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PubMed1984

Biochemical and immunohistochemical determination of 5-hydroxytryptamine located in mast cells in the trigeminal ganglion of the rat and guinea pig.

The presence of 5-hydroxytryptamine (5-HT), as well as its precursor (5-HTP) and metabolite (5-HIAA), were biochemically determinated in the trigeminal ganglion of the guinea pig and rat. The distribution of 5-HT in the ganglion and in its posterior root was studied using both indirect immunofluorescence and the peroxidase-antiperoxidase method. In order to increase the possible 5-HT content of primary sensory neurons for subsequent immunohistochemical visualization, animals were first treated with nialamide, an inhibitor of monoamine oxidase, and then loaded with L-tryptophan. Another group of animals received colchicine to inhibit intra-axonal transport of transmitter substances. However, even combined use of loading and colchicine treatment did not reveal 5-HT immunoreactivity in ganglion cells. The only source of 5-HT immunoreactivity in the trigeminal ganglion and its posterior root was mast cells. These cells were located around the ganglion in adjacent leptomeningeal and connective tissues, as well as between the ganglion cells and nerve fibers. Only occasionally were mast cells found in the posterior root of the ganglion.

5-Hydroxytryptophan↗
PubMed1982

Innervation of dog ciliary ganglion.

There are species differences with regard to the composition of the ciliary ganglion. For instance, in rabbits and cats it consists solely of oculomotor nerves and has no sympathetic or sensory innervation. The purpose of this study is to clarify the participation of these nerves in the ciliary ganglion of the dog by histochemical methods. Cholinesterase (ChE) activity was studied by Karnovsky's method and catecholamine fluorescence by the glyoxylic acid method. Furthermore, the origins of the respective nerves were investigated by a serial preparation method, involving unilateral cervical sympathectomy and tracer dye injection in the ganglion. The results obtained were: (1) Ciliary ganglion cells showed intense ChE activity. Oculomotor nerve fibers leading to the ganglion showed moderate ChE activity, while the reaction in the short ciliary nerves was strong. (2) Aminergic nerves were present in the intercellular space of the ciliary ganglion, and bilateral or central innervation was suggested by the results of cervical sympathectomy. (3) Connection between the ciliary and trigeminal ganglia was proved by the dye tracer study. The results show that the ciliary ganglion in dogs is composed of oculomotor, trigeminal and sympathetic nerves.

Animals↗
PubMed1995

Lactate dehydrogenase activity and isoform distribution in the rat pelvic ganglion: effects of diabetes and bladder outlet obstruction.

We have previously shown that the intramural motor nerves in the rat bladder can function in anoxic conditions. The present study aims to explore the distribution and activity of lactate dehydrogenase (LDH), the key enzyme for ATP generation in anoxia. The activity and isoform distribution pattern of LDH was studied in pelvic ganglia from male and female rats. A histochemical investigation showed that the LDH activity was intense in the ganglion cells, and weak in the other tissue components (nerve bundles, connective tissue). The male pelvic ganglion weighted 55% more than the female pelvic ganglion, the enzyme activity per unit ganglion weight was 60% higher and the total LDH activity was 155% higher. The isoform distribution was similar, with M4 being dominant isoform, followed by M3H. Infravesical outlet obstruction in the female rat induced a threefold increase in ganglion weight, and the total LDH activity increased twofold. In this hypertrophic female ganglion a decreased relative amount of M4, and an increased amount of MH3, was found. Diabetes in the male rat had no effect on ganglion weight or its contents and isoform distribution of LDH.

Animals↗
PubMed1987

Vasopressin stimulates the phosphorylation of an 83,000 Mr protein in the superior cervical ganglion.

1. 32P-Labeled proteins from the superior cervical ganglion of the rat were separated by two-dimensional gel electrophoresis and visualized by autoradiography. 2. The most heavily labeled phosphoprotein in the ganglion had a relative molecular weight of 83,000 and a pI of 4.5. Phosphorylation of this protein was increased by phorbol 12,13-dibutyrate, an activator of the Ca2+/phospholipid-dependent protein kinase, protein kinase C. This protein appears to be similar or identical to a specific protein kinase C substrate that has been described in other tissues (Blackshear, P. J., et al., J. Biol. Chem. 261:1459-1469, 1986). 3. Phosphorylation of this protein was also increased by treatment of the ganglion with phospholipase C (Bacillus cereus) but was not increased by 8-bromo-cyclic AMP or by nicotinic agonists. Vasopressin increased the hydrolysis of inositol-containing phospholipids in the ganglion and also increased the labeling of the 83,000 Mr protein. Thus, vasopressin appears to activate protein kinase C in the ganglion. 4. Muscarine, which also increased phospholipid metabolism in the ganglion, did not increase the phosphorylation of the 83,000 Mr protein. Muscarine and vasopressin stimulate phospholipid metabolism in different structures within the ganglion (Horwitz, J., et al., J. Pharmacol. Exp. Ther. 237:312-317, 1986). Muscarine may increase phospholipid metabolism in structures that do not contain significant amounts of the 83,000 Mr protein.

Animals↗
PubMed1983

Retrograde transneuronal regulation of the afferent innervation to the rat superior cervical sympathetic ganglion.

The superior cervical sympathetic ganglion of the rat receives its preganglionic afferent innervation through the cervical sympathetic trunk, and sends most of its postganglionic axons through two major nerves, the internal (ICN) and external carotid nerves (ECN). In the present study, the ICN alone or both the ICN and the ECN were cut in neonatal and adult rats. Two months after these lesions, ganglionic neurons, synapses and preganglionic axons were counted and compared with unoperated control values. After cutting the ICN alone in neonatal rats, ganglionic neurons were reduced in number by 70% and synapses were reduced by 50%, but there was no change in the number of preganglionic axons. Cutting both the ICN and ECN in neonates resulted in an 88% reduction of ganglionic neurons and an 83% reduction of synapses. In this case there was a 63% reduction in the number of preganglionic axons. After cutting either the ICN alone or both the ICN and the ECN in neonates, there was a hyperinnervation (increased number of synapses) of the remaining ganglionic neurons. In the adult rat, cutting either the ICN alone or both the ICN and ECN resulted in a smaller loss of ganglionic neurons, and there was no loss of preganglionic axons. There was no hyperinnervation of surviving neurons in adult rats. Thus, the response by preganglionic axons to a reduced number of ganglionic neurons differs in the neonate and adult rat. In the developing animal, the degenerative response to injury is much more severe than in the adult, but the reorganizational response is also greater.

Animals↗
PubMed1981

Effect of early postnatal division of the postganglionic nerves on the development of principal cells and small intensely fluorescent cells in the rat superior cervical ganglion.

The three main postganglionic nerve branches of the superior cervical ganglion were divided on one side in 3--4-day-old rats. Five, 10, 20 and 60 days after the operation, the number of principal cells and small intensely fluorescent (SIF) cells, and the ganglion volume were estimated from a complete series of sections through each ganglion, in which catecholamines were histochemically demonstrated by formaldehyde-induced fluorescence. As compared with the contralateral, intact ganglion, the operated ganglion showed a rapid loss of principal cell bodies to about 1/20th of the control value, and the normally large postnatal increase in the volume of the ganglion failed to take place in the operated ganglion. Sham operation experiments showed that these changes were due to nerve division rather than disturbed blood supply and manipulation. The number of SIF cells increased in the intact ganglia from about 200 cells/ganglion at birth and reached the adult value, about 600 cells/ganglion by the 23rd postnatal day. An essentially similar postnatal increase in Sif cell number occurred in the experimental ganglia in spite of the marked loss of principal cells. The relative number of SIF cells increased from less than 1% of all cells (SIF cells and principal cells) in the control ganglia to over 10% in the operated ganglia, in which large aggregates of SIF cells formed 20 and 60 days after nerve division. It is concluded that different sets of developmental rules may apply to the SIF cells and the principal cells.

Animals↗
PubMed1992

Division and migration of satellite glia in the embryonic rat superior cervical ganglion.

While distinct precursors committed to a neuronal or glial cell fate are generated from neural crest cells early in peripheral gangliogenesis, little is known about the subsequent generation and maturation of young satellite glia from restricted glial precursor cells. To examine the division and migration of glial precursor cells and their satellite cell progeny, morphological, immunocytochemical and culture techniques were applied to the developing rat superior cervical ganglion. At embryonic day (E)18.5, numerous clusters of nonneuronal cells appeared transiently in the ganglion. Individual cells with a similar morphology were present in E16.5 ganglia, and are likely to represent the precursor cells which generate these clusters. The clustered cells were distinguishable from neighbouring neurons as well as from endothelial cells and fibroblasts. Morphologically similar cells were present in nerve bundles at E18.5 and surrounding principal neurons and nerve bundles in the adult ganglion. Double-label studies of the E18.5 ganglion with tyrosine hydroxylase to identify noradrenergic neurons and propidium iodide counterstaining to visualize all cell nuclei revealed that the cells in clusters stained with propidium iodide but lacked tyrosine hydroxylase immunoreactivity. To determine if cell clusters arose from division, bromodeoxy-uridine, a thymidine analogue, was administered to pregnant mothers between E16.5-E18.5, and ganglionic cells examined at E18.5 both in vivo and in vitro. Numerous non-neuronal cells divided during this period in situ and composed portions of clusters. When dissociated, superior cervical ganglion satellite glia reacted with an NGF-receptor antibody (MAb 217c) and possessed a flattened shape, in contrast to bipolar Schwann cells. Over half of the 217c-immunoreactive glia at E18.5 had incorporated bromodeoxyuridine during E16.5-18.5 in vivo. At birth, non-neuronal cells were no longer grouped in clusters, but were associated with neuronal cell bodies and processes. These findings suggest that, between E16.5-E18.5, glial precursors divide rapidly to form clusters, and that, after the peak of neurogenesis, daughter cells migrate within the ganglion to associate with nerve cell bodies and processes where proliferation continues at a slower rate. Distinct cellular and molecular interactions are likely to trigger the initial rapid division of glial precursors, initiate their migration and association with neuron cell bodies, and control their subsequent slower division.

Animals↗
PubMed1988

An electron microscopic study of the nodose (inferior vagal) ganglion cells in the monkey.

The present study described the normal ultrastructure of the monkey nodose ganglion cells. Furthermore, experimental monkeys were subjected to supranodose vagotomy in order to ascertain if the present cell bodies would undergo degeneration following severance of their central processes. In the normal materials, most of the ganglion cells possessed a single neurite. However, occasional cells bearing more than one process in a sectioned profile were observed. The neurites, ranging between 2-4 microns in diameter, displayed a relatively regular contour. Their cytoplasm contained parallel arrays of microtubules, ribosomes, endoplasmic reticulum and slender mitochondria. The electron density of some of these neurites was abnormally high. Embedded in these darkened neurites were a variable number of swollen mitochondria characterized by disrupted cristae. Axon terminals containing round agranular and a few large dense cored vesicles formed synaptic contacts primarily with the neurites of some of the ganglion cells. Three days after superanodose vagotomy, darkened neurites were more commonly observed but their incidence was comparable to that of the normal ganglion in longer survival animals. Another reactive change was the appearance of axon terminals undergoing various degrees of degeneration. There was no evidence of cell death in the duration studied. It was concluded from this study that the occasional darkened neurites from the normal ganglion cells was probably undergoing 'spontaneous degeneration' which appeared to be accentuated when their central process was severed by supranodose vagotomy. The degeneration of axon terminals associated with some of the ganglion cells following the vagotomy suggested that they were derived from vagal descending fibres which were undergoing anterograde degeneration. The presence of synapses on some of the ganglion cells was also discussed and the possibility considered that the latter may represent 'aberrant' or displaced autonomic neurons.

Animals↗
PubMed1993

Ultrastructure of the macaque ciliary ganglion.

The primate ciliary ganglion is an obligatory relay in the pathways that control the lens and pupil for the near response and the light reflex, two functions which have been the target of increasing inquiry in behavioural physiology paradigms. This investigation provides a comprehensive description of the ultrastructure of the ciliary ganglion in the rhesus monkey (Macaca mulatta). The results indicate that the ciliary ganglion contains a heterogeneous population of neurons in terms of somatic size, cytoplasmic contents and somatodendritic distribution of terminals. Variations in the clear and dense-cored vesicle content of the synaptic profiles present in the ganglion suggest that the synaptic inputs are also heterogeneous and may mediate separate functions. Several characteristic ultrastructural features of the macaque ciliary ganglion are noteworthy. Despite the large size of the neuronal somata, most cells do not exhibit contacts directly onto the somatic membrane. However, the few somata that do receive direct input often display several axosomatic contacts. The vast majority of synaptic interactions occur in the perisomatic neuropil, where the postsynaptic elements consist of simple and complex somatic appendages, as well as dendrites with their appendages. There is little neuropil independent of these immediately perisomatic regions. In some cases, axonal terminals form the central element of complex glomeruli, in which they are presynaptic to numerous spine-like profiles. In other cases, axon terminals and their postsynaptic targets are found within shallow depressions in the somatic membrane or, occasionally, deeply embedded within the borders of the postganglionic neuron. The somata and all the non-myelinated neuronal elements are surrounded by interdigitating, electron-dense processes of satellite cells. These glial cells are sometimes found in shallow recesses, or deeply embedded within the borders of the neuronal somata. The complexity of the ultrastructure of the ciliary ganglion in the macaque suggests that this ganglion may not be a simple relay in the parasympathetic outflow to the eye, but may instead be the site of neuronal processing of the preganglionic input.

Animals↗
PubMed2006

Human pelvic extramural ganglion cells: a semiquantitative and immunohistochemical study.

In pelvic surgery, much attention is paid to nerve bundles but not to ganglion cells. Using serial section histology of 14 postmortem-treated hemipelvis (eight males, six females; mean, 79 years old), we examined the population number, distribution, and tyrosine hydroxylase-immunoreactivity (TH-IR; suggesting sympathetic neurons) of extramural pelvic ganglion cells. All pelvic ganglion cells were uniformly sized (25-30 microm) contrasting with small intramural rectal neurons. Abundant ganglion cells (30,000-140,000 unilaterally) existed not only along the pelvic viscera except for the rectum, but also along the hypogastric nerve, pelvic splanchnic nerve, pelvic plexus, and associated branches excluding those within the mesorectum. The intrapelvic ganglion cells outside the sympathetic trunk did not form macroscopically identifiable ganglia, but made small clusters (0.1-2.0 mm of maximum diameter) or were diffusely scattered within nerve bundles. More than half of these cells appeared TH-IR positive, although the positive/negative proportion differed between nerves and specimens. Greater numbers of ganglion cells were found in dorsosuperior sites (e.g., around the seminal vesicle) rather than in ventroinferior sites (e.g., along the urethra) in males, and vice versa in females. However, in total cell numbers, interindividual variations were evident rather than intergender difference. Due to significant interindividual variations in cell number, differences are likely to exist between patients in "resistance" to surgical stresses. We hypothesized that pelvic ganglion cells are liable to be damaged due to drying along the surgical margin, hypoxia in venous bleeding, pressure from surgical retractors, extension stress with taping and excess traction and/or direct injury with electrical scalpels.

Aged↗
PubMed2003

Intra-articular ganglion cysts of the cruciate ligaments: case report and review of the literature.

BACKGROUND: A ganglion can arise as a cystic lesion from a tendon sheath or a joint capsule and contain a glassy, clear, and jelly-like fluid. They can occur within muscles, menisci, and tendons. Intra-articular ganglion cysts of the knee joint are rare. We report on three ganglion cysts of the cruciate ligaments: Two were intercruciate, and one was located around the posterior cruciate ligament. METHODS: The clinical diagnosis was established using magnetic resonance imaging. All patients were treated successfully using arthroscopic debridement by basket punch and shaver. Subsequent histological examination confirmed the diagnosis. RESULTS: All three patients were asymptomatic at the postoperative follow-up of 16-36 months. CONCLUSION: A review of the literature reveals a controversial discussion about the clinical significance as well as the etiology of ganglion cysts arising from the cruciate ligaments. These case reports show that an intra-articular ganglion cyst of the cruciate ligaments is difficult to diagnose. A cyst does not necessarily have to be associated with specific clinical symptoms or a previous trauma. Preoperatively, MRI is essential when diagnosing ganglion cysts of the knee joint. An intra-articular ganglion cyst of the knee joint can be successfully treated by arthroscopy.

Adult↗
PubMed1997

Denervation-induced changes in perineuronal plexuses in the major pelvic ganglion of the rat: immunohistochemistry for vasoactive intestinal polypeptide and tyrosine hydroxylase and histochemistry for NADPH-diaphorase.

To characterize further the injury response of autonomic ganglia, we have examined the effect of chronic denervation on perineuronal plexuses that are immunoreactive for vasoactive intestinal polypeptide (VIP) and tyrosine hydroxylase (TH) or that stain for nicotinamide adenine dinucleotide phosphate (NADPH) in the rat major pelvic ganglion, and their relationship to an identified sub-population of neurons in the ganglion (the penile neurons). Penile neurons contain VIP and NADPH diaphorase (NADPH-D) but lack TH. VIP-immunoreactive (VIP-IR) and TH-IR perineuronal plexuses (baskets) are rare in the rat major pelvic ganglion and those present are not associated with penile neurons. A small increase in VIP-IR baskets occurs 2 weeks after proximal interruption of the pelvic nerve, but TH-IR baskets increase five-fold. The emergent VIP-IR and TH-IR baskets enclose TH-negative neurons, none of which are penile ganglion cells. These changes remain up to 4 weeks after denervation. Interrupting the pelvic nerve nearer the margin of the major pelvic ganglion results in a rapid, more dramatic increase in VIP-IR, in cell bodies and beaded fibers, than that seen with the more proximal lesion. About 27% of neurons in the ventral pole of the ganglion are enveloped by NADPH-D perineuronal baskets. The incidence of NADPH-D baskets falls to less than 1% after acute interruption of the pelvic and hypogastric nerves, but their frequency returns to control levels in chronically denervated ganglia. The rapid, vigorous changes in peptide (VIP) fibers after the pelvic nerve is cut close to the major pelvic ganglion may be attributable to the interruption of axons of postganglionic neurons and to preganglionic nerve fibers, whereas the slowly developing changes in VIP-IR and TH-IR fibers after more proximal lesions may represent the more modest effects of true decentralization. The source and significance of the VIP-IR, TH-IR, and NADPH-D baskets that appear in chronically denervated ganglia remain unclear.

Animals↗
PubMed1983

On the occurrence of gastrin releasing peptide (GRP)-like immunoreactive nerve fibers in the celiac ganglion of rats.

Gastrin releasing peptide (GRP)-like immunoreactive fibers occurred among and around ganglion cells in the forms of punctate structures or varicose processes in the celiac ganglion of rats. The density of the fibers varied from region to region in single sections. The immunoreactive nerve fibers were characterized by abundant large granular vesicles mixed with small clear vesicles, and they formed axo-dendritic synapses with principal ganglion cells. The immunoreactive material was localized on the granular core and also in the axoplasm. No immunoreactive ganglion cells were found in any portion of the ganglion. The present findings suggest that the GRP fibers are of extraganglionic origin and that GRP is involved in the ganglionic transmission of the prevertebral ganglion.

Animals↗
PubMed1992

Sympathetic preganglionic neurons in rabbit spinal cord that project to the stellate or the superior cervical ganglion.

The segmental distribution of sympathetic preganglionic neurons in the rabbit spinal cord that project to the stellate or the superior cervical ganglion was determined using retrograde tracing with cholera toxin B subunit from the stellate ganglion and wheat germ agglutinin-apo-horseradish peroxidase-gold from the superior cervical ganglion. Sympathetic preganglionic neurons that projected to the stellate ganglion were located in spinal segments T1 to T10. Sympathetic preganglionic neurons projecting to the superior cervical ganglion were found in segments T1 to T8. Both types of neuron had somata that were elongated in the rostrocaudal direction, and dendrites that were mainly confined to the intermediolateral cell column. Almost 95% of the neurons supplying the superior cervical ganglion had axons that passed through the stellate ganglion.

Animals↗
PubMed1992

Characterization of superior cervical ganglion neurons that project to the submandibular glands, the eyes, and the pineal gland in rats.

These studies sought to determine whether the cell bodies of rat superior cervical ganglion neurons projecting to three very different target organs differ in terms of their size, number, location within the ganglion and/or neuropeptide content, and whether these features are altered in response to neonatal deafferentiation of the ganglion. A series of retrograde tracer, immunocytochemical, and double-labeling studies revealed differences in the size, number, location and neuropeptide content of superior cervical ganglion neurons that project to the submandibular salivary glands, eyes, or pineal gland. The mean areas of the cell bodies of neurons projecting to the submandibular gland are largest, those projecting to the eye are smallest, and those projecting to the pineal are intermediate in size. Submandibular gland projecting neurons are found throughout the ganglion, while the eye and pineal projecting populations are localized to the rostral quadrants. The different subpopulations of target organ specific superior cervical ganglion neurons are heterogeneous in their content of vasoactive intestinal peptide-, neuropeptide Y- and somatostatin-like immunoreactivity. A greater percentage of submandibular gland than of pineal projecting neurons display vasoactive intestinal peptide-like immunoreactivity, but there are no differences in the percentage of neurons displaying neuropeptide Y- or somatostatin-like immunoreactivity between the target organ specific groups. Neonatal deafferentiation does not result in changes in the size, number or distribution of target organ specific neurons, or in the percentage of immunoreactive neurons in these populations. In conclusion, these studies provide evidence that the size and distribution of neurons and percentage of peptide-containing neurons in the superior cervical ganglion is related to the target organ innervated, but provides no evidence of exclusive target organ-peptide relationships.

Afferent Pathways↗
PubMed1986

Pre- and postnatal development of 5-hydroxytryptamine-immunoreactive cells in the superior cervical ganglion of the rat.

The pre- and postnatal development of 5-hydroxytryptamine (5-HT)-immunoreactive cells in the superior cervical ganglion of the rat was studied by indirect immunofluorescence method with an antibody to a conjugate of bovine serum albumin and 5-HT. The superior cervical ganglia from 11-day-old embryos to 90-day-old postnatal rats were examined. 5-HT-immunoreactive cells were first detected in the superior cervical ganglion on the 12th day of gestation. At this stage of development the ganglionic cells formed a condensed group, and most of them showed 5-HT-immunoreactivity. During later prenatal development the relative number of the 5-HT-immunoreactive cells in the ganglion decreased and most ganglionic cells appeared as non-reactive. 5-HT-immunoreactive cells showed some variation in size and fluorescence intensity during the whole prenatal development. In the ganglia of newborn rats a wide range of 5-HT-immunoreactive cell sizes was detected. Two types of 5-HT-immunoreactive cells were distinguished in the ganglia of 7- to 35-day-old rats: small (5-15 microns in diameter) cells and large (15-30 microns in diameter) cells, resembling in size small intensely fluorescent (SIF) cells and principal nerve (PN) cells, respectively. The relative number of the large 5-HT-immunoreactive cells gradually decreased after the first postnatal week, and these cells were not detected in the ganglia of 90-day-old rats. Small 5-HT-immunoreactive cells constantly formed clusters in the ganglia of postnatal rats. A marked, statistically significant increase in the density of 5-HT-immunoreactive cells occurred during the 4th postnatal week. The 5-HT-immunoreactive cells appeared in the prenatal superior cervical ganglion of the rat approximately at the same time as the cells showing formaldehyde-induced catecholamine fluorescence. Transient occurrence of the large 5-HT-immunoreactive cells during the first postnatal weeks of development indicates, that in the superior cervical ganglion of the rat, 5-hydroxytryptamine may be expressed in some developing PN cells early postnatally. After the 5th postnatal week, the large 5-HT-immunoreactive neuronal cells cannot be detected, and 5-HT is expressed only in the SIF cells.

Animals↗
PubMed1987

Location, distribution and projections of intracardiac ganglion cells in the rat.

Physiological studies indicate that cardiac parasympathetic nerves may act selectively at discrete cardiac sites. To determine anatomical sites at which selective integration of cardiac nerve activity may occur, the present study identified and described the location, distribution, and projections of intracardiac ganglion cells in the rat. The estimated 3992 ganglion cells per rat heart were located in 4 distinct groups, all above the atrioventricular groove: (1) between the superior vena cava and aorta (2.5% of total), (2) in the region of the superior interatrial septum (49.9%), (3) posterior to the left atrium (24.0%), and (4) posterior to the inferior interatrial septum and right atrium (23.5%). Only a few ganglion cells were located subepicardially within the infolding of the dorsal interatrial septum. Retrogradely transported fluorescent tracers injected into the left or right ventricles demonstrated that different groups of ganglion cells projected to discrete or selective regions of the heart. Projections to the left ventricle originate only from ganglion cells located posterior to the interatrial septum and the left atrium. In the rat, intracardiac ganglion cells, confined to 4 atrial regions, appear to have discrete sites of termination within the heart. It is proposed that selective activation of different intracardiac ganglion cell groups may elicit specific regional changes in cardiac parasympathetic nerve activity.

Animals↗
PubMed1982

Ganglion cell death within the developing retina: a regulatory role for retinal dendrites?

The effects of neonatal midbrain lesions on populations of retinal ganglion cells with ipsilateral or contralateral projections were investigated in hooded rats with the use of horseradish peroxidase. After bilateral lesions of the superior colliculus performed at birth, the number of contralaterally projecting ganglion cells is reduced but the number of ipsilaterally projecting cells is increased. Bilateral tectal lesions performed 5 days after birth reduce the number of both contralaterally and ipsilaterally projecting ganglion cells. Unilateral tecto-pretectal lesions performed at birth lead to extensive retrograde degeneration of contralaterally projecting ganglion cells in the opposite retina: but both the ipsilateral terminal fields of the same retina and its population of ipsilaterally projecting ganglion cells are increased. Cells located at the border between the temporal crescent and the nasal areas of the retina opposite an unilateral tecto-pretectal lesion were found to have their dendrites pointing towards the severely depleted nasal areas more frequently than in normal rats. These observations suggest that competitive interactions between retinal dendrites may play a role in regulating ganglion cell death in the developing retina. The increased population of ipsilaterally projecting ganglion cells would reflect the survival of neurones which would otherwise normally degenerate, resulting from reduced local interactions as a consequence of the massive removal of neighbouring contralaterally projecting cells.

Animals↗