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PubMed1994

The influence of the trigeminal ganglion on carotid blood flow in anaesthetized guinea-pigs.

1. The influence of the trigeminal ganglion on the carotid circulation has been investigated by measuring electrical stimulation-induced alterations in carotid arterial blood flow and resistance in anaesthetized guinea-pigs. The effects of several receptor antagonists were assessed to determine which neurotransmitters are involved in regulating carotid blood flow. 2. Arterial blood pressure and carotid vascular resistance were reduced by electrical stimulation (0.5 mA, 1 ms, 5 Hz, 60 s) of the trigeminal ganglion ipsilateral to the carotid artery from which flow was measured. No consistent effect of electrical stimulation on carotid blood flow was observed. However, when guinea-pigs were pretreated with guanethidine (30 mg kg-1, s.c., 24 h prior to experiments), stimulation produced little change in blood pressure, while carotid blood flow was increased and vascular resistance decreased, consistent with vasodilatation in the cranial circulation. Stimulation of the trigeminal ganglion contralateral to the carotid artery from which blood flow was measured, had little effect on either carotid blood flow or vascular resistance. 3. In animals pretreated with guanethidine, intravenous administration of the vasoactive intestinal polypeptide (VIP) receptor antagonist, [p-Cl-D-Phe6,Leu17]-VIP (50 micrograms kg-1) significantly attenuated the increase in carotid blood flow and decrease in carotid vascular resistance evoked by trigeminal ganglion stimulation. Responses evoked by trigeminal ganglion stimulation were, however, unaffected by intravenous injection of the tachykinin NK1 receptor antagonists, GR82334 (0.3 mg kg-1) and CP-99,994 (0.4 mg kg-1), calcitonin gene-related peptide (CGRP) receptor antagonist, CGRP8-37 (0.9 mg kg-1) and the ganglion blocking agent, hexamethonium (10 mg kg-1). 4. It is concluded that in the guanethidine-pretreated guinea-pig, electrical stimulation of the trigeminal ganglion increases carotid blood flow and produces an accompanying decrease in carotid vascular resistance, consistent with the dilatation of carotid blood vessels. The transmitter mediating this effect is most likely to be VIP.

Anesthesia↗
PubMed1983

Simultaneous visualization of aortic and [3H]5-hydroxytryptamine-accumulating cell bodies in the nodose ganglion of the cat.

1. Single- and double-tracer experiments were performed in cats to investigate the relationship between the aortic cells and the cell bodies accumulating 5-hydroxytryptamine (5-HT) in the nodose ganglion. In one series of experiments, horseradish peroxidase (HRP) was applied to the central end of the aortic nerve, anterogradely transported and accumulated in ganglionar perikarya. The distribution of HRP-positive neurones was reconstructed in serial sections through the nodose ganglion. In a second series of experiments, the distribution of [(3)H]5-HT-accumulating cell bodies was assessed following incubation of the nodose ganglion in [(3)H]5-HT. The third series of experiments combined the treatments of the preceding ones: anterograde transport of HRP in the aortic nerve followed by incubation of the nodose ganglion in [(3)H]5-HT.2. The results from these experiments provide more information with regard to (i) the topographical relationship between the aortic and [(3)H]5-HT-accumulating cell bodies in the same ganglion and (ii) the distribution and number of double-labelled neurones, giving further indications about histochemical components of the aortic nerve.3. The HRP experiments demonstrated that HRP-positive cells show a preferential pattern of topographical organization. They were mostly located in the medial border of the ganglion where the laryngeal and aortic nerves enter. On the other hand, [(3)H]5-HT-accumulating neurones were scattered throughout the ganglion.4. In double-tracer experiments, three populations of labelled cell bodies were distinguished in the same nodose ganglion: (1) single HRP-cells; (2) single [(3)H]5-HT-accumulating cells and (3) double-labelled cells. The distribution of the latter population exhibited no preferential localization. Quantitative estimates indicated that double-labelled neurones constituted 65-85% of the population of HRP-positive cell bodies.5. These results show that most aortic neurones are able to take up exogenous serotonin and may be serotonergic neurones. They suggest that serotonin may be involved in physiological effects mediated via the aortic nerves.

Animals↗
PubMed2005

Inner and outer retinal pathways both contribute to surround inhibition of salamander ganglion cells.

Illumination of the receptive-field surround reduces the sensitivity of a retinal ganglion cell to centre illumination. The steady, antagonistic receptive-field surround of retinal ganglion cells is classically attributed to the signalling of horizontal cells in the outer plexiform layer (OPL). However, amacrine cell signalling in the inner plexiform layer (IPL) also contributes to the steady receptive-field surround of the ganglion cell. We examined the contributions of these two forms of presynaptic lateral inhibition to ganglion cell light sensitivity by measuring the effects of surround illumination on EPSCs evoked by centre illumination. GABA(C) receptor antagonists reduced inhibition attributed to dim surround illumination, suggesting that this inhibition was mediated by signalling to bipolar cell axon terminals. Brighter surround illumination further reduced the light sensitivity of the ganglion cell. The bright surround effects on the EPSCs were insensitive to GABA receptor blockers. Perturbing outer retinal signalling with either carbenoxolone or cobalt blocked the effects of the bright surround illumination, but not the effects of dim surround illumination. We found that the light sensitivities of presynaptic, inhibitory pathways in the IPL and OPL were different. GABA(C) receptor blockers reduced dim surround inhibition, suggesting it was mediated in the IPL. By contrast, carbenoxolone and cobalt reduced bright surround, suggesting it was mediated by horizontal cells in the OPL. Direct amacrine cell input to ganglion cells, mediated by GABA(A) receptors, comprised another surround pathway that was most effectively activated by bright illumination. Our results suggest that surround activation of lateral pathways in the IPL and OPL differently modulate the sensitivity of the ganglion cell to centre illumination.

Animals↗
PubMed1987

Formation of retinal ganglion cell topography during prenatal development.

A fundamental feature of the mammalian visual system is the nonuniform distribution of ganglion cells across the retinal surface. To understand the ontogenetic processes leading to the formation of retinal ganglion cell topography, changes in the regional density of these neurons were studied in relation to ganglion cell loss and the pattern of retinal growth in the fetal cat. Midway through the gestation period, the density of these neurons was only two to three times greater in the area centralis than in the peripheral retina, whereas shortly before birth this central-to-peripheral difference was nearly 20-fold. Age-related changes in the ganglion cell distribution were found not to correspond in time or magnitude to the massive loss of ganglion cells that occurs during prenatal development. Rather, the formation of ganglion cell density gradients can be accounted for by unequal expansion of the growing fetal retina-peripheral regions expand more than the central region, thereby diluting the peripheral density of ganglion cells to a greater degree. Nonuniform growth, in conjunction with differential periods of neurogenesis of the different types of retinal cells, appears to be a dominant factor regulating overall retinal topography. These results suggest that the differential regional expansion of the fetal retina underlies the formation of magnification factors in the developing visual system.

Animals↗
PubMed1987

Transient morphological features of identified ganglion cells in living fetal and neonatal retina.

The function and morphology of retinal ganglion cells in the adult mammalian visual system has been well studied, but little is known about how the adult state is achieved. To address this question, the morphological changes that retinal ganglion cells undergo during development were studied. Ganglion cells were first identified by retrograde labeling with rhodamine latex microspheres deposited in retinorecipient targets in fetal and early postnatal cats. The structure of ganglion cells was then revealed by intracellular injection of Lucifer yellow in living retinas removed and maintained in vitro. As early as 2 weeks before birth, a morphologically diverse assortment of ganglion cells is present, some of which resemble the alpha, beta, and gamma classes found in the adult. However, in contrast to the adult, developing ganglion cells exhibit several transient features, including excessive axonal and dendritic branching and exuberant somatic and dendritic spines. These morphological features indicate that there is a transient network of connectivity that could play an important role in the final determination of retinal ganglion cell form and function.

Animals↗
PubMed1986

Activity of in situ stellate ganglion neurons of dogs recorded extracellularly.

Activity was recorded from 145 neurons in the in situ stellate ganglia of 36 dogs. The activity of 28 of these neurons, most of them located in the ganglia's cranial medial region, was related to the cardiac cycle primarily during systole. The activity of 16 of these cardiovascular-related neurons was modified by gentle mechanical distortion of the superior vena cava (1), heart (4), or thoracic aorta (11). Forty-one of the neurons were modified by respiration, with 17 being phase-locked to the respiratory cycle. Other neurons were activated by gentle mechanical distortion of localized regions of the thoracic wall (21% of all neurons), neck (18%), skin of the left foreleg (10%), or the mediastinum adjacent to the stellate ganglion (3%). Acutely decentralizing the stellate ganglion abolished the spontaneous activity of some, but not all, of these neurons including the respiratory or cardiovascular-related neurons. In the intact or acutely decentralized stellate ganglion, few neurons were activated by single short duration (1-4 ms) stimuli delivered to nerves attached directly or indirectly to the ganglion; however, most were activated by brief high frequency stimuli delivered in trains of 20-200 ms, or by single stimuli lasting 20-200 ms. As most cardiovascular, respiratory, or neck-related neurons in the stellate ganglion were not activated by single brief stimuli delivered to the cardiopulmonary nerves or vagosympathetic trunks, presumably they did not project their axons into the neck or thoracic organs. Thus, they were considered to be interneurons. It is postulated that interneurons in stellate ganglia can be modified by afferent receptors located in tissues of the neck, lungs, heart, or great thoracic vessels, whether the ganglion is intact or acutely decentralized. In addition, neurons in the stellate ganglion can be modified by mechanoreceptors located in the thoracic wall, abdominal wall, foreleg, or adjacent mediastinum. The majority of these neurons are activated by trains of impulses rather than single short duration impulses.

Action Potentials↗
PubMed2006

Selectivity for multiple stimulus features in retinal ganglion cells.

Under normal viewing conditions, retinal ganglion cells transmit to the brain an encoded version of the visual world. The retina parcels the visual scene into an array of spatiotemporal features, and each ganglion cell conveys information about a small set of these features. We study the temporal features represented by salamander retinal ganglion cells by stimulating with dynamic spatially uniform flicker and recording responses using a multi-electrode array. While standard reverse correlation methods determine a single stimulus feature--the spike-triggered average--multiple features can be relevant to spike generation. We apply covariance analysis to determine the set of features to which each ganglion cell is sensitive. Using this approach, we found that salamander ganglion cells represent a rich vocabulary of different features of a temporally modulated visual stimulus. Individual ganglion cells were sensitive to at least two and sometimes as many as six features in the stimulus. While a fraction of the cells can be described by a filter-and-fire cascade model, many cells have feature selectivity that has not previously been reported. These reverse models were able to account for 80-100% of the information encoded by ganglion cells.

Algorithms↗
PubMed1991

Electrophysiological evidence for a direct projection of direction-sensitive retinal ganglion cells to the turtle's accessory optic system.

1. The direct retinal input pathway to the basal optic nucleus (BON), the primary nucleus of the turtle accessory optic system, was characterized physiologically. We tested the hypothesis that directional information encoded in retinal ganglion cells can influence the BON via a direct pathway. Using an in vitro whole-brain, eyes-attached preparation, we demonstrated the directness of this pathway by 1) antidromic activation of retinal ganglion cells from the contralateral BON and 2) orthodromic activation of the BON from the contralateral optic nerve. 2. Of 72 physiologically classified retinal ganglion cells, 9 could be antidromically activated from the contralateral BON with low current (less than 200 micro A). Eight of these cells were direction-sensitive (DS). The ninth cell did not respond to visual stimulus movement. The antidromic latencies ranged from 2.2 to 6.1 ms with a mean of 3.8 ms. These latencies were quite consistent for each cell, having an average SD of 0.08 ms. Moreover, consistent responses could always be recorded at stimulation rates up to 100 Hz. 3. With current stimulation of the contralateral optic nerve, the orthodromic conduction latency of 17 BON single units ranged from 2.5 to 6.6 ms with a mean of 4.6 ms. These latencies were more variable for an individual cell, having an average SD of 0.3 ms. Responses to individual current pulses could never be consistently evoked at stimulation rates greater than 40 Hz. 4. DS responses were recorded in BON single units after the removal of the dorsal midbrain, including the optic tectum and pretectum as well as the telencephalon. Three of these cells were activated orthodromically by current stimulation delivered to the contralateral optic nerve. Thus directional information reaches the BON via a direct projection from the contralateral retina. 5. Visual response properties of DS retinal ganglion cells were compared with those of BON cells to examine the transformations that take place in the brain stem. Applying a limaçon model to the responses of both DS retinal ganglion cells and BON cells revealed that both types of cells have very similar direction tuning. However, the distribution of maximally responsive directions in the retina may differ from that of the BON. 6. Because DS retinal ganglion cells project directly to the BON, and because BON cells lose their direction sensitivity after retinal application of GABA antagonists, we conclude that the BON receives essential directional information directly from DS retinal ganglion cells. This directional information in the BON may represent a retinal slip error signal necessary for retinal image stabilization.

Animals↗
PubMed1993

Relative contribution of rod and cone inputs to bipolar cells and ganglion cells in the tiger salamander retina.

1. The relative contribution of rod and cone inputs to bipolar and ganglion cells were studied by comparing the response-irradiance relations, spectral sensitivities, and response waveforms of these neurons recorded from the isolated, flat-mounted tiger salamander retina under dark-adapted conditions. 2. Bipolar cells could be differentiated both on the basis of the polarity of the light response and on their relative rod/cone input. Thus some depolarizing bipolar cells appeared more strongly influenced by rod input (DBCR), whereas others were more influenced by cone input (DBCC). Similarly, hyperpolarizing bipolar cells could be divided into those that received rod-dominant input (HBCR) or cone-dominant input (HBCC). 3. The light onset response of sustained-ON ganglion cells reflected both rod-dominant input from DBCRs and cone-dominant input from DBCCs. 4. OFF ganglion cells displayed both a rod-dominant sustained light offset response and a cone-dominant transient light offset response, suggesting input from both HBCRs and HBCCs. 5. In ON-OFF ganglion cells, the light onset response was strongly rod dominated and was presumably mediated by DBCRs, whereas the light offset response displayed both rod and cone influence, suggesting input from HBCRs and HBCCs. The contribution of cones to the light onset response of ON-OFF ganglion cells was only observed in the presence of a rod-adapting background light. 6. A suppression of the light offset responses of OFF and ON-OFF ganglion cells was observed, which was dependent both on the wavelength and irradiance of the light stimulus. 7. These results indicate that the photoreceptor inputs to bipolar cells in the tiger salamander retina are segregated such that they form separate rod-dominant and cone-dominant pathways. Thus the response properties of the different types of ganglion cells are influenced not only by the excitatory and inhibitory inputs they receive from the bipolar and amacrine cells but also whether these inputs are provided through rod-dominant or cone-dominant pathways. The functional implications of these findings are discussed.

Ambystoma↗
PubMed1995

Interaction between center and surround in rabbit retinal ganglion cells.

1. The interaction between the center and surround mechanisms of a variety of rabbit retinal ganglion cell classes was examined in extracellular single-unit recordings in an isolated eyecup preparation. Ganglion cell classes studied included on and off brisk sustained and transient, on and off sluggish sustained and transient, on-off and on directionally selective, orientationally selective, and large field units. The surround effects observed were qualitatively similar in all these ganglion cell classes. 2. The average response-versus-contrast functions for stimuli within the ganglion cells' receptive-field centers were relatively linear between threshold and saturation for all ganglion cell classes examined. The major effect of surround stimulation on the center response-versus-contrast function was a reduction in the slope of the linear portion of the curve, rather than a downward, parallel shift of the function. Stimulation of the surround had no systematically significant effect on the contrast threshold for the center spot, and, when it did have a significant effect, it sometimes decreased, rather than increased the magnitude of threshold. 3. Step changes in surround contrast were most effective when they were made simultaneously with step changes in the center; surround inhibition decreased significantly when it preceded stimulation of the center by > 100 ms and was generally ineffective when preceding the center by > 500 ms. The decrease in the inhibitory effect of surround stimulation was a monotonic function of delay between 0 and 500 ms. 4. Stimulation of the surround by step changes in the contrast of a sine-wave grating annulus produced qualitatively similar results to those obtained for pure luminance modulations. This suggests that the surround mechanism observed in these experiments was not due to pure luminance adaptation within the surround. The inhibitory effect of sine-wave gratings in the surround decreased monotonically as a function of spatial frequency. 5. Stimulation with a spot and an annulus that were both entirely within the ganglion cell's excitatory receptive-field center typically yielded nonadditive summation at contrasts whose linear sum of responses were below saturation. The effect of an annulus within the receptive-field center on responses elicited by a central spot quantitatively resembled the inhibition elicited from annuli in the inhibitory surround, after the excitatory center response due to the annulus was taken into account. These results suggest that the inhibiton elicited from the surrounds of the ganglion cells in these experiments extended into their receptive-field centers.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Physiological↗
PubMed1997

Processing of color- and noncolor-coded signals in the gourami retina. III. Ganglion cells.

The dynamics of intracellular responses from ganglion cells, as well as that of spike discharges, were studied with the stimulus regimens and analytic procedures identical to those used to study the dynamics of the responses from horizontal and amacrine cells (,). The stimuli used were large fields of red and green light given as a pulsatile input or modulation about a mean luminance by a white-noise signal. Spike discharges evoked by a white-noise stimulus were analyzed in exactly the same manner as that used for analysis of analog responses. The canonical nature of kernels allowed us to correlate the first- and second-order components in a spike train with those of the intracellular responses from horizontal, amacrine, and ganglion cells. Both red and green stimuli given alone in darkness produced noncolor-coded responses from all ganglion cells. In the case of some cells, steady red illumination changed the polarity or waveform of the response to green light. Color-coded ganglions responded only to simultaneous color contrast. Nonlinearities recovered from intracellular responses, and spike discharges were similar to those found in responses from amacrine cells and were of two types, one characteristic of the C amacrine cells and the other characteristic of the N amacrine cells. The first-order kernels of most ganglion cells could be divided into two basic types, biphasic and triphasic. The combination of kernels of these two basic types with different polarities can produce a wide range of responses. Addition of two types of second-order nonlinearity could render color coding in this relatively simple retina as an extremely complex process. Color information appeared to be represented by the polarity, as well as the waveform, of the first-order kernel. The response dynamics is a means of transmission of color-coded information. Second-order components carry information about changes around a mean luminance regardless of the color of an input. Some spike discharges produced a well-defined cross-kernel between red and green inputs to show that a particular time sequence of red and green stimuli was detected by the retinal neuron network. The similarity between signatures of second-order kernels for both amacrine and ganglion cells indicates that signals undergo a minimal transformation in the temporal domain when they are transmitted from amacrine to ganglion cells and then transformed into a spike train. Under our experimental conditions, a single spike train carried simultaneously information about red and green inputs, as well as about linear and nonlinear components. In addition, the spike train also carries a cross-talk component. A spike train is a carrier of multiple signals. Conversely, many types of information in a stimulus are independently encoded into a spike train.

Animals↗
PubMed1998

Somatic and dendritic mosaics formed by large ganglion cells in the retina of the common house gecko (Hemidactylus frenatus).

Recent studies of large ganglion cells in fishes and frogs have identified a shared inventory of three basic types, with characteristic forms and spatially independent mosaic distributions. These anamniote types and mosaics are hard to match to the large ganglion cell types and mosaics of mammals, implying that the underlying developmental programmes have diverged during evolution. Reptiles and mammals both belong to the amniote lineage, so the point of divergence can be investigated by comparing the large ganglion cells of reptiles with those of mammals, taking fishes and frogs as outgroups. With this aim, ganglion cells of the common house gecko, Hemidactylus frenatus, were labelled with horse-radish peroxidase by an in vitro method and studied in retinal flatmounts. Two prominent, regular, spatially independent mosaics were consistently present. One (alpha a) was characterized by somata displaced into the inner nuclear layer and dendrites forming planar trees in sublamina a; the other (alpha ab) comprised large orthotopic somata and distinctive, bistratified dendrites that formed discrete planar subtrees in sublaminae a and b. These subtrees were joined by up to 40 vertical link segments, whose distribution was found to correlate with the underlying photoreceptor mosaic. Some specimens also contained patches of a third mosaic (alpha c), characterized by large orthotopic somata and very large flat trees in sublamina c, but the labelling of this type was inconsistent. These reptilian mosaics share several distinctive characters with anamniote alpha-cell mosaics but differ markedly from the ganglion cell mosaics of any known mammal. The most parsimonious conclusion is that those mosaic features that are shared by the ganglion cells of all nonmammals are homologous and primitive (symplesiomorphic), while those that are shared by all therian mammals are homologous and derived (synapomorphic). This is consistent with other differences between mammalian and nonmammalian eyes. Mosaic formation itself, however, seems to be a universal characteristic of large ganglion cells.

Animals↗
PubMedDate not supplied

Major biological effects of neurotrophic factors on retinal ganglion cells in mammals.

The mammalian visual system, particularly retinal ganglion cells, has been used for studying the functions of neurotrophic factors on neurons for many years. The major biological effects of neurotrophic factors on retinal ganglion cells observed so far are the promotion of viability and axonal regeneration. However, there are still some controversies regarding the effects of neurotrophic factors on retinal ganglion cells in the literature. This review is aimed to summarize the available information on the biological actions of these neurotrophic factors on survival and axonal regeneration of retinal ganglion cells and the expressions of neurotrophic factor receptors in the retina. Generally, brain-derived neurotrophic factor, neurotrophin-4/5, fibroblast growth factor and glial cell line-derived neurotrophic factor increase the survival of retinal ganglion cells while the effect of ciliary neurotrophic factor on the viability of adult retinal ganglion cells is controversial. The ciliary neurotrophic factor is the only effective factor in promoting long distance axonal regeneration of retinal ganglion cells whereas brain-derived neurotrophic factor and neurotrophin-4/5 only enhance neurite sprouting within the retina.

Adult↗
PubMedDate not supplied

Programmed cell death in the mouse cochleovestibular ganglion during development.

Programmed cell death (PCD) is as essential to development as is cell proliferation. Our objective was to elucidate the spatiotemporal occurrence of PCD during the development of the cochleovestibular ganglion. We performed a time-sequence study on the distribution of in situ PCD, apoptosis, during the development of the mouse cochleovestibular ganglion by using the TUNEL method to detect apoptosis histochemically. Apoptosis in the cochleovestibular ganglion was observed from the 11.5th gestational day (GD) to the 18. 5th GD. Apoptosis was seen most extensively in the vestibular ganglion cells at the 13.5th GD, while in the spiral ganglion cells apoptosis was maximal between the 15.5th and 16.5th GD. Because these times of peak apoptotic activity almost exactly corresponded to the events of innervation and terminal mitosis of the cochleovestibular ganglion cells, we infer that PCD is involved in the innervation and modulates the number of cochleovestibular ganglion cells overproduced by terminal mitosis.

Animals↗
PubMed2001

The retinal ganglion cell layer and visual acuity of the camel.

We examined the retinal ganglion cell layer of the dromedary camel, Camelus dromedarius. We have estimated that there are 8 million neurons in the ganglion cell layer of this large retina (mean area of 2,300 mm(-2)). However, only approximately 1 million are considered to be ganglion cells. The ganglion cells are arranged as two areas of high cell density, one in the temporal and one in the nasal retina. Densities of ganglion cells between these two high density regions is much lower, often less than 100 per mm(-2). In between these two high density regions, on the nasal side of the optic nerve head, is a unique and dense vertical streak of mostly non-ganglion cells; the function of this specialization is unknown. On the basis of ganglion cell density we estimate that the peak acuity in the dromedary camel is about 10 and 9.5 cycles per degree in the temporal and nasal high density regions respectively and falls to 2-3 cycles per degree in the central retina. Behavioral acuity was estimated for one bactrian camel and was found to be approximately 10 cyc deg(-1). The camel has a retina with a mean thickness of 104 microm, less than the 143 microm thickness that has previously been thought to be necessary for a retinal vasculature. Nevertheless, there is an extensive vitreal vasculature that does not appear to spare any retinal region.

Animals↗
PubMed1980

Quantitative and histomorphological studies on the geniculate ganglion of the facial nerve in man.

The human geniculate ganglion was studied histologically and quantitatively. It appeared pyramidal in shape. The mean diameter of the side of the triangle constituting its base was 1,050 micrometer and its mean height 1,800 micrometer; the volume of the ganglion was 26 X 10(7) micrometer 3. The ganglionic cells were arranged in clusters with longitudinally extending bundles of nerve fibres in between. At the apex of the ganglion compact neurons were delineated from those in the rest of the ganglion by a bundle of nerve fibres. Moreover, scattered solitary nerve cells were met with between fibres of the greater petrosal and the chorda tympani nerves. The mean neuronal population was 1,070, the mean cell volume 11,913 micrometer 3, the cell territory 242,990 micrometer 3 and the volume of the intercellular space 231,077 micrometer 3. Extraganglionic vessels approximated the ganglion perpendicular to its long axis, while further intraganglionic vessels extended in a direction parallel to the long axis of the ganglion and vertical terminal ramifications formed dense vascular channels around the capsule of the nerve cells. The significance of that pattern of blood supply was discussed.

Chorda Tympani Nerve↗
PubMed1979

Preeminence of the left stellate ganglion in the long Q-T syndrome.

In seven patients with Romano-Ward syndrome, stellate ganglion block or stimulation and pharmacologic interventions were made to assess their influence on duration of the O-T interval, electrical alteration of the T wave and ventricular tachydysrhythmias. Left stellate ganglion block and right stellate ganglion stimulation shortened Q-T interval, abolished alternans phenomena and suppressed tachydysrhythmias. Propranolol and phenytoin had a similar effect. In contrast, right stellate ganglion block, left stellate ganglion stimulation and prior administration of quinidine and procainamide had an opposite effect. These responses resemble observations in animal models which suggest that excessive or unopposed activity of the left, or subnormal activity of the right stellate ganglion, or both, account for the pathophysiologic manifestations of the long Q-T syndrome. They are also consistent with clinically correlated, cardiac neuropathologic findings in these patients. An analogous but acquired dysautonomia involving the left stellate ganglion and ischemic left ventricle may precipitate sudden coronary death.

Adult↗
PubMed2003

Retinal ganglion cells resistant to advanced glaucoma: a postmortem study of human retinas with the carbocyanine dye DiI.

PURPOSE: The present study was conducted to examine whether the morphology of the retinal ganglion cells is altered in advanced glaucoma. Perikaryal, axonal, and dendritic alterations were monitored in glaucoma-resistant retinal ganglion cells by postvitam application of the fluorescent dye DiI. METHODS: The retinas of four amaurotic glaucomatous eyes and four normal eyes enucleated after death were used in this study. The retinas were freed from surrounding tissue, prepared as flatmounts on a nitrocellulose filter, and fixed overnight in 4% paraformaldehyde. The retinal ganglion cells were labeled by introducing crystals of the fluorescent carbocyanine dye DiI, into the optic fiber layer. This dye diffuses along membranes of ganglion cell axons, completely labeling them and their cell bodies and dendrites. Further characterization of the retinas and optic nerves included hematoxylin-eosin and van Gieson histochemical staining as well as immunohistochemistry against glial fibrillary acidic protein. RESULTS: Because of the advanced stage of the disease, the retinas were almost completely depleted of ganglion cells, which had degenerated and therefore could not be stained. The few remaining ganglion cells were considered to be resistant to glaucoma. They showed drastic morphologic alterations, such as abnormal axonal beading, the cell bodies were normal in size but had irregular silhouettes or swellings, and there were fewer dendritic bifurcations. The size of the dendritic trees was smaller, implicating pruning of smaller dendritic branches. Glial cells were also detected immunocytochemically indicating their involvement in the pathologic course of glaucoma. CONCLUSIONS: The data suggest that the few ganglion cells that survive the elevated intraocular pressure associated with loss of visual function display morphologic changes that are manifested both on the cell body and on their intraretinal processes, including axons and dendrites.

Adult↗