Ciliary Ganglion Research Articles

Direct retino-iridal projections and intrinsic iris contraction mediate the pupillary light reflex in early vertebrates

The pupillary light reflex (PLR) adapts the amount of light reaching the retina, protecting it and improving image formation. Two PLR mechanisms have been described in vertebrates. First, the pretectum receives retinal inputs and projects to the Edinger-Westphal nucleus (EWN), which targets the ciliary ganglion through the oculomotor nerve (nIII). Postganglionic fibers enter the eye-globe, traveling to the iris sphincter muscle. Additionally, some vertebrates exhibit an iris-intrinsic PLR mechanism mediated by sphincter muscle cells that express melanopsin inducing muscle contraction. Given the high degree of conservation of the lamprey visual system, we investigated the mechanisms underlying the PLR to shed light onto their evolutionary origins. Recently, a PLR mediated by melanopsin was demonstrated in lampreys, suggested to be brain mediated. Remarkably, we found that PLR is instead mediated by direct retino-iridal cholinergic projections. This retina-mediated PLR acts synergistically with an iris-intrinsic mechanism that, as in other vertebrates, is mediated by melanopsin and has contribution of gap junctions between muscle fibers. In contrast, we show that lampreys lack the brain-mediated PLR. Our results suggest that two eye-intrinsic PLR mechanisms were present in early vertebrate evolution, whereas the brain-mediated PLR has a more recent origin.

Holmes-Adie syndrome associated with BNT162b2 mRNA COVID-19 vaccine

Adie’s tonic pupil is a neuro-ophthalmologic disorder with dilation and poor light response. When deep tendon reflex loss accompanies the tonic pupil, it is called Adie syndrome or Holmes-Adie syndrome. The pupillary symptoms result from damage to the ciliary ganglion and the post-ganglionic parasympathetic nerves. Corona virus 2, which causes severe acute respiratory syndrome, has been named corona virus 19 (COVID-19) by the World Health Organization. It has been reported that the coronavirus infection has neurological manifestations including pupillary involvement.[1,2] The cases of two patients with Adie’s tonic pupil 10–15 days after they had BNT16b2b mRNA (Pfizer, BioNTech, Germany) vaccine were reported. One of them had Holmes-Adie syndrome.[3,4] In this case report, we aim to describe two patients who are a married couple with possible coronavirus BNT16b2b mRNA vaccine (Pfizer, BioNTech, Germany)-related Holmes-Adie syndrome.

CASE REPORT : OLFACTORY GROOVE MENINGIOMA

Abstract
 Background: Olfactory Groove Meningiomas (OGM) are a rare cause of olfactory dysfunction. OGMs are benign, slow-growing tumors that cause non-specific symptoms, such as headaches, olfactory impairment, and psychiatric symptoms, such as depression, personality changes, decreased cognitive function, visual problems, or seizures.
 Aim: In this case report we would like to discuss about a rare case of olfactory groove meningioma with non-spesific symptoms presented in 47-year old female patient
 Case report: A 47-year old female with progressive blurred vision in the right eye for 3 months. Negative light perception in the right eye and fundus of the right eye indicated papillary atrophy. The direct and indirect light reflexes were negative in the right eye. We found Strong homogenous contrast enhancement extraaxial lesion accompanied by multiple dural tails in the left frontal convexity UK approximately 3.2 x 2.8 x 3.1 cm, Tuberculum sellae approximately 2.7 x 2.9 x 3 cm. Cranial decompression, frontal bone reconstruction, and tumor removal were performed. It was found that there was microcystic growth of tumor tissue, consisting of proliferation of meningoethelial cells, round to oval nuclei, smooth chromatin, visible intranuclear inclusions
 Discussion: OGM is a rare, benign tumor. Female patients were more likely to develop OGM than male patients. The ciliary ganglion of cranial nerve III may be affected by compression of the tumor, resulting in the absence of direct and indirect pupillary reflexes in the affected eyes.
 Conclusion: OGM is a slow-growing tumor that does not show significant symptoms at an early stage, making early detection difficult.
 Keyword: Olfactory Groove Meningioma, Blurred Vision, Meningioma

A RARE CASE OF UNILATERAL TRANSIENT MYDRIASIS AFTER BOTULINUM TOXIN INJECTION FOR COSMETIC PROCEDURE

Introduction: Botulinum toxin A (BTX-A) was first used for the aesthetic purposes in 1990 to reduce wrinkles caused by facial muscle. Its effect starts 3 to 4 days after application and lasts for 4 to 6 months. All the medical doctors, from plastic surgeons to dermatologists can administer botulinum toxin A injection effectively and safely. Ophthalmologists are also performing this procedure for blepharospasm. Case Report: A 35 year old female present to emergency department with complain of sudden onset of right eye blurred vision with tingling sensation of the right side of the face. Patient has been injected with BTX-A for a cosmetic procedure about a 2 weeks ago. On presentation, her right pupil measured 9 mm and was fixed, with no direct or consensual response to light, and her left pupil was 3 mm and had a normal light response. CT brain and cranial MRI revealed no optic nerve or cerebral dysfunction. Patient was counselled that the mydriasis would not be permanent. In follow up after 10 days her mydriasis was improved. Discussion: Botulinum neurotoxins inhibit the release of acetylcholine and act primarily at the peripheral cholinergic synapses. These agents act at the neuromuscular junction in skeletal muscle, causing transient muscle paresis. Botulinum toxins could therefore cause pupil dilatation by uptake into the parasympathetic neurons at the level of the ciliary ganglion or the parasympathetic neuromuscular junctions in the sphincter pupillae of the iris. Conclusion: Before botulinum injection for cosmetic purposes or to treat blepharospasm, patients should be warned about the possibility of developing toxin-induced ptosis and mydriasis.

Excision of massive orbital schwannoma through anterior orbital approach

Orbital schwannomas are rare, benign, slowly progressing, encapsulated tumors arising from Schwann cells of the peripheral sheath of the third, fourth, and sixth cranial nerves and ciliary ganglion. The present case is of a 32-year-old male with painless protrusion of left eye for 4 years. It was radiologically diagnosed as retro-orbital hemangioma, but histopathologic examination of the orbital tumor showed orbital schwannoma. The rarity of orbital schwannomas among orbital tumors and improvement in vision along with retained eyelid functions despite excision of a massive tumor make this a unique case.

Parasympathetic and sympathetic control of emmetropization in chick

Emmetropization can be altered by temporal visual stimulation and the spectral properties of the visual environment. The goal of the current experiment is to test the hypothesis that there is an interaction between these properties and autonomic innervation. For that purpose, selective lesions of the autonomic nervous system were performed in chickens followed by temporal stimulation. Parasympathetic lesioning involved transection of both the ciliary ganglion and the pterygopalatine ganglion (PPG_CGX; n = 38), while sympathetic lesioning involved transection of the superior cervical ganglion (SCGX; n = 49). After one week of recovery, chicks were then exposed to temporally modulated light (3 days, 2 Hz, Mean: 680 lux) that was either achromatic (with blue [RGB], or without blue [RG]), or chromatic (with blue [B/Y] or without blue [R/G]). Control birds with lesions, or unlesioned, were exposed to white [RGB] or yellow [RG] light. Ocular biometry and refraction (Lenstar and a Hartinger refractometer) was measured before and after exposure to light stimulation. Measurements were statistically analyzed for the effects of a lack of autonomic input and the type of temporal stimulation.In PPG_CGX lesioned eyes, there was no effect of the lesions one-week post-surgery. However, after exposure to achromatic modulation, the lens thickened (with blue) and the choroid thickened (without blue) but there was no effect on axial growth. Chromatic modulation thinned the choroid with R/G.In the SGX lesioned eye, there was no effect of the lesion 1-week post-surgery. However, after exposure to achromatic modulation (without blue), the lens thickened and there was a reduction in vitreous chamber depth and axial length. Chromatic modulation caused a small increase in vitreous chamber depth with R/G.Both autonomic lesion and visual stimulation were necessary to affect the growth of ocular components. The bidirectional responses observed in axial growth and in choroidal changes suggest that autonomic innervation combined with spectral cues from longitudinal chromatic aberration may provide a mechanism for homeostatic control of emmetropization.

Transient unilateral exotropia after an infraorbital local anesthetic injection: a case report

We report a case of transient unilateral exotropia, a rare complication that occurred after an infraorbital local anesthetic injection, and present the possible mechanism underlying this adverse effect. A 64-year-old man underwent an excisional biopsy under local anesthesia for bilateral lower eyelid masses. He received a subcutaneous injection of a local anesthetic (a combination of 1:100,000 epinephrine and 2% lidocaine). Intraoperatively, we observed a homogeneous, fat-attenuated mass with thin fibrous septae inside the orbital septum of each eye. Following excision of the masses, the patient developed severe diplopia accompanied by exotropia, impaired adduction, and mydriasis of the right eye. The pupillary light reflex, visual acuity, and visual field test results were within normal ranges. Notably, his symptoms completely resolved 4 hours postoperatively without intervention. To our knowledge, transient unilateral exotropia following infraorbital local anesthetic injection is rare. The exotropia was attributed to diffusion of the epinephrine/lidocaine solution, which may have affected the ciliary ganglion and the medial rectus muscle. Caution is warranted during local anesthetic injections in patients who undergo periorbital surgery.

Truncation mutations in MYRF underlie primary angle closure glaucoma.

Mutations in myelin regulatory factor (MYRF), a gene mapped to 11q12-q13.3, are responsible for autosomal dominant high hyperopia and seem to be associated with angle closure glaucoma, which is one of the leading causes of irreversible blindness worldwide. Whether there is a causal link from the MYRF mutations to the pathogenesis of primary angle-closure glaucoma (PACG) remains unclearat this time. Six truncation mutations, including five novel and onepreviously reported, in MYRF are identified in seven new probands with hyperopia, of whom all six adults have glaucoma, further confirming the association of MYRF mutations with PACG. Immunofluorescence microscopy demonstrates enriched expression of MYRF in the ciliary body and ganglion cell layer in humans and mice. Myrfmut/+ mice have elevated IOP and fewer ganglion cells along with thinner retinal nerve fiber layer with ganglion cell layer than wild-type. Transcriptome sequencing of Myrfmut/+ retinas shows downregulation of Dnmt3a, a gene previously associated with PACG. Co-immunoprecipitation demonstrates a physical association of DNMT3A with MYRF. DNA methylation sequencing identifies several glaucoma-related cell events in Myrfmut/+ retinas. The interaction between MYRF and DNMT3A underlies MYRF-associated PACG and provides clues for pursuing further investigation into the pathogenesis of PACG and therapeutic target.

Parasympathetic innervation of emmetropization

Emmetropization is affected by the temporal parameters of visual stimulation and the spectral composition of light, as well as by autonomic innervation. The goal of the current experiments is to test the hypothesis that different types of visual stimulation interact with ocular innervation in the process of emmetropization. For that, selective lesions of the autonomic nervous system were performed in chickens: involving transection of parasympathetic input to the eye from either the ciliary ganglion, innervating accommodation and pupil responses (CGX; n = 32), or pterygopalatine ganglion, innervating choroidal blood vessels and cornea (PPGX; n = 26). After 1 week of recovery, chicks were exposed to sinusoidally modulated light (3 days, 2 Hz, 680 lux) that was either achromatic (black to white [RGB], or black to yellow [RG]), or chromatic (blue to yellow [B/Y] or red to green [R/G]). Exposure to light stimulation was followed by ocular biometry (Lenstar and a Hartinger refractometer). Surgical conditions revealed a small reduction in anterior chamber depth with CGX but no other significant changes in ocular biometry/refraction under standard light conditions. With RGB achromatic stimulation, CGX eyes produced an effect on ocular components, with a further reduction in anterior chamber depth and an increase in vitreous chamber depth, while RG stimulation showed no effect. No effect was detected in PPGX under both achromatic protocols. With chromatic stimulation, CGX with R/G modulation increased eye length, while PPGX with B/Y modulation decreased eye length. We conclude that the two different types of parasympathetic innervations have antagonistic effects on eye growth and the anterior eye when challenged with the appropriate stimulus, with possible implications for the role of choroidal blood flow in emmetropization.

Ураження нервової системи в пацієнта із синдромом Еді (клінічний випадок)

Синдром Еді (Adie-Holmes), або синдром тонічної зіниці, — стан, що характеризується тріадою основних симптомів: одностороннім тонічним розширенням зіниці, парезом акомодації з відсутністю або значним зменшенням реакції зіниці на світло і зниженням сухожильних рефлексів. В основі захворювання лежить порушення функції парасимпатичної нервової системи. Синдром виникає внаслідок ураження циліарного ганглія, що забезпечує парасимпатичну іннервацію м’яза зіниці (m. sphincter pupillae), рогівки й оболонки очного яблука. Нерідко стан супроводжується порушенням функції спінальних гангліїв і, як наслідок, вегетативною дисфункцією у вигляді розладу потовиділення, зазвичай на одній стороні тіла, рідше — розладом серцевого ритму, лабільністю артеріального тиску. Частий супутник синдрому Еді — відсутність або зниження колінних рефлексів, рідше — ахіллових. Етіологія захворювання остаточно не з’ясована, не виключений бактеріальний або вірусний чинник. Діагностика синдрому Еді переважно заснована на клінічному зіставленні симптомів захворювання, а також на ретельному й всебічному огляді нейроофтальмолога з обов’язковим проведенням тестування зіничних реакцій за допомогою низьких доз пілокарпіну (характерне звуження зіниці). Незважаючи на позитивний прогноз щодо життя хворого і його працездатності, стан належить до групи складнокурабельних, а лікування зводиться до симптоматичної корекції зору.

ANATOMICAL STUDIES ON THE CRANIAL NERVES AND CRANIAL GANGLIA OF ANGUILLA ANGUILLA (LINNAEUS, 1758) EYE MUSCLE NERVES

The aim of this study is to analyze the ocular muscle nerves and the ciliary ganglion of the anguillid fish Anguilla anguilla. The ocular muscle nerves comprise the nervi oculomotorius, trochlearis and abducens. The oculomotor nerve leaves the cranial cavity together with the nervus abducens through a common foramen. It innervates four eye muscles rectus superior, rectus inferior, rectus medialis and the obliquus inferior muscles. It carries pure somatic motor fibers and visceromotor (parasympathetic) ones. There is no ciliary ganglion but, there is one ciliary nerve arising from the nervus oculomotorius. The trochlear nerve has its own foramen and carries pure somatic motor fibers to the superior obliquemuscle. The abducens nerve has a single root. It leaves the cranial cavity through a common foramen together with the nervus oculomotorius. It carries pure somatic motor fibers to the rectus lateralis muscle.

Tonic pupil secondary to varicella-zoster-virus (VZV) keratouveitis in a child

Abstract Introduction: An unusual case of tonic pupil in a 4-year-old male child secondary to Varicella-Zoster-Virus (VZV) keratouveitis is described in this case report. To the best of our knowledge, our report is the thirtieth case of tonic pupil following chickenpox infection in the literature. Patient concerns: A 4-year-old male child presented at our department in June 2019 with anisocoria and feeling generally unwell. The right pupil was noted by his mother to be larger than the left in normal, bright and dim illumination conditions. Of note, the child at the same time was suffering from chickenpox and the symptoms started approximately 4 days prior to the attendance at Accident and Emergency with a generalized vesicular rash. The mother also reported that the right eye was mildly red and uncomfortable and her son was complaining of photophobia. Diagnosis: Tonic pupil secondary to VZV keratouveitis. Interventions: Full past medical and ocular history was obtained. The patient underwent full ophthalmic examination including dilated fundoscopy. Visual acuity was recorded with Snellen Chart and Keeler chart of Minimum Angle of Resolution chart. Patient had Magnetic Resonance Imaging due to anisocoria to exclude intracranial pathology. The child was treated with intravenous Acyclovir and had a good recovery, though the anisocoria persisted. Outcomes: During the follow-ups in the Paediatric Ophthalmology Clinic, 0.125% pilocarpine test revealed profound miosis of the affected right pupil and normal response from the healthy left pupil. In addition, the range of accommodation was reduced in the affected right eye. The child was closely observed to prevent right eye amblyopia and the plan was to issue bifocals to maximize both near and distant visual acuity. Nevertheless, during close follow-up the accommodation reflex in the right eye recovered on its own and the child was eventually discharged from the clinic without executive bifocals. Conclusion: VZV keratouveitis leading to tonic pupil is a rare complication. The proposed pathophysiological mechanism is retrograde dissemination of the infection through the parasympathetic nerve fibers from the iris via the inferior branch of the third nerve to the ciliary ganglion. Our case emphasizes the potential amblyogenic consequences of tonic pupil.

Centrally Projecting Edinger-Westphal Nucleus in the Control of Sympathetic Outflow and Energy Homeostasis.

The centrally projecting Edinger-Westphal nucleus (EWcp) is a midbrain neuronal group, adjacent but segregated from the preganglionic Edinger-Westphal nucleus that projects to the ciliary ganglion. The EWcp plays a crucial role in stress responses and in maintaining energy homeostasis under conditions that require an adjustment of energy expenditure, by virtue of modulating heart rate and blood pressure, thermogenesis, food intake, and fat and glucose metabolism. This modulation is ultimately mediated by changes in the sympathetic outflow to several effector organs, including the adrenal gland, heart, kidneys, brown and white adipose tissues and pancreas, in response to environmental conditions and the animal’s energy state, providing for appropriate energy utilization. Classic neuroanatomical studies have shown that the EWcp receives inputs from forebrain regions involved in these functions and projects to presympathetic neuronal populations in the brainstem. Transneuronal tracing with pseudorabies virus has demonstrated that the EWcp is connected polysynaptically with central circuits that provide sympathetic innervation to all these effector organs that are critical for stress responses and energy homeostasis. We propose that EWcp integrates multimodal signals (stress, thermal, metabolic, endocrine, etc.) and modulates the sympathetic output simultaneously to multiple effector organs to maintain energy homeostasis under different conditions that require adjustments of energy demands.

Anatomical study on branching pattern and variations of orbital segment of the oculomotor nerve.

This study aims to revisit the anatomy of orbital segment of the third cranial nerve (CN III). The study also involved morphometric measurements of CN III muscular branches. Detailed description of observed anatomical variations and their incidence was also included. The study supplements earlier findings with detailed observations of the neuromuscular relations. The study was conducted on 52 orbits taken from 26 cadaveric heads (10 males and 16 females; Central European population). Anatomical variations of the orbital segment of the CN III observed on the examined material involved both the superior and inferior branch of this nerve. The muscular branch innervating the levator palpebrae superioris muscle occasionally pierces the superior rectus muscle. The nerve to the inferior oblique muscle may pierce and innervate the inferior rectus muscle. In rare instances, duplication of the parasympathetic root of the ciliary ganglion may also occur. Among the muscular branches, the smallest diameter reached the branch to the levator palpebrae superioris muscle. Among the three muscular branches derived from the inferior branch of the CN III, the nerve to the inferior oblique was the longest one. Its length varied from 28.9 mm to 37.4 mm. The shortest was the muscular branch to the inferior rectus muscle. Its length varied from 0 mm (when muscular sub-branches arose directly from the nerve to the inferior oblique muscle) to 7.58 mm. This study presented the characteristic of orbital segment of the CN III, including anatomical variations and morphometric measurements relevant to intraorbital procedures.

Anatomical evidence for the efferent pathway from the hypothalamus to autonomic innervation in the anterior chamber structures of eyes

The autonomic innervation in the anterior chamber (AC) structures might play an efferent role in neural intraocular pressure (IOP) regulation, the center of which is thought to be located in the hypothalamus. In this study, we identified the efferent pathway from the hypothalamus to the autonomic innervation in the AC structures. Retrograde trans-multisynaptic pseudorabies virus (PRV) expressing green or red fluorescent protein, PRV531 and PRV724, was injected into the right and left AC of five rats, respectively; PRV531 was injected into the right AC of another five rats, and a non-trans-synaptic tracer, FAST Dil, was injected into the right AC of five rats as a control. Fluorescence signals in autonomic ganglia,the spinal cord and the central nervous system (CNS) were observed. Seven days after FAST Dil right AC injection, FAST Dil-labeled neurons were observed in the ipsilateral autonomic ganglia, including the superior cervical ganglion, pterygopalatine ganglion, and ciliary ganglion, but not in the CNS. Four and a half days after PRV531 injection into the right AC, PRV531-labeled neurons could be observed in the ipsilateral autonomic ganglia and bilateral hypothalamus nuclei, especially in the suprachiasmatic nucleus, paraventricular nucleus, dorsomedial hypothalamus, perifornical hypothalamus and ventral mammillary nucleus. Fluorescence signals of PRV531 mainly located in the ipsilateral autonomic preganglionic nuclei (Edinger-Westphal nucleus, superior salivatory nucleus and intermediolateral nucleus), but not in sensory trigeminal nuclei. Four and a half days after PRV531 right AC injection and PRV724 left AC injection, PRV531-labeled, PRV724-labeled, and double-labeled neurons could be observed in the above mentioned bilateral hypothalamus nuclei; but few contralateral infection-involving neurons (including double-labeled neurons) could be detected in the autonomic preganglionic nuclei. Our results indicate that there exist a both crossed and uncrossed hypothalamo-pre-parasympathetic and -pre-sympathetic tracts in the efferent pathways between the bilateral hypothalamic nuclei and the autonomic innervation of the bilateral AC.

Adie’s Tonic Pupil Disclosing a Metastatic Breast Cancer: Case Report

Tonic pupil, or Adie’s pupil, is an autonomic disorder due to a loss of function of parasympathetic ciliary ganglion cells. Upon examination, the pupil appears tonically dilated and shrinks poorly to light, while reacting better to accommodation stimulus. The denervated iris sphincter is very sensitive to topical parasympathomimetic pilocarpine drops. Indeed, if Adie is present, the dilated pupil will constrict more than the normal pupil. Most cases are idiopathic or due to a viral infection and have a benign course. They usually occur in women between 20 and 40 years of age. Other reported causes of tonic pupils can be vascular, traumatic, inflammatory, paraneoplastic, and neoplastic. Breast cancer generally metastasizes to the brain in advanced stages and orbital localizations have sometimes been reported. In our case, a meningeal and retro-orbit cancer invasion caused a dysfunction of the parasympathetic fibers which lead to the pupil through the optical foramen. Indeed, first ophthalmic symptoms were only an enlarged pupil poorly responsive to light. This unusual clinical sign led to the discovery of an unknown breast cancer in an advanced stage. In young adult women, unilateral tonic pupils are considered a benign parasympathetic ocular disorder that is rarely observed in clinical practice. However, it can be found in numerous systemic diseases; thus instrumental and laboratory findings are mandatory. Tumors can also represent etiologic agents and secondary localizations from breast cancer to extra parenchymal CNS structures should be considered in differential diagnosis hypothesis.

Morphometric study of the ciliary ganglion and its pertinent intraorbital procedure.

Ciliary ganglion (CG) can be easily injured without notice in many intraorbital procedures. Surgical procedures approaching the lateral side of the orbit are at risk of CG injury which results in transient mydriasis and tonic pupil. This study aims to focus on the morphometric study of the CG which is pertinent to intraoperative procedure. Forty embalmed cadaveric globes were dissected to observe the location, shape and size of CG, characteristics and number of roots reaching CG, number of short ciliary nerve in the orbit. Distances from CG to posterior end of globe, optic nerve, lateral rectus muscle and its scleral insertion were measured. Ciliary ganglion was located between optic nerve and lateral rectus in every case. Its shape could be oval, round and irregular. Mean width of CG was 2.24 mm and mean length was 3.50 mm. Concerning the roots, all 3 roots were present in 29 (72.5%) cases. Absence of motor root was found in 7 (17.5%) cases. Absence of sympathetic root was found in 4 (5%) cases. The number of motor root could be 1, 2 and also 3 roots. Three motor roots were found in 1 case which originated from nerve to inferior oblique muscle. Only one sensory root was found in every specimen. One sympathetic root could be observed in most of the specimens and 6-14 short ciliary nerves were found. Mean distances from CG to posterior end of globe, optic nerve, lateral rectus muscle and its scleral insertion were 16.04 mm, 1.47 mm, 2.88 mm, and 31.53 mm, respectively. This study described the characteristic of CG, number of its nerve root and some measurements relevant to intraorbital procedures in Asian population. Moreover, a new parameter was the distance between CG and scleral insertion of the lateral rectus muscle. This parameter should be considered when performing operation involved the lateral rectus muscle and BTX-A injection to lateral rectus muscle to reduce CG injury.

Isolation and Culture of Chick Ciliary Ganglion Neurons.

Chick ciliary ganglia (CG) are part of the parasympathetic nervous system and are responsible for the innervation of the muscle tissues present in the eye. This ganglion is constituted by a homogenous population of ciliary and choroidal neurons that innervate striated and smooth muscle fibers, respectively. Each of these neuronal types regulate specific eye structures and functions. Over the years, neuronal cultures of the chick ciliary ganglia were shown to be effective cell models in the study of muscle-nervous system interactions, which communicate through cholinergic synapses. Ciliary ganglion neurons are, in its majority, cholinergic. This cell model has been shown to be useful comparatively to previously used heterogeneous cell models that comprise several neuronal types, besides cholinergic. Anatomically, the ciliary ganglion is localized between the optic nerve (ON) and the choroid fissure (CF). Here, we describe a detailed procedure for the dissection, dissociation and in vitro culture of ciliary ganglia neurons from chick embryos. We provide a step-by-step protocol in order to obtain highly pure and stable cellular cultures of CG neurons, highlighting key steps of the process. These cultures can be maintained in vitro for 15 days and, hereby, we show the normal development of CG cultures. The results also show that these neurons can interact with muscle fibers through neuro-muscular cholinergic synapses.

Isolation and Culture of Chick Ciliary Ganglion Neurons

Isolation and Culture of Chick Ciliary Ganglion Neurons

HSV-1 infection and pathogenesis in the tree shrew eye following corneal inoculation.

Herpes simplex virus type I (HSV-1) infection causes inflammation in the cornea known as herpes simplex virus keratitis (HSK), a common but serious corneal disease. It is not entirely clear whether the virus during recurring infection comes from the trigeminal ganglia or the eye tissue, including the retina and ciliary ganglion. Because the tree shrew is closely related to primates and tree shrew eye anatomic structures are similar to humans, we studied HSV-1 corneal infection in the tree shrew. We found that HSK symptoms closely mimic those found in human HSK showing typical punctiform and dendritic viral keratitis during the acute infection period. Following the HSV-specific lesions, complications such as stromal scarring, corneal thickening (primary infection), opacity, and neovascularization were observed. In the tree shrew model, following ocular inoculation, the cornea becomes infected, and viral protein can be detected using anti-HSV-1 antibodies in the epithelial layer and retina neuronal ganglion cells. The HSV-1 transcripts, ICP0, ICP4, and LAT can be detected at 3days post-infection (dpi), peaking at 5dpi. After 2weeks, ICP4 and ICP0 transcripts are reduced to a basal level, but the Latency Associated Transcripts (LATs) continue to accumulate. Interestingly, after the acute infection, we still detected abundant active HSV-1 in tree shrew eyes. Further, we found HSV-1 persistent in the ciliary ganglion and cornea. These findings are discussed in support of the tree shrew as a non-human primate HSK model, which could be useful for mechanistic studies of HSK.