to dilate MMAs that were isolated from rats and pressurized ex vivo. PACAP38 potently dilated pressurized MMAs with an EC(50) of 1 pM. The PAC1 receptor antagonist, PACAP(6-38), abolished MMA dilation caused by picomolar concentrations of PACAP. In contrast, cerebellar arteries isolated from the brain surface were ~1,000-fold less sensitive to PACAP than MMAs. Although cerebellar arteries expressed transcripts for all three PACAP receptor subtypes (PAC1, VPAC1, and VPAC2 receptors) by RT-PCR analyses, MMA demonstrated only PAC1 and VPAC2 receptor expression. Further, multiple variants of the PAC1 receptor were identified in the MMA. The expression of PAC1 receptors and the high potency of PACAP to induce MMA vasodilation are consistent with their potential roles in the etiology of migraine.

The Accessory Posterolateral Nerve: An Immunohistological Analysis

Recent endoscopic dissection studies have redefined the postganglionic pterygopalatine autonomic pathways suggesting that neurovascular rami, termed "accessory posterolateral nerves," project directly through the palatine bone to innervate the posterolateral nasal mucosa rather than traveling with trigeminal arborizations. The goal of this study was to characterize these accessory posterolateral nerves by immunohistochemistry to determine their morphology and composition. This is an Institutional Review Board approved study in seven patients in whom the presence of accessory posterolateral nerves were surgically identified exiting the perpendicular plate of the palatine bone and sampled. The presence of neural tissue was confirmed by hematoxylin and eosin and S-100 protein staining. Nerves were then stained with anti-human choline acetyl-transferase (ChAT; 1:100) and anti-human dopamine beta-hydroxylase (DBH; 1:100) followed by a fluorescein isothiocyanate-labeled secondary antibody to test for the presence of peripheral parasympathetic and sympathetic fibers, respectively. Human cadaveric sensory nerves were used as a negative control. All seven samples contained neural elements. Two specimens were also associated with arteries. All nerves were comprised of a single fascicle containing an approximately equal distribution of ChAT(+) and DBH(+) fibers. This histological study supports prior descriptions defining a newly recognized neural pathway for innervation of the nasal mucosa. Our data confirm that these accessory posterolateral nerves project directly through the perpendicular plate of the palatine bone and are composed of autonomic fibers. Recognition of this pathway may be exploited in the treatment of sinonasal disease resulting from autonomic dysregulation.

The Effect of Gag Reflex on Cardiac Sympatovagal Tone

Heart velocity may be influenced by gagging. The medulla oblongata receives the afferents of gag reflex. Neuronal pools of vomiting, salivation and cardiac parasympathetic fibers are very close in this area. So, their activities may be changed by spillover from each other. Using the heart rate variability (HRV) analysis, the effect of gagging on cardiac sympatovagal balance was studied. ECG was recorded from 12 healthy nonsmoker volunteer students for 10 minutes in the sitting position between 10 and 11 AM. Gagging was elicited by tactile stimulation of the posterior pharyngeal wall. At 1 kHz sampling rate, HRV was calculated. The mean of heart rate at low and high frequencies (LF: 0.04-0.15; HF: 0.15-0.4 Hz) were compared before and after the stimulus. The mean of average heart rate, LF and HF in normalized units (nu) and the ratio of them (LF/HF) before and after the gagging were 89.9 ± 3 and 95.2 ± 3 bpm; 44.2 ± 5.8 and 21.2 ± 4; 31.1 ± 5.3 and 39.4 ± 3.8; and 1.7 ± 0.3 and 0.6 ± 0.2 respectively. Gagging increased heart velocity and had differential effect on two branches of cardiac autonomic nerves. The paradoxical relation between average heart rate and HRV indexes of sympatovagal tone may be due to unequal rate of change in autonomic fiber activities which is masked by 5 minutes interval averaging.

Analysis of Nerve Supply Pattern in Thoracic Duct in Young and Elderly Men

Analysis of the innervation pattern of the thoracic duct in young and elderly human subjects has been performed. The subdivision of the vessels in cervical and lumbar region were taken in consideration. Immunostaining for general nerve fibers with a PGP 9.5 marker disclosed a diffuse innervation of the thoracic duct in young subjects, which was strongly reduced in elderly subjects. In young subjects, tyrosine hydroxylase (TH) and neuropeptide Y (NPY) immunoreactive fibers, markers of noradrenergic postganglionic sympathetic fibers, were frequent; choline acetyltransferase (ChAT) immunoreactive fibers, marker of cholinergic parasympathetic nerve fibers, were also well represented. Therefore, the influence of sympathetic and parasympathetic nerve systems on the thoracic duct can be confirmed. The immunoreactivity of vasoactive intestinal peptide (VIP), a neuropeptide frequently present in cholinergic parasympathetic nerve fibers, was scarcely present. Dopamine-positive fibers were observed in few short nerve fibers. Substance P (SP)-positive fibers were widely distributed in the medial and intimal smooth muscle layers, suggesting their involvement as contractile modulating fibers and sensitive fibers. In elderly subjects, an evident reduction of all specific nerve fibers analyzed was detected, the ChAT-positive fibers being the most affected. The lymphatic vessel thoracic duct is able to regulate hydrodynamic lymph flow by intrinsic contraction of its smooth muscle layer. Therefore, analysis of the thoracic duct innervation pattern may be important in assessing the regulation of vessel contraction. These findings called attention to the reduction of lymphatic drainage functionality affecting fluid balance in the elderly.

Consequences of the ablation of nonpeptidergic afferents in an animal model of trigeminal neuropathic pain

Damage to peripheral nerves causes significant remodeling of peripheral innervation and can lead to neuropathic pain. Most nociceptive primary afferents are unmyelinated (C fibers) and subdivided into peptidergic and nonpeptidergic fibers. Previous studies have found nerve injury in the trigeminal system to induce changes in small-diameter primary afferent innervation and cause significant autonomic sprouting into the upper dermis of the lower-lip skin of the rat. In this study, we used the ribosomal toxin, saporin, conjugated to the lectin IB4 to specifically ablate the nonpeptidergic nociceptive C fibers, to see if loss of these fibers was enough to induce autonomic fiber sprouting. IB4-saporin treatment led to specific and permanent ablation of the IB4-positive, P2X3-immunoreactive fibers and led to sprouting of parasympathetic fibers into the upper dermis, but not of sympathetic fibers. These changes were associated with significant increase in glial-derived nerve growth factor levels in the lower-lip skin. While IB4-saporin treatment had no effect on evoked mechanical thresholds when von Frey hairs were applied to the lower-lip skin, ablation of nonpeptidergic fibers in a chronic constriction injury model caused significant sympathetic and parasympathetic fiber sprouting, and led to an exacerbated pain response. This was an unexpected finding, as it has been suggested that nonpeptidergic fibers play a major role in mechanical pain, and suggests that these fibers play a complex role in the development of neuropathic pain.

Anatomic Study of Periprostatic Nerve Distribution: Immunohistochemical Differentiation of Parasympathetic and Sympathetic Nerve Fibres

BackgroundMany authors advocate a high anterior incision during nerve-sparing radical prostatectomy (RP) to improve potency results. Despite a growing number of studies describing autonomic nerves in the ventrolateral position of the prostate, little is known about their quality and their role in erectile function. ObjectiveThe intention of this study was a detailed characterisation of the topographic distribution of periprostatic nerves, including immunohistochemical differentiation of proerectile parasympathetic from sympathetic nerves. Design, setting, and participantsA total of 228 whole-mount sections of 38 prostates (base, middle, apex) from patients following non–nerve-sparing laparoscopic RP were analysed. Immunohistochemical analysis was performed using antibodies against tyrosine hydroxylase for sympathetic and vesicular acetylcholine transporter for parasympathetic nerve fibre staining. Outcome measurements and statistical analysisQuantification of periprostatic parasympathetic and sympathetic nerves was performed after defining prostatic regions via a digital grid. Differences among three independent variables were tested with the nonparametric Kruskal-Wallis test. Results and limitationsThe total number of parasympathetic nerves did not decrease from the base to the apex. They were dispersed at the base and mainly located dorsolaterally at the apex, with 14.6% above the horizontal line at the base and only 1.5% at the apex. In contrast, the total number of sympathetic nerves decreased significantly from base to apex, with a constant proportion of ventrolateral nerves between 9% (base) and 6.2% (apex). This anatomic study is limited by the investigation of postprostatectomy specimens and the lack of functional results. ConclusionsDespite the presence of ventrolateral periprostatic nerves, only a minority of these nerves seems to have a parasympathetic proerectile quality. The arguments in favour of a high anterior incision during nerve-sparing prostatectomy might not only include preserved nerves but also other factors, such as reduced traction or improved anatomic support of the neural structures.

Cluster headache with ptosis responsive to intranasal lidocaine application: a case report

IntroductionThe application of lidocaine to the nasal mucosal area corresponding to the sphenopalatine fossa has been shown to be effective at extinguishing pain attacks in patients with a cluster headache. In this report, the effectiveness of local administration of lidocaine on cluster headache attacks as a symptomatic treatment of this disorder is discussed.Cases presentationA 22-year-old Turkish man presented with a five-year history of severe, repeated, unilateral periorbital pain and headache, diagnosed as a typical cluster headache. He suffered from rhinorrhea, lacrimation and ptosis during headaches. He had tried several unsuccessful daily medications. We applied a cotton tip with lidocaine hydrochloride into his left nostril for 10 minutes. The ptosis responded to the treatment and the intensity of his headache decreased.ConclusionIntranasal lidocaine is a useful treatment for the acute management of a cluster headache. Intranasal lidocaine blocks the neural transmission of the sphenopalatine ganglion, which contributes to the trigeminal nerve as well as containing both parasympathetic and sympathetic fibers.

Spread of OnabotulinumtoxinA After Bladder Injection. Experimental Study Using the Distribution of Cleaved SNAP-25 as the Marker of the Toxin Action

BackgroundOnabotulinumtoxinA (Onabot/A) has been used to treat detrusor overactivity disorders. The treatment is based on several injections of toxin throughout the bladder wall. However, injection protocols are not well established among clinicians, varying in dose and dilution. ObjectiveStudy the distribution and neurochemistry of cleaved synaptosome-associated protein of 25 kDa (cSNAP-25) after Onabot/A administration in the guinea pig bladder. In addition, we analyzed which factor, dose or volume, contributes more to the diffusion of the toxin. Design, setting, and participantsGuinea pig bladders were treated with Onabot/A via intramural injection or an instillation. MeasurementsBladder cryostat sections were processed for single or dual immunohistochemistry staining with antibodies against cSNAP-25, vesicular acetylcholine transporter, tyrosine hydroxylase, and calcitonin gene-related peptide. Different administration methods and doses were analyzed. Statistical analysis was performed using the chi-square test for colocalization studies after multiple injections and the t test for the evaluation of affected fibers after a single injection. Results and limitationscSNAP-25 immunoreactive fibers were abundant throughout the bladder tissue in the mucosa and muscular layer. Double labeling showed that parasympathetic fibers are more affected than sympathetic or sensory. A single Onabot/A injection is more effective if diluted in a higher volume. Onabot/A instillation in the bladder does not cleave SNAP-25 protein. ConclusionsA single Onabot/A injection spreads the neurotoxin activity to the opposite side of the guinea pig bladder. This action is more evident when high saline volumes are used to dissolve Onabot/A. The toxin cleaves the SNAP-25 protein mainly in cholinergic but also in adrenergic and sensory fibers. In contrast with intramural injection, instillation of Onabot/A does not cleave SNAP-25 in nerve fibers.

Endoscopic resection of an anterior skull‐base Schwannoma

Sinonasal Schwannomas represent less than 4% of all head and neck Schwannomas. These neural sheath tumors arise from the ophthalmic and maxillary divisions of the trigeminal nerve, as well as autonomic nerves from sympathetic fibers of the carotid plexus and parasympathetic fibers of the sphenopalatine ganglion. Patients commonly present with nonspecific symptoms such as nasal obstruction, epistaxis, and anosmia. Nasal endoscopy usually reveals a unilateral polypoid mass. Diagnostic imaging with computed tomography (CT) and magnetic resonance (MR) is typically nonspecific. Diagnosis may be delayed due to the masquerade of common sinonasal conditions, such as allergic rhinitis and chronic rhinosinusitis. We report a case involving a 51-year-old male with an anterior skull-base Schwannoma that was excised endoscopically. Clinical features, imaging characteristics, histopathology, and treatment of sinonasal Schwannomas are discussed.