A superficial dissection approach to the sphenopalatine (pterygopalatine) ganglion to emphasize osteopathic clinical relevance.

The sphenopalatine (pterygopalatine) ganglion (SPG) is the most superficial ganglia to manipulate from the oral cavity. It has parasympathetic and sensory fibers directly affecting the paranasal sinuses as well as the palatine, nasal, pharyngeal, and lacrimal glands. The SPG can be manipulated intraorally by students and physicians utilizing osteopathic manipulative treatment (OMT) to relieve congestion associated with sinusitis, allergies, headaches, and upper respiratory infections. Within osteopathic medical education programs, students have anecdotally had difficulty identifying this ganglion due to its deep anatomic location and lack of direct visualization. In this article, we discuss that cadaveric dissection with a superficial to deep approach to the SPG has the ability to allow medical students and physicians to better understand the three-dimensional location and osteopathic clinical relevance of this ganglion.

Neuromodulation for the Sphenopalatine Ganglion-a Narrative Review.

PURPOSE OF REVIEW: To provide an integrated overview of the current state of knowledge of neuromodulation for the sphenopalatine ganglion (SPG) by reviewing relevant and significant literature. RECENT FINDINGS: There are several case reports and clinical trials evaluating neuromodulation for the SPG. We identified two blinded, randomized clinical trials for patients with chronic cluster headache. The randomized trials and additional studies demonstrated the long-term safety, efficacy, and cost-effectiveness of neuromodulation for the SPG. Recent studies in Europe and the USA suggest that SPG neuromodulation is a novel modality with clinical importance for treating acute cluster headaches and reducing the frequency of attacks.

Onabotulinum toxin A block of the sphenopalatine ganglion in patients with persistent idiopathic facial pain: a randomized, triple-blind, placebo-controlled, exploratory, cross-over study.

OBJECTIVE: To investigate the efficacy and safety of injecting onabotulinum toxin A (BTA) towards the sphenopalatine ganglion (SPG) using the MultiGuide® in patients with persistent idiopathic facial pain (PIFP). METHODS: This cross-over, exploratory study compared the injection of 25 units BTA versus placebo in patients who met modified ICDH-3 criteria for PIFP. Daily pain diaries were registered for a 4-week baseline, a 12-week follow-up after each injection, and an 8-week conceptual washout period in between. The primary efficacy endpoint was the change from baseline to weeks 5-8 in average pain intensity using a numeric rating scale. Adverse events were recorded. RESULTS: Of 30 patients who were randomized to treatment, 29 were evaluable. In weeks 5-8, there was no statistically significant difference in average pain intensity between BTA versus placebo (0.00; 95% CI = -0.57 to 0.57) (P = 0.996). Following both BTA and placebo injections, five participants reported at least a 30% reduction in average pain during weeks 5-8 (P = 1.000). No serious adverse events were reported. Post-hoc analyses indicated a possible carry-over effect. CONCLUSIONS: Injection of BTA toward the SPG with the MultiGuide® did not appear to provide a reduction in pain reduction at 5-8 weeks, although this finding may be influenced by a carry-over effect. The injection appears to otherwise be safe and well-tolerated in patients with PIFP.Trial Registration: The study protocol is registered in ClinicalTrial.gov (NCT03462290) and EUDRACT (number: 2017-002518-30).

Sphenopalatine ganglion volumetry in episodic cluster headache: from symptom laterality to cranial autonomic symptoms.

BACKGROUND: Sphenopalatine ganglion (SPG) is a peripheral structure that plays an important role in cluster headache (CH). Hence, a reliable method to measure the volume of SPG is crucial for studying the peripheral mechanism of CH. Additionally, the association between the clinical profiles and the morphology of the SPG in CH remains undetermined. This study aims to use the manual measurement of SPG volume to investigate its associations with CH, including headache laterality, cranial autonomic symptoms (CASs), presence of restlessness or agitation, and other clinical profiles. METHODS: We prospectively recruited consecutive CH patients at a tertiary medical center between April 2020 and April 2022. A total of eighty side-locked, in-bout, episodic CH patients and 40 non-headache healthy controls received 1.5 T brain MRI focusing on structural neuroimaging of the SPG. The manual measurement process for SPG was under axial and sagittal FIESTA imaging, with reference T2 weight images (sagittal and axial) for localization. The inter-observer agreement of the SPG volume (both sides of the SPG from CH patients and controls) between the two observers was calculated. In CH patients, clinical profiles and the number of CASs (range 0-5) were recorded to analyze their association with SPG volume. RESULTS: The inter-observer agreement between the two raters was excellent for the new SPG volumetry method at 0.88 (95% CI: 0.84-0.90, p < 0.001). The mean [SD] SPG volume was larger in CH patients than in non-headache controls (35.89 [12.94] vs. 26.13 [8.62] µL, p < 0.001). In CH patients, the SPG volume was larger on the pain side than on the non-pain side (38.87 [14.71] vs. 32.91 [12.70] µL, p < 0.001). The number of CASs was positively moderately correlated with the pain-side SPG volume (Pearson r = 0.320, p = 0.004) but not the non-pain side SPG volume (Pearson r = 0.207, p = 0.066). CONCLUSIONS: This proof-of-concept study successfully measured the SPG volume and demonstrated its associations with symptomatology in patients with episodic CH. The direct measurement of SPG provide insights into studies on peripheral mechanism of CH.

Expression of the gap junction protein connexin36 in small intensely fluorescent (SIF) cells in cardiac parasympathetic ganglia of rodents.

In mammals, several endocrine cell types are electrically coupled by connexin36 (Cx36)-containing gap junctions, which mediate intercellular communication and allow regulated and synchronized cellular activity through exchange of ions and small metabolites via formation of intercellular channels that link plasma membranes of apposing cells. One cell type thought to be endocrine-like in nature are small intensely fluorescent (SIF) cells that store catecholamines in their dense-core vesicles and reside in autonomic ganglia. Here, using immunofluorescence approaches, we examined whether SIF cells located specifically in cardiac parasympathetic ganglia of adult and neonatal mice and adult rats follow patterns of Cx36 expression seen in other endocrine cells. In these ganglia, SIF cells were identified by their distinct small soma size, autofluorescence at 475 nm, and immunolabelling for their markers tyrosine hydroxylase and vesicular monoamine transporter-1. SIF cells were often found in pairs or clusters among principal cholinergic neurons. Immunofluorescence labelling of Cx36 occurred exclusively as fine puncta that appeared at contacts between SIF cell processes and somata or at somato-somatic appositions of SIF cells. These puncta were absent in cardiac parasympathetic ganglia of Cx36 null mice. Transgenic mice expressing enhanced green fluorescent protein reporter for Cx36 expression displayed labelling for the reporter in SIF cells. The results suggest that Cx36-containing gap junctions electrically couple SIF cells, which is consistent with previous suggestions that these may be classified as endocrine-type cells that secrete catecholamines into the bloodstream in a regulated manner.

The pterygopalatine ganglion, palatine nerves and vessels: dissection and pathway / El ganglio pterigopalatino, nervios palatinos y vasos: disección y trayecto

SUMMARY: Background and Objectives: The palatine nerves and vessels cross the pterygopalatine fossa, the palatine canals, the palatine foramina and the submucosal space, at the level of the hard palate and the palatine recess of the maxillary sinus. Their trajectory is long, complicated and difficult to highlight on a single dissection piece. In the literature that we studied, we did not find clear images that fully highlight the real configuration of the pterygopalatine ganglion and nerves and of the palatine vessels. Our aim was to provide a clear and representative dissection of the pterygopalatine ganglion and of the palatine neurovascular bundle throughout its pathway in a simple, coherent and useful presentation for the practitioners interested in the regional pathology. We resected the posterior and inferomedial osseous walls of the maxillary sinus and highlighted the neurovascular structures in the pterygopalatine fossa and the wall of the maxillary sinus. We photographed the dissection fields and detailed the important relations. The images that we obtained are clear, simple and easy to interpret and use. We successfully highlighted the aspect and the main relations of the pterygopalatine ganglion and the pathway and distribution of the palatine nerves and vessels, from their origin to the terminal plexuses. There is a broad spectrum of clinical procedures or situations that require a proper knowledge and understanding of the anatomical pathway and relations of the palatine neurovascular elements. This includes the various types of regional anesthesia, tumor resection surgery, flaps of the palatine mucosa, the LeFort osteotomy etc. Demonstration of the pterygopalatine ganglion and its relations is useful in endoscopic interventions at the level of the pterygopalatine fossa.

RESUMEN: Los nervios y vasos palatinos atraviesan la fosa pterigopalatina, además de los canales palatinos, los forámenes palatinos y el espacio submucoso a nivel del paladar duro y el receso palatino del seno maxilar. Su trayectoria es larga, complicada y difícil de destacar en una sola pieza de disección. En la literatura que estudiamos, no encontramos imágenes claras que resalten completamente la configuración real del ganglio y los nervios pterigopalatinos y de los vasos palatinos. Nuestro objetivo fue proporcionar una disección clara y representativa del ganglio pterigopalatino y del haz neurovascular palatino a lo largo de su trayecto en una presentación simple, coherente y útil para los médicos interesados en la patología regional. Resecamos las paredes óseas posterior e inferomedial del seno maxilar y resaltamos las estructuras neurovasculares en la fosa pterigopalatina y la pared del seno maxilar. Fotografiamos los campos de disección y detallamos las relaciones importantes. Las imágenes que obtuvimos son claras, sencillas y de fácil interpretación. Resaltamos con éxito el aspecto y las principales relaciones del ganglio pterigopalatino y el trayecto y distribución de los nervios y vasos palatinos, desde su origen hasta los plexos terminales. En conclusion, existe un amplio espectro de procedimientos o situaciones clínicas que requieren un adecuado conocimiento y comprensión del trayecto anatómico y las relaciones de los elementos neurovasculares palatinos. Esto incluye los distintos tipos de anestesia regional, cirugía de resección tumoral, colgajos de mucosa palatina, osteotomía de LeFort, etc. La demostración del ganglio pterigopalatino y sus relaciones es útil en intervenciones endoscópicas a nivel de la fosa pterigopalatina.

Electrical Stimulation for Cerebral Vasospasm After Subarachnoid Hemorrhage: A Systematic Review.

OBJECTIVES: Cerebral vasospasm is a severe and potentially lethal complication in patients with subarachnoid hemorrhage (SAH). Its pathogenesis is still not completely understood. The efficacy of current treatments, such as triple-H therapy or calcium channel blockers, is unsatisfactory, and a new therapy model would therefore be valuable. Electrical stimulation may have a considerable influence on cerebrovascular innervation. This systematic review gives an overview of the studies that have applied electrical stimulation in models of cerebral vasospasm. MATERIALS AND METHODS: We performed a systematic review of the literature, searching PubMed and Ovid Embase with the keywords "electric stimulation," "cerebral vasospasm," "subarachnoid hemorrhage," "sympathetic," and "parasympathetic." Additional papers were identified from the reference lists of the articles identified in the literature search. RESULTS: Increased cerebral blood flow (CBF) is a widely observed effect of spinal cord stimulation and sphenopalatine ganglion stimulation in models of physiological conditions or experimental cerebral vasospasm. Most studies were conducted in animals, 15 under physiological conditions and 11 in animals with SAH. Eight studies in humans were identified that examined the stimulation effect on CBF under physiological conditions. Only two studies looked at patients after SAH: one applied spinal cord stimulation (SCS) and the other transcutaneous electrical neurostimulation. Different mechanisms leading to stimulation-induced CBF increase that were discussed included "reversible functional sympathectomy," activation of brainstem vasomotor centers, involvement of central ascending pathways, release of neurohumoral factors, and interaction with sympathetic, parasympathetic, and trigeminal innervation. The results indicate that electrical stimulation is a promising procedure for prevention and treatment of cerebral vasospasm. CONCLUSION: Electrical stimulation, especially SCS and sphenopalatine ganglion stimulation, is a promising adjunct for existing therapies for vasospasm after SAH. Further experiments and prospective clinical studies are needed to establish its potential usefulness as a therapy or prevention option.

[Sphenopalatine ganglion stimulation in the treatment of chronic refractory cluster headache. A preliminary multicenter study in Russia]. / Stimulyatsiya krylonebnogo gangliya v lechenii khronicheskoi klasternoi golovnoi boli. Rezul'taty pervogo mul'titsentrovogo opyta v Rossii.

OBJECTIVE: To analyze the results of sphenopalatine ganglion stimulation in treatment of chronic headache. MATERIALS AND METHODS: Medical histories of patients who underwent sphenopalatine ganglion stimulation in 4 clinical centers have been analyzed. The analysis included the type of pain and its characteristics, methods of surgery, CT, MRI, radiography before and after surgery. The follow-up data of patients with implanted pulse generators was collected in an outpatient clinic or by telephone review. RESULTS: The study included 15 patients with chronic refractory headache, including 14 with cluster headache and one female patient with features of trigeminal autonomic cephalgia without a clear definition of the type of pain. Trial stimulation was performed in 10 patients to determine analgesic effect. Among them stimulation was favorable in 7 cases, and 6 of them underwent pulse generator implantation. In total, 11 (73%) patients underwent implantation with a follow-up from 1 to 60 months. Among them only 6 (54%) patients use stimulation, the remaining 5 (46%) cases had device-related complications (migration, infection of system). Cluster headache has a significant improvement in long-term follow-up. CONCLUSIONS: Sphenopalatine ganglion stimulation may have high potential in the treatment of chronic drug-resistant cluster headache. The complication rate demonstrates that operative technique should be improved.

Brain barriers and their potential role in migraine pathophysiology.

Migraine is a ubiquitous neurologic disease that afflicts people of all ages. Its molecular pathogenesis involves peptides that promote intracranial vasodilation and modulate nociceptive transmission upon release from sensory afferents of cells in the trigeminal ganglion and parasympathetic efferents of cells in the sphenopalatine ganglion. Experimental data have confirmed that intravenous infusion of these vasoactive peptides induce migraine attacks in people with migraine, but it remains a point of scientific contention whether their site of action lies outside or within the central nervous system. In this context, it has been hypothesized that transient dysfunction of brain barriers before or during migraine attacks might facilitate the passage of migraine-inducing peptides into the central nervous system. Here, we review evidence suggestive of brain barrier dysfunction in migraine pathogenesis and conclude with lessons learned in order to provide directions for future research efforts.

Neurostimulation Treatment in Chronic Cluster Headache-a Narrative Review.

PURPOSE OF REVIEW: In this narrative review, the current literature on neurostimulation methods in the treatment of chronic cluster headache is evaluated. These neurostimulation methods include deep brain stimulation, vagus nerve stimulation, greater occipital nerve stimulation, sphenopalatine ganglion stimulation, transcranial magnetic stimulation, transcranial direct current stimulation, supraorbital nerve stimulation, and cervical spinal cord stimulation. RECENT FINDINGS: Altogether, only nVNS and SPG stimulation are supported by at least one positive sham-controlled clinical trial for preventive and acute attack (only SPG stimulation) treatment. Other clinical trials either did not control at all or controlled by differences in the stimulation technique itself but not by a sham-control. Case series report higher responder rates. The evidence for these neurostimulation methods in the treatment of chronic cluster headache is poor and in part contradictive. However, except deep brain stimulation, tolerability and safety of these methods are good so that in refractory situations application might be justified in individual cases.

Generation of a new six1-null line in Xenopus tropicalis for study of development and congenital disease.

The vertebrate Six (Sine oculis homeobox) family of homeodomain transcription factors plays critical roles in the development of several organs. Six1 plays a central role in cranial placode development, including the precursor tissues of the inner ear, as well as other cranial sensory organs and the kidney. In humans, mutations in SIX1 underlie some cases of Branchio-oto-renal (BOR) syndrome, which is characterized by moderate-to-severe hearing loss. We utilized CRISPR/Cas9 technology to establish a six1 mutant line in Xenopus tropicalis that is available to the research community. We demonstrate that at larval stages, the six1-null animals show severe disruptions in gene expression of putative Six1 target genes in the otic vesicle, cranial ganglia, branchial arch, and neural tube. At tadpole stages, six1-null animals display dysmorphic Meckel's, ceratohyal, and otic capsule cartilage morphology. This mutant line will be of value for the study of the development of several organs as well as congenital syndromes that involve these tissues.

Revisión sistemática sobre la eficacia y seguridad de los neuroestimuladores periféricos del ganglio esfenopalatino para el tratamiento de la cefalea crónica en racimos refractaria / Systematic review of the safety and effectiveness of peripheral neurostimulation of the sphenopalatine ganglion for the treatment of refractory chronic cluster headache

Introducción: El objetivo es evaluar la eficacia y seguridad de los neuroestimuladores periféricos del ganglio esfenopalatino (GEP) para el tratamiento de la cefalea en racimos crónica refractaria al tratamiento.DesarrolloRevisión sistemática de la literatura científica. Se identificaron estudios mediante una búsqueda en diferentes bases de datos. Las estrategias de búsqueda se realizaron hasta el 31 de octubre de 2016, incluyendo ensayos clínicos, revisiones sistemáticas o metaanálisis, informes de evaluación de tecnologías sanitarias y guías de práctica clínica que recogieran medidas de eficacia/efectividad o efectos adversos asociados al tratamiento. Se excluyeron estudios de cohortes, casos y controles, series de casos, revisiones narrativas, cartas al director, artículos de opinión, editoriales y estudios duplicados o desfasados por estudios posteriores de la misma institución. Respecto a la eficacia, los resultados son positivos tras la estimulación del GEP en relación con el alivio de dolor, el número de episodios, el uso de la medicación o la calidad de vida del paciente. En relación con la seguridad, hay un número importante de efectos adversos en los primeros 30 días de la intervención y en algunos pacientes fue necesaria la retirada del dispositivo. Los datos de seguimiento son a corto plazo y escasos.ConclusionesLos resultados resultan prometedores a pesar de que la evidencia disponible es limitada. Consideramos fundamental continuar con la investigación sobre la seguridad y eficacia de los neuroestimuladores del GEP en la cefalea en racimos crónica. En aquellos casos en que pueda estar indicada la intervención, el tratamiento debería realizarse supervisado en un estudio de monitorización. (AU)

Introduction: This study aimed to assess the safety and effectiveness of peripheral neurostimulation of the sphenopalatine ganglion (SPG) in the treatment of refractory chronic cluster headache.DevelopmentVarious medical databases were used to perform a systematic review of the scientific literature. The search for articles continued until 31 October 2016, and included clinical trials, systematic reviews and/or meta-analyses, health technology assessment reports, and clinical practice guidelines that included measurements of efficiency/effectiveness or adverse effects associated with the treatment. The review excluded cohort studies, case-control studies, case series, literature reviews, letters to the editor, opinion pieces, editorials, and studies that had been duplicated or outdated by later publications from the same institution. Regarding effectiveness, we found that SPG stimulation had positive results for pain relief, attack frequency, medication use, and patients’ quality of life. In the results regarding safety, we found a significant number of adverse events in the first 30 days following the intervention. Removal of the device was necessary in some patients. Little follow-up data, and no long-term data, is available.ConclusionsThese results are promising, despite the limited evidence available. We consider it essential for research to continue into the safety and efficacy of SPG stimulation for patients with refractory chronic cluster headache. In cases where this intervention may be indicated, treatment should be closely monitored. (AU)

Systematic review of the safety and effectiveness of peripheral neurostimulation of the sphenopalatine ganglion for the treatment of refractory chronic cluster headache.

INTRODUCTION: This study aimed to assess the safety and effectiveness of peripheral neurostimulation of the sphenopalatine ganglion (SPG) in the treatment of refractory chronic cluster headache. DEVELOPMENT: Various medical databases were used to perform a systematic review of the scientific literature. The search for articles continued until 31 October 2016, and included clinical trials, systematic reviews and/or meta-analyses, health technology assessment reports, and clinical practice guidelines that included measurements of efficiency/effectiveness or adverse effects associated with the treatment. The review excluded cohort studies, case-control studies, case series, literature reviews, letters to the editor, opinion pieces, editorials, and studies that had been duplicated or outdated by later publications from the same institution. Regarding effectiveness, we found that SPG stimulation had positive results for pain relief, attack frequency, medication use, and patients' quality of life. In the results regarding safety, we found a significant number of adverse events in the first 30 days following the intervention. Removal of the device was necessary in some patients. Little follow-up data, and no long-term data, is available. CONCLUSIONS: These results are promising, despite the limited evidence available. We consider it essential for research to continue into the safety and efficacy of SPG stimulation for patients with refractory chronic cluster headache. In cases where this intervention may be indicated, treatment should be closely monitored.

Imaging in vivo acetylcholine release in the peripheral nervous system with a fluorescent nanosensor.

The ability to monitor the release of neurotransmitters during synaptic transmission would significantly impact the diagnosis and treatment of neurological diseases. Here, we present a DNA-based enzymatic nanosensor for quantitative detection of acetylcholine (ACh) in the peripheral nervous system of living mice. ACh nanosensors consist of DNA as a scaffold, acetylcholinesterase as a recognition component, pH-sensitive fluorophores as signal generators, and α-bungarotoxin as a targeting moiety. We demonstrate the utility of the nanosensors in the submandibular ganglia of living mice to sensitively detect ACh ranging from 0.228 to 358 µM. In addition, the sensor response upon electrical stimulation of the efferent nerve is dose dependent, reversible, and we observe a reduction of ∼76% in sensor signal upon pharmacological inhibition of ACh release. Equipped with an advanced imaging processing tool, we further spatially resolve ACh signal propagation on the tissue level. Our platform enables sensitive measurement and mapping of ACh transmission in the peripheral nervous system.

Molecular mechanisms of hearing loss in Nager syndrome.

Nager syndrome is a rare human developmental disorder characterized by hypoplastic neural crest-derived craniofacial bones and limb defects. Mutations in SF3B4 gene, which encodes a component of the spliceosome, are a major cause for Nager. A review of the literature indicates that 45% of confirmed cases are also affected by conductive, sensorineural or mixed hearing loss. Conductive hearing loss is due to defective middle ear ossicles, which are neural crest derived, while sensorineural hearing loss typically results from defective inner ear or vestibulocochlear nerve, which are both derived from the otic placode. Animal model of Nager syndrome indicates that upon Sf3b4 knockdown cranial neural crest progenitors are depleted, which may account for the conductive hearing loss in these patients. To determine whether Sf3b4 plays a role in otic placode formation we analyzed the impact of Sf3b4 knockdown on otic development. Sf3b4-depleted Xenopus embryos exhibited reduced expression of several pan-placodal genes six1, dmrta1 and foxi4.1. We confirmed the dependence of placode genes expression on Sf3b4 function in animal cap explants expressing noggin, a BMP antagonist critical to induce placode fate in the ectoderm. Later in development, Sf3b4 morphant embryos had reduced expression of pax8, tbx2, otx2, bmp4 and wnt3a at the otic vesicle stage, and altered otic vesicle development. We propose that in addition to the neural crest, Sf3b4 is required for otic development, which may account for sensorineural hearing loss in Nager syndrome.

Role of the superior salivatory nucleus in parasympathetic control of choroidal blood flow and in maintenance of retinal health.

The vasodilatory pterygopalatine ganglion (PPG) innervation of the choroid is under the control of preganglionic input from the superior salivatory nucleus (SSN), the parasympathetic portion of the facial motor nucleus. We sought to confirm that choroidal SSN drives a choroid-wide vasodilation and determine if such control is important for retinal health. To the former end, we found, using transscleral laser Doppler flowmetry, that electrical activation of choroidal SSN significantly increased choroidal blood flow (ChBF), at a variety of choroidal sites that included more posterior as well as more anterior ones. We further found that the increases in ChBF were significantly reduced by inhibition of neuronal nitric oxide synthase (nNOS), thus implicating nitrergic PPG terminals in the SSN-elicited ChBF increases. To evaluate the role of parasympathetic control of ChBF in maintaining retinal health, some rats received unilateral lesions of SSN, and were evaluated functionally and histologically. In eyes ipsilateral to choroidal SSN destruction, we found that the flash-evoked scotopic electroretinogram a-wave and b-wave peak amplitudes were both significantly reduced by 10 weeks post lesion. Choroidal baroregulation was evaluated in some of these rats, and found to be impaired in the low systemic arterial blood pressure (ABP) range where vasodilation normally serves to maintain stable ChBF. In retina ipsilateral to SSN destruction, the abundance of Müller cell processes immunolabeled for glial fibrillary acidic protein (GFAP) and GFAP message were significantly upregulated. Our studies indicate that the SSN-PPG circuit mediates parasympathetic vasodilation of choroid, which appears to contribute to ChBF baroregulation during low ABP. Our results further indicate that impairment in this adaptive mechanism results in retinal dysfunction and pathology within months of the ChBF disturbance, indicating its importance for retinal health.

Spatiotemporal mapping of sensory and motor innervation of the embryonic and postnatal mouse urinary bladder.

The primary function of the urinary bladder is to store urine (continence) until a suitable time for voiding (micturition). These distinct processes are determined by the coordinated activation of sensory and motor components of the nervous system, which matures to enable voluntary control at the time of weaning. Our aim was to define the development and maturation of the nerve-organ interface of the mouse urinary bladder by mapping the organ and tissue distribution of major classes of autonomic (motor) and sensory axons. Innervation of the bladder was evident from E13 and progressed dorsoventrally. Increasing defasciculation of axon bundles to single axons within the muscle occurred through the prenatal period, and in several classes of axons underwent further maturation until P7. Urothelial innervation occurred more slowly than muscle innervation and showed a clear regional difference, from E18 the bladder neck having the highest density of urothelial nerves. These features of innervation were similar in males and females but varied in timing and tissue density between different axon classes. We also analysed the pelvic ganglion, the major source of motor axons that innervate the lower urinary tract and other pelvic organs. Cholinergic, nitrergic (subset of cholinergic) and noradrenergic neuronal cell bodies were present prior to visualization of these axon classes within the bladder. Examination of cholinergic structures within the pelvic ganglion indicated that connections from spinal preganglionic neurons to pelvic ganglion neurons were already present by E12, a time at which these autonomic ganglion neurons had not yet innervated the bladder. These putative preganglionic inputs increased in density prior to birth as axon terminal fields continued to expand within the bladder tissues. Our studies also revealed in numerous pelvic ganglion neurons an unexpected transient expression of calcitonin gene-related peptide, a peptide commonly used to visualise the peptidergic class of visceral sensory axons. Together, our outcomes enhance our understanding of neural regulatory elements in the lower urinary tract during development and provide a foundation for studies of plasticity and regenerative capacity in the adult system.

Interactions of Eosinophils with Nerves.

Eosinophils affect nerve structure and function in organs such as lungs and skin, which contributes to disease pathogenesis. We have developed methods for culturing primary sensory and parasympathetic neurons in multiple species and have refined these techniques for coculture with eosinophils. Eosinophil-nerve coculture has been an essential tool for testing interactions between these cell types. Here we describe methods for coculturing primary parasympathetic ganglia, vagal sensory nerves, and dorsal root sensory nerves with eosinophils.

Parasympathetic neurons in the human submandibular ganglion.

The submandibular ganglion (SMG) contains parasympathetic neurons which innervate the submandibular gland. In this study, immunohistochemistry for vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), choline acetyltransferase (ChAT), dopamine ß-hydroxylase (DBH), tyrosine hydroxylase (TH), and the transient receptor potential cation channel subfamily V members 1 (TRPV1) and 2 (TRPV2) was performed on the human SMG. In the SMG, 17.5 % and 8.9 % of parasympathetic neurons were immunoreactive for VIP and TRPV2, respectively. SMG neurons mostly contained ChAT- and DBH-immunoreactivity. In addition, subpopulations of SMG neurons were surrounded by VIP (69.6 %)-, TRPV2 (54.4 %)- and DBH (9.5 %)-immunoreactive (-ir) nerve fibers. SMG neurons with pericellular VIP- and TRPV2-ir nerve fibers were significantly larger than VIP- and TRPV2-ir SMG neurons, respectively. Other neurochemical substances were rare in the SMG. In the human submandibular gland, TRPV1- and TRPV2-ir nerve fiber profiles were seen around blood vessels. Double fluorescence method also demonstrated that TRPV2-ir nerve fiber profiles were located around myoepithelial and acinar cells in the submandibular gland. VIP and TRPV2 are probably expressed by both pre- and post-ganglionic neurons innervating the submandibular and sublingual glands. VIP, DBH and TRPV2 may have functions about regulation of salivary components in the salivary glands and neuronal activity in the SMG.