Dissertations / Theses on the topic 'Superior Cervical Ganglion, pathology'

Thesis (Ph. D.)--Southern Illinois University Carbondale, 2007.
"Department of Pharmacology." Keywords: Saturated fatty acids, Superior cervical ganglion, Depolarization Includes bibliographical references (p. 121-134). Also available online.

This thesis details my examination of several mechanisms for modulation of N-type calcium channels in neonatal rat superior cervical ganglion (SCG) neurons. The first part of this work characterizes cross-talk between two distinct mechanisms of modulation: readily-reversible inhibition induced by activation of heterotrimeric G-proteins (termed G-protein-mediated inhibition), and phosphorylation of the channel by protein kinase C (PKC). Data previously presented by other groups suggested that one effect of activating PKC is to prevent G-protein-mediated inhibition. The goal of this project was to confirm this hypothesis by testing functional competition between these two pathways. My findings show that G-protein-mediated inhibition blocks the effects of activating PKC, and that phosphorylation by PKC blocks G-protein-mediated inhibition, confirming that these two mechanisms are mutually exclusive. In addition, I investigated the effect of activating PKC on whole-cell barium currents in the absence of G-protein-mediated inhibition. When endogenous G-proteins were inactivated by dialyzing the cell with GDP-β-S, a guanine nucleotide that prevents activation of the G-protein's α subunit, activation of PKC with phorbol esters was without obvious effect on whole-cell current amplitude, fast and holding potential-dependent inactivation, and voltage-dependent activation, suggesting that PKC's principal role in modulating these currents is to prevent G-protein-mediated inhibition. From these results, I advanced Bean's 1989 model of reluctant and willing gating (induced by G-protein-mediated inhibition and relief of that inhibition, respectively). In this expanded model, reluctant channels, inhibited by G-proteins, are resistant to phosphylation by PKC (reluctant/P-resistant). Unmodulated channels are called willing/available, as they exhibit willing gating, and are available for either binding to a G-protein or phosphorylation by PKC. Finally, phosphorylation of a willing/available channel by PKC drives the channel into the willing/G-resistant state, in which the channel gates willingly, and is resistant to G-protein-mediated inhibition. These results are published in the Journal of General Physiology(2000; 115:277-286), and are presented in this thesis as Chapter II. In addition to membrane-delimited inhibition, N-type calcium channels are also subject to inhibition via a diffusible second-messenger pathway. In SCG neurons, this inhibition can be observed following stimulation of M1 muscarinic receptors by the agonist oxotremorine-M. Our lab previously hypothesized that the diffusible messenger involved might be the polyunsaturated fatty acid arachidonic acid (AA). To test this hypothesis, our lab examined the effect of bath-applied AA on whole-cell SCG calcium currents, and demonstrated that AA induces inhibition with similar properties as M1 muscarinic inhibition. An analysis of AA's effects on unitary N-type calcium currents, published by Liu and Rittenhouse in Journal of Physiology(2000; 525:391-404), revealed that this inhibition is mediated, at least in part, by both a significant increase in the occurrence of null-activity sweeps and a significant decrease in mean closed dwell time. Based on these results, our lab conducted an examination of AA's effects on whole-cell currents in SCG neurons, and found that AA-induced inhibition is mediated by an increase in holding potential-dependent inactivation and appears independent of AA metabolism. When I examined AA's effects in greater detail, I discovered that, in addition to inhibition, AA also appeared to cause significant enhancement of whole-cell currents. The results characterizing AA's general effects on whole-cell calcium currents in SCG neurons have been published in American Journal of Physiology - Cell Physiology(2001; 280:C1293-C1305). Because my finding that AA enhances whole-cell neuronal calcium currents revealed a novel pathway through which this current can be modulated, I proceeded to characterize this effect. My results showed that enhancement develops significantly faster than inhibition, suggesting different mechanisms or pathways. In addition, dialyzing the cell with BSA, a protein that binds fatty acids, blocked the majority of AA-induced inhibition, but did not reduce enhancement, suggesting that enhancement is independent of inhibition and might be mediated at an extracellular site. Using fatty acid analogs that cannot cross the cell membrane, I confirmed that enhancement occurs extracellularly. My data also indicate that AA-induced enhancement of whole-cell currents does not require metabolism of AA, consistent with enhancement being mediated directly by AA. I also examined the biophysical characteristics of enhancement, and found that both an increase in the voltage sensitivity of activation and an increase in activation kinetics underlie this effect. Finally, using both pharmacological agents and a recombinant cell line, I presented the first demonstration that AA enhances N-type calcium current. These findings are described in detail in a paper recently published in American Journal of Physiology - Cell Physiology(2001; 280:C1306-C1318), and are presented in this thesis as Chapter III. In our investigation of AA's effects on whole-cell calcium currents, we utilized a voltage protocol, in conjunction with pharmacology, to enhance the level of L-type current in these cells. Since whole-cell calcium currents in SCG neurons are comprised of mostly (80-85%) N-type current, with the remaining current comprised of mostly L-type current, this approach allowed us to examine both N- and L-type currents. When currents are recorded in the presence of 1 μM FPL 64174 (FPL), a benzoyl pyrrole L-type calcium channel agonist first described in 1989, stepping the membrane potential to -40 mV following a test pulse to +10 mV generates a slowly-deactivating ("tail") current. This tail current is made up entirely of L-type current, and allows us to readily investigate the effect of various modulatory mechanisms on this current type. Although FPL has been used for almost a decade to study L-type calcium currents, activity of FPL on N-type calcium currents has not been investigated. Because our lab routinely uses micromolar concentrations of FPL to measure whole-cell and unitary calcium currents in neuronal cells, I tested whether FPL has any effects on N-type calcium current. Therefore, I examined the effect of FPL on whole-cell calcium currents in an HEK 293 cell line that expresses recombinant N-type calcium channels. Application of 1 and 10 μM FPL caused significant, voltage-independent inhibition of currents, demonstrating that FPL inhibits N-type calcium current. Thus, at micromolar concentrations, FPL is not selective for L-type calcium current, and any examination of its effects on whole-cell calcium currents should take this into account. The results describing FPL's effects on L- and N-type calcium currents are included in a manuscript currently in preparation, and are presented as Chapter IV.

Immunohistochemical studies have shown opioid peptides in sympathetic ganglia and preganglionic neurons. An inhibitory action of opioids has been demonstrated in some central and peripheral synapses. However, a physiological role of endogenous opioids in sympathetic ganglia has not been well characterized. The present study investigated endogenous opioid action in the SCG of the cat. The results obtained show that an endogenous opioid is released from preganglionic axon terminals, in a frequency range that matches the natural activity of sympathetic preganglionic neurons, and inhibits ganglionic transmission by acting on post-synaptic opiate receptors of the $ mu$ and $ delta$ subtypes coupled to PTX-sensitive G protein. The size of the store of the endogenous opioid in the preganglionic axon terminals is small and readily exhaustible. Protein synthesis and axonal transport are required for maintenance of the store. The opioid inhibition is under control of the PKC system. This study provides the first thorough characterization of the properties of an opioid-mediated inhibitory mechanism in a well-defined synapse.

Levetiracetam (LEV) is a prominent antiepileptic drug (AED) with an unknown mechanism of action. Within this thesis, electrophysiological, biochemical and imaging approaches were combined to investigate potential effects of LEV on action potential (AP) -dependent synaptic transmission and presynaptic voltage-dependent Ca2+ channel (VDCC) activity in superior cervical ganglion neurons (SCGNs). The putative role of LEV's molecular target, synaptic vesicle protein 2A (SV2A) in mediating LEV effects was investigated using the R-enantiomer, UCB L060, which exerts a lOOO-fold lower SV2A binding affinity than LEV. In these experiments, LEV inhibited synaptic transmission in SCG model synapses in a time-dependent manner, significantly reducing excitatory postsynaptic potential (EPSP) amplitudes and surface areas when applied for 2:30 min in comparison to UCB L060. In isolated SCGNs and recombinantly expressed Cav2.2 channels in HEK293 cells, LEV pretreatment (2:1 h), but not acute external application, significantly inhibited whole-cell IBa- Antibody labelling of SV2A in SCGNs revealed that the protein was predominantly expressed in close proximity to the plasma membrane and did not appear to redistribute or change its total expression in response to LEV pretreatment. Intracellular LEV application significantly inhibited IBa rapidly after establishing the whole-cell configuration to an extent comparable to that following LEV pretreatment; however, neither pretreatment nor intracellular application of UCB L060 produced any inhibitory effects in these experiments, which indicates an intracellular site of action. Under physiological conditions, LEV reduced both, fast and slow AP after- hyperpolarisations in a Ca2+ -dependent manner but did not affect the AP waveform or resting membrane potential. Additionally, LEV increased AP latency and slowed the repolarisation rates in a Ca2+-independent manner, suggesting further mechanisms associated with reduced excitability . Taken together, the presented results identify presynaptic VDCCs as targets for the archetypal SV2A ligand, LEV, potentially acting via an SV2A-dependent, intracellular pathway to inhibit presynaptic Ca2+ influx.

Su amžiumi susiję struktūriniai simpatinės nervų sistemos pokyčiai sukelia įvairių organų funkcijos sutrikimus. Simpatinio kamieno viršutiniai kakliniai mazgai, pagrindiniai galvos smegenų kraujagyslių simpatinės inervacijos šaltiniai, yra svarbūs galvos smegenų kraujotakos autonominės reguliacijos centrai. Tačiau žmogaus simpatinių mazgų morfofunkciniai tyrimai yra pavieniai. Todėl šio darbo tikslas buvo ištirti trijų amžiaus grupių žmonių ir mirusiųjų dėl išeminio galvos smegenų infarkto simpatinio kamieno viršutinio kaklinio mazgo morfologinius bei neurocheminius ypatumus, ir nustatyti jų sąsajas su amžiumi ir išeminiu galvos smegenų infarktu. Tyrimo rezultatai rodo, kad amžiaus eigoje vystosi žmogaus simpatinio kamieno viršutinio kaklinio mazgo neuronų morfologinių parametrų, neurofilamentų baltymo, nervų augimo faktoriaus receptorių p75 imunoreaktyvumo pokyčiai. Skirtingose amžiaus grupėse aptinkami neuronų ir satelitinių ląstelių apoptoz����s požymiai. Pagyvenusio amžiaus žmonių, mirusių dėl išeminio galvos smegenų infarkto, simpatiniuose mazguose vystosi neuropatologinės alteracijos požymiai: padidėja neuronų afinitetas baziniams dažams, atsiranda neuronų su degeneraciniais ir hipertrofijos požymiais židiniai, satelitinių ląstelių proliferacija, limfocitų židininė infiltracija, sumažėja neuronų kūno, branduolio, citoplazmos plotai, aptinkamas didesnis neurofilamentams ir nervų augimo faktoriaus receptoriams p75 imunoreaktyvių neuronų skaičius, didesnis apoptozinis... [toliau žr. visą tekstą]
Age-related structural changes of the sympathetic nervous system cause the disturbance of the involuntary functions of various organs. The superior cervical ganglia are the main source of sympathetic innervation of the cerebral arteries and important center of autonomic regulation of the cerebral circulation. However, only single morphofunctional studies of the human sympathetic ganglia are performed. Therefore, the aim of the study was to investigate morphological and neurochemical peculiarities of the human superior cervical ganglion in three age groups and in the subjects dead of ischemic cerebral infarction and establish their relation to age and ischemic cerebral infarction. The results of the present study show that changes of neurons morphologic parameters and immunoreactivity to neurofilament and nerve growth factor receptor p75 in the human superior cervical ganglion are developed in the course of aging. Morphological features of apoptosis in the sympathetic neurons and satellite cells in different age groups are detected. The signs of neuropathological alteration of the sympathetic ganglion of subjects with ischemic cerebral infarction were the following: increased tinctorial affinity of neurons, foci of neurons with features of neuron death and hypertrophy, proliferation of satellite cells, focal lymphocyte infiltration, decrease of neuron body, nucleus, cytoplasm area, increase of neurofilament and nerve growth factor receptor p75 immunoreactive neurons... [to full text]

碩士
國立中正大學
心理學研究所
92
Superior cervical ganglion (SCG) is a sympathetic postganglionic station that projects to the head and neck areas. Our injection of neural tracer, wheat germ agglutinin-horseradish peroxidase (WGA-HRP), into the SCG had been labeled the motor neurons in the brainstem and the cervical sympathetic trunk (CST). To get the distribution details and pattern of these neurons, we injected WGA-HRP to the SCG and prepared peripherally the whole mount of the SCG, CST, medial cervical ganglion, and inferior cervical ganglion. On both sides, neurons are distributed alongside the CST and group together as one single ganglion-like cluster near the rostral medial cervical ganglion of the right side and the rostral inferior cervical ganglion of the left side. Moreover, this cluster has the pattern of asymmetrical lateralization with larger size on the left side. We termed these newly identified neuronal clusters as “pre-middle cervical ganglia”, which should not be excluded in any physiological examination to the fibers in the sympathetic trunk. Centrally, the distribution of the preganglionic neurons of the SCG was examined by systematical sections of the brainstem and spinal cord. Neurons were labeled in the cervical spinal cord ranging from C1 to C4 and from T1 to T4, and in the intermediate reticular nuclei and perifacial zone of the pons. In the pons, it was located from Bregma -10.0 mm to -11.0 mm rather than -15.0 mm. The spinal distribution was consistent with the description in the literature.

碩士
國防醫學院
生物及解剖學研究所
87
Sympathectomy had been shown to result in an increased density of fibers immunoreactive for sensory peptides in peripheral targets innervated by both sensory and sympathetic neurons . Trigeminal ganglion is the targets of both autonomic and sensory innervation which contains peptidergic and sympathetic catecholaminergic fibers. This suggests that there might exist anatomical and functional interactions between sympathetic and sensory systems. In this study, we examined the origins of sympathetic innervation on trigeminal ganglion by HRP retrograde transport technique and further studied the sympathetic innervation by examination of immunoreactivities for dopamine β-hydroxylase (DBH) , calcitonin gene related peptide (CGRP) and substance-P ( SP ) in bilateral trigeminal ganglia followed unilateral superior cervical ganglionectomy. HRP labeled neurons, which restrictedly located at rostral portion, were only found in the ipsilateral superior cervical ganglion (SCG). After unilateral SCG ganglionectomy, the ipsilateral trigeminal DBH immunostaining was dramatically decreased while CGRP and SP immunostaining in the ipsilateral trigeminal ganglion were elevated in response to SCG ganglionectomy. In the lower medulla, CGRP and SP immunostaining were increased in both interpolaris and caudal portion of ventral spinal trigeminal nucleus and in paratrigeminal nucleus. The data demonstrate that trigeminal sympathetic VI innervation was originated from ipsilateral SCG. These results may provide anatomical evidence of autonomic modulation on sensory system.

碩士
國防醫學院
生物及解剖學研究所
85
Recently, viruses are wildly used for experimental neural tract tracing because they can infect and replicate within neurons and are transported within the axons. However, issues of continued virus gene expression, pathogenicity and reversion to wild type still remain. The recombinant adeno-associated virus (AAV), a virus with a single strain DNA, is considerable a safe neural tracer because of its special properties of (1) the specific integration, non-pathogenecity of wild-type and non-replication without helper virus and (2) AAV could infect the non-mitotic neurons. The purposes of this study are : (1) to evaluate the efficacy of AAV to be as a novel neural tracer; (2) to study the origins of the afferent fiber of the superior cervical ganglion (SCG) of the rabbits. AAV and /or HRP were injected into the unilateral SCG of the rabbits. Three days after the tracer injected, rabbits were sacrificed by perfusion with Ringer's solution and fixative. The bilateral SCG, stellate ganglion, nodose ganglion, trigeminal ganglion, dorsal root ganglia and the spinal cord from C1 to L1 were removed and sectioned, then processed for HRP and β-Gal histochemical reactions. Results show that: (1) the HRP labeling neurons were located in the ipsilateral intermediolateral nucleus (IML) of the spinal segments from C8 to T7 and the ipsilateral stellate ganglion; (2) the AAV positive neurons were found in bilateral SCG, trigeminal ganglion and dorsal root ganglia from C1 to L5 but not in the IML and stellate ganglion. Results suggest that AAV appeared to be able to label the sensory neurons rather than the sympathetic preganglionic neurons.