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At least 1,153 records · Page 64Linked to original sources
PubMed1993

Appearance of neuropeptide Y-like immunoreactive cells in the rat trigeminal ganglion following dental injuries.

The effects of these injuries on the presence and distribution of neuropeptide Y (NPY)-immunoreactive (-IR) neurones were examined immunohistochemically. In the normal trigeminal ganglion: some perivascular nerves displayed NPY-IR but there were no NPY-IR ganglionic cells. Fourteen days after extraction or pulp exposure of the upper first molar, NPY-IR cells appeared in the maxillary region of the trigeminal ganglion. About 90% of the injury-evoked NPY-IR cells had medium to large diameters (more than 300 microns2 in cross-sectional area). Shallow cavity preparation, however, did not induce the appearance of NPY-IR cells in the trigeminal ganglion. These results indicate the dental injuries alter the primary sensory neurones in the trigeminal ganglion.

Animals↗
PubMed1981

A morphometric study of mouse trigeminal ganglion after unilateral destruction of vibrissae follicles at birth.

A morphometric study of the trigeminal ganglion after unilateral vibrissae follicles' coagulation in newborn mice has shown the following: (a) a 42.8% decrease of the total volume of the ganglion on the deafferented side with reference to the normal side; a 61.5% decrease of the ophthalmic-maxillary part of the ganglion where neurons whose axons innervate vibrissae follicles are located, and only a 24.1% decrease in the common part; (b) a 54.8% decrease of the neuronal cell body volume in the ophthalmic-maxillary part and practically no change in the common part, and (c) a 64.5% decrease of the volume occupied by the nerve fibers in the ophthalmic-maxillary part and only a 28.1% decrease in the common part. A comparison of the section areas in ganglion and of the bulk area of neuronal cell bodies at different levels has also been performed. Counting of the neuronal cell bodies in the ophthalmic-maxillary part of the ganglion indicated a mean neuronal loss of 36.5%. Peripheral reinnervation of the common fur by regenerated axons of neurons which previously innervated vibrissae, although unlikely, cannot be completely excluded.

Afferent Pathways↗
PubMed1984

Action of iontophoretically applied dopamine on cat retinal ganglion cells.

Iontophoretically applied dopamine reversibly altered both the spontaneous firing rates and the light evoked responses of retinal ganglion cells in the intact eye of the cat. The effects of dopamine were the same for all cell classes encountered: on brisk-transient, off brisk-transient, on brisk-sustained, off brisk-sustained, sluggish and non-concentrically organized cells. Dopamine reduced the spontaneous firing rates of all cells. In response to light stimulation, the inhibitory response phase (light off in on ganglion cells, light on in off ganglion cells) was also reduced by dopamine. However, the excitatory response phase (light on in on ganglion cells, light off in off ganglion cells) was only consistently reduced for optimal spot stimulation: for wholefield or annular stimulation the excitatory response phase was reduced in 76% of cells, whereas for the remaining cells it was unchanged or even increased. The net effect of these alterations was to cause a shift in the centre surround balance of the cell output in favour of the centre for 82% of concentrically organized cells. These results are discussed in the context of present anatomical knowledge.

Action Potentials↗
PubMed1985

Retinal ganglion cell loss produced by intraocular kainic acid in cats: variation with somal size and eccentricity.

Eight eyes of adult cats were injected with different doses of kainic acid (KA) and examined following survival times of either 5 or 12 days. At a survival time of 12 days, a dose of 76 nmol produced an 18% loss of ganglion cells in the center of the area centralis (AC), 70% loss at a location 2 mm from the AC, and 95% loss at a location 6 mm from the AC. Larger doses (240, 760 and 2400 nmol) produced losses comparable to that observed for 76 nmol. For example, 2400 nmol produced a 35% loss in the AC, 81% at 2 mm, and 88% at 6 mm. At a survival time of 5 days, doses of 240 and 760 nmol produced a loss of ganglion cells comparable to that seen at 12 days. In one eye, a large dose of KA (7600 nmol) produced total loss of ganglion cells at a survival time of 5 days. By comparing loss of cells in restricted somal diameter ranges at different retinal eccentricities, it was possible to distinguish two significant correlations that were largely independent of survival time and dose: (1) at 2 mm, loss of cells with somal diameters larger than 21 micron significantly exceeded loss of cells with smaller somata. In particular, alpha cells were totally eliminated in 6 of the 8 KA-treated eyes. (2) The mean loss of ganglion cells with somal diameters less than 21 micron was significantly greater at 2 mm and 6 mm than in the AC. Together, these results show that loss of ganglion cells produced by KA varies somal size and retinal eccentricity.

Animals↗
PubMed1985

Loss and displacement of ganglion cells after optic nerve regeneration in adult Rana pipiens.

After studying pathway selection in the brain of Rana pipiens during unilateral optic nerve regeneration, several frogs were allowed to survive for lengthy periods for use in the present investigation. Retina flat-mounts were prepared from both eyes at 42-50 weeks postoperation. In some cases, HRP was infiltrated into both optic nerves prior to sacrifice to assist in identifying retinal ganglion cells. All specimens showed reduced cell-densities in the ganglion cell layer of the eye that had sustained the nerve regeneration. In addition, many ganglion cells were displaced, abnormally, into the inner plexiform layer, and the normally-situated cells formed irregular bands and islands in some parts of the retina. Cell-counts showed an apparently time-related change in neuron number ranging from a loss of 41% compared with the unaffected eye at 42 weeks, to losses as great as 71% at 50 weeks. The probable number of displaced amacrine cells in the ganglion cell layer, assumed to be unaffected by the experiment, was estimated at a maximum of 16%. Possible factors underlying the loss and displacement of ganglion cells are discussed.

Animals↗
PubMed1988

GABAergic ganglion cells in the rabbit retina.

The ganglion cells are the output neurons of the retina. There is, however, relatively little known about the neurotransmitters used by these cells. In the present study, ganglion cells identified with a ganglion cell-specific monoclonal antibody (AB5) are shown in separate double-label experiments to be gamma-aminobutyric acid (GABA)-like immunoreactive and to possess a high-affinity uptake mechanism for [3H]GABA accumulation. The localization of these markers of GABA activity to AB5-labelled ganglion cells provides the first definitive evidence for the presence of a classical transmitter in retinal ganglion cells and suggests that GABA may perform a role as a neurotransmitter in these cells.

Animals↗
PubMed1989

The retinohypothalamic tract in the cat: retinal ganglion cell morphology and pattern of projection.

The pattern of retinal projection to the hypothalamus and the morphological properties of the retinal ganglion cells that comprise the retinohypothalamic tract have been examined in the cat. Intraocular injections of horseradish peroxidase revealed a dense retinal projection to the ventral suprachiasmatic nucleus; however, lighter projections were seen in the dorsal suprachiasmatic nucleus, and in hypothalamic regions both dorsal and lateral to the suprachiasmatic nucleus. Intrasuprachiasmatic nucleus injections of horseradish peroxidase retrogradely labelled retinal ganglion cells that were small to medium in soma size. The labelled ganglion cells exhibited long thin dendrites that were sparsely branched. The labelled retinal ganglion cells exhibited a significant change in soma size associated with retinal eccentricity. The morphological characteristics of the ganglion cells that project to the suprachiasmatic nucleus are similar to those of gamma cells.

Animals↗
PubMed1991

Retinal distribution of ganglion cells which project to the ipsilateral optic tectum in Bufo marinus.

The retinotectal projection in anura is mainly crossed, although a small proportion of optic axons projects to the ipsilateral tectum. Using the fluorescent carbocyanide dye, DiI, we mapped the retinal topography of ganglion cells which project to the ipsilateral tectum in adult Bufo marinus. DiI was injected into particular locations in the right tectum. After 10 days survival both the right and the left retinals were wholemounted and the number and retinal position of retrogradely filled ganglion cells were determined. The contralateral and ipsilateral cells were visuotopically distributed in the retina in the majority of experiments. However, in two cases cells were located in visuotopically disparate parts of the retina. The ipsilateral cells represented 3.7% of contralaterally projecting cells in the temporal retina, 0.1% in the nasal and dorsal retina and 0.6% of the ventral retina. The density of ipsilaterally projecting ganglion cells varied from a top of 25 cells/mm2 in the temporal retina, 9 cells/mm2 in the nasal, 3 cells/mm2 in the dorsal to 11 cells/mm2 in the ventral retina. The diversity of size and shape of retrogradely filled ganglion cells indicated that the ipsilateral population corresponded to a heterogeneous class of ganglion cell types. The functional significance of the direct ipsilateral retinotectal projection of the anuran visual system has yet to be elucidated. However, in light of the involvement of the indirect ipsilateral retinotectal projection in binocular vision, the direct pathway is likely to be associated with a retino-tecto-spinal circuit subserving postural adjustment to visually derived stimulation.

Animals↗
PubMed1991

Dynamics of neurotensin stores in the stellate ganglion of the cat.

Neurotensin (NT) within the stellate ganglion (SG) of the cat is present in axon terminals of extrinsic, presumably preganglionic, neurons and may play a role in ganglionic transmission. NT content of the SG, and of the preganglionic axons which innervate it, was determined by radioimmunoassay in the anesthetized cat under various experimental conditions in order to understand the factors determining the size of the ganglionic NT stores. The immunoreactive NT (iNT) from extracts of SG and its preganglionic inputs (white rami T2 and T3, sympathetic trunk between SG and T4 white ramus) coeluted with synthetic NT(1-13) on RP-HPLC. NT accumulated proximal to ligatures on the preganglionic inputs of the SG. The daily rate of axonal transport of NT, estimated from the accumulation, represents 28.7% of the ganglionic stores of NT. Preganglionic stimulation at 2 Hz for 100 min did not change ganglionic NT content. Preganglionic stimulation at 40 Hz reduced the NT content to 70.4 +/- 1.8% of control in 10 min and to 34.7 +/- 4.2% of control in 20 min. Additional 100 min of 40 Hz stimulation produced no further depletion. The residual iNT, which coeluted with NT1-13, presumably represents a pool of unreleasable NT. Post-depletion recovery was complete in 7 days and showed an initial rapid phase over the first 24 h followed by a slower phase over the remaining 6 days. Pepsin treatment, which has previously been shown to generate iNT from NT precursor in liver and other tissues, provided no evidence of the NT precursor in extracts of SG and its preganglionic input.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1992

GABA-like immunoreactive neurons in the retina of Bufo marinus: evidence for the presence of GABA-containing ganglion cells.

gamma-Aminobutyric acid (GABA)-like immunoreactive (IR) neurons in the retina of the cane toad Bufo marinus were revealed using immunohistochemistry on retinal wholemount preparation and sectioned material. GABA-IR neurons included horizontal, bipolar and amacrine cells in the inner nuclear layer and small to medium sized cells in the ganglion cell layer. A few IR axons were seen in the optic fiber layer of the retina. Following the injection of the carbocyanine dye, DiI into the optic tectum ganglion cells were retrogradely filled. A small population of DiI-filled ganglion cells (2.8%) was found to be GABA-IR. GABA-IR neurons in the ganglion cell layer without DiI label were considered to be displaced amacrine cells of which 45.3% were GABA positive. It is proposed that GABA-containing ganglion cells may form an inhibitory projection to visual centers of the anuran brain.

Animals↗
PubMed1992

Signal shaping by voltage-gated currents in retinal ganglion cells.

The role of voltage-gated currents in information processing by retinal ganglion cells was assessed by comparing the light-evoked current and voltage responses of identified ganglion cells with those produced by current injection. These experiments show that the light-evoked signal is clipped at the bipolar-to-ganglion cell synapse because the synaptic current evoked by illumination with bright light is greater than that which the cell can convert into a change in action potential frequency. Ganglion cell responses to injected current fell into 2 classes: those producing sustained spiking responses and those producing transient responses. Further, this division is correlated with the light response of the cells; those producing transient responses to exogenous current produced transient responses to light, while those with sustained responses to current injection produced sustained responses to light flashes. The voltage-gated currents present in the ganglion cell membrane contribute to information processing in the retina by clipping the light-evoked signal and by producing transcience in the output of the retina.

Action Potentials↗
PubMed1993

The receptors activated by exogenous and endogenous opioids in the superior cervical ganglion of the cat.

Nicotinic transmission in the superior cervical ganglion of the cat was studied in vivo and in vitro by recording the postganglionic compound action potential evoked, under partial block with hexamethonium, by supramaximal 0.2 Hz stimulation of the cervical sympathetic trunk. The compound action potential was depressed following a stimulus train (5 Hz, 40 s) applied to the same set of axons. The inhibition was antagonized by naloxone, suggesting mediation by endogenous opioids. Agonists selective for mu-, delta- and kappa-opioid receptors, injected into the arterial supply of the in situ ganglion or added to the perfusion fluid in the in vitro ganglion, also produced a naloxone-sensitive inhibition of the compound action potential. The synaptic inhibition was antagonized by the delta-selective antagonist ICI 174,864 and by the mu-selective antagonist CTAP, but not by the kappa-selective antagonist Nor-BNI. These results suggest that all three main types of opioid receptors are present in the ganglion but only mu- and delta-receptors are involved in the inhibition of ganglionic transmission mediated by the endogenous opioids.

Amino Acid Sequence↗
PubMed1993

Bilateral projections of single retinal ganglion cells to the lateral geniculate nuclei and superior colliculi in the albino rat.

Employing fluorescent retrograde double/triple labeling, we investigated bilateral projections of single retinal ganglion cells to the lateral geniculate nuclei (LGN) and superior colliculi (SC) in the albino rat. After separate injections of Fast Blue (FB) and Diamidino Yellow (DY), respectively, into the right and left LGN, a large number of retrogradely-labeled cells were distributed all over the retina contralateral to each injection. Ipsilaterally projecting ganglion cells, which were labeled with one tracer injected into the LGN, were found predominantly in the lower-temporal retinal region; approximately 56% (120-140 cells per retina) of them were further labeled with the other tracer injected into the contralateral LGN. The vast majority of these double-labeled cells were of large type (more than 20 microns in diameter). Similar findings were obtained after separate injections of FB and DY, respectively, into the right and left SC, or respectively, into the right SC and left LGN. After separate injections of FB, DY and rhodamine-B-isothiocyanate, respectively, into the bilateral LGN and unilateral SC, or respectively, into the unilateral LGN and bilateral SC, a number of cells triple-labeled with all tracers were localized in the lower-temporal retinal region; most of them were of large type. Thus, the bilateral projections from the lower-temporal retinal region representing binocular vision in the rat are indicated to be achieved not only by separate populations of ganglion cells each exclusively serving one side of the brain, but also by axon collaterals from single ganglion cells; the ganglion cells projecting bilaterally to the LGN or/and SC are primarily of large type corresponding probably to the Y cell in the cat retina.

Amidines↗
PubMed1994

Immunocytochemical localization of calcium/calmodulin-dependent protein kinase II isoforms in the ganglion cells of the rat retina: immunofluorescence histochemistry combined with a fluorescent retrograde tracer.

To determine whether or not calcium/calmodulin-dependent protein kinase II (CaM kinase II) is localized in the ganglion cells in the rat retina, we labeled ganglion cells by injection of Fast blue (FB) into the lateral geniculate nucleus and then stained the retina immunohistochemically with monoclonal antibodies which react specifically with the alpha and beta isoforms of CaM kinase II. Eighty and 90% of the FB-labeled ganglion cells in the ganglion cell layer were immunoreactive with the alpha and beta antibodies, respectively, suggesting that both alpha and beta isoforms of CaM kinase II are expressed in most ganglion cells which project to the lateral geniculate nucleus.

Animals↗
PubMed1995

Calretinin-containing preganglionic nerve terminals in the rat superior cervical ganglion surround neurons projecting to the submandibular salivary gland.

The distribution and targets of calretinin-immunoreactive preganglionic nerve terminals in the superior cervical ganglion of the rat were examined using immunohistochemistry and retrograde neuronal tracing. Calretinin-immunoreactive nerve terminals were found throughout the ganglion, forming distinct pericellular baskets around a sub-population of postganglionic neurons. The targets of postganglionic neurons surrounded by calretinin-immunoreactive nerve terminals were determined after injection of tracer into the submandibular salivary gland, the extra-orbital lacrimal gland, the thyroid gland, the anterior chamber of the eye or the skin of the forehead. Only when tracer was injected into the submandibular gland were neurons labelled that were surrounded by calretinin-immunoreactive nerve terminals. When immunohistochemistry using antisera to neuropeptide Y was combined with retrograde tracing, only submandibular gland projecting neurons lacking neuropeptide Y were surrounded by calretinin-immunoreactive terminals. When retrograde neuronal tracer was injected into the superior cervical ganglion, a proportion of retrogradely-labelled neurons in the upper thoracic spinal cord showed relatively weak calretinin-immunoreactivity. All calretinin-immunoreactive terminals in the superior cervical ganglion disappeared following section of the sympathetic chain distal to the superior cervical ganglion. Thus, calretinin is present in a population of preganglionic neurons projecting exclusively to neuropeptide Y non-immunoreactive (presumably secretomotor) neurons innervating the submandibular salivary gland of the rat.

Animals↗
PubMed1987

Trigeminal ganglion cells cocultured with gut express vasoactive intestinal peptide.

The plasticity of neural crest cells for the expression of adrenergic and cholinergic transmitter phenotypes has been well studied. The object of this study was to determine if cells of a sensory ganglion are capable of neuropeptide transmitter plasticity. We studied whether cells of the trigeminal ganglion, which do not express the neuropeptide vasoactive intestinal peptide (VIP) in vivo, would express this peptide when grown with a tissue the gut, that contains large numbers of VIP neurons. Embryonic aneural chick rectum was explanted with the embryonic quail trigeminal ganglion on the chorioallantoic membrane of chick hosts for 7-8 days. The explants were fixed, sectioned, and stained for VIP immunoreactivity (IR), for neurofilament protein immunoreactivity, and for the quail nucleolar marker. In sections of the explants we observed two populations of quail neurons: small (10-13 microns) VIP-IR cells and large (25-32 microns) cells lacking VIP-IR and resembling native trigeminal neurons. Trigeminal ganglia explanted with embryonic heart or trigeminal ganglia explanted alone lacked small VIP-IR cells but contained large VIP-negative neurons. These results show that cells of the trigeminal ganglion grown with the gut can express a neuropeptide they do not express in the absence of the gut or in vivo. Thus the embryonic trigeminal ganglion contains cells that are plastic with respect to neuropeptide expression.

Animals↗
PubMed1989

The development of retinal ganglion cells deprived of their targets.

The influence of central targets on the morphological differentiation of retinal ganglion cells was investigated in Xenopus laevis. Since the ganglion cells mature into distinct morphological subtypes after their axons have reached their central targets, it is possible that the target tissues may influence or specify this aspect of neuronal cell development. To test this idea, Xenopus eyebuds were target-deprived by transplantation to the flank region of host embryos where they developed ectopically. The grafted eyes grew at normal rates, but could not make any projections into the central nervous system. To examine the morphological differentiation of the retinal ganglion cells their structures were revealed using an in vitro retinal preparation and intracellular injections of the dye Lucifer yellow. The elaboration and maturation of ganglion cell dendrites were found to be indistinguishable between control and transplanted eyes throughout development. Thus, the development of retinal ganglion cells into distinct morphological classes can occur even when their axons do not interact with the appropriate central targets.

Animals↗
PubMed1975

Control of peripheral vascular resistance in perfused hindquarters of dogs: lack of effect of nicotinic and muscarinic ganglion block.

The effects of nicotinic and muscarinic ganglion blockade were studied on the peripheral resistance of the perfused hindlimbs of the dog. Nicotinic ganglion blockade by chlorisondamine (1 mg/kg) significantly reduced reflex vasomotor responses but did not significantly alter hindlimb peripheral resistance. Combined nicotinic ganglion blockade by chlorisondamine (1 mg/kg) and muscarinic ganglion blockade by atropine (50mug/kg) abolished the reflex vasomotor response but did not alter hindlimb peripheral resistance. It was concluded that autoregulatory mechanisms are capable of maintaining a peripheral resistance after block of both muscarinic and nicotinic ganglion transmission.

Animals↗